updating phpseclib to latest cvs - fixes a bunch of key generation issues

9 files changed, 10434 insertions, 9369 deletions

diff --git a/plugins/OStatus/extlib/Crypt/AES.php b/plugins/OStatus/extlib/Crypt/AES.php
index 4b062c4f2..68ab4db09 100644
--- a/plugins/OStatus/extlib/Crypt/AES.php
+++ b/plugins/OStatus/extlib/Crypt/AES.php
@@ -1,421 +1,479 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP implementation of AES.

- *

- * Uses mcrypt, if available, and an internal implementation, otherwise.

- *

- * PHP versions 4 and 5

- *

- * If {@link Crypt_AES::setKeyLength() setKeyLength()} isn't called, it'll be calculated from

- * {@link Crypt_AES::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 136-bits

- * it'll be null-padded to 160-bits and 160 bits will be the key length until {@link Crypt_Rijndael::setKey() setKey()}

- * is called, again, at which point, it'll be recalculated.

- *

- * Since Crypt_AES extends Crypt_Rijndael, some functions are available to be called that, in the context of AES, don't

- * make a whole lot of sense.  {@link Crypt_AES::setBlockLength() setBlockLength()}, for instance.  Calling that function,

- * however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/AES.php');

- *

- *    $aes = new Crypt_AES();

- *

- *    $aes->setKey('abcdefghijklmnop');

- *

- *    $size = 10 * 1024;

- *    $plaintext = '';

- *    for ($i = 0; $i < $size; $i++) {

- *        $plaintext.= 'a';

- *    }

- *

- *    echo $aes->decrypt($aes->encrypt($plaintext));

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_AES

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVIII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: AES.php,v 1.5 2009/11/23 19:06:06 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**

- * Include Crypt_Rijndael

- */

-require_once 'Rijndael.php';

-

-/**#@+

- * @access public

- * @see Crypt_AES::encrypt()

- * @see Crypt_AES::decrypt()

- */

-/**

- * Encrypt / decrypt using the Electronic Code Book mode.

- *

- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29

- */

-define('CRYPT_AES_MODE_ECB', 1);

-/**

- * Encrypt / decrypt using the Code Book Chaining mode.

- *

- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29

- */

-define('CRYPT_AES_MODE_CBC', 2);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Crypt_AES::Crypt_AES()

- */

-/**

- * Toggles the internal implementation

- */

-define('CRYPT_AES_MODE_INTERNAL', 1);

-/**

- * Toggles the mcrypt implementation

- */

-define('CRYPT_AES_MODE_MCRYPT', 2);

-/**#@-*/

-

-/**

- * Pure-PHP implementation of AES.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_AES

- */

-class Crypt_AES extends Crypt_Rijndael {

-    /**

-     * MCrypt parameters

-     *

-     * @see Crypt_AES::setMCrypt()

-     * @var Array

-     * @access private

-     */

-    var $mcrypt = array('', '');

-

-    /**

-     * Default Constructor.

-     *

-     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be

-     * CRYPT_AES_MODE_ECB or CRYPT_AES_MODE_CBC.  If not explictly set, CRYPT_AES_MODE_CBC will be used.

-     *

-     * @param optional Integer $mode

-     * @return Crypt_AES

-     * @access public

-     */

-    function Crypt_AES($mode = CRYPT_AES_MODE_CBC)

-    {

-        if ( !defined('CRYPT_AES_MODE') ) {

-            switch (true) {

-                case extension_loaded('mcrypt'):

-                    // i'd check to see if aes was supported, by doing in_array('des', mcrypt_list_algorithms('')),

-                    // but since that can be changed after the object has been created, there doesn't seem to be

-                    // a lot of point...

-                    define('CRYPT_AES_MODE', CRYPT_AES_MODE_MCRYPT);

-                    break;

-                default:

-                    define('CRYPT_AES_MODE', CRYPT_AES_MODE_INTERNAL);

-            }

-        }

-

-        switch ( CRYPT_AES_MODE ) {

-            case CRYPT_AES_MODE_MCRYPT:

-                switch ($mode) {

-                    case CRYPT_AES_MODE_ECB:

-                        $this->mode = MCRYPT_MODE_ECB;

-                        break;

-                    case CRYPT_AES_MODE_CBC:

-                    default:

-                        $this->mode = MCRYPT_MODE_CBC;

-                }

-

-                break;

-            default:

-                switch ($mode) {

-                    case CRYPT_AES_MODE_ECB:

-                        $this->mode = CRYPT_RIJNDAEL_MODE_ECB;

-                        break;

-                    case CRYPT_AES_MODE_CBC:

-                    default:

-                        $this->mode = CRYPT_RIJNDAEL_MODE_CBC;

-                }

-        }

-

-        if (CRYPT_AES_MODE == CRYPT_AES_MODE_INTERNAL) {

-            parent::Crypt_Rijndael($this->mode);

-        }

-    }

-

-    /**

-     * Dummy function

-     *

-     * Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.

-     *

-     * @access public

-     * @param Integer $length

-     */

-    function setBlockLength($length)

-    {

-        return;

-    }

-

-    /**

-     * Encrypts a message.

-     *

-     * $plaintext will be padded with up to 16 additional bytes.  Other AES implementations may or may not pad in the

-     * same manner.  Other common approaches to padding and the reasons why it's necessary are discussed in the following

-     * URL:

-     *

-     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}

-     *

-     * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.

-     * strlen($plaintext) will still need to be a multiple of 16, however, arbitrary values can be added to make it that

-     * length.

-     *

-     * @see Crypt_AES::decrypt()

-     * @access public

-     * @param String $plaintext

-     */

-    function encrypt($plaintext)

-    {

-        if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {

-            $this->_mcryptSetup();

-            $plaintext = $this->_pad($plaintext);

-

-            $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);

-            mcrypt_generic_init($td, $this->key, $this->encryptIV);

-

-            $ciphertext = mcrypt_generic($td, $plaintext);

-

-            mcrypt_generic_deinit($td);

-            mcrypt_module_close($td);

-

-            if ($this->continuousBuffer) {

-                $this->encryptIV = substr($ciphertext, -16);

-            }

-

-            return $ciphertext;

-        }

-

-        return parent::encrypt($plaintext);

-    }

-

-    /**

-     * Decrypts a message.

-     *

-     * If strlen($ciphertext) is not a multiple of 16, null bytes will be added to the end of the string until it is.

-     *

-     * @see Crypt_AES::encrypt()

-     * @access public

-     * @param String $ciphertext

-     */

-    function decrypt($ciphertext)

-    {

-        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :

-        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."

-        $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 15) & 0xFFFFFFF0, chr(0));

-

-        if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {

-            $this->_mcryptSetup();

-

-            $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);

-            mcrypt_generic_init($td, $this->key, $this->decryptIV);

-

-            $plaintext = mdecrypt_generic($td, $ciphertext);

-

-            mcrypt_generic_deinit($td);

-            mcrypt_module_close($td);

-

-            if ($this->continuousBuffer) {

-                $this->decryptIV = substr($ciphertext, -16);

-            }

-

-            return $this->_unpad($plaintext);

-        }

-

-        return parent::decrypt($ciphertext);

-    }

-

-    /**

-     * Sets MCrypt parameters. (optional)

-     *

-     * If MCrypt is being used, empty strings will be used, unless otherwise specified.

-     *

-     * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open

-     * @access public

-     * @param optional Integer $algorithm_directory

-     * @param optional Integer $mode_directory

-     */

-    function setMCrypt($algorithm_directory = '', $mode_directory = '')

-    {

-        $this->mcrypt = array($algorithm_directory, $mode_directory);

-    }

-

-    /**

-     * Setup mcrypt

-     *

-     * Validates all the variables.

-     *

-     * @access private

-     */

-    function _mcryptSetup()

-    {

-        if (!$this->changed) {

-            return;

-        }

-

-        if (!$this->explicit_key_length) {

-            // this just copied from Crypt_Rijndael::_setup()

-            $length = strlen($this->key) >> 2;

-            if ($length > 8) {

-                $length = 8;

-            } else if ($length < 4) {

-                $length = 4;

-            }

-            $this->Nk = $length;

-            $this->key_size = $length << 2;

-        }

-

-        switch ($this->Nk) {

-            case 4: // 128

-                $this->key_size = 16;

-                break;

-            case 5: // 160

-            case 6: // 192

-                $this->key_size = 24;

-                break;

-            case 7: // 224

-            case 8: // 256

-                $this->key_size = 32;

-        }

-

-        $this->key = substr($this->key, 0, $this->key_size);

-        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, 16), 16, chr(0));

-

-        $this->changed = false;

-    }

-

-    /**

-     * Encrypts a block

-     *

-     * Optimized over Crypt_Rijndael's implementation by means of loop unrolling.

-     *

-     * @see Crypt_Rijndael::_encryptBlock()

-     * @access private

-     * @param String $in

-     * @return String

-     */

-    function _encryptBlock($in)

-    {

-        $state = unpack('N*word', $in);

-

-        // addRoundKey and reindex $state

-        $state = array(

-            $state['word1'] ^ $this->w[0][0],

-            $state['word2'] ^ $this->w[0][1],

-            $state['word3'] ^ $this->w[0][2],

-            $state['word4'] ^ $this->w[0][3]

-        );

-

-        // shiftRows + subWord + mixColumns + addRoundKey

-        // we could loop unroll this and use if statements to do more rounds as necessary, but, in my tests, that yields

-        // only a marginal improvement.  since that also, imho, hinders the readability of the code, i've opted not to do it.

-        for ($round = 1; $round < $this->Nr; $round++) {

-            $state = array(

-                $this->t0[$state[0] & 0xFF000000] ^ $this->t1[$state[1] & 0x00FF0000] ^ $this->t2[$state[2] & 0x0000FF00] ^ $this->t3[$state[3] & 0x000000FF] ^ $this->w[$round][0],

-                $this->t0[$state[1] & 0xFF000000] ^ $this->t1[$state[2] & 0x00FF0000] ^ $this->t2[$state[3] & 0x0000FF00] ^ $this->t3[$state[0] & 0x000000FF] ^ $this->w[$round][1],

-                $this->t0[$state[2] & 0xFF000000] ^ $this->t1[$state[3] & 0x00FF0000] ^ $this->t2[$state[0] & 0x0000FF00] ^ $this->t3[$state[1] & 0x000000FF] ^ $this->w[$round][2],

-                $this->t0[$state[3] & 0xFF000000] ^ $this->t1[$state[0] & 0x00FF0000] ^ $this->t2[$state[1] & 0x0000FF00] ^ $this->t3[$state[2] & 0x000000FF] ^ $this->w[$round][3]

-            );

-

-        }

-

-        // subWord

-        $state = array(

-            $this->_subWord($state[0]),

-            $this->_subWord($state[1]),

-            $this->_subWord($state[2]),

-            $this->_subWord($state[3])

-        );

-

-        // shiftRows + addRoundKey

-        $state = array(

-            ($state[0] & 0xFF000000) ^ ($state[1] & 0x00FF0000) ^ ($state[2] & 0x0000FF00) ^ ($state[3] & 0x000000FF) ^ $this->w[$this->Nr][0],

-            ($state[1] & 0xFF000000) ^ ($state[2] & 0x00FF0000) ^ ($state[3] & 0x0000FF00) ^ ($state[0] & 0x000000FF) ^ $this->w[$this->Nr][1],

-            ($state[2] & 0xFF000000) ^ ($state[3] & 0x00FF0000) ^ ($state[0] & 0x0000FF00) ^ ($state[1] & 0x000000FF) ^ $this->w[$this->Nr][2],

-            ($state[3] & 0xFF000000) ^ ($state[0] & 0x00FF0000) ^ ($state[1] & 0x0000FF00) ^ ($state[2] & 0x000000FF) ^ $this->w[$this->Nr][3]

-        );

-

-        return pack('N*', $state[0], $state[1], $state[2], $state[3]);

-    }

-

-    /**

-     * Decrypts a block

-     *

-     * Optimized over Crypt_Rijndael's implementation by means of loop unrolling.

-     *

-     * @see Crypt_Rijndael::_decryptBlock()

-     * @access private

-     * @param String $in

-     * @return String

-     */

-    function _decryptBlock($in)

-    {

-        $state = unpack('N*word', $in);

-

-        // addRoundKey and reindex $state

-        $state = array(

-            $state['word1'] ^ $this->dw[$this->Nr][0],

-            $state['word2'] ^ $this->dw[$this->Nr][1],

-            $state['word3'] ^ $this->dw[$this->Nr][2],

-            $state['word4'] ^ $this->dw[$this->Nr][3]

-        );

-

-

-        // invShiftRows + invSubBytes + invMixColumns + addRoundKey

-        for ($round = $this->Nr - 1; $round > 0; $round--) {

-            $state = array(

-                $this->dt0[$state[0] & 0xFF000000] ^ $this->dt1[$state[3] & 0x00FF0000] ^ $this->dt2[$state[2] & 0x0000FF00] ^ $this->dt3[$state[1] & 0x000000FF] ^ $this->dw[$round][0],

-                $this->dt0[$state[1] & 0xFF000000] ^ $this->dt1[$state[0] & 0x00FF0000] ^ $this->dt2[$state[3] & 0x0000FF00] ^ $this->dt3[$state[2] & 0x000000FF] ^ $this->dw[$round][1],

-                $this->dt0[$state[2] & 0xFF000000] ^ $this->dt1[$state[1] & 0x00FF0000] ^ $this->dt2[$state[0] & 0x0000FF00] ^ $this->dt3[$state[3] & 0x000000FF] ^ $this->dw[$round][2],

-                $this->dt0[$state[3] & 0xFF000000] ^ $this->dt1[$state[2] & 0x00FF0000] ^ $this->dt2[$state[1] & 0x0000FF00] ^ $this->dt3[$state[0] & 0x000000FF] ^ $this->dw[$round][3]

-            );

-        }

-

-        // invShiftRows + invSubWord + addRoundKey

-        $state = array(

-            $this->_invSubWord(($state[0] & 0xFF000000) ^ ($state[3] & 0x00FF0000) ^ ($state[2] & 0x0000FF00) ^ ($state[1] & 0x000000FF)) ^ $this->dw[0][0],

-            $this->_invSubWord(($state[1] & 0xFF000000) ^ ($state[0] & 0x00FF0000) ^ ($state[3] & 0x0000FF00) ^ ($state[2] & 0x000000FF)) ^ $this->dw[0][1],

-            $this->_invSubWord(($state[2] & 0xFF000000) ^ ($state[1] & 0x00FF0000) ^ ($state[0] & 0x0000FF00) ^ ($state[3] & 0x000000FF)) ^ $this->dw[0][2],

-            $this->_invSubWord(($state[3] & 0xFF000000) ^ ($state[2] & 0x00FF0000) ^ ($state[1] & 0x0000FF00) ^ ($state[0] & 0x000000FF)) ^ $this->dw[0][3]

-        );

-

-        return pack('N*', $state[0], $state[1], $state[2], $state[3]);

-    }

-}

-

-// vim: ts=4:sw=4:et:

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementation of AES.
+ *
+ * Uses mcrypt, if available, and an internal implementation, otherwise.
+ *
+ * PHP versions 4 and 5
+ *
+ * If {@link Crypt_AES::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
+ * {@link Crypt_AES::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 136-bits
+ * it'll be null-padded to 160-bits and 160 bits will be the key length until {@link Crypt_Rijndael::setKey() setKey()}
+ * is called, again, at which point, it'll be recalculated.
+ *
+ * Since Crypt_AES extends Crypt_Rijndael, some functions are available to be called that, in the context of AES, don't
+ * make a whole lot of sense.  {@link Crypt_AES::setBlockLength() setBlockLength()}, for instance.  Calling that function,
+ * however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/AES.php');
+ *
+ *    $aes = new Crypt_AES();
+ *
+ *    $aes->setKey('abcdefghijklmnop');
+ *
+ *    $size = 10 * 1024;
+ *    $plaintext = '';
+ *    for ($i = 0; $i < $size; $i++) {
+ *        $plaintext.= 'a';
+ *    }
+ *
+ *    echo $aes->decrypt($aes->encrypt($plaintext));
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_AES
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVIII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: AES.php,v 1.7 2010/02/09 06:10:25 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**
+ * Include Crypt_Rijndael
+ */
+require_once 'Rijndael.php';
+
+/**#@+
+ * @access public
+ * @see Crypt_AES::encrypt()
+ * @see Crypt_AES::decrypt()
+ */
+/**
+ * Encrypt / decrypt using the Counter mode.
+ *
+ * Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
+ */
+define('CRYPT_AES_MODE_CTR', -1);
+/**
+ * Encrypt / decrypt using the Electronic Code Book mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
+ */
+define('CRYPT_AES_MODE_ECB', 1);
+/**
+ * Encrypt / decrypt using the Code Book Chaining mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
+ */
+define('CRYPT_AES_MODE_CBC', 2);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_AES::Crypt_AES()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_AES_MODE_INTERNAL', 1);
+/**
+ * Toggles the mcrypt implementation
+ */
+define('CRYPT_AES_MODE_MCRYPT', 2);
+/**#@-*/
+
+/**
+ * Pure-PHP implementation of AES.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_AES
+ */
+class Crypt_AES extends Crypt_Rijndael {
+    /**
+     * mcrypt resource for encryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
+     *
+     * @see Crypt_AES::encrypt()
+     * @var String
+     * @access private
+     */
+    var $enmcrypt;
+
+    /**
+     * mcrypt resource for decryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
+     *
+     * @see Crypt_AES::decrypt()
+     * @var String
+     * @access private
+     */
+    var $demcrypt;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be
+     * CRYPT_AES_MODE_ECB or CRYPT_AES_MODE_CBC.  If not explictly set, CRYPT_AES_MODE_CBC will be used.
+     *
+     * @param optional Integer $mode
+     * @return Crypt_AES
+     * @access public
+     */
+    function Crypt_AES($mode = CRYPT_AES_MODE_CBC)
+    {
+        if ( !defined('CRYPT_AES_MODE') ) {
+            switch (true) {
+                case extension_loaded('mcrypt'):
+                    // i'd check to see if aes was supported, by doing in_array('des', mcrypt_list_algorithms('')),
+                    // but since that can be changed after the object has been created, there doesn't seem to be
+                    // a lot of point...
+                    define('CRYPT_AES_MODE', CRYPT_AES_MODE_MCRYPT);
+                    break;
+                default:
+                    define('CRYPT_AES_MODE', CRYPT_AES_MODE_INTERNAL);
+            }
+        }
+
+        switch ( CRYPT_AES_MODE ) {
+            case CRYPT_AES_MODE_MCRYPT:
+                switch ($mode) {
+                    case CRYPT_AES_MODE_ECB:
+                        $this->mode = MCRYPT_MODE_ECB;
+                        break;
+                    case CRYPT_AES_MODE_CTR:
+                        // ctr doesn't have a constant associated with it even though it appears to be fairly widely
+                        // supported.  in lieu of knowing just how widely supported it is, i've, for now, opted not to
+                        // include a compatibility layer.  the layer has been implemented but, for now, is commented out.
+                        $this->mode = 'ctr';
+                        //$this->mode = in_array('ctr', mcrypt_list_modes()) ? 'ctr' : CRYPT_AES_MODE_CTR;
+                        break;
+                    case CRYPT_AES_MODE_CBC:
+                    default:
+                        $this->mode = MCRYPT_MODE_CBC;
+                }
+
+                break;
+            default:
+                switch ($mode) {
+                    case CRYPT_AES_MODE_ECB:
+                        $this->mode = CRYPT_RIJNDAEL_MODE_ECB;
+                        break;
+                    case CRYPT_AES_MODE_CTR:
+                        $this->mode = CRYPT_RIJNDAEL_MODE_CTR;
+                        break;
+                    case CRYPT_AES_MODE_CBC:
+                    default:
+                        $this->mode = CRYPT_RIJNDAEL_MODE_CBC;
+                }
+        }
+
+        if (CRYPT_AES_MODE == CRYPT_AES_MODE_INTERNAL) {
+            parent::Crypt_Rijndael($this->mode);
+        }
+    }
+
+    /**
+     * Dummy function
+     *
+     * Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.
+     *
+     * @access public
+     * @param Integer $length
+     */
+    function setBlockLength($length)
+    {
+        return;
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * $plaintext will be padded with up to 16 additional bytes.  Other AES implementations may or may not pad in the
+     * same manner.  Other common approaches to padding and the reasons why it's necessary are discussed in the following
+     * URL:
+     *
+     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
+     *
+     * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.
+     * strlen($plaintext) will still need to be a multiple of 16, however, arbitrary values can be added to make it that
+     * length.
+     *
+     * @see Crypt_AES::decrypt()
+     * @access public
+     * @param String $plaintext
+     */
+    function encrypt($plaintext)
+    {
+        if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
+            $this->_mcryptSetup();
+            /*
+            if ($this->mode == CRYPT_AES_MODE_CTR) {
+                $iv = $this->encryptIV;
+                $xor = mcrypt_generic($this->enmcrypt, $this->_generate_xor(strlen($plaintext), $iv));
+                $ciphertext = $plaintext ^ $xor;
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $iv;
+                }
+                return $ciphertext;
+            }
+            */
+
+            if ($this->mode != 'ctr') {
+                $plaintext = $this->_pad($plaintext);
+            }
+
+            $ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
+            }
+
+            return $ciphertext;
+        }
+
+        return parent::encrypt($plaintext);
+    }
+
+    /**
+     * Decrypts a message.
+     *
+     * If strlen($ciphertext) is not a multiple of 16, null bytes will be added to the end of the string until it is.
+     *
+     * @see Crypt_AES::encrypt()
+     * @access public
+     * @param String $ciphertext
+     */
+    function decrypt($ciphertext)
+    {
+        if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
+            $this->_mcryptSetup();
+            /*
+            if ($this->mode == CRYPT_AES_MODE_CTR) {
+                $iv = $this->decryptIV;
+                $xor = mcrypt_generic($this->enmcrypt, $this->_generate_xor(strlen($ciphertext), $iv));
+                $plaintext = $ciphertext ^ $xor;
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $iv;
+                }
+                return $plaintext;
+            }
+            */
+
+            if ($this->mode != 'ctr') {
+                // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :
+                // "The data is padded with "\0" to make sure the length of the data is n * blocksize."
+                $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 15) & 0xFFFFFFF0, chr(0));
+            }
+
+            $plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
+            }
+
+            return $this->mode != 'ctr' ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        return parent::decrypt($ciphertext);
+    }
+
+    /**
+     * Setup mcrypt
+     *
+     * Validates all the variables.
+     *
+     * @access private
+     */
+    function _mcryptSetup()
+    {
+        if (!$this->changed) {
+            return;
+        }
+
+        if (!$this->explicit_key_length) {
+            // this just copied from Crypt_Rijndael::_setup()
+            $length = strlen($this->key) >> 2;
+            if ($length > 8) {
+                $length = 8;
+            } else if ($length < 4) {
+                $length = 4;
+            }
+            $this->Nk = $length;
+            $this->key_size = $length << 2;
+        }
+
+        switch ($this->Nk) {
+            case 4: // 128
+                $this->key_size = 16;
+                break;
+            case 5: // 160
+            case 6: // 192
+                $this->key_size = 24;
+                break;
+            case 7: // 224
+            case 8: // 256
+                $this->key_size = 32;
+        }
+
+        $this->key = substr($this->key, 0, $this->key_size);
+        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, 16), 16, chr(0));
+
+        if (!isset($this->enmcrypt)) {
+            $mode = $this->mode;
+            //$mode = $this->mode == CRYPT_AES_MODE_CTR ? MCRYPT_MODE_ECB : $this->mode;
+
+            $this->demcrypt = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', $mode, '');
+            $this->enmcrypt = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', $mode, '');
+        } // else should mcrypt_generic_deinit be called?
+
+        mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
+        mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
+
+        $this->changed = false;
+    }
+
+    /**
+     * Encrypts a block
+     *
+     * Optimized over Crypt_Rijndael's implementation by means of loop unrolling.
+     *
+     * @see Crypt_Rijndael::_encryptBlock()
+     * @access private
+     * @param String $in
+     * @return String
+     */
+    function _encryptBlock($in)
+    {
+        $state = unpack('N*word', $in);
+
+        $Nr = $this->Nr;
+        $w = $this->w;
+        $t0 = $this->t0;
+        $t1 = $this->t1;
+        $t2 = $this->t2;
+        $t3 = $this->t3;
+
+        // addRoundKey and reindex $state
+        $state = array(
+            $state['word1'] ^ $w[0][0],
+            $state['word2'] ^ $w[0][1],
+            $state['word3'] ^ $w[0][2],
+            $state['word4'] ^ $w[0][3]
+        );
+
+        // shiftRows + subWord + mixColumns + addRoundKey
+        // we could loop unroll this and use if statements to do more rounds as necessary, but, in my tests, that yields
+        // only a marginal improvement.  since that also, imho, hinders the readability of the code, i've opted not to do it.
+        for ($round = 1; $round < $this->Nr; $round++) {
+            $state = array(
+                $t0[$state[0] & 0xFF000000] ^ $t1[$state[1] & 0x00FF0000] ^ $t2[$state[2] & 0x0000FF00] ^ $t3[$state[3] & 0x000000FF] ^ $w[$round][0],
+                $t0[$state[1] & 0xFF000000] ^ $t1[$state[2] & 0x00FF0000] ^ $t2[$state[3] & 0x0000FF00] ^ $t3[$state[0] & 0x000000FF] ^ $w[$round][1],
+                $t0[$state[2] & 0xFF000000] ^ $t1[$state[3] & 0x00FF0000] ^ $t2[$state[0] & 0x0000FF00] ^ $t3[$state[1] & 0x000000FF] ^ $w[$round][2],
+                $t0[$state[3] & 0xFF000000] ^ $t1[$state[0] & 0x00FF0000] ^ $t2[$state[1] & 0x0000FF00] ^ $t3[$state[2] & 0x000000FF] ^ $w[$round][3]
+            );
+
+        }
+
+        // subWord
+        $state = array(
+            $this->_subWord($state[0]),
+            $this->_subWord($state[1]),
+            $this->_subWord($state[2]),
+            $this->_subWord($state[3])
+        );
+
+        // shiftRows + addRoundKey
+        $state = array(
+            ($state[0] & 0xFF000000) ^ ($state[1] & 0x00FF0000) ^ ($state[2] & 0x0000FF00) ^ ($state[3] & 0x000000FF) ^ $this->w[$this->Nr][0],
+            ($state[1] & 0xFF000000) ^ ($state[2] & 0x00FF0000) ^ ($state[3] & 0x0000FF00) ^ ($state[0] & 0x000000FF) ^ $this->w[$this->Nr][1],
+            ($state[2] & 0xFF000000) ^ ($state[3] & 0x00FF0000) ^ ($state[0] & 0x0000FF00) ^ ($state[1] & 0x000000FF) ^ $this->w[$this->Nr][2],
+            ($state[3] & 0xFF000000) ^ ($state[0] & 0x00FF0000) ^ ($state[1] & 0x0000FF00) ^ ($state[2] & 0x000000FF) ^ $this->w[$this->Nr][3]
+        );
+
+        return pack('N*', $state[0], $state[1], $state[2], $state[3]);
+    }
+
+    /**
+     * Decrypts a block
+     *
+     * Optimized over Crypt_Rijndael's implementation by means of loop unrolling.
+     *
+     * @see Crypt_Rijndael::_decryptBlock()
+     * @access private
+     * @param String $in
+     * @return String
+     */
+    function _decryptBlock($in)
+    {
+        $state = unpack('N*word', $in);
+
+        $Nr = $this->Nr;
+        $dw = $this->dw;
+        $dt0 = $this->dt0;
+        $dt1 = $this->dt1;
+        $dt2 = $this->dt2;
+        $dt3 = $this->dt3;
+
+        // addRoundKey and reindex $state
+        $state = array(
+            $state['word1'] ^ $dw[$this->Nr][0],
+            $state['word2'] ^ $dw[$this->Nr][1],
+            $state['word3'] ^ $dw[$this->Nr][2],
+            $state['word4'] ^ $dw[$this->Nr][3]
+        );
+
+
+        // invShiftRows + invSubBytes + invMixColumns + addRoundKey
+        for ($round = $this->Nr - 1; $round > 0; $round--) {
+            $state = array(
+                $dt0[$state[0] & 0xFF000000] ^ $dt1[$state[3] & 0x00FF0000] ^ $dt2[$state[2] & 0x0000FF00] ^ $dt3[$state[1] & 0x000000FF] ^ $dw[$round][0],
+                $dt0[$state[1] & 0xFF000000] ^ $dt1[$state[0] & 0x00FF0000] ^ $dt2[$state[3] & 0x0000FF00] ^ $dt3[$state[2] & 0x000000FF] ^ $dw[$round][1],
+                $dt0[$state[2] & 0xFF000000] ^ $dt1[$state[1] & 0x00FF0000] ^ $dt2[$state[0] & 0x0000FF00] ^ $dt3[$state[3] & 0x000000FF] ^ $dw[$round][2],
+                $dt0[$state[3] & 0xFF000000] ^ $dt1[$state[2] & 0x00FF0000] ^ $dt2[$state[1] & 0x0000FF00] ^ $dt3[$state[0] & 0x000000FF] ^ $dw[$round][3]
+            );
+        }
+
+        // invShiftRows + invSubWord + addRoundKey
+        $state = array(
+            $this->_invSubWord(($state[0] & 0xFF000000) ^ ($state[3] & 0x00FF0000) ^ ($state[2] & 0x0000FF00) ^ ($state[1] & 0x000000FF)) ^ $dw[0][0],
+            $this->_invSubWord(($state[1] & 0xFF000000) ^ ($state[0] & 0x00FF0000) ^ ($state[3] & 0x0000FF00) ^ ($state[2] & 0x000000FF)) ^ $dw[0][1],
+            $this->_invSubWord(($state[2] & 0xFF000000) ^ ($state[1] & 0x00FF0000) ^ ($state[0] & 0x0000FF00) ^ ($state[3] & 0x000000FF)) ^ $dw[0][2],
+            $this->_invSubWord(($state[3] & 0xFF000000) ^ ($state[2] & 0x00FF0000) ^ ($state[1] & 0x0000FF00) ^ ($state[0] & 0x000000FF)) ^ $dw[0][3]
+        );
+
+        return pack('N*', $state[0], $state[1], $state[2], $state[3]);
+    }
+}
+
+// vim: ts=4:sw=4:et:
 // vim6: fdl=1:
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/DES.php b/plugins/OStatus/extlib/Crypt/DES.php
index 3fd0b65ec..985ed25b5 100644
--- a/plugins/OStatus/extlib/Crypt/DES.php
+++ b/plugins/OStatus/extlib/Crypt/DES.php
@@ -1,851 +1,945 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP implementation of DES.

- *

- * Uses mcrypt, if available, and an internal implementation, otherwise.

- *

- * PHP versions 4 and 5

- *

- * Useful resources are as follows:

- *

- *  - {@link http://en.wikipedia.org/wiki/DES_supplementary_material Wikipedia: DES supplementary material}

- *  - {@link http://www.itl.nist.gov/fipspubs/fip46-2.htm FIPS 46-2 - (DES), Data Encryption Standard}

- *  - {@link http://www.cs.eku.edu/faculty/styer/460/Encrypt/JS-DES.html JavaScript DES Example}

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/DES.php');

- *

- *    $des = new Crypt_DES();

- *

- *    $des->setKey('abcdefgh');

- *

- *    $size = 10 * 1024;

- *    $plaintext = '';

- *    for ($i = 0; $i < $size; $i++) {

- *        $plaintext.= 'a';

- *    }

- *

- *    echo $des->decrypt($des->encrypt($plaintext));

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_DES

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: DES.php,v 1.9 2009/11/23 19:06:06 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**#@+

- * @access private

- * @see Crypt_DES::_prepareKey()

- * @see Crypt_DES::_processBlock()

- */

-/**

- * Contains array_reverse($keys[CRYPT_DES_DECRYPT])

- */

-define('CRYPT_DES_ENCRYPT', 0);

-/**

- * Contains array_reverse($keys[CRYPT_DES_ENCRYPT])

- */

-define('CRYPT_DES_DECRYPT', 1);

-/**#@-*/

-

-/**#@+

- * @access public

- * @see Crypt_DES::encrypt()

- * @see Crypt_DES::decrypt()

- */

-/**

- * Encrypt / decrypt using the Electronic Code Book mode.

- *

- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29

- */

-define('CRYPT_DES_MODE_ECB', 1);

-/**

- * Encrypt / decrypt using the Code Book Chaining mode.

- *

- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29

- */

-define('CRYPT_DES_MODE_CBC', 2);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Crypt_DES::Crypt_DES()

- */

-/**

- * Toggles the internal implementation

- */

-define('CRYPT_DES_MODE_INTERNAL', 1);

-/**

- * Toggles the mcrypt implementation

- */

-define('CRYPT_DES_MODE_MCRYPT', 2);

-/**#@-*/

-

-/**

- * Pure-PHP implementation of DES.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_DES

- */

-class Crypt_DES {

-    /**

-     * The Key Schedule

-     *

-     * @see Crypt_DES::setKey()

-     * @var Array

-     * @access private

-     */

-    var $keys = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * The Encryption Mode

-     *

-     * @see Crypt_DES::Crypt_DES()

-     * @var Integer

-     * @access private

-     */

-    var $mode;

-

-    /**

-     * Continuous Buffer status

-     *

-     * @see Crypt_DES::enableContinuousBuffer()

-     * @var Boolean

-     * @access private

-     */

-    var $continuousBuffer = false;

-

-    /**

-     * Padding status

-     *

-     * @see Crypt_DES::enablePadding()

-     * @var Boolean

-     * @access private

-     */

-    var $padding = true;

-

-    /**

-     * The Initialization Vector

-     *

-     * @see Crypt_DES::setIV()

-     * @var String

-     * @access private

-     */

-    var $iv = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * A "sliding" Initialization Vector

-     *

-     * @see Crypt_DES::enableContinuousBuffer()

-     * @var String

-     * @access private

-     */

-    var $encryptIV = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * A "sliding" Initialization Vector

-     *

-     * @see Crypt_DES::enableContinuousBuffer()

-     * @var String

-     * @access private

-     */

-    var $decryptIV = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * MCrypt parameters

-     *

-     * @see Crypt_DES::setMCrypt()

-     * @var Array

-     * @access private

-     */

-    var $mcrypt = array('', '');

-

-    /**

-     * Default Constructor.

-     *

-     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be

-     * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC.  If not explictly set, CRYPT_DES_MODE_CBC will be used.

-     *

-     * @param optional Integer $mode

-     * @return Crypt_DES

-     * @access public

-     */

-    function Crypt_DES($mode = CRYPT_MODE_DES_CBC)

-    {

-        if ( !defined('CRYPT_DES_MODE') ) {

-            switch (true) {

-                case extension_loaded('mcrypt'):

-                    // i'd check to see if des was supported, by doing in_array('des', mcrypt_list_algorithms('')),

-                    // but since that can be changed after the object has been created, there doesn't seem to be

-                    // a lot of point...

-                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT);

-                    break;

-                default:

-                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL);

-            }

-        }

-

-        switch ( CRYPT_DES_MODE ) {

-            case CRYPT_DES_MODE_MCRYPT:

-                switch ($mode) {

-                    case CRYPT_DES_MODE_ECB:

-                        $this->mode = MCRYPT_MODE_ECB;

-                        break;

-                    case CRYPT_DES_MODE_CBC:

-                    default:

-                        $this->mode = MCRYPT_MODE_CBC;

-                }

-

-                break;

-            default:

-                switch ($mode) {

-                    case CRYPT_DES_MODE_ECB:

-                    case CRYPT_DES_MODE_CBC:

-                        $this->mode = $mode;

-                        break;

-                    default:

-                        $this->mode = CRYPT_DES_MODE_CBC;

-                }

-        }

-    }

-

-    /**

-     * Sets the key.

-     *

-     * Keys can be of any length.  DES, itself, uses 64-bit keys (eg. strlen($key) == 8), however, we

-     * only use the first eight, if $key has more then eight characters in it, and pad $key with the

-     * null byte if it is less then eight characters long.

-     *

-     * DES also requires that every eighth bit be a parity bit, however, we'll ignore that.

-     *

-     * If the key is not explicitly set, it'll be assumed to be all zero's.

-     *

-     * @access public

-     * @param String $key

-     */

-    function setKey($key)

-    {

-        $this->keys = ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) ? substr($key, 0, 8) : $this->_prepareKey($key);

-    }

-

-    /**

-     * Sets the initialization vector. (optional)

-     *

-     * SetIV is not required when CRYPT_DES_MODE_ECB is being used.  If not explictly set, it'll be assumed

-     * to be all zero's.

-     *

-     * @access public

-     * @param String $iv

-     */

-    function setIV($iv)

-    {

-        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));;

-    }

-

-    /**

-     * Sets MCrypt parameters. (optional)

-     *

-     * If MCrypt is being used, empty strings will be used, unless otherwise specified.

-     *

-     * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open

-     * @access public

-     * @param optional Integer $algorithm_directory

-     * @param optional Integer $mode_directory

-     */

-    function setMCrypt($algorithm_directory = '', $mode_directory = '')

-    {

-        $this->mcrypt = array($algorithm_directory, $mode_directory);

-    }

-

-    /**

-     * Encrypts a message.

-     *

-     * $plaintext will be padded with up to 8 additional bytes.  Other DES implementations may or may not pad in the

-     * same manner.  Other common approaches to padding and the reasons why it's necessary are discussed in the following

-     * URL:

-     *

-     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}

-     *

-     * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.

-     * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that

-     * length.

-     *

-     * @see Crypt_DES::decrypt()

-     * @access public

-     * @param String $plaintext

-     */

-    function encrypt($plaintext)

-    {

-        $plaintext = $this->_pad($plaintext);

-

-        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {

-            $td = mcrypt_module_open(MCRYPT_DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);

-            mcrypt_generic_init($td, $this->keys, $this->encryptIV);

-

-            $ciphertext = mcrypt_generic($td, $plaintext);

-

-            mcrypt_generic_deinit($td);

-            mcrypt_module_close($td);

-

-            if ($this->continuousBuffer) {

-                $this->encryptIV = substr($ciphertext, -8);

-            }

-

-            return $ciphertext;

-        }

-

-        if (!is_array($this->keys)) {

-            $this->keys = $this->_prepareKey("\0\0\0\0\0\0\0\0");

-        }

-

-        $ciphertext = '';

-        switch ($this->mode) {

-            case CRYPT_DES_MODE_ECB:

-                for ($i = 0; $i < strlen($plaintext); $i+=8) {

-                    $ciphertext.= $this->_processBlock(substr($plaintext, $i, 8), CRYPT_DES_ENCRYPT);

-                }

-                break;

-            case CRYPT_DES_MODE_CBC:

-                $xor = $this->encryptIV;

-                for ($i = 0; $i < strlen($plaintext); $i+=8) {

-                    $block = substr($plaintext, $i, 8);

-                    $block = $this->_processBlock($block ^ $xor, CRYPT_DES_ENCRYPT);

-                    $xor = $block;

-                    $ciphertext.= $block;

-                }

-                if ($this->continuousBuffer) {

-                    $this->encryptIV = $xor;

-                }

-        }

-

-        return $ciphertext;

-    }

-

-    /**

-     * Decrypts a message.

-     *

-     * If strlen($ciphertext) is not a multiple of 8, null bytes will be added to the end of the string until it is.

-     *

-     * @see Crypt_DES::encrypt()

-     * @access public

-     * @param String $ciphertext

-     */

-    function decrypt($ciphertext)

-    {

-        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :

-        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."

-        $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 0xFFFFFFF8, chr(0));

-

-        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {

-            $td = mcrypt_module_open(MCRYPT_DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);

-            mcrypt_generic_init($td, $this->keys, $this->decryptIV);

-

-            $plaintext = mdecrypt_generic($td, $ciphertext);

-

-            mcrypt_generic_deinit($td);

-            mcrypt_module_close($td);

-

-            if ($this->continuousBuffer) {

-                $this->decryptIV = substr($ciphertext, -8);

-            }

-

-            return $this->_unpad($plaintext);

-        }

-

-        if (!is_array($this->keys)) {

-            $this->keys = $this->_prepareKey("\0\0\0\0\0\0\0\0");

-        }

-

-        $plaintext = '';

-        switch ($this->mode) {

-            case CRYPT_DES_MODE_ECB:

-                for ($i = 0; $i < strlen($ciphertext); $i+=8) {

-                    $plaintext.= $this->_processBlock(substr($ciphertext, $i, 8), CRYPT_DES_DECRYPT);

-                }

-                break;

-            case CRYPT_DES_MODE_CBC:

-                $xor = $this->decryptIV;

-                for ($i = 0; $i < strlen($ciphertext); $i+=8) {

-                    $block = substr($ciphertext, $i, 8);

-                    $plaintext.= $this->_processBlock($block, CRYPT_DES_DECRYPT) ^ $xor;

-                    $xor = $block;

-                }

-                if ($this->continuousBuffer) {

-                    $this->decryptIV = $xor;

-                }

-        }

-

-        return $this->_unpad($plaintext);

-    }

-

-    /**

-     * Treat consecutive "packets" as if they are a continuous buffer.

-     *

-     * Say you have a 16-byte plaintext $plaintext.  Using the default behavior, the two following code snippets

-     * will yield different outputs:

-     *

-     * <code>

-     *    echo $des->encrypt(substr($plaintext, 0, 8));

-     *    echo $des->encrypt(substr($plaintext, 8, 8));

-     * </code>

-     * <code>

-     *    echo $des->encrypt($plaintext);

-     * </code>

-     *

-     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates

-     * another, as demonstrated with the following:

-     *

-     * <code>

-     *    $des->encrypt(substr($plaintext, 0, 8));

-     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));

-     * </code>

-     * <code>

-     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));

-     * </code>

-     *

-     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different

-     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /

-     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.

-     *

-     * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each

-     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that

-     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),

-     * however, they are also less intuitive and more likely to cause you problems.

-     *

-     * @see Crypt_DES::disableContinuousBuffer()

-     * @access public

-     */

-    function enableContinuousBuffer()

-    {

-        $this->continuousBuffer = true;

-    }

-

-    /**

-     * Treat consecutive packets as if they are a discontinuous buffer.

-     *

-     * The default behavior.

-     *

-     * @see Crypt_DES::enableContinuousBuffer()

-     * @access public

-     */

-    function disableContinuousBuffer()

-    {

-        $this->continuousBuffer = false;

-        $this->encryptIV = $this->iv;

-        $this->decryptIV = $this->iv;

-    }

-

-    /**

-     * Pad "packets".

-     *

-     * DES works by encrypting eight bytes at a time.  If you ever need to encrypt or decrypt something that's not

-     * a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight.

-     *

-     * Padding is enabled by default.  Sometimes, however, it is undesirable to pad strings.  Such is the case in SSH1,

-     * where "packets" are padded with random bytes before being encrypted.  Unpad these packets and you risk stripping

-     * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is

-     * transmitted separately)

-     *

-     * @see Crypt_DES::disablePadding()

-     * @access public

-     */

-    function enablePadding()

-    {

-        $this->padding = true;

-    }

-

-    /**

-     * Do not pad packets.

-     *

-     * @see Crypt_DES::enablePadding()

-     * @access public

-     */

-    function disablePadding()

-    {

-        $this->padding = false;

-    }

-

-    /**

-     * Pads a string

-     *

-     * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8).

-     * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7)

-     *

-     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless

-     * and padding will, hence forth, be enabled.

-     *

-     * @see Crypt_DES::_unpad()

-     * @access private

-     */

-    function _pad($text)

-    {

-        $length = strlen($text);

-

-        if (!$this->padding) {

-            if (($length & 7) == 0) {

-                return $text;

-            } else {

-                user_error("The plaintext's length ($length) is not a multiple of the block size (8)", E_USER_NOTICE);

-                $this->padding = true;

-            }

-        }

-

-        $pad = 8 - ($length & 7);

-        return str_pad($text, $length + $pad, chr($pad));

-    }

-

-    /**

-     * Unpads a string

-     *

-     * If padding is enabled and the reported padding length is invalid, padding will be, hence forth, disabled.

-     *

-     * @see Crypt_DES::_pad()

-     * @access private

-     */

-    function _unpad($text)

-    {

-        if (!$this->padding) {

-            return $text;

-        }

-

-        $length = ord($text[strlen($text) - 1]);

-

-        if (!$length || $length > 8) {

-            user_error("The number of bytes reported as being padded ($length) is invalid (block size = 8)", E_USER_NOTICE);

-            $this->padding = false;

-            return $text;

-        }

-

-        return substr($text, 0, -$length);

-    }

-

-    /**

-     * Encrypts or decrypts a 64-bit block

-     *

-     * $mode should be either CRYPT_DES_ENCRYPT or CRYPT_DES_DECRYPT.  See

-     * {@link http://en.wikipedia.org/wiki/Image:Feistel.png Feistel.png} to get a general

-     * idea of what this function does.

-     *

-     * @access private

-     * @param String $block

-     * @param Integer $mode

-     * @return String

-     */

-    function _processBlock($block, $mode)

-    {

-        // s-boxes.  in the official DES docs, they're described as being matrices that

-        // one accesses by using the first and last bits to determine the row and the

-        // middle four bits to determine the column.  in this implementation, they've

-        // been converted to vectors

-        static $sbox = array(

-            array(

-                14,  0,  4, 15, 13,  7,  1,  4,  2, 14, 15,  2, 11, 13,  8,  1,

-                 3, 10 ,10,  6,  6, 12, 12, 11,  5,  9,  9,  5,  0,  3,  7,  8,

-                 4, 15,  1, 12, 14,  8,  8,  2, 13,  4,  6,  9,  2,  1, 11,  7,

-                15,  5, 12, 11,  9,  3,  7, 14,  3, 10, 10,  0,  5,  6,  0, 13

-            ),

-            array(

-                15,  3,  1, 13,  8,  4, 14,  7,  6, 15, 11,  2,  3,  8,  4, 14,

-                 9, 12,  7,  0,  2,  1, 13, 10, 12,  6,  0,  9,  5, 11, 10,  5,

-                 0, 13, 14,  8,  7, 10, 11,  1, 10,  3,  4, 15, 13,  4,  1,  2,

-                 5, 11,  8,  6, 12,  7,  6, 12,  9,  0,  3,  5,  2, 14, 15,  9

-            ),

-            array(

-                10, 13,  0,  7,  9,  0, 14,  9,  6,  3,  3,  4, 15,  6,  5, 10,

-                 1,  2, 13,  8, 12,  5,  7, 14, 11, 12,  4, 11,  2, 15,  8,  1,

-                13,  1,  6, 10,  4, 13,  9,  0,  8,  6, 15,  9,  3,  8,  0,  7,

-                11,  4,  1, 15,  2, 14, 12,  3,  5, 11, 10,  5, 14,  2,  7, 12

-            ),

-            array(

-                 7, 13, 13,  8, 14, 11,  3,  5,  0,  6,  6, 15,  9,  0, 10,  3,

-                 1,  4,  2,  7,  8,  2,  5, 12, 11,  1, 12, 10,  4, 14, 15,  9,

-                10,  3,  6, 15,  9,  0,  0,  6, 12, 10, 11,  1,  7, 13, 13,  8,

-                15,  9,  1,  4,  3,  5, 14, 11,  5, 12,  2,  7,  8,  2,  4, 14

-            ),

-            array(

-                 2, 14, 12, 11,  4,  2,  1, 12,  7,  4, 10,  7, 11, 13,  6,  1,

-                 8,  5,  5,  0,  3, 15, 15, 10, 13,  3,  0,  9, 14,  8,  9,  6,

-                 4, 11,  2,  8,  1, 12, 11,  7, 10,  1, 13, 14,  7,  2,  8, 13,

-                15,  6,  9, 15, 12,  0,  5,  9,  6, 10,  3,  4,  0,  5, 14,  3

-            ),

-            array(

-                12, 10,  1, 15, 10,  4, 15,  2,  9,  7,  2, 12,  6,  9,  8,  5,

-                 0,  6, 13,  1,  3, 13,  4, 14, 14,  0,  7, 11,  5,  3, 11,  8,

-                 9,  4, 14,  3, 15,  2,  5, 12,  2,  9,  8,  5, 12, 15,  3, 10,

-                 7, 11,  0, 14,  4,  1, 10,  7,  1,  6, 13,  0, 11,  8,  6, 13

-            ),

-            array(

-                 4, 13, 11,  0,  2, 11, 14,  7, 15,  4,  0,  9,  8,  1, 13, 10,

-                 3, 14, 12,  3,  9,  5,  7, 12,  5,  2, 10, 15,  6,  8,  1,  6,

-                 1,  6,  4, 11, 11, 13, 13,  8, 12,  1,  3,  4,  7, 10, 14,  7,

-                10,  9, 15,  5,  6,  0,  8, 15,  0, 14,  5,  2,  9,  3,  2, 12

-            ),

-            array(

-                13,  1,  2, 15,  8, 13,  4,  8,  6, 10, 15,  3, 11,  7,  1,  4,

-                10, 12,  9,  5,  3,  6, 14, 11,  5,  0,  0, 14, 12,  9,  7,  2,

-                 7,  2, 11,  1,  4, 14,  1,  7,  9,  4, 12, 10, 14,  8,  2, 13,

-                 0, 15,  6, 12, 10,  9, 13,  0, 15,  3,  3,  5,  5,  6,  8, 11

-            )

-        );

-

-        $temp = unpack('Na/Nb', $block);

-        $block = array($temp['a'], $temp['b']);

-

-        // because php does arithmetic right shifts, if the most significant bits are set, right

-        // shifting those into the correct position will add 1's - not 0's.  this will intefere

-        // with the | operation unless a second & is done.  so we isolate these bits and left shift

-        // them into place.  we then & each block with 0x7FFFFFFF to prevennt 1's from being added

-        // for any other shifts.

-        $msb = array(

-            ($block[0] >> 31) & 1,

-            ($block[1] >> 31) & 1

-        );

-        $block[0] &= 0x7FFFFFFF;

-        $block[1] &= 0x7FFFFFFF;

-

-        // we isolate the appropriate bit in the appropriate integer and shift as appropriate.  in

-        // some cases, there are going to be multiple bits in the same integer that need to be shifted

-        // in the same way.  we combine those into one shift operation.

-        $block = array(

-            (($block[1] & 0x00000040) << 25) | (($block[1] & 0x00004000) << 16) |

-            (($block[1] & 0x00400001) <<  7) | (($block[1] & 0x40000100) >>  2) |

-            (($block[0] & 0x00000040) << 21) | (($block[0] & 0x00004000) << 12) |

-            (($block[0] & 0x00400001) <<  3) | (($block[0] & 0x40000100) >>  6) |

-            (($block[1] & 0x00000010) << 19) | (($block[1] & 0x00001000) << 10) |

-            (($block[1] & 0x00100000) <<  1) | (($block[1] & 0x10000000) >>  8) |

-            (($block[0] & 0x00000010) << 15) | (($block[0] & 0x00001000) <<  6) |

-            (($block[0] & 0x00100000) >>  3) | (($block[0] & 0x10000000) >> 12) |

-            (($block[1] & 0x00000004) << 13) | (($block[1] & 0x00000400) <<  4) |

-            (($block[1] & 0x00040000) >>  5) | (($block[1] & 0x04000000) >> 14) |

-            (($block[0] & 0x00000004) <<  9) | ( $block[0] & 0x00000400       ) |

-            (($block[0] & 0x00040000) >>  9) | (($block[0] & 0x04000000) >> 18) |

-            (($block[1] & 0x00010000) >> 11) | (($block[1] & 0x01000000) >> 20) |

-            (($block[0] & 0x00010000) >> 15) | (($block[0] & 0x01000000) >> 24)

-        ,

-            (($block[1] & 0x00000080) << 24) | (($block[1] & 0x00008000) << 15) |

-            (($block[1] & 0x00800002) <<  6) | (($block[0] & 0x00000080) << 20) |

-            (($block[0] & 0x00008000) << 11) | (($block[0] & 0x00800002) <<  2) |

-            (($block[1] & 0x00000020) << 18) | (($block[1] & 0x00002000) <<  9) |

-            ( $block[1] & 0x00200000       ) | (($block[1] & 0x20000000) >>  9) |

-            (($block[0] & 0x00000020) << 14) | (($block[0] & 0x00002000) <<  5) |

-            (($block[0] & 0x00200000) >>  4) | (($block[0] & 0x20000000) >> 13) |

-            (($block[1] & 0x00000008) << 12) | (($block[1] & 0x00000800) <<  3) |

-            (($block[1] & 0x00080000) >>  6) | (($block[1] & 0x08000000) >> 15) |

-            (($block[0] & 0x00000008) <<  8) | (($block[0] & 0x00000800) >>  1) |

-            (($block[0] & 0x00080000) >> 10) | (($block[0] & 0x08000000) >> 19) |

-            (($block[1] & 0x00000200) >>  3) | (($block[0] & 0x00000200) >>  7) |

-            (($block[1] & 0x00020000) >> 12) | (($block[1] & 0x02000000) >> 21) |

-            (($block[0] & 0x00020000) >> 16) | (($block[0] & 0x02000000) >> 25) |

-            ($msb[1] << 28) | ($msb[0] << 24)

-        );

-

-        for ($i = 0; $i < 16; $i++) {

-            // start of "the Feistel (F) function" - see the following URL:

-            // http://en.wikipedia.org/wiki/Image:Data_Encryption_Standard_InfoBox_Diagram.png

-            $temp = (($sbox[0][((($block[1] >> 27) & 0x1F) | (($block[1] & 1) << 5)) ^ $this->keys[$mode][$i][0]]) << 28)

-                  | (($sbox[1][(($block[1] & 0x1F800000) >> 23) ^ $this->keys[$mode][$i][1]]) << 24)

-                  | (($sbox[2][(($block[1] & 0x01F80000) >> 19) ^ $this->keys[$mode][$i][2]]) << 20)

-                  | (($sbox[3][(($block[1] & 0x001F8000) >> 15) ^ $this->keys[$mode][$i][3]]) << 16)

-                  | (($sbox[4][(($block[1] & 0x0001F800) >> 11) ^ $this->keys[$mode][$i][4]]) << 12)

-                  | (($sbox[5][(($block[1] & 0x00001F80) >>  7) ^ $this->keys[$mode][$i][5]]) <<  8)

-                  | (($sbox[6][(($block[1] & 0x000001F8) >>  3) ^ $this->keys[$mode][$i][6]]) <<  4)

-                  | ( $sbox[7][((($block[1] & 0x1F) << 1) | (($block[1] >> 31) & 1)) ^ $this->keys[$mode][$i][7]]);

-

-            $msb = ($temp >> 31) & 1;

-            $temp &= 0x7FFFFFFF;

-            $newBlock = (($temp & 0x00010000) << 15) | (($temp & 0x02020120) <<  5)

-                      | (($temp & 0x00001800) << 17) | (($temp & 0x01000000) >> 10)

-                      | (($temp & 0x00000008) << 24) | (($temp & 0x00100000) <<  6)

-                      | (($temp & 0x00000010) << 21) | (($temp & 0x00008000) <<  9)

-                      | (($temp & 0x00000200) << 12) | (($temp & 0x10000000) >> 27)

-                      | (($temp & 0x00000040) << 14) | (($temp & 0x08000000) >>  8)

-                      | (($temp & 0x00004000) <<  4) | (($temp & 0x00000002) << 16)

-                      | (($temp & 0x00442000) >>  6) | (($temp & 0x40800000) >> 15)

-                      | (($temp & 0x00000001) << 11) | (($temp & 0x20000000) >> 20)

-                      | (($temp & 0x00080000) >> 13) | (($temp & 0x00000004) <<  3)

-                      | (($temp & 0x04000000) >> 22) | (($temp & 0x00000480) >>  7)

-                      | (($temp & 0x00200000) >> 19) | ($msb << 23);

-            // end of "the Feistel (F) function" - $newBlock is F's output

-

-            $temp = $block[1];

-            $block[1] = $block[0] ^ $newBlock;

-            $block[0] = $temp;

-        }

-

-        $msb = array(

-            ($block[0] >> 31) & 1,

-            ($block[1] >> 31) & 1

-        );

-        $block[0] &= 0x7FFFFFFF;

-        $block[1] &= 0x7FFFFFFF;

-

-        $block = array(

-            (($block[0] & 0x01000004) <<  7) | (($block[1] & 0x01000004) <<  6) |

-            (($block[0] & 0x00010000) << 13) | (($block[1] & 0x00010000) << 12) |

-            (($block[0] & 0x00000100) << 19) | (($block[1] & 0x00000100) << 18) |

-            (($block[0] & 0x00000001) << 25) | (($block[1] & 0x00000001) << 24) |

-            (($block[0] & 0x02000008) >>  2) | (($block[1] & 0x02000008) >>  3) |

-            (($block[0] & 0x00020000) <<  4) | (($block[1] & 0x00020000) <<  3) |

-            (($block[0] & 0x00000200) << 10) | (($block[1] & 0x00000200) <<  9) |

-            (($block[0] & 0x00000002) << 16) | (($block[1] & 0x00000002) << 15) |

-            (($block[0] & 0x04000000) >> 11) | (($block[1] & 0x04000000) >> 12) |

-            (($block[0] & 0x00040000) >>  5) | (($block[1] & 0x00040000) >>  6) |

-            (($block[0] & 0x00000400) <<  1) | ( $block[1] & 0x00000400       ) |

-            (($block[0] & 0x08000000) >> 20) | (($block[1] & 0x08000000) >> 21) |

-            (($block[0] & 0x00080000) >> 14) | (($block[1] & 0x00080000) >> 15) |

-            (($block[0] & 0x00000800) >>  8) | (($block[1] & 0x00000800) >>  9)

-        ,

-            (($block[0] & 0x10000040) <<  3) | (($block[1] & 0x10000040) <<  2) |

-            (($block[0] & 0x00100000) <<  9) | (($block[1] & 0x00100000) <<  8) |

-            (($block[0] & 0x00001000) << 15) | (($block[1] & 0x00001000) << 14) |

-            (($block[0] & 0x00000010) << 21) | (($block[1] & 0x00000010) << 20) |

-            (($block[0] & 0x20000080) >>  6) | (($block[1] & 0x20000080) >>  7) |

-            ( $block[0] & 0x00200000       ) | (($block[1] & 0x00200000) >>  1) |

-            (($block[0] & 0x00002000) <<  6) | (($block[1] & 0x00002000) <<  5) |

-            (($block[0] & 0x00000020) << 12) | (($block[1] & 0x00000020) << 11) |

-            (($block[0] & 0x40000000) >> 15) | (($block[1] & 0x40000000) >> 16) |

-            (($block[0] & 0x00400000) >>  9) | (($block[1] & 0x00400000) >> 10) |

-            (($block[0] & 0x00004000) >>  3) | (($block[1] & 0x00004000) >>  4) |

-            (($block[0] & 0x00800000) >> 18) | (($block[1] & 0x00800000) >> 19) |

-            (($block[0] & 0x00008000) >> 12) | (($block[1] & 0x00008000) >> 13) |

-            ($msb[0] <<  7) | ($msb[1] <<  6)

-        );

-

-        return pack('NN', $block[0], $block[1]);

-    }

-

-    /**

-     * Creates the key schedule.

-     *

-     * @access private

-     * @param String $key

-     * @return Array

-     */

-    function _prepareKey($key)

-    {

-        static $shifts = array( // number of key bits shifted per round

-            1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1

-        );

-

-        // pad the key and remove extra characters as appropriate.

-        $key = str_pad(substr($key, 0, 8), 8, chr(0));

-

-        $temp = unpack('Na/Nb', $key);

-        $key = array($temp['a'], $temp['b']);

-        $msb = array(

-            ($key[0] >> 31) & 1,

-            ($key[1] >> 31) & 1

-        );

-        $key[0] &= 0x7FFFFFFF;

-        $key[1] &= 0x7FFFFFFF;

-

-        $key = array(

-            (($key[1] & 0x00000002) << 26) | (($key[1] & 0x00000204) << 17) |

-            (($key[1] & 0x00020408) <<  8) | (($key[1] & 0x02040800) >>  1) |

-            (($key[0] & 0x00000002) << 22) | (($key[0] & 0x00000204) << 13) |

-            (($key[0] & 0x00020408) <<  4) | (($key[0] & 0x02040800) >>  5) |

-            (($key[1] & 0x04080000) >> 10) | (($key[0] & 0x04080000) >> 14) |

-            (($key[1] & 0x08000000) >> 19) | (($key[0] & 0x08000000) >> 23) |

-            (($key[0] & 0x00000010) >>  1) | (($key[0] & 0x00001000) >> 10) |

-            (($key[0] & 0x00100000) >> 19) | (($key[0] & 0x10000000) >> 28)

-        ,

-            (($key[1] & 0x00000080) << 20) | (($key[1] & 0x00008000) << 11) |

-            (($key[1] & 0x00800000) <<  2) | (($key[0] & 0x00000080) << 16) |

-            (($key[0] & 0x00008000) <<  7) | (($key[0] & 0x00800000) >>  2) |

-            (($key[1] & 0x00000040) << 13) | (($key[1] & 0x00004000) <<  4) |

-            (($key[1] & 0x00400000) >>  5) | (($key[1] & 0x40000000) >> 14) |

-            (($key[0] & 0x00000040) <<  9) | ( $key[0] & 0x00004000       ) |

-            (($key[0] & 0x00400000) >>  9) | (($key[0] & 0x40000000) >> 18) |

-            (($key[1] & 0x00000020) <<  6) | (($key[1] & 0x00002000) >>  3) |

-            (($key[1] & 0x00200000) >> 12) | (($key[1] & 0x20000000) >> 21) |

-            (($key[0] & 0x00000020) <<  2) | (($key[0] & 0x00002000) >>  7) |

-            (($key[0] & 0x00200000) >> 16) | (($key[0] & 0x20000000) >> 25) |

-            (($key[1] & 0x00000010) >>  1) | (($key[1] & 0x00001000) >> 10) |

-            (($key[1] & 0x00100000) >> 19) | (($key[1] & 0x10000000) >> 28) |

-            ($msb[1] << 24) | ($msb[0] << 20)

-        ); 

-

-        $keys = array();

-        for ($i = 0; $i < 16; $i++) {

-            $key[0] <<= $shifts[$i];

-            $temp = ($key[0] & 0xF0000000) >> 28;

-            $key[0] = ($key[0] | $temp) & 0x0FFFFFFF;

-

-            $key[1] <<= $shifts[$i];

-            $temp = ($key[1] & 0xF0000000) >> 28;

-            $key[1] = ($key[1] | $temp) & 0x0FFFFFFF;

-

-            $temp = array(

-                (($key[1] & 0x00004000) >>  9) | (($key[1] & 0x00000800) >>  7) |

-                (($key[1] & 0x00020000) >> 14) | (($key[1] & 0x00000010) >>  2) |

-                (($key[1] & 0x08000000) >> 26) | (($key[1] & 0x00800000) >> 23)

-            ,

-                (($key[1] & 0x02400000) >> 20) | (($key[1] & 0x00000001) <<  4) |

-                (($key[1] & 0x00002000) >> 10) | (($key[1] & 0x00040000) >> 18) |

-                (($key[1] & 0x00000080) >>  6)

-            ,

-                ( $key[1] & 0x00000020       ) | (($key[1] & 0x00000200) >>  5) |

-                (($key[1] & 0x00010000) >> 13) | (($key[1] & 0x01000000) >> 22) |

-                (($key[1] & 0x00000004) >>  1) | (($key[1] & 0x00100000) >> 20)

-            ,

-                (($key[1] & 0x00001000) >>  7) | (($key[1] & 0x00200000) >> 17) |

-                (($key[1] & 0x00000002) <<  2) | (($key[1] & 0x00000100) >>  6) |

-                (($key[1] & 0x00008000) >> 14) | (($key[1] & 0x04000000) >> 26)

-            ,

-                (($key[0] & 0x00008000) >> 10) | ( $key[0] & 0x00000010       ) |

-                (($key[0] & 0x02000000) >> 22) | (($key[0] & 0x00080000) >> 17) |

-                (($key[0] & 0x00000200) >>  8) | (($key[0] & 0x00000002) >>  1)

-            ,

-                (($key[0] & 0x04000000) >> 21) | (($key[0] & 0x00010000) >> 12) |

-                (($key[0] & 0x00000020) >>  2) | (($key[0] & 0x00000800) >>  9) |

-                (($key[0] & 0x00800000) >> 22) | (($key[0] & 0x00000100) >>  8)

-            ,

-                (($key[0] & 0x00001000) >>  7) | (($key[0] & 0x00000088) >>  3) |

-                (($key[0] & 0x00020000) >> 14) | (($key[0] & 0x00000001) <<  2) |

-                (($key[0] & 0x00400000) >> 21)

-            ,

-                (($key[0] & 0x00000400) >>  5) | (($key[0] & 0x00004000) >> 10) |

-                (($key[0] & 0x00000040) >>  3) | (($key[0] & 0x00100000) >> 18) |

-                (($key[0] & 0x08000000) >> 26) | (($key[0] & 0x01000000) >> 24)

-            );

-

-            $keys[] = $temp;

-        }

-

-        $temp = array(

-            CRYPT_DES_ENCRYPT => $keys,

-            CRYPT_DES_DECRYPT => array_reverse($keys)

-        );

-

-        return $temp;

-    }

-}

-

-// vim: ts=4:sw=4:et:

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementation of DES.
+ *
+ * Uses mcrypt, if available, and an internal implementation, otherwise.
+ *
+ * PHP versions 4 and 5
+ *
+ * Useful resources are as follows:
+ *
+ *  - {@link http://en.wikipedia.org/wiki/DES_supplementary_material Wikipedia: DES supplementary material}
+ *  - {@link http://www.itl.nist.gov/fipspubs/fip46-2.htm FIPS 46-2 - (DES), Data Encryption Standard}
+ *  - {@link http://www.cs.eku.edu/faculty/styer/460/Encrypt/JS-DES.html JavaScript DES Example}
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/DES.php');
+ *
+ *    $des = new Crypt_DES();
+ *
+ *    $des->setKey('abcdefgh');
+ *
+ *    $size = 10 * 1024;
+ *    $plaintext = '';
+ *    for ($i = 0; $i < $size; $i++) {
+ *        $plaintext.= 'a';
+ *    }
+ *
+ *    echo $des->decrypt($des->encrypt($plaintext));
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_DES
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: DES.php,v 1.12 2010/02/09 06:10:26 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**#@+
+ * @access private
+ * @see Crypt_DES::_prepareKey()
+ * @see Crypt_DES::_processBlock()
+ */
+/**
+ * Contains array_reverse($keys[CRYPT_DES_DECRYPT])
+ */
+define('CRYPT_DES_ENCRYPT', 0);
+/**
+ * Contains array_reverse($keys[CRYPT_DES_ENCRYPT])
+ */
+define('CRYPT_DES_DECRYPT', 1);
+/**#@-*/
+
+/**#@+
+ * @access public
+ * @see Crypt_DES::encrypt()
+ * @see Crypt_DES::decrypt()
+ */
+/**
+ * Encrypt / decrypt using the Counter mode.
+ *
+ * Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
+ */
+define('CRYPT_DES_MODE_CTR', -1);
+/**
+ * Encrypt / decrypt using the Electronic Code Book mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
+ */
+define('CRYPT_DES_MODE_ECB', 1);
+/**
+ * Encrypt / decrypt using the Code Book Chaining mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
+ */
+define('CRYPT_DES_MODE_CBC', 2);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_DES::Crypt_DES()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_DES_MODE_INTERNAL', 1);
+/**
+ * Toggles the mcrypt implementation
+ */
+define('CRYPT_DES_MODE_MCRYPT', 2);
+/**#@-*/
+
+/**
+ * Pure-PHP implementation of DES.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_DES
+ */
+class Crypt_DES {
+    /**
+     * The Key Schedule
+     *
+     * @see Crypt_DES::setKey()
+     * @var Array
+     * @access private
+     */
+    var $keys = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * The Encryption Mode
+     *
+     * @see Crypt_DES::Crypt_DES()
+     * @var Integer
+     * @access private
+     */
+    var $mode;
+
+    /**
+     * Continuous Buffer status
+     *
+     * @see Crypt_DES::enableContinuousBuffer()
+     * @var Boolean
+     * @access private
+     */
+    var $continuousBuffer = false;
+
+    /**
+     * Padding status
+     *
+     * @see Crypt_DES::enablePadding()
+     * @var Boolean
+     * @access private
+     */
+    var $padding = true;
+
+    /**
+     * The Initialization Vector
+     *
+     * @see Crypt_DES::setIV()
+     * @var String
+     * @access private
+     */
+    var $iv = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_DES::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $encryptIV = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_DES::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $decryptIV = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * mcrypt resource for encryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
+     *
+     * @see Crypt_AES::encrypt()
+     * @var String
+     * @access private
+     */
+    var $enmcrypt;
+
+    /**
+     * mcrypt resource for decryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
+     *
+     * @see Crypt_AES::decrypt()
+     * @var String
+     * @access private
+     */
+    var $demcrypt;
+
+    /**
+     * Does the (en|de)mcrypt resource need to be (re)initialized?
+     *
+     * @see setKey()
+     * @see setIV()
+     * @var Boolean
+     * @access private
+     */
+    var $changed = true;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be
+     * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC.  If not explictly set, CRYPT_DES_MODE_CBC will be used.
+     *
+     * @param optional Integer $mode
+     * @return Crypt_DES
+     * @access public
+     */
+    function Crypt_DES($mode = CRYPT_MODE_DES_CBC)
+    {
+        if ( !defined('CRYPT_DES_MODE') ) {
+            switch (true) {
+                case extension_loaded('mcrypt'):
+                    // i'd check to see if des was supported, by doing in_array('des', mcrypt_list_algorithms('')),
+                    // but since that can be changed after the object has been created, there doesn't seem to be
+                    // a lot of point...
+                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT);
+                    break;
+                default:
+                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL);
+            }
+        }
+
+        switch ( CRYPT_DES_MODE ) {
+            case CRYPT_DES_MODE_MCRYPT:
+                switch ($mode) {
+                    case CRYPT_DES_MODE_ECB:
+                        $this->mode = MCRYPT_MODE_ECB;
+                        break;
+                    case CRYPT_DES_MODE_CTR:
+                        $this->mode = 'ctr';
+                        //$this->mode = in_array('ctr', mcrypt_list_modes()) ? 'ctr' : CRYPT_DES_MODE_CTR;
+                        break;
+                    case CRYPT_DES_MODE_CBC:
+                    default:
+                        $this->mode = MCRYPT_MODE_CBC;
+                }
+
+                break;
+            default:
+                switch ($mode) {
+                    case CRYPT_DES_MODE_ECB:
+                    case CRYPT_DES_MODE_CTR:
+                    case CRYPT_DES_MODE_CBC:
+                        $this->mode = $mode;
+                        break;
+                    default:
+                        $this->mode = CRYPT_DES_MODE_CBC;
+                }
+        }
+    }
+
+    /**
+     * Sets the key.
+     *
+     * Keys can be of any length.  DES, itself, uses 64-bit keys (eg. strlen($key) == 8), however, we
+     * only use the first eight, if $key has more then eight characters in it, and pad $key with the
+     * null byte if it is less then eight characters long.
+     *
+     * DES also requires that every eighth bit be a parity bit, however, we'll ignore that.
+     *
+     * If the key is not explicitly set, it'll be assumed to be all zero's.
+     *
+     * @access public
+     * @param String $key
+     */
+    function setKey($key)
+    {
+        $this->keys = ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) ? substr($key, 0, 8) : $this->_prepareKey($key);
+        $this->changed = true;
+    }
+
+    /**
+     * Sets the initialization vector. (optional)
+     *
+     * SetIV is not required when CRYPT_DES_MODE_ECB is being used.  If not explictly set, it'll be assumed
+     * to be all zero's.
+     *
+     * @access public
+     * @param String $iv
+     */
+    function setIV($iv)
+    {
+        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));
+        $this->changed = true;
+    }
+
+    /**
+     * Generate CTR XOR encryption key
+     *
+     * Encrypt the output of this and XOR it against the ciphertext / plaintext to get the
+     * plaintext / ciphertext in CTR mode.
+     *
+     * @see Crypt_DES::decrypt()
+     * @see Crypt_DES::encrypt()
+     * @access public
+     * @param Integer $length
+     * @param String $iv
+     */
+    function _generate_xor($length, &$iv)
+    {
+        $xor = '';
+        $num_blocks = ($length + 7) >> 3;
+        for ($i = 0; $i < $num_blocks; $i++) {
+            $xor.= $iv;
+            for ($j = 4; $j <= 8; $j+=4) {
+                $temp = substr($iv, -$j, 4);
+                switch ($temp) {
+                    case "\xFF\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x00\x00\x00\x00", -$j, 4);
+                        break;
+                    case "\x7F\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x80\x00\x00\x00", -$j, 4);
+                        break 2;
+                    default:
+                        extract(unpack('Ncount', $temp));
+                        $iv = substr_replace($iv, pack('N', $count + 1), -$j, 4);
+                        break 2;
+                }
+            }
+        }
+
+        return $xor;
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * $plaintext will be padded with up to 8 additional bytes.  Other DES implementations may or may not pad in the
+     * same manner.  Other common approaches to padding and the reasons why it's necessary are discussed in the following
+     * URL:
+     *
+     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
+     *
+     * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.
+     * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that
+     * length.
+     *
+     * @see Crypt_DES::decrypt()
+     * @access public
+     * @param String $plaintext
+     */
+    function encrypt($plaintext)
+    {
+        if ($this->mode != CRYPT_DES_MODE_CTR && $this->mode != 'ctr') {
+            $plaintext = $this->_pad($plaintext);
+        }
+
+        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
+            if ($this->changed) {
+                if (!isset($this->enmcrypt)) {
+                    $this->enmcrypt = mcrypt_module_open(MCRYPT_DES, '', $this->mode, '');
+                }
+                mcrypt_generic_init($this->enmcrypt, $this->keys, $this->encryptIV);
+                $this->changed = false;
+            }
+
+            $ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->enmcrypt, $this->keys, $this->encryptIV);
+            }
+
+            return $ciphertext;
+        }
+
+        if (!is_array($this->keys)) {
+            $this->keys = $this->_prepareKey("\0\0\0\0\0\0\0\0");
+        }
+
+        $ciphertext = '';
+        switch ($this->mode) {
+            case CRYPT_DES_MODE_ECB:
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $ciphertext.= $this->_processBlock(substr($plaintext, $i, 8), CRYPT_DES_ENCRYPT);
+                }
+                break;
+            case CRYPT_DES_MODE_CBC:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8);
+                    $block = $this->_processBlock($block ^ $xor, CRYPT_DES_ENCRYPT);
+                    $xor = $block;
+                    $ciphertext.= $block;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+                break;
+            case CRYPT_DES_MODE_CTR:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8);
+                    $key = $this->_processBlock($this->_generate_xor(8, $xor), CRYPT_DES_ENCRYPT);
+                    $ciphertext.= $block ^ $key;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+        }
+
+        return $ciphertext;
+    }
+
+    /**
+     * Decrypts a message.
+     *
+     * If strlen($ciphertext) is not a multiple of 8, null bytes will be added to the end of the string until it is.
+     *
+     * @see Crypt_DES::encrypt()
+     * @access public
+     * @param String $ciphertext
+     */
+    function decrypt($ciphertext)
+    {
+        if ($this->mode != CRYPT_DES_MODE_CTR && $this->mode != 'ctr') {
+            // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :
+            // "The data is padded with "\0" to make sure the length of the data is n * blocksize."
+            $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 0xFFFFFFF8, chr(0));
+        }
+
+        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
+            if ($this->changed) {
+                if (!isset($this->demcrypt)) {
+                    $this->demcrypt = mcrypt_module_open(MCRYPT_DES, '', $this->mode, '');
+                }
+                mcrypt_generic_init($this->demcrypt, $this->keys, $this->decryptIV);
+                $this->changed = false;
+            }
+
+            $plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->demcrypt, $this->keys, $this->decryptIV);
+            }
+
+            return $this->mode != 'ctr' ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        if (!is_array($this->keys)) {
+            $this->keys = $this->_prepareKey("\0\0\0\0\0\0\0\0");
+        }
+
+        $plaintext = '';
+        switch ($this->mode) {
+            case CRYPT_DES_MODE_ECB:
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $plaintext.= $this->_processBlock(substr($ciphertext, $i, 8), CRYPT_DES_DECRYPT);
+                }
+                break;
+            case CRYPT_DES_MODE_CBC:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $block = substr($ciphertext, $i, 8);
+                    $plaintext.= $this->_processBlock($block, CRYPT_DES_DECRYPT) ^ $xor;
+                    $xor = $block;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+                break;
+            case CRYPT_DES_MODE_CTR:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $block = substr($ciphertext, $i, 8);
+                    $key = $this->_processBlock($this->_generate_xor(8, $xor), CRYPT_DES_ENCRYPT);
+                    $plaintext.= $block ^ $key;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+        }
+
+        return $this->mode != CRYPT_DES_MODE_CTR ? $this->_unpad($plaintext) : $plaintext;
+    }
+
+    /**
+     * Treat consecutive "packets" as if they are a continuous buffer.
+     *
+     * Say you have a 16-byte plaintext $plaintext.  Using the default behavior, the two following code snippets
+     * will yield different outputs:
+     *
+     * <code>
+     *    echo $des->encrypt(substr($plaintext, 0, 8));
+     *    echo $des->encrypt(substr($plaintext, 8, 8));
+     * </code>
+     * <code>
+     *    echo $des->encrypt($plaintext);
+     * </code>
+     *
+     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates
+     * another, as demonstrated with the following:
+     *
+     * <code>
+     *    $des->encrypt(substr($plaintext, 0, 8));
+     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     * <code>
+     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     *
+     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different
+     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /
+     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.
+     *
+     * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each
+     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that
+     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),
+     * however, they are also less intuitive and more likely to cause you problems.
+     *
+     * @see Crypt_DES::disableContinuousBuffer()
+     * @access public
+     */
+    function enableContinuousBuffer()
+    {
+        $this->continuousBuffer = true;
+    }
+
+    /**
+     * Treat consecutive packets as if they are a discontinuous buffer.
+     *
+     * The default behavior.
+     *
+     * @see Crypt_DES::enableContinuousBuffer()
+     * @access public
+     */
+    function disableContinuousBuffer()
+    {
+        $this->continuousBuffer = false;
+        $this->encryptIV = $this->iv;
+        $this->decryptIV = $this->iv;
+    }
+
+    /**
+     * Pad "packets".
+     *
+     * DES works by encrypting eight bytes at a time.  If you ever need to encrypt or decrypt something that's not
+     * a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight.
+     *
+     * Padding is enabled by default.  Sometimes, however, it is undesirable to pad strings.  Such is the case in SSH1,
+     * where "packets" are padded with random bytes before being encrypted.  Unpad these packets and you risk stripping
+     * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is
+     * transmitted separately)
+     *
+     * @see Crypt_DES::disablePadding()
+     * @access public
+     */
+    function enablePadding()
+    {
+        $this->padding = true;
+    }
+
+    /**
+     * Do not pad packets.
+     *
+     * @see Crypt_DES::enablePadding()
+     * @access public
+     */
+    function disablePadding()
+    {
+        $this->padding = false;
+    }
+
+    /**
+     * Pads a string
+     *
+     * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8).
+     * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7)
+     *
+     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless
+     * and padding will, hence forth, be enabled.
+     *
+     * @see Crypt_DES::_unpad()
+     * @access private
+     */
+    function _pad($text)
+    {
+        $length = strlen($text);
+
+        if (!$this->padding) {
+            if (($length & 7) == 0) {
+                return $text;
+            } else {
+                user_error("The plaintext's length ($length) is not a multiple of the block size (8)", E_USER_NOTICE);
+                $this->padding = true;
+            }
+        }
+
+        $pad = 8 - ($length & 7);
+        return str_pad($text, $length + $pad, chr($pad));
+    }
+
+    /**
+     * Unpads a string
+     *
+     * If padding is enabled and the reported padding length is invalid the encryption key will be assumed to be wrong
+     * and false will be returned.
+     *
+     * @see Crypt_DES::_pad()
+     * @access private
+     */
+    function _unpad($text)
+    {
+        if (!$this->padding) {
+            return $text;
+        }
+
+        $length = ord($text[strlen($text) - 1]);
+
+        if (!$length || $length > 8) {
+            return false;
+        }
+
+        return substr($text, 0, -$length);
+    }
+
+    /**
+     * Encrypts or decrypts a 64-bit block
+     *
+     * $mode should be either CRYPT_DES_ENCRYPT or CRYPT_DES_DECRYPT.  See
+     * {@link http://en.wikipedia.org/wiki/Image:Feistel.png Feistel.png} to get a general
+     * idea of what this function does.
+     *
+     * @access private
+     * @param String $block
+     * @param Integer $mode
+     * @return String
+     */
+    function _processBlock($block, $mode)
+    {
+        // s-boxes.  in the official DES docs, they're described as being matrices that
+        // one accesses by using the first and last bits to determine the row and the
+        // middle four bits to determine the column.  in this implementation, they've
+        // been converted to vectors
+        static $sbox = array(
+            array(
+                14,  0,  4, 15, 13,  7,  1,  4,  2, 14, 15,  2, 11, 13,  8,  1,
+                 3, 10 ,10,  6,  6, 12, 12, 11,  5,  9,  9,  5,  0,  3,  7,  8,
+                 4, 15,  1, 12, 14,  8,  8,  2, 13,  4,  6,  9,  2,  1, 11,  7,
+                15,  5, 12, 11,  9,  3,  7, 14,  3, 10, 10,  0,  5,  6,  0, 13
+            ),
+            array(
+                15,  3,  1, 13,  8,  4, 14,  7,  6, 15, 11,  2,  3,  8,  4, 14,
+                 9, 12,  7,  0,  2,  1, 13, 10, 12,  6,  0,  9,  5, 11, 10,  5,
+                 0, 13, 14,  8,  7, 10, 11,  1, 10,  3,  4, 15, 13,  4,  1,  2,
+                 5, 11,  8,  6, 12,  7,  6, 12,  9,  0,  3,  5,  2, 14, 15,  9
+            ),
+            array(
+                10, 13,  0,  7,  9,  0, 14,  9,  6,  3,  3,  4, 15,  6,  5, 10,
+                 1,  2, 13,  8, 12,  5,  7, 14, 11, 12,  4, 11,  2, 15,  8,  1,
+                13,  1,  6, 10,  4, 13,  9,  0,  8,  6, 15,  9,  3,  8,  0,  7,
+                11,  4,  1, 15,  2, 14, 12,  3,  5, 11, 10,  5, 14,  2,  7, 12
+            ),
+            array(
+                 7, 13, 13,  8, 14, 11,  3,  5,  0,  6,  6, 15,  9,  0, 10,  3,
+                 1,  4,  2,  7,  8,  2,  5, 12, 11,  1, 12, 10,  4, 14, 15,  9,
+                10,  3,  6, 15,  9,  0,  0,  6, 12, 10, 11,  1,  7, 13, 13,  8,
+                15,  9,  1,  4,  3,  5, 14, 11,  5, 12,  2,  7,  8,  2,  4, 14
+            ),
+            array(
+                 2, 14, 12, 11,  4,  2,  1, 12,  7,  4, 10,  7, 11, 13,  6,  1,
+                 8,  5,  5,  0,  3, 15, 15, 10, 13,  3,  0,  9, 14,  8,  9,  6,
+                 4, 11,  2,  8,  1, 12, 11,  7, 10,  1, 13, 14,  7,  2,  8, 13,
+                15,  6,  9, 15, 12,  0,  5,  9,  6, 10,  3,  4,  0,  5, 14,  3
+            ),
+            array(
+                12, 10,  1, 15, 10,  4, 15,  2,  9,  7,  2, 12,  6,  9,  8,  5,
+                 0,  6, 13,  1,  3, 13,  4, 14, 14,  0,  7, 11,  5,  3, 11,  8,
+                 9,  4, 14,  3, 15,  2,  5, 12,  2,  9,  8,  5, 12, 15,  3, 10,
+                 7, 11,  0, 14,  4,  1, 10,  7,  1,  6, 13,  0, 11,  8,  6, 13
+            ),
+            array(
+                 4, 13, 11,  0,  2, 11, 14,  7, 15,  4,  0,  9,  8,  1, 13, 10,
+                 3, 14, 12,  3,  9,  5,  7, 12,  5,  2, 10, 15,  6,  8,  1,  6,
+                 1,  6,  4, 11, 11, 13, 13,  8, 12,  1,  3,  4,  7, 10, 14,  7,
+                10,  9, 15,  5,  6,  0,  8, 15,  0, 14,  5,  2,  9,  3,  2, 12
+            ),
+            array(
+                13,  1,  2, 15,  8, 13,  4,  8,  6, 10, 15,  3, 11,  7,  1,  4,
+                10, 12,  9,  5,  3,  6, 14, 11,  5,  0,  0, 14, 12,  9,  7,  2,
+                 7,  2, 11,  1,  4, 14,  1,  7,  9,  4, 12, 10, 14,  8,  2, 13,
+                 0, 15,  6, 12, 10,  9, 13,  0, 15,  3,  3,  5,  5,  6,  8, 11
+            )
+        );
+
+        $keys = $this->keys;
+
+        $temp = unpack('Na/Nb', $block);
+        $block = array($temp['a'], $temp['b']);
+
+        // because php does arithmetic right shifts, if the most significant bits are set, right
+        // shifting those into the correct position will add 1's - not 0's.  this will intefere
+        // with the | operation unless a second & is done.  so we isolate these bits and left shift
+        // them into place.  we then & each block with 0x7FFFFFFF to prevennt 1's from being added
+        // for any other shifts.
+        $msb = array(
+            ($block[0] >> 31) & 1,
+            ($block[1] >> 31) & 1
+        );
+        $block[0] &= 0x7FFFFFFF;
+        $block[1] &= 0x7FFFFFFF;
+
+        // we isolate the appropriate bit in the appropriate integer and shift as appropriate.  in
+        // some cases, there are going to be multiple bits in the same integer that need to be shifted
+        // in the same way.  we combine those into one shift operation.
+        $block = array(
+            (($block[1] & 0x00000040) << 25) | (($block[1] & 0x00004000) << 16) |
+            (($block[1] & 0x00400001) <<  7) | (($block[1] & 0x40000100) >>  2) |
+            (($block[0] & 0x00000040) << 21) | (($block[0] & 0x00004000) << 12) |
+            (($block[0] & 0x00400001) <<  3) | (($block[0] & 0x40000100) >>  6) |
+            (($block[1] & 0x00000010) << 19) | (($block[1] & 0x00001000) << 10) |
+            (($block[1] & 0x00100000) <<  1) | (($block[1] & 0x10000000) >>  8) |
+            (($block[0] & 0x00000010) << 15) | (($block[0] & 0x00001000) <<  6) |
+            (($block[0] & 0x00100000) >>  3) | (($block[0] & 0x10000000) >> 12) |
+            (($block[1] & 0x00000004) << 13) | (($block[1] & 0x00000400) <<  4) |
+            (($block[1] & 0x00040000) >>  5) | (($block[1] & 0x04000000) >> 14) |
+            (($block[0] & 0x00000004) <<  9) | ( $block[0] & 0x00000400       ) |
+            (($block[0] & 0x00040000) >>  9) | (($block[0] & 0x04000000) >> 18) |
+            (($block[1] & 0x00010000) >> 11) | (($block[1] & 0x01000000) >> 20) |
+            (($block[0] & 0x00010000) >> 15) | (($block[0] & 0x01000000) >> 24)
+        ,
+            (($block[1] & 0x00000080) << 24) | (($block[1] & 0x00008000) << 15) |
+            (($block[1] & 0x00800002) <<  6) | (($block[0] & 0x00000080) << 20) |
+            (($block[0] & 0x00008000) << 11) | (($block[0] & 0x00800002) <<  2) |
+            (($block[1] & 0x00000020) << 18) | (($block[1] & 0x00002000) <<  9) |
+            ( $block[1] & 0x00200000       ) | (($block[1] & 0x20000000) >>  9) |
+            (($block[0] & 0x00000020) << 14) | (($block[0] & 0x00002000) <<  5) |
+            (($block[0] & 0x00200000) >>  4) | (($block[0] & 0x20000000) >> 13) |
+            (($block[1] & 0x00000008) << 12) | (($block[1] & 0x00000800) <<  3) |
+            (($block[1] & 0x00080000) >>  6) | (($block[1] & 0x08000000) >> 15) |
+            (($block[0] & 0x00000008) <<  8) | (($block[0] & 0x00000800) >>  1) |
+            (($block[0] & 0x00080000) >> 10) | (($block[0] & 0x08000000) >> 19) |
+            (($block[1] & 0x00000200) >>  3) | (($block[0] & 0x00000200) >>  7) |
+            (($block[1] & 0x00020000) >> 12) | (($block[1] & 0x02000000) >> 21) |
+            (($block[0] & 0x00020000) >> 16) | (($block[0] & 0x02000000) >> 25) |
+            ($msb[1] << 28) | ($msb[0] << 24)
+        );
+
+        for ($i = 0; $i < 16; $i++) {
+            // start of "the Feistel (F) function" - see the following URL:
+            // http://en.wikipedia.org/wiki/Image:Data_Encryption_Standard_InfoBox_Diagram.png
+            $temp = (($sbox[0][((($block[1] >> 27) & 0x1F) | (($block[1] & 1) << 5)) ^ $keys[$mode][$i][0]]) << 28)
+                  | (($sbox[1][(($block[1] & 0x1F800000) >> 23) ^ $keys[$mode][$i][1]]) << 24)
+                  | (($sbox[2][(($block[1] & 0x01F80000) >> 19) ^ $keys[$mode][$i][2]]) << 20)
+                  | (($sbox[3][(($block[1] & 0x001F8000) >> 15) ^ $keys[$mode][$i][3]]) << 16)
+                  | (($sbox[4][(($block[1] & 0x0001F800) >> 11) ^ $keys[$mode][$i][4]]) << 12)
+                  | (($sbox[5][(($block[1] & 0x00001F80) >>  7) ^ $keys[$mode][$i][5]]) <<  8)
+                  | (($sbox[6][(($block[1] & 0x000001F8) >>  3) ^ $keys[$mode][$i][6]]) <<  4)
+                  | ( $sbox[7][((($block[1] & 0x1F) << 1) | (($block[1] >> 31) & 1)) ^ $keys[$mode][$i][7]]);
+
+            $msb = ($temp >> 31) & 1;
+            $temp &= 0x7FFFFFFF;
+            $newBlock = (($temp & 0x00010000) << 15) | (($temp & 0x02020120) <<  5)
+                      | (($temp & 0x00001800) << 17) | (($temp & 0x01000000) >> 10)
+                      | (($temp & 0x00000008) << 24) | (($temp & 0x00100000) <<  6)
+                      | (($temp & 0x00000010) << 21) | (($temp & 0x00008000) <<  9)
+                      | (($temp & 0x00000200) << 12) | (($temp & 0x10000000) >> 27)
+                      | (($temp & 0x00000040) << 14) | (($temp & 0x08000000) >>  8)
+                      | (($temp & 0x00004000) <<  4) | (($temp & 0x00000002) << 16)
+                      | (($temp & 0x00442000) >>  6) | (($temp & 0x40800000) >> 15)
+                      | (($temp & 0x00000001) << 11) | (($temp & 0x20000000) >> 20)
+                      | (($temp & 0x00080000) >> 13) | (($temp & 0x00000004) <<  3)
+                      | (($temp & 0x04000000) >> 22) | (($temp & 0x00000480) >>  7)
+                      | (($temp & 0x00200000) >> 19) | ($msb << 23);
+            // end of "the Feistel (F) function" - $newBlock is F's output
+
+            $temp = $block[1];
+            $block[1] = $block[0] ^ $newBlock;
+            $block[0] = $temp;
+        }
+
+        $msb = array(
+            ($block[0] >> 31) & 1,
+            ($block[1] >> 31) & 1
+        );
+        $block[0] &= 0x7FFFFFFF;
+        $block[1] &= 0x7FFFFFFF;
+
+        $block = array(
+            (($block[0] & 0x01000004) <<  7) | (($block[1] & 0x01000004) <<  6) |
+            (($block[0] & 0x00010000) << 13) | (($block[1] & 0x00010000) << 12) |
+            (($block[0] & 0x00000100) << 19) | (($block[1] & 0x00000100) << 18) |
+            (($block[0] & 0x00000001) << 25) | (($block[1] & 0x00000001) << 24) |
+            (($block[0] & 0x02000008) >>  2) | (($block[1] & 0x02000008) >>  3) |
+            (($block[0] & 0x00020000) <<  4) | (($block[1] & 0x00020000) <<  3) |
+            (($block[0] & 0x00000200) << 10) | (($block[1] & 0x00000200) <<  9) |
+            (($block[0] & 0x00000002) << 16) | (($block[1] & 0x00000002) << 15) |
+            (($block[0] & 0x04000000) >> 11) | (($block[1] & 0x04000000) >> 12) |
+            (($block[0] & 0x00040000) >>  5) | (($block[1] & 0x00040000) >>  6) |
+            (($block[0] & 0x00000400) <<  1) | ( $block[1] & 0x00000400       ) |
+            (($block[0] & 0x08000000) >> 20) | (($block[1] & 0x08000000) >> 21) |
+            (($block[0] & 0x00080000) >> 14) | (($block[1] & 0x00080000) >> 15) |
+            (($block[0] & 0x00000800) >>  8) | (($block[1] & 0x00000800) >>  9)
+        ,
+            (($block[0] & 0x10000040) <<  3) | (($block[1] & 0x10000040) <<  2) |
+            (($block[0] & 0x00100000) <<  9) | (($block[1] & 0x00100000) <<  8) |
+            (($block[0] & 0x00001000) << 15) | (($block[1] & 0x00001000) << 14) |
+            (($block[0] & 0x00000010) << 21) | (($block[1] & 0x00000010) << 20) |
+            (($block[0] & 0x20000080) >>  6) | (($block[1] & 0x20000080) >>  7) |
+            ( $block[0] & 0x00200000       ) | (($block[1] & 0x00200000) >>  1) |
+            (($block[0] & 0x00002000) <<  6) | (($block[1] & 0x00002000) <<  5) |
+            (($block[0] & 0x00000020) << 12) | (($block[1] & 0x00000020) << 11) |
+            (($block[0] & 0x40000000) >> 15) | (($block[1] & 0x40000000) >> 16) |
+            (($block[0] & 0x00400000) >>  9) | (($block[1] & 0x00400000) >> 10) |
+            (($block[0] & 0x00004000) >>  3) | (($block[1] & 0x00004000) >>  4) |
+            (($block[0] & 0x00800000) >> 18) | (($block[1] & 0x00800000) >> 19) |
+            (($block[0] & 0x00008000) >> 12) | (($block[1] & 0x00008000) >> 13) |
+            ($msb[0] <<  7) | ($msb[1] <<  6)
+        );
+
+        return pack('NN', $block[0], $block[1]);
+    }
+
+    /**
+     * Creates the key schedule.
+     *
+     * @access private
+     * @param String $key
+     * @return Array
+     */
+    function _prepareKey($key)
+    {
+        static $shifts = array( // number of key bits shifted per round
+            1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
+        );
+
+        // pad the key and remove extra characters as appropriate.
+        $key = str_pad(substr($key, 0, 8), 8, chr(0));
+
+        $temp = unpack('Na/Nb', $key);
+        $key = array($temp['a'], $temp['b']);
+        $msb = array(
+            ($key[0] >> 31) & 1,
+            ($key[1] >> 31) & 1
+        );
+        $key[0] &= 0x7FFFFFFF;
+        $key[1] &= 0x7FFFFFFF;
+
+        $key = array(
+            (($key[1] & 0x00000002) << 26) | (($key[1] & 0x00000204) << 17) |
+            (($key[1] & 0x00020408) <<  8) | (($key[1] & 0x02040800) >>  1) |
+            (($key[0] & 0x00000002) << 22) | (($key[0] & 0x00000204) << 13) |
+            (($key[0] & 0x00020408) <<  4) | (($key[0] & 0x02040800) >>  5) |
+            (($key[1] & 0x04080000) >> 10) | (($key[0] & 0x04080000) >> 14) |
+            (($key[1] & 0x08000000) >> 19) | (($key[0] & 0x08000000) >> 23) |
+            (($key[0] & 0x00000010) >>  1) | (($key[0] & 0x00001000) >> 10) |
+            (($key[0] & 0x00100000) >> 19) | (($key[0] & 0x10000000) >> 28)
+        ,
+            (($key[1] & 0x00000080) << 20) | (($key[1] & 0x00008000) << 11) |
+            (($key[1] & 0x00800000) <<  2) | (($key[0] & 0x00000080) << 16) |
+            (($key[0] & 0x00008000) <<  7) | (($key[0] & 0x00800000) >>  2) |
+            (($key[1] & 0x00000040) << 13) | (($key[1] & 0x00004000) <<  4) |
+            (($key[1] & 0x00400000) >>  5) | (($key[1] & 0x40000000) >> 14) |
+            (($key[0] & 0x00000040) <<  9) | ( $key[0] & 0x00004000       ) |
+            (($key[0] & 0x00400000) >>  9) | (($key[0] & 0x40000000) >> 18) |
+            (($key[1] & 0x00000020) <<  6) | (($key[1] & 0x00002000) >>  3) |
+            (($key[1] & 0x00200000) >> 12) | (($key[1] & 0x20000000) >> 21) |
+            (($key[0] & 0x00000020) <<  2) | (($key[0] & 0x00002000) >>  7) |
+            (($key[0] & 0x00200000) >> 16) | (($key[0] & 0x20000000) >> 25) |
+            (($key[1] & 0x00000010) >>  1) | (($key[1] & 0x00001000) >> 10) |
+            (($key[1] & 0x00100000) >> 19) | (($key[1] & 0x10000000) >> 28) |
+            ($msb[1] << 24) | ($msb[0] << 20)
+        ); 
+
+        $keys = array();
+        for ($i = 0; $i < 16; $i++) {
+            $key[0] <<= $shifts[$i];
+            $temp = ($key[0] & 0xF0000000) >> 28;
+            $key[0] = ($key[0] | $temp) & 0x0FFFFFFF;
+
+            $key[1] <<= $shifts[$i];
+            $temp = ($key[1] & 0xF0000000) >> 28;
+            $key[1] = ($key[1] | $temp) & 0x0FFFFFFF;
+
+            $temp = array(
+                (($key[1] & 0x00004000) >>  9) | (($key[1] & 0x00000800) >>  7) |
+                (($key[1] & 0x00020000) >> 14) | (($key[1] & 0x00000010) >>  2) |
+                (($key[1] & 0x08000000) >> 26) | (($key[1] & 0x00800000) >> 23)
+            ,
+                (($key[1] & 0x02400000) >> 20) | (($key[1] & 0x00000001) <<  4) |
+                (($key[1] & 0x00002000) >> 10) | (($key[1] & 0x00040000) >> 18) |
+                (($key[1] & 0x00000080) >>  6)
+            ,
+                ( $key[1] & 0x00000020       ) | (($key[1] & 0x00000200) >>  5) |
+                (($key[1] & 0x00010000) >> 13) | (($key[1] & 0x01000000) >> 22) |
+                (($key[1] & 0x00000004) >>  1) | (($key[1] & 0x00100000) >> 20)
+            ,
+                (($key[1] & 0x00001000) >>  7) | (($key[1] & 0x00200000) >> 17) |
+                (($key[1] & 0x00000002) <<  2) | (($key[1] & 0x00000100) >>  6) |
+                (($key[1] & 0x00008000) >> 14) | (($key[1] & 0x04000000) >> 26)
+            ,
+                (($key[0] & 0x00008000) >> 10) | ( $key[0] & 0x00000010       ) |
+                (($key[0] & 0x02000000) >> 22) | (($key[0] & 0x00080000) >> 17) |
+                (($key[0] & 0x00000200) >>  8) | (($key[0] & 0x00000002) >>  1)
+            ,
+                (($key[0] & 0x04000000) >> 21) | (($key[0] & 0x00010000) >> 12) |
+                (($key[0] & 0x00000020) >>  2) | (($key[0] & 0x00000800) >>  9) |
+                (($key[0] & 0x00800000) >> 22) | (($key[0] & 0x00000100) >>  8)
+            ,
+                (($key[0] & 0x00001000) >>  7) | (($key[0] & 0x00000088) >>  3) |
+                (($key[0] & 0x00020000) >> 14) | (($key[0] & 0x00000001) <<  2) |
+                (($key[0] & 0x00400000) >> 21)
+            ,
+                (($key[0] & 0x00000400) >>  5) | (($key[0] & 0x00004000) >> 10) |
+                (($key[0] & 0x00000040) >>  3) | (($key[0] & 0x00100000) >> 18) |
+                (($key[0] & 0x08000000) >> 26) | (($key[0] & 0x01000000) >> 24)
+            );
+
+            $keys[] = $temp;
+        }
+
+        $temp = array(
+            CRYPT_DES_ENCRYPT => $keys,
+            CRYPT_DES_DECRYPT => array_reverse($keys)
+        );
+
+        return $temp;
+    }
+}
+
+// vim: ts=4:sw=4:et:
 // vim6: fdl=1:
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/Hash.php b/plugins/OStatus/extlib/Crypt/Hash.php
index ef3a85802..e4dfde331 100644
--- a/plugins/OStatus/extlib/Crypt/Hash.php
+++ b/plugins/OStatus/extlib/Crypt/Hash.php
@@ -1,816 +1,816 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions.

- *

- * Uses hash() or mhash() if available and an internal implementation, otherwise.  Currently supports the following:

- *

- * md2, md5, md5-96, sha1, sha1-96, sha256, sha384, and sha512

- *

- * If {@link Crypt_Hash::setKey() setKey()} is called, {@link Crypt_Hash::hash() hash()} will return the HMAC as opposed to

- * the hash.  If no valid algorithm is provided, sha1 will be used.

- *

- * PHP versions 4 and 5

- *

- * {@internal The variable names are the same as those in 

- * {@link http://tools.ietf.org/html/rfc2104#section-2 RFC2104}.}}

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/Hash.php');

- *

- *    $hash = new Crypt_Hash('sha1');

- *

- *    $hash->setKey('abcdefg');

- *

- *    echo base64_encode($hash->hash('abcdefg'));

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_Hash

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: Hash.php,v 1.6 2009/11/23 23:37:07 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**#@+

- * @access private

- * @see Crypt_Hash::Crypt_Hash()

- */

-/**

- * Toggles the internal implementation

- */

-define('CRYPT_HASH_MODE_INTERNAL', 1);

-/**

- * Toggles the mhash() implementation, which has been deprecated on PHP 5.3.0+.

- */

-define('CRYPT_HASH_MODE_MHASH',    2);

-/**

- * Toggles the hash() implementation, which works on PHP 5.1.2+.

- */

-define('CRYPT_HASH_MODE_HASH',     3);

-/**#@-*/

-

-/**

- * Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_Hash

- */

-class Crypt_Hash {

-    /**

-     * Byte-length of compression blocks / key (Internal HMAC)

-     *

-     * @see Crypt_Hash::setAlgorithm()

-     * @var Integer

-     * @access private

-     */

-    var $b;

-

-    /**

-     * Byte-length of hash output (Internal HMAC)

-     *

-     * @see Crypt_Hash::setHash()

-     * @var Integer

-     * @access private

-     */

-    var $l = false;

-

-    /**

-     * Hash Algorithm

-     *

-     * @see Crypt_Hash::setHash()

-     * @var String

-     * @access private

-     */

-    var $hash;

-

-    /**

-     * Key

-     *

-     * @see Crypt_Hash::setKey()

-     * @var String

-     * @access private

-     */

-    var $key = '';

-

-    /**

-     * Outer XOR (Internal HMAC)

-     *

-     * @see Crypt_Hash::setKey()

-     * @var String

-     * @access private

-     */

-    var $opad;

-

-    /**

-     * Inner XOR (Internal HMAC)

-     *

-     * @see Crypt_Hash::setKey()

-     * @var String

-     * @access private

-     */

-    var $ipad;

-

-    /**

-     * Default Constructor.

-     *

-     * @param optional String $hash

-     * @return Crypt_Hash

-     * @access public

-     */

-    function Crypt_Hash($hash = 'sha1')

-    {

-        if ( !defined('CRYPT_HASH_MODE') ) {

-            switch (true) {

-                case extension_loaded('hash'):

-                    define('CRYPT_HASH_MODE', CRYPT_HASH_MODE_HASH);

-                    break;

-                case extension_loaded('mhash'):

-                    define('CRYPT_HASH_MODE', CRYPT_HASH_MODE_MHASH);

-                    break;

-                default:

-                    define('CRYPT_HASH_MODE', CRYPT_HASH_MODE_INTERNAL);

-            }

-        }

-

-        $this->setHash($hash);

-    }

-

-    /**

-     * Sets the key for HMACs

-     *

-     * Keys can be of any length.

-     *

-     * @access public

-     * @param String $key

-     */

-    function setKey($key)

-    {

-        $this->key = $key;

-    }

-

-    /**

-     * Sets the hash function.

-     *

-     * @access public

-     * @param String $hash

-     */

-    function setHash($hash)

-    {

-        switch ($hash) {

-            case 'md5-96':

-            case 'sha1-96':

-                $this->l = 12; // 96 / 8 = 12

-                break;

-            case 'md2':

-            case 'md5':

-                $this->l = 16;

-                break;

-            case 'sha1':

-                $this->l = 20;

-                break;

-            case 'sha256':

-                $this->l = 32;

-                break;

-            case 'sha384':

-                $this->l = 48;

-                break;

-            case 'sha512':

-                $this->l = 64;

-        }

-

-        switch ($hash) {

-            case 'md2':

-                $mode = CRYPT_HASH_MODE_INTERNAL;

-                break;

-            case 'sha384':

-            case 'sha512':

-                $mode = CRYPT_HASH_MODE == CRYPT_HASH_MODE_MHASH ? CRYPT_HASH_MODE_INTERNAL : CRYPT_HASH_MODE;

-                break;

-            default:

-                $mode = CRYPT_HASH_MODE;

-        }

-

-        switch ( $mode ) {

-            case CRYPT_HASH_MODE_MHASH:

-                switch ($hash) {

-                    case 'md5':

-                    case 'md5-96':

-                        $this->hash = MHASH_MD5;

-                        break;

-                    case 'sha256':

-                        $this->hash = MHASH_SHA256;

-                        break;

-                    case 'sha1':

-                    case 'sha1-96':

-                    default:

-                        $this->hash = MHASH_SHA1;

-                }

-                return;

-            case CRYPT_HASH_MODE_HASH:

-                switch ($hash) {

-                    case 'md5':

-                    case 'md5-96':

-                        $this->hash = 'md5';

-                        return;

-                    case 'sha256':

-                    case 'sha384':

-                    case 'sha512':

-                        $this->hash = $hash;

-                        return;

-                    case 'sha1':

-                    case 'sha1-96':

-                    default:

-                        $this->hash = 'sha1';

-                }

-                return;

-        }

-

-        switch ($hash) {

-            case 'md2':

-                 $this->b = 16;

-                 $this->hash = array($this, '_md2');

-                 break;

-            case 'md5':

-            case 'md5-96':

-                 $this->b = 64;

-                 $this->hash = array($this, '_md5');

-                 break;

-            case 'sha256':

-                 $this->b = 64;

-                 $this->hash = array($this, '_sha256');

-                 break;

-            case 'sha384':

-            case 'sha512':

-                 $this->b = 128;

-                 $this->hash = array($this, '_sha512');

-                 break;

-            case 'sha1':

-            case 'sha1-96':

-            default:

-                 $this->b = 64;

-                 $this->hash = array($this, '_sha1');

-        }

-

-        $this->ipad = str_repeat(chr(0x36), $this->b);

-        $this->opad = str_repeat(chr(0x5C), $this->b);

-    }

-

-    /**

-     * Compute the HMAC.

-     *

-     * @access public

-     * @param String $text

-     * @return String

-     */

-    function hash($text)

-    {

-        $mode = is_array($this->hash) ? CRYPT_HASH_MODE_INTERNAL : CRYPT_HASH_MODE;

-

-        if (!empty($this->key)) {

-            switch ( $mode ) {

-                case CRYPT_HASH_MODE_MHASH:

-                    $output = mhash($this->hash, $text, $this->key);

-                    break;

-                case CRYPT_HASH_MODE_HASH:

-                    $output = hash_hmac($this->hash, $text, $this->key, true);

-                    break;

-                case CRYPT_HASH_MODE_INTERNAL:

-                    /* "Applications that use keys longer than B bytes will first hash the key using H and then use the

-                        resultant L byte string as the actual key to HMAC."

-

-                        -- http://tools.ietf.org/html/rfc2104#section-2 */

-                    $key = strlen($this->key) > $this->b ? call_user_func($this->$hash, $this->key) : $this->key;

-

-                    $key    = str_pad($key, $this->b, chr(0));      // step 1

-                    $temp   = $this->ipad ^ $key;                   // step 2

-                    $temp  .= $text;                                // step 3

-                    $temp   = call_user_func($this->hash, $temp);   // step 4

-                    $output = $this->opad ^ $key;                   // step 5

-                    $output.= $temp;                                // step 6

-                    $output = call_user_func($this->hash, $output); // step 7

-            }

-        } else {

-            switch ( $mode ) {

-                case CRYPT_HASH_MODE_MHASH:

-                    $output = mhash($this->hash, $text);

-                    break;

-                case CRYPT_HASH_MODE_HASH:

-                    $output = hash($this->hash, $text, true);

-                    break;

-                case CRYPT_HASH_MODE_INTERNAL:

-                    $output = call_user_func($this->hash, $text);

-            }

-        }

-

-        return substr($output, 0, $this->l);

-    }

-

-    /**

-     * Returns the hash length (in bytes)

-     *

-     * @access private

-     * @return Integer

-     */

-    function getLength()

-    {

-        return $this->l;

-    }

-

-    /**

-     * Wrapper for MD5

-     *

-     * @access private

-     * @param String $text

-     */

-    function _md5($m)

-    {

-        return pack('H*', md5($m));

-    }

-

-    /**

-     * Wrapper for SHA1

-     *

-     * @access private

-     * @param String $text

-     */

-    function _sha1($m)

-    {

-        return pack('H*', sha1($m));

-    }

-

-    /**

-     * Pure-PHP implementation of MD2

-     *

-     * See {@link http://tools.ietf.org/html/rfc1319 RFC1319}.

-     *

-     * @access private

-     * @param String $text

-     */

-    function _md2($m)

-    {

-        static $s = array(

-             41,  46,  67, 201, 162, 216, 124,   1,  61,  54,  84, 161, 236, 240, 6,

-             19,  98, 167,   5, 243, 192, 199, 115, 140, 152, 147,  43, 217, 188,

-             76, 130, 202,  30, 155,  87,  60, 253, 212, 224,  22, 103,  66, 111, 24,

-            138,  23, 229,  18, 190,  78, 196, 214, 218, 158, 222,  73, 160, 251,

-            245, 142, 187,  47, 238, 122, 169, 104, 121, 145,  21, 178,   7,  63,

-            148, 194,  16, 137,  11,  34,  95,  33, 128, 127,  93, 154,  90, 144, 50,

-             39,  53,  62, 204, 231, 191, 247, 151,   3, 255,  25,  48, 179,  72, 165,

-            181, 209, 215,  94, 146,  42, 172,  86, 170, 198,  79, 184,  56, 210,

-            150, 164, 125, 182, 118, 252, 107, 226, 156, 116,   4, 241,  69, 157,

-            112,  89, 100, 113, 135,  32, 134,  91, 207, 101, 230,  45, 168,   2, 27,

-             96,  37, 173, 174, 176, 185, 246,  28,  70,  97, 105,  52,  64, 126, 15,

-             85,  71, 163,  35, 221,  81, 175,  58, 195,  92, 249, 206, 186, 197,

-            234,  38,  44,  83,  13, 110, 133,  40, 132,   9, 211, 223, 205, 244, 65,

-            129,  77,  82, 106, 220,  55, 200, 108, 193, 171, 250,  36, 225, 123,

-              8,  12, 189, 177,  74, 120, 136, 149, 139, 227,  99, 232, 109, 233,

-            203, 213, 254,  59,   0,  29,  57, 242, 239, 183,  14, 102,  88, 208, 228,

-            166, 119, 114, 248, 235, 117,  75,  10,  49,  68,  80, 180, 143, 237,

-             31,  26, 219, 153, 141,  51, 159,  17, 131, 20

-        );

-

-        // Step 1. Append Padding Bytes

-        $pad = 16 - (strlen($m) & 0xF);

-        $m.= str_repeat(chr($pad), $pad);

-

-        $length = strlen($m);

-

-        // Step 2. Append Checksum

-        $c = str_repeat(chr(0), 16);

-        $l = chr(0);

-        for ($i = 0; $i < $length; $i+= 16) {

-            for ($j = 0; $j < 16; $j++) {

-                $c[$j] = chr($s[ord($m[$i + $j] ^ $l)]);

-                $l = $c[$j];

-            }

-        }

-        $m.= $c;

-

-        $length+= 16;

-

-        // Step 3. Initialize MD Buffer

-        $x = str_repeat(chr(0), 48);

-

-        // Step 4. Process Message in 16-Byte Blocks

-        for ($i = 0; $i < $length; $i+= 16) {

-            for ($j = 0; $j < 16; $j++) {

-                $x[$j + 16] = $m[$i + $j];

-                $x[$j + 32] = $x[$j + 16] ^ $x[$j];

-            }

-            $t = chr(0);

-            for ($j = 0; $j < 18; $j++) {

-                for ($k = 0; $k < 48; $k++) {

-                    $x[$k] = $t = $x[$k] ^ chr($s[ord($t)]);

-                    //$t = $x[$k] = $x[$k] ^ chr($s[ord($t)]);

-                }

-                $t = chr(ord($t) + $j);

-            }

-        }

-

-        // Step 5. Output

-        return substr($x, 0, 16);

-    }

-

-    /**

-     * Pure-PHP implementation of SHA256

-     *

-     * See {@link http://en.wikipedia.org/wiki/SHA_hash_functions#SHA-256_.28a_SHA-2_variant.29_pseudocode SHA-256 (a SHA-2 variant) pseudocode - Wikipedia}.

-     *

-     * @access private

-     * @param String $text

-     */

-    function _sha256($m)

-    {

-        if (extension_loaded('suhosin')) {

-            return pack('H*', sha256($m));

-        }

-

-        // Initialize variables

-        $hash = array(

-            0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19

-        );

-        // Initialize table of round constants

-        // (first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311)

-        static $k = array(

-            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,

-            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,

-            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,

-            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,

-            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,

-            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,

-            0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,

-            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2

-        );

-

-        // Pre-processing

-        $length = strlen($m);

-        // to round to nearest 56 mod 64, we'll add 64 - (length + (64 - 56)) % 64

-        $m.= str_repeat(chr(0), 64 - (($length + 8) & 0x3F));

-        $m[$length] = chr(0x80);

-        // we don't support hashing strings 512MB long

-        $m.= pack('N2', 0, $length << 3);

-

-        // Process the message in successive 512-bit chunks

-        $chunks = str_split($m, 64);

-        foreach ($chunks as $chunk) {

-            $w = array();

-            for ($i = 0; $i < 16; $i++) {

-                extract(unpack('Ntemp', $this->_string_shift($chunk, 4)));

-                $w[] = $temp;

-            }

-

-            // Extend the sixteen 32-bit words into sixty-four 32-bit words

-            for ($i = 16; $i < 64; $i++) {

-                $s0 = $this->_rightRotate($w[$i - 15],  7) ^

-                      $this->_rightRotate($w[$i - 15], 18) ^

-                      $this->_rightShift( $w[$i - 15],  3);

-                $s1 = $this->_rightRotate($w[$i - 2], 17) ^

-                      $this->_rightRotate($w[$i - 2], 19) ^

-                      $this->_rightShift( $w[$i - 2], 10);

-                $w[$i] = $this->_add($w[$i - 16], $s0, $w[$i - 7], $s1);

-

-            }

-

-            // Initialize hash value for this chunk

-            list($a, $b, $c, $d, $e, $f, $g, $h) = $hash;

-

-            // Main loop

-            for ($i = 0; $i < 64; $i++) {

-                $s0 = $this->_rightRotate($a,  2) ^

-                      $this->_rightRotate($a, 13) ^

-                      $this->_rightRotate($a, 22);

-                $maj = ($a & $b) ^

-                       ($a & $c) ^

-                       ($b & $c);

-                $t2 = $this->_add($s0, $maj);

-

-                $s1 = $this->_rightRotate($e,  6) ^

-                      $this->_rightRotate($e, 11) ^

-                      $this->_rightRotate($e, 25);

-                $ch = ($e & $f) ^

-                      ($this->_not($e) & $g);

-                $t1 = $this->_add($h, $s1, $ch, $k[$i], $w[$i]);

-

-                $h = $g;

-                $g = $f;

-                $f = $e;

-                $e = $this->_add($d, $t1);

-                $d = $c;

-                $c = $b;

-                $b = $a;

-                $a = $this->_add($t1, $t2);

-            }

-

-            // Add this chunk's hash to result so far

-            $hash = array(

-                $this->_add($hash[0], $a),

-                $this->_add($hash[1], $b),

-                $this->_add($hash[2], $c),

-                $this->_add($hash[3], $d),

-                $this->_add($hash[4], $e),

-                $this->_add($hash[5], $f),

-                $this->_add($hash[6], $g),

-                $this->_add($hash[7], $h)

-            );

-        }

-

-        // Produce the final hash value (big-endian)

-        return pack('N8', $hash[0], $hash[1], $hash[2], $hash[3], $hash[4], $hash[5], $hash[6], $hash[7]);

-    }

-

-    /**

-     * Pure-PHP implementation of SHA384 and SHA512

-     *

-     * @access private

-     * @param String $text

-     */

-    function _sha512($m)

-    {

-        if (!class_exists('Math_BigInteger')) {

-            require_once('Math/BigInteger.php');

-        }

-

-        static $init384, $init512, $k;

-

-        if (!isset($k)) {

-            // Initialize variables

-            $init384 = array( // initial values for SHA384

-                'cbbb9d5dc1059ed8', '629a292a367cd507', '9159015a3070dd17', '152fecd8f70e5939', 

-                '67332667ffc00b31', '8eb44a8768581511', 'db0c2e0d64f98fa7', '47b5481dbefa4fa4'

-            );

-            $init512 = array( // initial values for SHA512

-                '6a09e667f3bcc908', 'bb67ae8584caa73b', '3c6ef372fe94f82b', 'a54ff53a5f1d36f1', 

-                '510e527fade682d1', '9b05688c2b3e6c1f', '1f83d9abfb41bd6b', '5be0cd19137e2179'

-            );

-

-            for ($i = 0; $i < 8; $i++) {

-                $init384[$i] = new Math_BigInteger($init384[$i], 16);

-                $init384[$i]->setPrecision(64);

-                $init512[$i] = new Math_BigInteger($init512[$i], 16);

-                $init512[$i]->setPrecision(64);

-            }

-

-            // Initialize table of round constants

-            // (first 64 bits of the fractional parts of the cube roots of the first 80 primes 2..409)

-            $k = array(

-                '428a2f98d728ae22', '7137449123ef65cd', 'b5c0fbcfec4d3b2f', 'e9b5dba58189dbbc',

-                '3956c25bf348b538', '59f111f1b605d019', '923f82a4af194f9b', 'ab1c5ed5da6d8118',

-                'd807aa98a3030242', '12835b0145706fbe', '243185be4ee4b28c', '550c7dc3d5ffb4e2',

-                '72be5d74f27b896f', '80deb1fe3b1696b1', '9bdc06a725c71235', 'c19bf174cf692694',

-                'e49b69c19ef14ad2', 'efbe4786384f25e3', '0fc19dc68b8cd5b5', '240ca1cc77ac9c65',

-                '2de92c6f592b0275', '4a7484aa6ea6e483', '5cb0a9dcbd41fbd4', '76f988da831153b5',

-                '983e5152ee66dfab', 'a831c66d2db43210', 'b00327c898fb213f', 'bf597fc7beef0ee4',

-                'c6e00bf33da88fc2', 'd5a79147930aa725', '06ca6351e003826f', '142929670a0e6e70',

-                '27b70a8546d22ffc', '2e1b21385c26c926', '4d2c6dfc5ac42aed', '53380d139d95b3df',

-                '650a73548baf63de', '766a0abb3c77b2a8', '81c2c92e47edaee6', '92722c851482353b',

-                'a2bfe8a14cf10364', 'a81a664bbc423001', 'c24b8b70d0f89791', 'c76c51a30654be30',

-                'd192e819d6ef5218', 'd69906245565a910', 'f40e35855771202a', '106aa07032bbd1b8',

-                '19a4c116b8d2d0c8', '1e376c085141ab53', '2748774cdf8eeb99', '34b0bcb5e19b48a8',

-                '391c0cb3c5c95a63', '4ed8aa4ae3418acb', '5b9cca4f7763e373', '682e6ff3d6b2b8a3',

-                '748f82ee5defb2fc', '78a5636f43172f60', '84c87814a1f0ab72', '8cc702081a6439ec',

-                '90befffa23631e28', 'a4506cebde82bde9', 'bef9a3f7b2c67915', 'c67178f2e372532b',

-                'ca273eceea26619c', 'd186b8c721c0c207', 'eada7dd6cde0eb1e', 'f57d4f7fee6ed178',

-                '06f067aa72176fba', '0a637dc5a2c898a6', '113f9804bef90dae', '1b710b35131c471b',

-                '28db77f523047d84', '32caab7b40c72493', '3c9ebe0a15c9bebc', '431d67c49c100d4c',

-                '4cc5d4becb3e42b6', '597f299cfc657e2a', '5fcb6fab3ad6faec', '6c44198c4a475817'

-            );

-

-            for ($i = 0; $i < 80; $i++) {

-                $k[$i] = new Math_BigInteger($k[$i], 16);

-            }

-        }

-

-        $hash = $this->l == 48 ? $init384 : $init512;

-

-        // Pre-processing

-        $length = strlen($m);

-        // to round to nearest 112 mod 128, we'll add 128 - (length + (128 - 112)) % 128

-        $m.= str_repeat(chr(0), 128 - (($length + 16) & 0x7F));

-        $m[$length] = chr(0x80);

-        // we don't support hashing strings 512MB long

-        $m.= pack('N4', 0, 0, 0, $length << 3);

-

-        // Process the message in successive 1024-bit chunks

-        $chunks = str_split($m, 128);

-        foreach ($chunks as $chunk) {

-            $w = array();

-            for ($i = 0; $i < 16; $i++) {

-                $temp = new Math_BigInteger($this->_string_shift($chunk, 8), 256);

-                $temp->setPrecision(64);

-                $w[] = $temp;

-            }

-

-            // Extend the sixteen 32-bit words into eighty 32-bit words

-            for ($i = 16; $i < 80; $i++) {

-                $temp = array(

-                          $w[$i - 15]->bitwise_rightRotate(1),

-                          $w[$i - 15]->bitwise_rightRotate(8),

-                          $w[$i - 15]->bitwise_rightShift(7)

-                );

-                $s0 = $temp[0]->bitwise_xor($temp[1]);

-                $s0 = $s0->bitwise_xor($temp[2]);

-                $temp = array(

-                          $w[$i - 2]->bitwise_rightRotate(19),

-                          $w[$i - 2]->bitwise_rightRotate(61),

-                          $w[$i - 2]->bitwise_rightShift(6)

-                );

-                $s1 = $temp[0]->bitwise_xor($temp[1]);

-                $s1 = $s1->bitwise_xor($temp[2]);

-                $w[$i] = $w[$i - 16]->copy();

-                $w[$i] = $w[$i]->add($s0);

-                $w[$i] = $w[$i]->add($w[$i - 7]);

-                $w[$i] = $w[$i]->add($s1);

-            }

-

-            // Initialize hash value for this chunk

-            $a = $hash[0]->copy();

-            $b = $hash[1]->copy();

-            $c = $hash[2]->copy();

-            $d = $hash[3]->copy();

-            $e = $hash[4]->copy();

-            $f = $hash[5]->copy();

-            $g = $hash[6]->copy();

-            $h = $hash[7]->copy();

-

-            // Main loop

-            for ($i = 0; $i < 80; $i++) {

-                $temp = array(

-                    $a->bitwise_rightRotate(28),

-                    $a->bitwise_rightRotate(34),

-                    $a->bitwise_rightRotate(39)

-                );

-                $s0 = $temp[0]->bitwise_xor($temp[1]);

-                $s0 = $s0->bitwise_xor($temp[2]);

-                $temp = array(

-                    $a->bitwise_and($b),

-                    $a->bitwise_and($c),

-                    $b->bitwise_and($c)

-                );

-                $maj = $temp[0]->bitwise_xor($temp[1]);

-                $maj = $maj->bitwise_xor($temp[2]);

-                $t2 = $s0->add($maj);

-

-                $temp = array(

-                    $e->bitwise_rightRotate(14),

-                    $e->bitwise_rightRotate(18),

-                    $e->bitwise_rightRotate(41)

-                );

-                $s1 = $temp[0]->bitwise_xor($temp[1]);

-                $s1 = $s1->bitwise_xor($temp[2]);

-                $temp = array(

-                    $e->bitwise_and($f),

-                    $g->bitwise_and($e->bitwise_not())

-                );

-                $ch = $temp[0]->bitwise_xor($temp[1]);

-                $t1 = $h->add($s1);

-                $t1 = $t1->add($ch);

-                $t1 = $t1->add($k[$i]);

-                $t1 = $t1->add($w[$i]);

-

-                $h = $g->copy();

-                $g = $f->copy();

-                $f = $e->copy();

-                $e = $d->add($t1);

-                $d = $c->copy();

-                $c = $b->copy();

-                $b = $a->copy();

-                $a = $t1->add($t2);

-            }

-

-            // Add this chunk's hash to result so far

-            $hash = array(

-                $hash[0]->add($a),

-                $hash[1]->add($b),

-                $hash[2]->add($c),

-                $hash[3]->add($d),

-                $hash[4]->add($e),

-                $hash[5]->add($f),

-                $hash[6]->add($g),

-                $hash[7]->add($h)

-            );

-        }

-

-        // Produce the final hash value (big-endian)

-        // (Crypt_Hash::hash() trims the output for hashes but not for HMACs.  as such, we trim the output here)

-        $temp = $hash[0]->toBytes() . $hash[1]->toBytes() . $hash[2]->toBytes() . $hash[3]->toBytes() .

-                $hash[4]->toBytes() . $hash[5]->toBytes();

-        if ($this->l != 48) {

-            $temp.= $hash[6]->toBytes() . $hash[7]->toBytes();

-        }

-

-        return $temp;

-    }

-

-    /**

-     * Right Rotate

-     *

-     * @access private

-     * @param Integer $int

-     * @param Integer $amt

-     * @see _sha256()

-     * @return Integer

-     */

-    function _rightRotate($int, $amt)

-    {

-        $invamt = 32 - $amt;

-        $mask = (1 << $invamt) - 1;

-        return (($int << $invamt) & 0xFFFFFFFF) | (($int >> $amt) & $mask);

-    }

-

-    /**

-     * Right Shift

-     *

-     * @access private

-     * @param Integer $int

-     * @param Integer $amt

-     * @see _sha256()

-     * @return Integer

-     */

-    function _rightShift($int, $amt)

-    {

-        $mask = (1 << (32 - $amt)) - 1;

-        return ($int >> $amt) & $mask;

-    }

-

-    /**

-     * Not

-     *

-     * @access private

-     * @param Integer $int

-     * @see _sha256()

-     * @return Integer

-     */

-    function _not($int)

-    {

-        return ~$int & 0xFFFFFFFF;

-    }

-

-    /**

-     * Add

-     *

-     * _sha256() adds multiple unsigned 32-bit integers.  Since PHP doesn't support unsigned integers and since the

-     * possibility of overflow exists, care has to be taken.  Math_BigInteger() could be used but this should be faster.

-     *

-     * @param String $string

-     * @param optional Integer $index

-     * @return String

-     * @see _sha256()

-     * @access private

-     */

-    function _add()

-    {

-        static $mod;

-        if (!isset($mod)) {

-            $mod = pow(2, 32);

-        }

-

-        $result = 0;

-        $arguments = func_get_args();

-        foreach ($arguments as $argument) {

-            $result+= $argument < 0 ? ($argument & 0x7FFFFFFF) + 0x80000000 : $argument;

-        }

-

-        return fmod($result, $mod);

-    }

-

-    /**

-     * String Shift

-     *

-     * Inspired by array_shift

-     *

-     * @param String $string

-     * @param optional Integer $index

-     * @return String

-     * @access private

-     */

-    function _string_shift(&$string, $index = 1)

-    {

-        $substr = substr($string, 0, $index);

-        $string = substr($string, $index);

-        return $substr;

-    }

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions.
+ *
+ * Uses hash() or mhash() if available and an internal implementation, otherwise.  Currently supports the following:
+ *
+ * md2, md5, md5-96, sha1, sha1-96, sha256, sha384, and sha512
+ *
+ * If {@link Crypt_Hash::setKey() setKey()} is called, {@link Crypt_Hash::hash() hash()} will return the HMAC as opposed to
+ * the hash.  If no valid algorithm is provided, sha1 will be used.
+ *
+ * PHP versions 4 and 5
+ *
+ * {@internal The variable names are the same as those in 
+ * {@link http://tools.ietf.org/html/rfc2104#section-2 RFC2104}.}}
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/Hash.php');
+ *
+ *    $hash = new Crypt_Hash('sha1');
+ *
+ *    $hash->setKey('abcdefg');
+ *
+ *    echo base64_encode($hash->hash('abcdefg'));
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_Hash
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: Hash.php,v 1.6 2009/11/23 23:37:07 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**#@+
+ * @access private
+ * @see Crypt_Hash::Crypt_Hash()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_HASH_MODE_INTERNAL', 1);
+/**
+ * Toggles the mhash() implementation, which has been deprecated on PHP 5.3.0+.
+ */
+define('CRYPT_HASH_MODE_MHASH',    2);
+/**
+ * Toggles the hash() implementation, which works on PHP 5.1.2+.
+ */
+define('CRYPT_HASH_MODE_HASH',     3);
+/**#@-*/
+
+/**
+ * Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_Hash
+ */
+class Crypt_Hash {
+    /**
+     * Byte-length of compression blocks / key (Internal HMAC)
+     *
+     * @see Crypt_Hash::setAlgorithm()
+     * @var Integer
+     * @access private
+     */
+    var $b;
+
+    /**
+     * Byte-length of hash output (Internal HMAC)
+     *
+     * @see Crypt_Hash::setHash()
+     * @var Integer
+     * @access private
+     */
+    var $l = false;
+
+    /**
+     * Hash Algorithm
+     *
+     * @see Crypt_Hash::setHash()
+     * @var String
+     * @access private
+     */
+    var $hash;
+
+    /**
+     * Key
+     *
+     * @see Crypt_Hash::setKey()
+     * @var String
+     * @access private
+     */
+    var $key = '';
+
+    /**
+     * Outer XOR (Internal HMAC)
+     *
+     * @see Crypt_Hash::setKey()
+     * @var String
+     * @access private
+     */
+    var $opad;
+
+    /**
+     * Inner XOR (Internal HMAC)
+     *
+     * @see Crypt_Hash::setKey()
+     * @var String
+     * @access private
+     */
+    var $ipad;
+
+    /**
+     * Default Constructor.
+     *
+     * @param optional String $hash
+     * @return Crypt_Hash
+     * @access public
+     */
+    function Crypt_Hash($hash = 'sha1')
+    {
+        if ( !defined('CRYPT_HASH_MODE') ) {
+            switch (true) {
+                case extension_loaded('hash'):
+                    define('CRYPT_HASH_MODE', CRYPT_HASH_MODE_HASH);
+                    break;
+                case extension_loaded('mhash'):
+                    define('CRYPT_HASH_MODE', CRYPT_HASH_MODE_MHASH);
+                    break;
+                default:
+                    define('CRYPT_HASH_MODE', CRYPT_HASH_MODE_INTERNAL);
+            }
+        }
+
+        $this->setHash($hash);
+    }
+
+    /**
+     * Sets the key for HMACs
+     *
+     * Keys can be of any length.
+     *
+     * @access public
+     * @param String $key
+     */
+    function setKey($key)
+    {
+        $this->key = $key;
+    }
+
+    /**
+     * Sets the hash function.
+     *
+     * @access public
+     * @param String $hash
+     */
+    function setHash($hash)
+    {
+        switch ($hash) {
+            case 'md5-96':
+            case 'sha1-96':
+                $this->l = 12; // 96 / 8 = 12
+                break;
+            case 'md2':
+            case 'md5':
+                $this->l = 16;
+                break;
+            case 'sha1':
+                $this->l = 20;
+                break;
+            case 'sha256':
+                $this->l = 32;
+                break;
+            case 'sha384':
+                $this->l = 48;
+                break;
+            case 'sha512':
+                $this->l = 64;
+        }
+
+        switch ($hash) {
+            case 'md2':
+                $mode = CRYPT_HASH_MODE_INTERNAL;
+                break;
+            case 'sha384':
+            case 'sha512':
+                $mode = CRYPT_HASH_MODE == CRYPT_HASH_MODE_MHASH ? CRYPT_HASH_MODE_INTERNAL : CRYPT_HASH_MODE;
+                break;
+            default:
+                $mode = CRYPT_HASH_MODE;
+        }
+
+        switch ( $mode ) {
+            case CRYPT_HASH_MODE_MHASH:
+                switch ($hash) {
+                    case 'md5':
+                    case 'md5-96':
+                        $this->hash = MHASH_MD5;
+                        break;
+                    case 'sha256':
+                        $this->hash = MHASH_SHA256;
+                        break;
+                    case 'sha1':
+                    case 'sha1-96':
+                    default:
+                        $this->hash = MHASH_SHA1;
+                }
+                return;
+            case CRYPT_HASH_MODE_HASH:
+                switch ($hash) {
+                    case 'md5':
+                    case 'md5-96':
+                        $this->hash = 'md5';
+                        return;
+                    case 'sha256':
+                    case 'sha384':
+                    case 'sha512':
+                        $this->hash = $hash;
+                        return;
+                    case 'sha1':
+                    case 'sha1-96':
+                    default:
+                        $this->hash = 'sha1';
+                }
+                return;
+        }
+
+        switch ($hash) {
+            case 'md2':
+                 $this->b = 16;
+                 $this->hash = array($this, '_md2');
+                 break;
+            case 'md5':
+            case 'md5-96':
+                 $this->b = 64;
+                 $this->hash = array($this, '_md5');
+                 break;
+            case 'sha256':
+                 $this->b = 64;
+                 $this->hash = array($this, '_sha256');
+                 break;
+            case 'sha384':
+            case 'sha512':
+                 $this->b = 128;
+                 $this->hash = array($this, '_sha512');
+                 break;
+            case 'sha1':
+            case 'sha1-96':
+            default:
+                 $this->b = 64;
+                 $this->hash = array($this, '_sha1');
+        }
+
+        $this->ipad = str_repeat(chr(0x36), $this->b);
+        $this->opad = str_repeat(chr(0x5C), $this->b);
+    }
+
+    /**
+     * Compute the HMAC.
+     *
+     * @access public
+     * @param String $text
+     * @return String
+     */
+    function hash($text)
+    {
+        $mode = is_array($this->hash) ? CRYPT_HASH_MODE_INTERNAL : CRYPT_HASH_MODE;
+
+        if (!empty($this->key)) {
+            switch ( $mode ) {
+                case CRYPT_HASH_MODE_MHASH:
+                    $output = mhash($this->hash, $text, $this->key);
+                    break;
+                case CRYPT_HASH_MODE_HASH:
+                    $output = hash_hmac($this->hash, $text, $this->key, true);
+                    break;
+                case CRYPT_HASH_MODE_INTERNAL:
+                    /* "Applications that use keys longer than B bytes will first hash the key using H and then use the
+                        resultant L byte string as the actual key to HMAC."
+
+                        -- http://tools.ietf.org/html/rfc2104#section-2 */
+                    $key = strlen($this->key) > $this->b ? call_user_func($this->$hash, $this->key) : $this->key;
+
+                    $key    = str_pad($key, $this->b, chr(0));      // step 1
+                    $temp   = $this->ipad ^ $key;                   // step 2
+                    $temp  .= $text;                                // step 3
+                    $temp   = call_user_func($this->hash, $temp);   // step 4
+                    $output = $this->opad ^ $key;                   // step 5
+                    $output.= $temp;                                // step 6
+                    $output = call_user_func($this->hash, $output); // step 7
+            }
+        } else {
+            switch ( $mode ) {
+                case CRYPT_HASH_MODE_MHASH:
+                    $output = mhash($this->hash, $text);
+                    break;
+                case CRYPT_HASH_MODE_HASH:
+                    $output = hash($this->hash, $text, true);
+                    break;
+                case CRYPT_HASH_MODE_INTERNAL:
+                    $output = call_user_func($this->hash, $text);
+            }
+        }
+
+        return substr($output, 0, $this->l);
+    }
+
+    /**
+     * Returns the hash length (in bytes)
+     *
+     * @access private
+     * @return Integer
+     */
+    function getLength()
+    {
+        return $this->l;
+    }
+
+    /**
+     * Wrapper for MD5
+     *
+     * @access private
+     * @param String $text
+     */
+    function _md5($m)
+    {
+        return pack('H*', md5($m));
+    }
+
+    /**
+     * Wrapper for SHA1
+     *
+     * @access private
+     * @param String $text
+     */
+    function _sha1($m)
+    {
+        return pack('H*', sha1($m));
+    }
+
+    /**
+     * Pure-PHP implementation of MD2
+     *
+     * See {@link http://tools.ietf.org/html/rfc1319 RFC1319}.
+     *
+     * @access private
+     * @param String $text
+     */
+    function _md2($m)
+    {
+        static $s = array(
+             41,  46,  67, 201, 162, 216, 124,   1,  61,  54,  84, 161, 236, 240, 6,
+             19,  98, 167,   5, 243, 192, 199, 115, 140, 152, 147,  43, 217, 188,
+             76, 130, 202,  30, 155,  87,  60, 253, 212, 224,  22, 103,  66, 111, 24,
+            138,  23, 229,  18, 190,  78, 196, 214, 218, 158, 222,  73, 160, 251,
+            245, 142, 187,  47, 238, 122, 169, 104, 121, 145,  21, 178,   7,  63,
+            148, 194,  16, 137,  11,  34,  95,  33, 128, 127,  93, 154,  90, 144, 50,
+             39,  53,  62, 204, 231, 191, 247, 151,   3, 255,  25,  48, 179,  72, 165,
+            181, 209, 215,  94, 146,  42, 172,  86, 170, 198,  79, 184,  56, 210,
+            150, 164, 125, 182, 118, 252, 107, 226, 156, 116,   4, 241,  69, 157,
+            112,  89, 100, 113, 135,  32, 134,  91, 207, 101, 230,  45, 168,   2, 27,
+             96,  37, 173, 174, 176, 185, 246,  28,  70,  97, 105,  52,  64, 126, 15,
+             85,  71, 163,  35, 221,  81, 175,  58, 195,  92, 249, 206, 186, 197,
+            234,  38,  44,  83,  13, 110, 133,  40, 132,   9, 211, 223, 205, 244, 65,
+            129,  77,  82, 106, 220,  55, 200, 108, 193, 171, 250,  36, 225, 123,
+              8,  12, 189, 177,  74, 120, 136, 149, 139, 227,  99, 232, 109, 233,
+            203, 213, 254,  59,   0,  29,  57, 242, 239, 183,  14, 102,  88, 208, 228,
+            166, 119, 114, 248, 235, 117,  75,  10,  49,  68,  80, 180, 143, 237,
+             31,  26, 219, 153, 141,  51, 159,  17, 131, 20
+        );
+
+        // Step 1. Append Padding Bytes
+        $pad = 16 - (strlen($m) & 0xF);
+        $m.= str_repeat(chr($pad), $pad);
+
+        $length = strlen($m);
+
+        // Step 2. Append Checksum
+        $c = str_repeat(chr(0), 16);
+        $l = chr(0);
+        for ($i = 0; $i < $length; $i+= 16) {
+            for ($j = 0; $j < 16; $j++) {
+                $c[$j] = chr($s[ord($m[$i + $j] ^ $l)]);
+                $l = $c[$j];
+            }
+        }
+        $m.= $c;
+
+        $length+= 16;
+
+        // Step 3. Initialize MD Buffer
+        $x = str_repeat(chr(0), 48);
+
+        // Step 4. Process Message in 16-Byte Blocks
+        for ($i = 0; $i < $length; $i+= 16) {
+            for ($j = 0; $j < 16; $j++) {
+                $x[$j + 16] = $m[$i + $j];
+                $x[$j + 32] = $x[$j + 16] ^ $x[$j];
+            }
+            $t = chr(0);
+            for ($j = 0; $j < 18; $j++) {
+                for ($k = 0; $k < 48; $k++) {
+                    $x[$k] = $t = $x[$k] ^ chr($s[ord($t)]);
+                    //$t = $x[$k] = $x[$k] ^ chr($s[ord($t)]);
+                }
+                $t = chr(ord($t) + $j);
+            }
+        }
+
+        // Step 5. Output
+        return substr($x, 0, 16);
+    }
+
+    /**
+     * Pure-PHP implementation of SHA256
+     *
+     * See {@link http://en.wikipedia.org/wiki/SHA_hash_functions#SHA-256_.28a_SHA-2_variant.29_pseudocode SHA-256 (a SHA-2 variant) pseudocode - Wikipedia}.
+     *
+     * @access private
+     * @param String $text
+     */
+    function _sha256($m)
+    {
+        if (extension_loaded('suhosin')) {
+            return pack('H*', sha256($m));
+        }
+
+        // Initialize variables
+        $hash = array(
+            0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
+        );
+        // Initialize table of round constants
+        // (first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311)
+        static $k = array(
+            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+            0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
+        );
+
+        // Pre-processing
+        $length = strlen($m);
+        // to round to nearest 56 mod 64, we'll add 64 - (length + (64 - 56)) % 64
+        $m.= str_repeat(chr(0), 64 - (($length + 8) & 0x3F));
+        $m[$length] = chr(0x80);
+        // we don't support hashing strings 512MB long
+        $m.= pack('N2', 0, $length << 3);
+
+        // Process the message in successive 512-bit chunks
+        $chunks = str_split($m, 64);
+        foreach ($chunks as $chunk) {
+            $w = array();
+            for ($i = 0; $i < 16; $i++) {
+                extract(unpack('Ntemp', $this->_string_shift($chunk, 4)));
+                $w[] = $temp;
+            }
+
+            // Extend the sixteen 32-bit words into sixty-four 32-bit words
+            for ($i = 16; $i < 64; $i++) {
+                $s0 = $this->_rightRotate($w[$i - 15],  7) ^
+                      $this->_rightRotate($w[$i - 15], 18) ^
+                      $this->_rightShift( $w[$i - 15],  3);
+                $s1 = $this->_rightRotate($w[$i - 2], 17) ^
+                      $this->_rightRotate($w[$i - 2], 19) ^
+                      $this->_rightShift( $w[$i - 2], 10);
+                $w[$i] = $this->_add($w[$i - 16], $s0, $w[$i - 7], $s1);
+
+            }
+
+            // Initialize hash value for this chunk
+            list($a, $b, $c, $d, $e, $f, $g, $h) = $hash;
+
+            // Main loop
+            for ($i = 0; $i < 64; $i++) {
+                $s0 = $this->_rightRotate($a,  2) ^
+                      $this->_rightRotate($a, 13) ^
+                      $this->_rightRotate($a, 22);
+                $maj = ($a & $b) ^
+                       ($a & $c) ^
+                       ($b & $c);
+                $t2 = $this->_add($s0, $maj);
+
+                $s1 = $this->_rightRotate($e,  6) ^
+                      $this->_rightRotate($e, 11) ^
+                      $this->_rightRotate($e, 25);
+                $ch = ($e & $f) ^
+                      ($this->_not($e) & $g);
+                $t1 = $this->_add($h, $s1, $ch, $k[$i], $w[$i]);
+
+                $h = $g;
+                $g = $f;
+                $f = $e;
+                $e = $this->_add($d, $t1);
+                $d = $c;
+                $c = $b;
+                $b = $a;
+                $a = $this->_add($t1, $t2);
+            }
+
+            // Add this chunk's hash to result so far
+            $hash = array(
+                $this->_add($hash[0], $a),
+                $this->_add($hash[1], $b),
+                $this->_add($hash[2], $c),
+                $this->_add($hash[3], $d),
+                $this->_add($hash[4], $e),
+                $this->_add($hash[5], $f),
+                $this->_add($hash[6], $g),
+                $this->_add($hash[7], $h)
+            );
+        }
+
+        // Produce the final hash value (big-endian)
+        return pack('N8', $hash[0], $hash[1], $hash[2], $hash[3], $hash[4], $hash[5], $hash[6], $hash[7]);
+    }
+
+    /**
+     * Pure-PHP implementation of SHA384 and SHA512
+     *
+     * @access private
+     * @param String $text
+     */
+    function _sha512($m)
+    {
+        if (!class_exists('Math_BigInteger')) {
+            require_once('Math/BigInteger.php');
+        }
+
+        static $init384, $init512, $k;
+
+        if (!isset($k)) {
+            // Initialize variables
+            $init384 = array( // initial values for SHA384
+                'cbbb9d5dc1059ed8', '629a292a367cd507', '9159015a3070dd17', '152fecd8f70e5939', 
+                '67332667ffc00b31', '8eb44a8768581511', 'db0c2e0d64f98fa7', '47b5481dbefa4fa4'
+            );
+            $init512 = array( // initial values for SHA512
+                '6a09e667f3bcc908', 'bb67ae8584caa73b', '3c6ef372fe94f82b', 'a54ff53a5f1d36f1', 
+                '510e527fade682d1', '9b05688c2b3e6c1f', '1f83d9abfb41bd6b', '5be0cd19137e2179'
+            );
+
+            for ($i = 0; $i < 8; $i++) {
+                $init384[$i] = new Math_BigInteger($init384[$i], 16);
+                $init384[$i]->setPrecision(64);
+                $init512[$i] = new Math_BigInteger($init512[$i], 16);
+                $init512[$i]->setPrecision(64);
+            }
+
+            // Initialize table of round constants
+            // (first 64 bits of the fractional parts of the cube roots of the first 80 primes 2..409)
+            $k = array(
+                '428a2f98d728ae22', '7137449123ef65cd', 'b5c0fbcfec4d3b2f', 'e9b5dba58189dbbc',
+                '3956c25bf348b538', '59f111f1b605d019', '923f82a4af194f9b', 'ab1c5ed5da6d8118',
+                'd807aa98a3030242', '12835b0145706fbe', '243185be4ee4b28c', '550c7dc3d5ffb4e2',
+                '72be5d74f27b896f', '80deb1fe3b1696b1', '9bdc06a725c71235', 'c19bf174cf692694',
+                'e49b69c19ef14ad2', 'efbe4786384f25e3', '0fc19dc68b8cd5b5', '240ca1cc77ac9c65',
+                '2de92c6f592b0275', '4a7484aa6ea6e483', '5cb0a9dcbd41fbd4', '76f988da831153b5',
+                '983e5152ee66dfab', 'a831c66d2db43210', 'b00327c898fb213f', 'bf597fc7beef0ee4',
+                'c6e00bf33da88fc2', 'd5a79147930aa725', '06ca6351e003826f', '142929670a0e6e70',
+                '27b70a8546d22ffc', '2e1b21385c26c926', '4d2c6dfc5ac42aed', '53380d139d95b3df',
+                '650a73548baf63de', '766a0abb3c77b2a8', '81c2c92e47edaee6', '92722c851482353b',
+                'a2bfe8a14cf10364', 'a81a664bbc423001', 'c24b8b70d0f89791', 'c76c51a30654be30',
+                'd192e819d6ef5218', 'd69906245565a910', 'f40e35855771202a', '106aa07032bbd1b8',
+                '19a4c116b8d2d0c8', '1e376c085141ab53', '2748774cdf8eeb99', '34b0bcb5e19b48a8',
+                '391c0cb3c5c95a63', '4ed8aa4ae3418acb', '5b9cca4f7763e373', '682e6ff3d6b2b8a3',
+                '748f82ee5defb2fc', '78a5636f43172f60', '84c87814a1f0ab72', '8cc702081a6439ec',
+                '90befffa23631e28', 'a4506cebde82bde9', 'bef9a3f7b2c67915', 'c67178f2e372532b',
+                'ca273eceea26619c', 'd186b8c721c0c207', 'eada7dd6cde0eb1e', 'f57d4f7fee6ed178',
+                '06f067aa72176fba', '0a637dc5a2c898a6', '113f9804bef90dae', '1b710b35131c471b',
+                '28db77f523047d84', '32caab7b40c72493', '3c9ebe0a15c9bebc', '431d67c49c100d4c',
+                '4cc5d4becb3e42b6', '597f299cfc657e2a', '5fcb6fab3ad6faec', '6c44198c4a475817'
+            );
+
+            for ($i = 0; $i < 80; $i++) {
+                $k[$i] = new Math_BigInteger($k[$i], 16);
+            }
+        }
+
+        $hash = $this->l == 48 ? $init384 : $init512;
+
+        // Pre-processing
+        $length = strlen($m);
+        // to round to nearest 112 mod 128, we'll add 128 - (length + (128 - 112)) % 128
+        $m.= str_repeat(chr(0), 128 - (($length + 16) & 0x7F));
+        $m[$length] = chr(0x80);
+        // we don't support hashing strings 512MB long
+        $m.= pack('N4', 0, 0, 0, $length << 3);
+
+        // Process the message in successive 1024-bit chunks
+        $chunks = str_split($m, 128);
+        foreach ($chunks as $chunk) {
+            $w = array();
+            for ($i = 0; $i < 16; $i++) {
+                $temp = new Math_BigInteger($this->_string_shift($chunk, 8), 256);
+                $temp->setPrecision(64);
+                $w[] = $temp;
+            }
+
+            // Extend the sixteen 32-bit words into eighty 32-bit words
+            for ($i = 16; $i < 80; $i++) {
+                $temp = array(
+                          $w[$i - 15]->bitwise_rightRotate(1),
+                          $w[$i - 15]->bitwise_rightRotate(8),
+                          $w[$i - 15]->bitwise_rightShift(7)
+                );
+                $s0 = $temp[0]->bitwise_xor($temp[1]);
+                $s0 = $s0->bitwise_xor($temp[2]);
+                $temp = array(
+                          $w[$i - 2]->bitwise_rightRotate(19),
+                          $w[$i - 2]->bitwise_rightRotate(61),
+                          $w[$i - 2]->bitwise_rightShift(6)
+                );
+                $s1 = $temp[0]->bitwise_xor($temp[1]);
+                $s1 = $s1->bitwise_xor($temp[2]);
+                $w[$i] = $w[$i - 16]->copy();
+                $w[$i] = $w[$i]->add($s0);
+                $w[$i] = $w[$i]->add($w[$i - 7]);
+                $w[$i] = $w[$i]->add($s1);
+            }
+
+            // Initialize hash value for this chunk
+            $a = $hash[0]->copy();
+            $b = $hash[1]->copy();
+            $c = $hash[2]->copy();
+            $d = $hash[3]->copy();
+            $e = $hash[4]->copy();
+            $f = $hash[5]->copy();
+            $g = $hash[6]->copy();
+            $h = $hash[7]->copy();
+
+            // Main loop
+            for ($i = 0; $i < 80; $i++) {
+                $temp = array(
+                    $a->bitwise_rightRotate(28),
+                    $a->bitwise_rightRotate(34),
+                    $a->bitwise_rightRotate(39)
+                );
+                $s0 = $temp[0]->bitwise_xor($temp[1]);
+                $s0 = $s0->bitwise_xor($temp[2]);
+                $temp = array(
+                    $a->bitwise_and($b),
+                    $a->bitwise_and($c),
+                    $b->bitwise_and($c)
+                );
+                $maj = $temp[0]->bitwise_xor($temp[1]);
+                $maj = $maj->bitwise_xor($temp[2]);
+                $t2 = $s0->add($maj);
+
+                $temp = array(
+                    $e->bitwise_rightRotate(14),
+                    $e->bitwise_rightRotate(18),
+                    $e->bitwise_rightRotate(41)
+                );
+                $s1 = $temp[0]->bitwise_xor($temp[1]);
+                $s1 = $s1->bitwise_xor($temp[2]);
+                $temp = array(
+                    $e->bitwise_and($f),
+                    $g->bitwise_and($e->bitwise_not())
+                );
+                $ch = $temp[0]->bitwise_xor($temp[1]);
+                $t1 = $h->add($s1);
+                $t1 = $t1->add($ch);
+                $t1 = $t1->add($k[$i]);
+                $t1 = $t1->add($w[$i]);
+
+                $h = $g->copy();
+                $g = $f->copy();
+                $f = $e->copy();
+                $e = $d->add($t1);
+                $d = $c->copy();
+                $c = $b->copy();
+                $b = $a->copy();
+                $a = $t1->add($t2);
+            }
+
+            // Add this chunk's hash to result so far
+            $hash = array(
+                $hash[0]->add($a),
+                $hash[1]->add($b),
+                $hash[2]->add($c),
+                $hash[3]->add($d),
+                $hash[4]->add($e),
+                $hash[5]->add($f),
+                $hash[6]->add($g),
+                $hash[7]->add($h)
+            );
+        }
+
+        // Produce the final hash value (big-endian)
+        // (Crypt_Hash::hash() trims the output for hashes but not for HMACs.  as such, we trim the output here)
+        $temp = $hash[0]->toBytes() . $hash[1]->toBytes() . $hash[2]->toBytes() . $hash[3]->toBytes() .
+                $hash[4]->toBytes() . $hash[5]->toBytes();
+        if ($this->l != 48) {
+            $temp.= $hash[6]->toBytes() . $hash[7]->toBytes();
+        }
+
+        return $temp;
+    }
+
+    /**
+     * Right Rotate
+     *
+     * @access private
+     * @param Integer $int
+     * @param Integer $amt
+     * @see _sha256()
+     * @return Integer
+     */
+    function _rightRotate($int, $amt)
+    {
+        $invamt = 32 - $amt;
+        $mask = (1 << $invamt) - 1;
+        return (($int << $invamt) & 0xFFFFFFFF) | (($int >> $amt) & $mask);
+    }
+
+    /**
+     * Right Shift
+     *
+     * @access private
+     * @param Integer $int
+     * @param Integer $amt
+     * @see _sha256()
+     * @return Integer
+     */
+    function _rightShift($int, $amt)
+    {
+        $mask = (1 << (32 - $amt)) - 1;
+        return ($int >> $amt) & $mask;
+    }
+
+    /**
+     * Not
+     *
+     * @access private
+     * @param Integer $int
+     * @see _sha256()
+     * @return Integer
+     */
+    function _not($int)
+    {
+        return ~$int & 0xFFFFFFFF;
+    }
+
+    /**
+     * Add
+     *
+     * _sha256() adds multiple unsigned 32-bit integers.  Since PHP doesn't support unsigned integers and since the
+     * possibility of overflow exists, care has to be taken.  Math_BigInteger() could be used but this should be faster.
+     *
+     * @param String $string
+     * @param optional Integer $index
+     * @return String
+     * @see _sha256()
+     * @access private
+     */
+    function _add()
+    {
+        static $mod;
+        if (!isset($mod)) {
+            $mod = pow(2, 32);
+        }
+
+        $result = 0;
+        $arguments = func_get_args();
+        foreach ($arguments as $argument) {
+            $result+= $argument < 0 ? ($argument & 0x7FFFFFFF) + 0x80000000 : $argument;
+        }
+
+        return fmod($result, $mod);
+    }
+
+    /**
+     * String Shift
+     *
+     * Inspired by array_shift
+     *
+     * @param String $string
+     * @param optional Integer $index
+     * @return String
+     * @access private
+     */
+    function _string_shift(&$string, $index = 1)
+    {
+        $substr = substr($string, 0, $index);
+        $string = substr($string, $index);
+        return $substr;
+    }
 }
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/RC4.php b/plugins/OStatus/extlib/Crypt/RC4.php
index 6f82b2413..1e4d8b489 100644
--- a/plugins/OStatus/extlib/Crypt/RC4.php
+++ b/plugins/OStatus/extlib/Crypt/RC4.php
@@ -1,493 +1,493 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP implementation of RC4.

- *

- * Uses mcrypt, if available, and an internal implementation, otherwise.

- *

- * PHP versions 4 and 5

- *

- * Useful resources are as follows:

- *

- *  - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}

- *  - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}

- *

- * RC4 is also known as ARCFOUR or ARC4.  The reason is elaborated upon at Wikipedia.  This class is named RC4 and not

- * ARCFOUR or ARC4 because RC4 is how it is refered to in the SSH1 specification.

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/RC4.php');

- *

- *    $rc4 = new Crypt_RC4();

- *

- *    $rc4->setKey('abcdefgh');

- *

- *    $size = 10 * 1024;

- *    $plaintext = '';

- *    for ($i = 0; $i < $size; $i++) {

- *        $plaintext.= 'a';

- *    }

- *

- *    echo $rc4->decrypt($rc4->encrypt($plaintext));

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_RC4

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: RC4.php,v 1.8 2009/06/09 04:00:38 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**#@+

- * @access private

- * @see Crypt_RC4::Crypt_RC4()

- */

-/**

- * Toggles the internal implementation

- */

-define('CRYPT_RC4_MODE_INTERNAL', 1);

-/**

- * Toggles the mcrypt implementation

- */

-define('CRYPT_RC4_MODE_MCRYPT', 2);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Crypt_RC4::_crypt()

- */

-define('CRYPT_RC4_ENCRYPT', 0);

-define('CRYPT_RC4_DECRYPT', 1);

-/**#@-*/

-

-/**

- * Pure-PHP implementation of RC4.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_RC4

- */

-class Crypt_RC4 {

-    /**

-     * The Key

-     *

-     * @see Crypt_RC4::setKey()

-     * @var String

-     * @access private

-     */

-    var $key = "\0";

-

-    /**

-     * The Key Stream for encryption

-     *

-     * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object

-     *

-     * @see Crypt_RC4::setKey()

-     * @var Array

-     * @access private

-     */

-    var $encryptStream = false;

-

-    /**

-     * The Key Stream for decryption

-     *

-     * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object

-     *

-     * @see Crypt_RC4::setKey()

-     * @var Array

-     * @access private

-     */

-    var $decryptStream = false;

-

-    /**

-     * The $i and $j indexes for encryption

-     *

-     * @see Crypt_RC4::_crypt()

-     * @var Integer

-     * @access private

-     */

-    var $encryptIndex = 0;

-

-    /**

-     * The $i and $j indexes for decryption

-     *

-     * @see Crypt_RC4::_crypt()

-     * @var Integer

-     * @access private

-     */

-    var $decryptIndex = 0;

-

-    /**

-     * MCrypt parameters

-     *

-     * @see Crypt_RC4::setMCrypt()

-     * @var Array

-     * @access private

-     */

-    var $mcrypt = array('', '');

-

-    /**

-     * The Encryption Algorithm

-     *

-     * Only used if CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT.  Only possible values are MCRYPT_RC4 or MCRYPT_ARCFOUR.

-     *

-     * @see Crypt_RC4::Crypt_RC4()

-     * @var Integer

-     * @access private

-     */

-    var $mode;

-

-    /**

-     * Default Constructor.

-     *

-     * Determines whether or not the mcrypt extension should be used.

-     *

-     * @param optional Integer $mode

-     * @return Crypt_RC4

-     * @access public

-     */

-    function Crypt_RC4()

-    {

-        if ( !defined('CRYPT_RC4_MODE') ) {

-            switch (true) {

-                case extension_loaded('mcrypt') && (defined('MCRYPT_ARCFOUR') || defined('MCRYPT_RC4')):

-                    // i'd check to see if rc4 was supported, by doing in_array('arcfour', mcrypt_list_algorithms('')),

-                    // but since that can be changed after the object has been created, there doesn't seem to be

-                    // a lot of point...

-                    define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_MCRYPT);

-                    break;

-                default:

-                    define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL);

-            }

-        }

-

-        switch ( CRYPT_RC4_MODE ) {

-            case CRYPT_RC4_MODE_MCRYPT:

-                switch (true) {

-                    case defined('MCRYPT_ARCFOUR'):

-                        $this->mode = MCRYPT_ARCFOUR;

-                        break;

-                    case defined('MCRYPT_RC4');

-                        $this->mode = MCRYPT_RC4;

-                }

-        }

-    }

-

-    /**

-     * Sets the key.

-     *

-     * Keys can be between 1 and 256 bytes long.  If they are longer then 256 bytes, the first 256 bytes will

-     * be used.  If no key is explicitly set, it'll be assumed to be a single null byte.

-     *

-     * @access public

-     * @param String $key

-     */

-    function setKey($key)

-    {

-        $this->key = $key;

-

-        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {

-            return;

-        }

-

-        $keyLength = strlen($key);

-        $keyStream = array();

-        for ($i = 0; $i < 256; $i++) {

-            $keyStream[$i] = $i;

-        }

-        $j = 0;

-        for ($i = 0; $i < 256; $i++) {

-            $j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;

-            $temp = $keyStream[$i];

-            $keyStream[$i] = $keyStream[$j];

-            $keyStream[$j] = $temp;

-        }

-

-        $this->encryptIndex = $this->decryptIndex = array(0, 0);

-        $this->encryptStream = $this->decryptStream = $keyStream;

-    }

-

-    /**

-     * Dummy function.

-     *

-     * Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1].

-     * If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before

-     * calling setKey().

-     *

-     * [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way.  Since, in that protocol,

-     * the IV's are relatively easy to predict, an attack described by

-     * {@link http://www.drizzle.com/~aboba/IEEE/rc4_ksaproc.pdf Scott Fluhrer, Itsik Mantin, and Adi Shamir}

-     * can be used to quickly guess at the rest of the key.  The following links elaborate:

-     *

-     * {@link http://www.rsa.com/rsalabs/node.asp?id=2009 http://www.rsa.com/rsalabs/node.asp?id=2009}

-     * {@link http://en.wikipedia.org/wiki/Related_key_attack http://en.wikipedia.org/wiki/Related_key_attack}

-     *

-     * @param String $iv

-     * @see Crypt_RC4::setKey()

-     * @access public

-     */

-    function setIV($iv)

-    {

-    }

-

-    /**

-     * Sets MCrypt parameters. (optional)

-     *

-     * If MCrypt is being used, empty strings will be used, unless otherwise specified.

-     *

-     * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open

-     * @access public

-     * @param optional Integer $algorithm_directory

-     * @param optional Integer $mode_directory

-     */

-    function setMCrypt($algorithm_directory = '', $mode_directory = '')

-    {

-        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {

-            $this->mcrypt = array($algorithm_directory, $mode_directory);

-            $this->_closeMCrypt();

-        }

-    }

-

-    /**

-     * Encrypts a message.

-     *

-     * @see Crypt_RC4::_crypt()

-     * @access public

-     * @param String $plaintext

-     */

-    function encrypt($plaintext)

-    {

-        return $this->_crypt($plaintext, CRYPT_RC4_ENCRYPT);

-    }

-

-    /**

-     * Decrypts a message.

-     *

-     * $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).

-     * Atleast if the continuous buffer is disabled.

-     *

-     * @see Crypt_RC4::_crypt()

-     * @access public

-     * @param String $ciphertext

-     */

-    function decrypt($ciphertext)

-    {

-        return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT);

-    }

-

-    /**

-     * Encrypts or decrypts a message.

-     *

-     * @see Crypt_RC4::encrypt()

-     * @see Crypt_RC4::decrypt()

-     * @access private

-     * @param String $text

-     * @param Integer $mode

-     */

-    function _crypt($text, $mode)

-    {

-        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {

-            $keyStream = $mode == CRYPT_RC4_ENCRYPT ? 'encryptStream' : 'decryptStream';

-

-            if ($this->$keyStream === false) {

-                $this->$keyStream = mcrypt_module_open($this->mode, $this->mcrypt[0], MCRYPT_MODE_STREAM, $this->mcrypt[1]);

-                mcrypt_generic_init($this->$keyStream, $this->key, '');

-            } else if (!$this->continuousBuffer) {

-                mcrypt_generic_init($this->$keyStream, $this->key, '');

-            }

-            $newText = mcrypt_generic($this->$keyStream, $text);

-            if (!$this->continuousBuffer) {

-                mcrypt_generic_deinit($this->$keyStream);

-            }

-

-            return $newText;

-        }

-

-        if ($this->encryptStream === false) {

-            $this->setKey($this->key);

-        }

-

-        switch ($mode) {

-            case CRYPT_RC4_ENCRYPT:

-                $keyStream = $this->encryptStream;

-                list($i, $j) = $this->encryptIndex;

-                break;

-            case CRYPT_RC4_DECRYPT:

-                $keyStream = $this->decryptStream;

-                list($i, $j) = $this->decryptIndex;

-        }

-

-        $newText = '';

-        for ($k = 0; $k < strlen($text); $k++) {

-            $i = ($i + 1) & 255;

-            $j = ($j + $keyStream[$i]) & 255;

-            $temp = $keyStream[$i];

-            $keyStream[$i] = $keyStream[$j];

-            $keyStream[$j] = $temp;

-            $temp = $keyStream[($keyStream[$i] + $keyStream[$j]) & 255];

-            $newText.= chr(ord($text[$k]) ^ $temp);

-        }

-

-        if ($this->continuousBuffer) {

-            switch ($mode) {

-                case CRYPT_RC4_ENCRYPT:

-                    $this->encryptStream = $keyStream;

-                    $this->encryptIndex = array($i, $j);

-                    break;

-                case CRYPT_RC4_DECRYPT:

-                    $this->decryptStream = $keyStream;

-                    $this->decryptIndex = array($i, $j);

-            }

-        }

-

-        return $newText;

-    }

-

-    /**

-     * Treat consecutive "packets" as if they are a continuous buffer.

-     *

-     * Say you have a 16-byte plaintext $plaintext.  Using the default behavior, the two following code snippets

-     * will yield different outputs:

-     *

-     * <code>

-     *    echo $rc4->encrypt(substr($plaintext, 0, 8));

-     *    echo $rc4->encrypt(substr($plaintext, 8, 8));

-     * </code>

-     * <code>

-     *    echo $rc4->encrypt($plaintext);

-     * </code>

-     *

-     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates

-     * another, as demonstrated with the following:

-     *

-     * <code>

-     *    $rc4->encrypt(substr($plaintext, 0, 8));

-     *    echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));

-     * </code>

-     * <code>

-     *    echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));

-     * </code>

-     *

-     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different

-     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /

-     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.

-     *

-     * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each

-     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that

-     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),

-     * however, they are also less intuitive and more likely to cause you problems.

-     *

-     * @see Crypt_RC4::disableContinuousBuffer()

-     * @access public

-     */

-    function enableContinuousBuffer()

-    {

-        $this->continuousBuffer = true;

-    }

-

-    /**

-     * Treat consecutive packets as if they are a discontinuous buffer.

-     *

-     * The default behavior.

-     *

-     * @see Crypt_RC4::enableContinuousBuffer()

-     * @access public

-     */

-    function disableContinuousBuffer()

-    {

-        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_INTERNAL ) {

-            $this->encryptIndex = $this->decryptIndex = array(0, 0);

-            $this->setKey($this->key);

-        }

-

-        $this->continuousBuffer = false;

-    }

-

-    /**

-     * Dummy function.

-     *

-     * Since RC4 is a stream cipher and not a block cipher, no padding is necessary.  The only reason this function is

-     * included is so that you can switch between a block cipher and a stream cipher transparently.

-     *

-     * @see Crypt_RC4::disablePadding()

-     * @access public

-     */

-    function enablePadding()

-    {

-    }

-

-    /**

-     * Dummy function.

-     *

-     * @see Crypt_RC4::enablePadding()

-     * @access public

-     */

-    function disablePadding()

-    {

-    }

-

-    /**

-     * Class destructor.

-     *

-     * Will be called, automatically, if you're using PHP5.  If you're using PHP4, call it yourself.  Only really

-     * needs to be called if mcrypt is being used.

-     *

-     * @access public

-     */

-    function __destruct()

-    {

-        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {

-            $this->_closeMCrypt();

-        }

-    }

-

-    /**

-     * Properly close the MCrypt objects.

-     *

-     * @access prviate

-     */

-    function _closeMCrypt()

-    {

-        if ( $this->encryptStream !== false ) {

-            if ( $this->continuousBuffer ) {

-                mcrypt_generic_deinit($this->encryptStream);

-            }

-

-            mcrypt_module_close($this->encryptStream);

-

-            $this->encryptStream = false;

-        }

-

-        if ( $this->decryptStream !== false ) {

-            if ( $this->continuousBuffer ) {

-                mcrypt_generic_deinit($this->decryptStream);

-            }

-

-            mcrypt_module_close($this->decryptStream);

-

-            $this->decryptStream = false;

-        }

-    }

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementation of RC4.
+ *
+ * Uses mcrypt, if available, and an internal implementation, otherwise.
+ *
+ * PHP versions 4 and 5
+ *
+ * Useful resources are as follows:
+ *
+ *  - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}
+ *  - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}
+ *
+ * RC4 is also known as ARCFOUR or ARC4.  The reason is elaborated upon at Wikipedia.  This class is named RC4 and not
+ * ARCFOUR or ARC4 because RC4 is how it is refered to in the SSH1 specification.
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/RC4.php');
+ *
+ *    $rc4 = new Crypt_RC4();
+ *
+ *    $rc4->setKey('abcdefgh');
+ *
+ *    $size = 10 * 1024;
+ *    $plaintext = '';
+ *    for ($i = 0; $i < $size; $i++) {
+ *        $plaintext.= 'a';
+ *    }
+ *
+ *    echo $rc4->decrypt($rc4->encrypt($plaintext));
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_RC4
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: RC4.php,v 1.8 2009/06/09 04:00:38 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**#@+
+ * @access private
+ * @see Crypt_RC4::Crypt_RC4()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_RC4_MODE_INTERNAL', 1);
+/**
+ * Toggles the mcrypt implementation
+ */
+define('CRYPT_RC4_MODE_MCRYPT', 2);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_RC4::_crypt()
+ */
+define('CRYPT_RC4_ENCRYPT', 0);
+define('CRYPT_RC4_DECRYPT', 1);
+/**#@-*/
+
+/**
+ * Pure-PHP implementation of RC4.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_RC4
+ */
+class Crypt_RC4 {
+    /**
+     * The Key
+     *
+     * @see Crypt_RC4::setKey()
+     * @var String
+     * @access private
+     */
+    var $key = "\0";
+
+    /**
+     * The Key Stream for encryption
+     *
+     * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object
+     *
+     * @see Crypt_RC4::setKey()
+     * @var Array
+     * @access private
+     */
+    var $encryptStream = false;
+
+    /**
+     * The Key Stream for decryption
+     *
+     * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object
+     *
+     * @see Crypt_RC4::setKey()
+     * @var Array
+     * @access private
+     */
+    var $decryptStream = false;
+
+    /**
+     * The $i and $j indexes for encryption
+     *
+     * @see Crypt_RC4::_crypt()
+     * @var Integer
+     * @access private
+     */
+    var $encryptIndex = 0;
+
+    /**
+     * The $i and $j indexes for decryption
+     *
+     * @see Crypt_RC4::_crypt()
+     * @var Integer
+     * @access private
+     */
+    var $decryptIndex = 0;
+
+    /**
+     * MCrypt parameters
+     *
+     * @see Crypt_RC4::setMCrypt()
+     * @var Array
+     * @access private
+     */
+    var $mcrypt = array('', '');
+
+    /**
+     * The Encryption Algorithm
+     *
+     * Only used if CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT.  Only possible values are MCRYPT_RC4 or MCRYPT_ARCFOUR.
+     *
+     * @see Crypt_RC4::Crypt_RC4()
+     * @var Integer
+     * @access private
+     */
+    var $mode;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.
+     *
+     * @param optional Integer $mode
+     * @return Crypt_RC4
+     * @access public
+     */
+    function Crypt_RC4()
+    {
+        if ( !defined('CRYPT_RC4_MODE') ) {
+            switch (true) {
+                case extension_loaded('mcrypt') && (defined('MCRYPT_ARCFOUR') || defined('MCRYPT_RC4')):
+                    // i'd check to see if rc4 was supported, by doing in_array('arcfour', mcrypt_list_algorithms('')),
+                    // but since that can be changed after the object has been created, there doesn't seem to be
+                    // a lot of point...
+                    define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_MCRYPT);
+                    break;
+                default:
+                    define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL);
+            }
+        }
+
+        switch ( CRYPT_RC4_MODE ) {
+            case CRYPT_RC4_MODE_MCRYPT:
+                switch (true) {
+                    case defined('MCRYPT_ARCFOUR'):
+                        $this->mode = MCRYPT_ARCFOUR;
+                        break;
+                    case defined('MCRYPT_RC4');
+                        $this->mode = MCRYPT_RC4;
+                }
+        }
+    }
+
+    /**
+     * Sets the key.
+     *
+     * Keys can be between 1 and 256 bytes long.  If they are longer then 256 bytes, the first 256 bytes will
+     * be used.  If no key is explicitly set, it'll be assumed to be a single null byte.
+     *
+     * @access public
+     * @param String $key
+     */
+    function setKey($key)
+    {
+        $this->key = $key;
+
+        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
+            return;
+        }
+
+        $keyLength = strlen($key);
+        $keyStream = array();
+        for ($i = 0; $i < 256; $i++) {
+            $keyStream[$i] = $i;
+        }
+        $j = 0;
+        for ($i = 0; $i < 256; $i++) {
+            $j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;
+            $temp = $keyStream[$i];
+            $keyStream[$i] = $keyStream[$j];
+            $keyStream[$j] = $temp;
+        }
+
+        $this->encryptIndex = $this->decryptIndex = array(0, 0);
+        $this->encryptStream = $this->decryptStream = $keyStream;
+    }
+
+    /**
+     * Dummy function.
+     *
+     * Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1].
+     * If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before
+     * calling setKey().
+     *
+     * [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way.  Since, in that protocol,
+     * the IV's are relatively easy to predict, an attack described by
+     * {@link http://www.drizzle.com/~aboba/IEEE/rc4_ksaproc.pdf Scott Fluhrer, Itsik Mantin, and Adi Shamir}
+     * can be used to quickly guess at the rest of the key.  The following links elaborate:
+     *
+     * {@link http://www.rsa.com/rsalabs/node.asp?id=2009 http://www.rsa.com/rsalabs/node.asp?id=2009}
+     * {@link http://en.wikipedia.org/wiki/Related_key_attack http://en.wikipedia.org/wiki/Related_key_attack}
+     *
+     * @param String $iv
+     * @see Crypt_RC4::setKey()
+     * @access public
+     */
+    function setIV($iv)
+    {
+    }
+
+    /**
+     * Sets MCrypt parameters. (optional)
+     *
+     * If MCrypt is being used, empty strings will be used, unless otherwise specified.
+     *
+     * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open
+     * @access public
+     * @param optional Integer $algorithm_directory
+     * @param optional Integer $mode_directory
+     */
+    function setMCrypt($algorithm_directory = '', $mode_directory = '')
+    {
+        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
+            $this->mcrypt = array($algorithm_directory, $mode_directory);
+            $this->_closeMCrypt();
+        }
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * @see Crypt_RC4::_crypt()
+     * @access public
+     * @param String $plaintext
+     */
+    function encrypt($plaintext)
+    {
+        return $this->_crypt($plaintext, CRYPT_RC4_ENCRYPT);
+    }
+
+    /**
+     * Decrypts a message.
+     *
+     * $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).
+     * Atleast if the continuous buffer is disabled.
+     *
+     * @see Crypt_RC4::_crypt()
+     * @access public
+     * @param String $ciphertext
+     */
+    function decrypt($ciphertext)
+    {
+        return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT);
+    }
+
+    /**
+     * Encrypts or decrypts a message.
+     *
+     * @see Crypt_RC4::encrypt()
+     * @see Crypt_RC4::decrypt()
+     * @access private
+     * @param String $text
+     * @param Integer $mode
+     */
+    function _crypt($text, $mode)
+    {
+        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
+            $keyStream = $mode == CRYPT_RC4_ENCRYPT ? 'encryptStream' : 'decryptStream';
+
+            if ($this->$keyStream === false) {
+                $this->$keyStream = mcrypt_module_open($this->mode, $this->mcrypt[0], MCRYPT_MODE_STREAM, $this->mcrypt[1]);
+                mcrypt_generic_init($this->$keyStream, $this->key, '');
+            } else if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->$keyStream, $this->key, '');
+            }
+            $newText = mcrypt_generic($this->$keyStream, $text);
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_deinit($this->$keyStream);
+            }
+
+            return $newText;
+        }
+
+        if ($this->encryptStream === false) {
+            $this->setKey($this->key);
+        }
+
+        switch ($mode) {
+            case CRYPT_RC4_ENCRYPT:
+                $keyStream = $this->encryptStream;
+                list($i, $j) = $this->encryptIndex;
+                break;
+            case CRYPT_RC4_DECRYPT:
+                $keyStream = $this->decryptStream;
+                list($i, $j) = $this->decryptIndex;
+        }
+
+        $newText = '';
+        for ($k = 0; $k < strlen($text); $k++) {
+            $i = ($i + 1) & 255;
+            $j = ($j + $keyStream[$i]) & 255;
+            $temp = $keyStream[$i];
+            $keyStream[$i] = $keyStream[$j];
+            $keyStream[$j] = $temp;
+            $temp = $keyStream[($keyStream[$i] + $keyStream[$j]) & 255];
+            $newText.= chr(ord($text[$k]) ^ $temp);
+        }
+
+        if ($this->continuousBuffer) {
+            switch ($mode) {
+                case CRYPT_RC4_ENCRYPT:
+                    $this->encryptStream = $keyStream;
+                    $this->encryptIndex = array($i, $j);
+                    break;
+                case CRYPT_RC4_DECRYPT:
+                    $this->decryptStream = $keyStream;
+                    $this->decryptIndex = array($i, $j);
+            }
+        }
+
+        return $newText;
+    }
+
+    /**
+     * Treat consecutive "packets" as if they are a continuous buffer.
+     *
+     * Say you have a 16-byte plaintext $plaintext.  Using the default behavior, the two following code snippets
+     * will yield different outputs:
+     *
+     * <code>
+     *    echo $rc4->encrypt(substr($plaintext, 0, 8));
+     *    echo $rc4->encrypt(substr($plaintext, 8, 8));
+     * </code>
+     * <code>
+     *    echo $rc4->encrypt($plaintext);
+     * </code>
+     *
+     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates
+     * another, as demonstrated with the following:
+     *
+     * <code>
+     *    $rc4->encrypt(substr($plaintext, 0, 8));
+     *    echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     * <code>
+     *    echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     *
+     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different
+     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /
+     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.
+     *
+     * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each
+     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that
+     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),
+     * however, they are also less intuitive and more likely to cause you problems.
+     *
+     * @see Crypt_RC4::disableContinuousBuffer()
+     * @access public
+     */
+    function enableContinuousBuffer()
+    {
+        $this->continuousBuffer = true;
+    }
+
+    /**
+     * Treat consecutive packets as if they are a discontinuous buffer.
+     *
+     * The default behavior.
+     *
+     * @see Crypt_RC4::enableContinuousBuffer()
+     * @access public
+     */
+    function disableContinuousBuffer()
+    {
+        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_INTERNAL ) {
+            $this->encryptIndex = $this->decryptIndex = array(0, 0);
+            $this->setKey($this->key);
+        }
+
+        $this->continuousBuffer = false;
+    }
+
+    /**
+     * Dummy function.
+     *
+     * Since RC4 is a stream cipher and not a block cipher, no padding is necessary.  The only reason this function is
+     * included is so that you can switch between a block cipher and a stream cipher transparently.
+     *
+     * @see Crypt_RC4::disablePadding()
+     * @access public
+     */
+    function enablePadding()
+    {
+    }
+
+    /**
+     * Dummy function.
+     *
+     * @see Crypt_RC4::enablePadding()
+     * @access public
+     */
+    function disablePadding()
+    {
+    }
+
+    /**
+     * Class destructor.
+     *
+     * Will be called, automatically, if you're using PHP5.  If you're using PHP4, call it yourself.  Only really
+     * needs to be called if mcrypt is being used.
+     *
+     * @access public
+     */
+    function __destruct()
+    {
+        if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
+            $this->_closeMCrypt();
+        }
+    }
+
+    /**
+     * Properly close the MCrypt objects.
+     *
+     * @access prviate
+     */
+    function _closeMCrypt()
+    {
+        if ( $this->encryptStream !== false ) {
+            if ( $this->continuousBuffer ) {
+                mcrypt_generic_deinit($this->encryptStream);
+            }
+
+            mcrypt_module_close($this->encryptStream);
+
+            $this->encryptStream = false;
+        }
+
+        if ( $this->decryptStream !== false ) {
+            if ( $this->continuousBuffer ) {
+                mcrypt_generic_deinit($this->decryptStream);
+            }
+
+            mcrypt_module_close($this->decryptStream);
+
+            $this->decryptStream = false;
+        }
+    }
 }
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/RSA.php b/plugins/OStatus/extlib/Crypt/RSA.php
index b9a4e23eb..f0a75962c 100644
--- a/plugins/OStatus/extlib/Crypt/RSA.php
+++ b/plugins/OStatus/extlib/Crypt/RSA.php
@@ -1,1929 +1,2108 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP PKCS#1 (v2.1) compliant implementation of RSA.

- *

- * PHP versions 4 and 5

- *

- * Here's an example of how to encrypt and decrypt text with this library:

- * <code>

- * <?php

- *    include('Crypt/RSA.php');

- *

- *    $rsa = new Crypt_RSA();

- *    extract($rsa->createKey());

- *

- *    $plaintext = 'terrafrost';

- *

- *    $rsa->loadKey($privatekey);

- *    $ciphertext = $rsa->encrypt($plaintext);

- *

- *    $rsa->loadKey($publickey);

- *    echo $rsa->decrypt($ciphertext);

- * ?>

- * </code>

- *

- * Here's an example of how to create signatures and verify signatures with this library:

- * <code>

- * <?php

- *    include('Crypt/RSA.php');

- *

- *    $rsa = new Crypt_RSA();

- *    extract($rsa->createKey());

- *

- *    $plaintext = 'terrafrost';

- *

- *    $rsa->loadKey($privatekey);

- *    $signature = $rsa->sign($plaintext);

- *

- *    $rsa->loadKey($publickey);

- *    echo $rsa->verify($plaintext, $signature) ? 'verified' : 'unverified';

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_RSA

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMIX Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: RSA.php,v 1.3 2009/12/04 21:05:32 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**

- * Include Math_BigInteger

- */

-require_once('Math/BigInteger.php');

-

-/**

- * Include Crypt_Random

- */

-require_once('Crypt/Random.php');

-

-/**

- * Include Crypt_Hash

- */

-require_once('Crypt/Hash.php');

-

-/**#@+

- * @access public

- * @see Crypt_RSA::encrypt()

- * @see Crypt_RSA::decrypt()

- */

-/**

- * Use {@link http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding Optimal Asymmetric Encryption Padding}

- * (OAEP) for encryption / decryption.

- *

- * Uses sha1 by default.

- *

- * @see Crypt_RSA::setHash()

- * @see Crypt_RSA::setMGFHash()

- */

-define('CRYPT_RSA_ENCRYPTION_OAEP',  1);

-/**

- * Use PKCS#1 padding.

- *

- * Although CRYPT_RSA_ENCRYPTION_OAEP offers more security, including PKCS#1 padding is necessary for purposes of backwards

- * compatability with protocols (like SSH-1) written before OAEP's introduction.

- */

-define('CRYPT_RSA_ENCRYPTION_PKCS1', 2);

-/**#@-*/

-

-/**#@+

- * @access public

- * @see Crypt_RSA::sign()

- * @see Crypt_RSA::verify()

- * @see Crypt_RSA::setHash()

- */

-/**

- * Use the Probabilistic Signature Scheme for signing

- *

- * Uses sha1 by default.

- *

- * @see Crypt_RSA::setSaltLength()

- * @see Crypt_RSA::setMGFHash()

- */

-define('CRYPT_RSA_SIGNATURE_PSS',  1);

-/**

- * Use the PKCS#1 scheme by default.

- *

- * Although CRYPT_RSA_SIGNATURE_PSS offers more security, including PKCS#1 signing is necessary for purposes of backwards

- * compatability with protocols (like SSH-2) written before PSS's introduction.

- */

-define('CRYPT_RSA_SIGNATURE_PKCS1', 2);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Crypt_RSA::createKey()

- */

-/**

- * ASN1 Integer

- */

-define('CRYPT_RSA_ASN1_INTEGER',   2);

-/**

- * ASN1 Sequence (with the constucted bit set)

- */

-define('CRYPT_RSA_ASN1_SEQUENCE', 48);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Crypt_RSA::Crypt_RSA()

- */

-/**

- * To use the pure-PHP implementation

- */

-define('CRYPT_RSA_MODE_INTERNAL', 1);

-/**

- * To use the OpenSSL library

- *

- * (if enabled; otherwise, the internal implementation will be used)

- */

-define('CRYPT_RSA_MODE_OPENSSL', 2);

-/**#@-*/

-

-/**#@+

- * @access public

- * @see Crypt_RSA::createKey()

- * @see Crypt_RSA::setPrivateKeyFormat()

- */

-/**

- * PKCS#1 formatted private key

- *

- * Used by OpenSSH

- */

-define('CRYPT_RSA_PRIVATE_FORMAT_PKCS1', 0);

-/**#@-*/

-

-/**#@+

- * @access public

- * @see Crypt_RSA::createKey()

- * @see Crypt_RSA::setPublicKeyFormat()

- */

-/**

- * Raw public key

- *

- * An array containing two Math_BigInteger objects.

- *

- * The exponent can be indexed with any of the following:

- *

- * 0, e, exponent, publicExponent

- *

- * The modulus can be indexed with any of the following:

- *

- * 1, n, modulo, modulus

- */

-define('CRYPT_RSA_PUBLIC_FORMAT_RAW', 1);

-/**

- * PKCS#1 formatted public key

- */

-define('CRYPT_RSA_PUBLIC_FORMAT_PKCS1', 2);

-/**

- * OpenSSH formatted public key

- *

- * Place in $HOME/.ssh/authorized_keys

- */

-define('CRYPT_RSA_PUBLIC_FORMAT_OPENSSH', 3);

-/**#@-*/

-

-/**

- * Pure-PHP PKCS#1 compliant implementation of RSA.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_RSA

- */

-class Crypt_RSA {

-    /**

-     * Precomputed Zero

-     *

-     * @var Array

-     * @access private

-     */

-    var $zero;

-

-    /**

-     * Precomputed One

-     *

-     * @var Array

-     * @access private

-     */

-    var $one;

-

-    /**

-     * Private Key Format

-     *

-     * @var Integer

-     * @access private

-     */

-    var $privateKeyFormat = CRYPT_RSA_PRIVATE_FORMAT_PKCS1;

-

-    /**

-     * Public Key Format

-     *

-     * @var Integer

-     * @access public

-     */

-    var $publicKeyFormat = CRYPT_RSA_PUBLIC_FORMAT_PKCS1;

-

-    /**

-     * Modulus (ie. n)

-     *

-     * @var Math_BigInteger

-     * @access private

-     */

-    var $modulus;

-

-    /**

-     * Modulus length

-     *

-     * @var Math_BigInteger

-     * @access private

-     */

-    var $k;

-

-    /**

-     * Exponent (ie. e or d)

-     *

-     * @var Math_BigInteger

-     * @access private

-     */

-    var $exponent;

-

-    /**

-     * Primes for Chinese Remainder Theorem (ie. p and q)

-     *

-     * @var Array

-     * @access private

-     */

-    var $primes;

-

-    /**

-     * Exponents for Chinese Remainder Theorem (ie. dP and dQ)

-     *

-     * @var Array

-     * @access private

-     */

-    var $exponents;

-

-    /**

-     * Coefficients for Chinese Remainder Theorem (ie. qInv)

-     *

-     * @var Array

-     * @access private

-     */

-    var $coefficients;

-

-    /**

-     * Hash name

-     *

-     * @var String

-     * @access private

-     */

-    var $hashName;

-

-    /**

-     * Hash function

-     *

-     * @var Crypt_Hash

-     * @access private

-     */

-    var $hash;

-

-    /**

-     * Length of hash function output

-     *

-     * @var Integer

-     * @access private

-     */

-    var $hLen;

-

-    /**

-     * Length of salt

-     *

-     * @var Integer

-     * @access private

-     */

-    var $sLen;

-

-    /**

-     * Hash function for the Mask Generation Function

-     *

-     * @var Crypt_Hash

-     * @access private

-     */

-    var $mgfHash;

-

-    /**

-     * Encryption mode

-     *

-     * @var Integer

-     * @access private

-     */

-    var $encryptionMode = CRYPT_RSA_ENCRYPTION_OAEP;

-

-    /**

-     * Signature mode

-     *

-     * @var Integer

-     * @access private

-     */

-    var $signatureMode = CRYPT_RSA_SIGNATURE_PSS;

-

-    /**

-     * Public Exponent

-     *

-     * @var Mixed

-     * @access private

-     */

-    var $publicExponent = false;

-

-    /**

-     * Password

-     *

-     * @var String

-     * @access private

-     */

-    var $password = '';

-

-    /**

-     * The constructor

-     *

-     * If you want to make use of the openssl extension, you'll need to set the mode manually, yourself.  The reason

-     * Crypt_RSA doesn't do it is because OpenSSL doesn't fail gracefully.  openssl_pkey_new(), in particular, requires

-     * openssl.cnf be present somewhere and, unfortunately, the only real way to find out is too late.

-     *

-     * @return Crypt_RSA

-     * @access public

-     */

-    function Crypt_RSA()

-    {

-        if ( !defined('CRYPT_RSA_MODE') ) {

-            switch (true) {

-                //case extension_loaded('openssl') && version_compare(PHP_VERSION, '4.2.0', '>='):

-                //    define('CRYPT_RSA_MODE', CRYPT_RSA_MODE_OPENSSL);

-                //    break;

-                default:

-                    define('CRYPT_RSA_MODE', CRYPT_RSA_MODE_INTERNAL);

-            }

-        }

-

-        $this->zero = new Math_BigInteger();

-        $this->one = new Math_BigInteger(1);

-

-        $this->hash = new Crypt_Hash('sha1');

-        $this->hLen = $this->hash->getLength();

-        $this->hashName = 'sha1';

-        $this->mgfHash = new Crypt_Hash('sha1');

-    }

-

-    /**

-     * Create public / private key pair

-     *

-     * Returns an array with the following three elements:

-     *  - 'privatekey': The private key.

-     *  - 'publickey':  The public key.

-     *  - 'partialkey': A partially computed key (if the execution time exceeded $timeout).

-     *                  Will need to be passed back to Crypt_RSA::createKey() as the third parameter for further processing.

-     *

-     * @access public

-     * @param optional Integer $bits

-     * @param optional Integer $timeout

-     * @param optional Math_BigInteger $p

-     */

-    function createKey($bits = 1024, $timeout = false, $primes = array())

-    {

-        if ( CRYPT_RSA_MODE == CRYPT_RSA_MODE_OPENSSL ) {

-            $rsa = openssl_pkey_new(array('private_key_bits' => $bits));

-            openssl_pkey_export($rsa, $privatekey);

-            $publickey = openssl_pkey_get_details($rsa);

-            $publickey = $publickey['key'];

-

-            if ($this->privateKeyFormat != CRYPT_RSA_PRIVATE_FORMAT_PKCS1) {

-                $privatekey = call_user_func_array(array($this, '_convertPrivateKey'), array_values($this->_parseKey($privatekey, CRYPT_RSA_PRIVATE_FORMAT_PKCS1)));

-                $publickey = call_user_func_array(array($this, '_convertPublicKey'), array_values($this->_parseKey($publickey, CRYPT_RSA_PUBLIC_FORMAT_PKCS1)));

-            }

-

-            return array(

-                'privatekey' => $privatekey,

-                'publickey' => $publickey,

-                'partialkey' => false

-            );

-        }

-

-        static $e;

-        if (!isset($e)) {

-            if (!defined('CRYPT_RSA_EXPONENT')) {

-                // http://en.wikipedia.org/wiki/65537_%28number%29

-                define('CRYPT_RSA_EXPONENT', '65537');

-            }

-            if (!defined('CRYPT_RSA_COMMENT')) {

-                define('CRYPT_RSA_COMMENT', 'phpseclib-generated-key');

-            }

-            // per <http://cseweb.ucsd.edu/~hovav/dist/survey.pdf#page=5>, this number ought not result in primes smaller

-            // than 256 bits.

-            if (!defined('CRYPT_RSA_SMALLEST_PRIME')) {

-                define('CRYPT_RSA_SMALLEST_PRIME', 4096);

-            }

-

-            $e = new Math_BigInteger(CRYPT_RSA_EXPONENT);

-        }

-

-        extract($this->_generateMinMax($bits));

-        $absoluteMin = $min;

-        $temp = $bits >> 1;

-        if ($temp > CRYPT_RSA_SMALLEST_PRIME) {

-            $num_primes = floor($bits / CRYPT_RSA_SMALLEST_PRIME);

-            $temp = CRYPT_RSA_SMALLEST_PRIME;

-        } else {

-            $num_primes = 2;

-        }

-        extract($this->_generateMinMax($temp + $bits % $temp));

-        $finalMax = $max;

-        extract($this->_generateMinMax($temp));

-

-        $exponents = $coefficients = array();

-        $generator = new Math_BigInteger();

-        $generator->setRandomGenerator('crypt_random');

-

-        $n = $this->one->copy();

-        $lcm = array(

-            'top' => $this->one->copy(),

-            'bottom' => false

-        );

-

-        $start = time();

-        $i0 = count($primes) + 1;

-

-        do {

-            for ($i = $i0; $i <= $num_primes; $i++) {

-                if ($timeout !== false) {

-                    $timeout-= time() - $start;

-                    $start = time();

-                    if ($timeout <= 0) {

-                        return array(

-                            'privatekey' => '',

-                            'publickey'  => '',

-                            'partialkey' => $primes

-                        );

-                    }

-                }

-                if ($i == $num_primes) {

-                    list($min, $temp) = $absoluteMin->divide($n);

-                    if (!$temp->equals($this->zero)) {

-                        $min = $min->add($this->one); // ie. ceil()

-                    }

-                    $primes[$i] = $generator->randomPrime($min, $finalMax, $timeout);

-                } else {

-                    $primes[$i] = $generator->randomPrime($min, $max, $timeout);

-                }

-

-                if ($primes[$i] === false) { // if we've reached the timeout

-                    return array(

-                        'privatekey' => '',

-                        'publickey'  => '',

-                        'partialkey' => array_slice($primes, 0, $i - 1)

-                    );

-                }

-

-                // the first coefficient is calculated differently from the rest

-                // ie. instead of being $primes[1]->modInverse($primes[2]), it's $primes[2]->modInverse($primes[1])

-                if ($i > 2) {

-                    $coefficients[$i] = $n->modInverse($primes[$i]);

-                }

-

-                $n = $n->multiply($primes[$i]);

-

-                $temp = $primes[$i]->subtract($this->one);

-

-                // textbook RSA implementations use Euler's totient function instead of the least common multiple.

-                // see http://en.wikipedia.org/wiki/Euler%27s_totient_function

-                $lcm['top'] = $lcm['top']->multiply($temp);

-                $lcm['bottom'] = $lcm['bottom'] === false ? $temp : $lcm['bottom']->gcd($temp);

-

-                $exponents[$i] = $e->modInverse($temp);

-            }

-

-            list($lcm) = $lcm['top']->divide($lcm['bottom']);

-            $gcd = $lcm->gcd($e);

-            $i0 = 1;

-        } while (!$gcd->equals($this->one));

-

-        $d = $e->modInverse($lcm);

-

-        $coefficients[2] = $primes[2]->modInverse($primes[1]);

-

-        // from <http://tools.ietf.org/html/rfc3447#appendix-A.1.2>:

-        // RSAPrivateKey ::= SEQUENCE {

-        //     version           Version,

-        //     modulus           INTEGER,  -- n

-        //     publicExponent    INTEGER,  -- e

-        //     privateExponent   INTEGER,  -- d

-        //     prime1            INTEGER,  -- p

-        //     prime2            INTEGER,  -- q

-        //     exponent1         INTEGER,  -- d mod (p-1)

-        //     exponent2         INTEGER,  -- d mod (q-1)

-        //     coefficient       INTEGER,  -- (inverse of q) mod p

-        //     otherPrimeInfos   OtherPrimeInfos OPTIONAL

-        // }

-

-        return array(

-            'privatekey' => $this->_convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients),

-            'publickey'  => $this->_convertPublicKey($n, $e),

-            'partialkey' => false

-        );

-    }

-

-    /**

-     * Convert a private key to the appropriate format.

-     *

-     * @access private

-     * @see setPrivateKeyFormat()

-     * @param String $RSAPrivateKey

-     * @return String

-     */

-    function _convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients)

-    {

-        $num_primes = count($primes);

-

-        $raw = array(

-            'version' => $num_primes == 2 ? chr(0) : chr(1), // two-prime vs. multi

-            'modulus' => $n->toBytes(true),

-            'publicExponent' => $e->toBytes(true),

-            'privateExponent' => $d->toBytes(true),

-            'prime1' => $primes[1]->toBytes(true),

-            'prime2' => $primes[2]->toBytes(true),

-            'exponent1' => $exponents[1]->toBytes(true),

-            'exponent2' => $exponents[2]->toBytes(true),

-            'coefficient' => $coefficients[2]->toBytes(true)

-        );

-

-        // if the format in question does not support multi-prime rsa and multi-prime rsa was used,

-        // call _convertPublicKey() instead.

-        switch ($this->privateKeyFormat) {

-            default: // eg. CRYPT_RSA_PRIVATE_FORMAT_PKCS1

-                $components = array();

-                foreach ($raw as $name => $value) {

-                    $components[$name] = pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($value)), $value);

-                }

-

-                $RSAPrivateKey = implode('', $components);

-

-                if ($num_primes > 2) {

-                    $OtherPrimeInfos = '';

-                    for ($i = 3; $i <= $num_primes; $i++) {

-                        // OtherPrimeInfos ::= SEQUENCE SIZE(1..MAX) OF OtherPrimeInfo

-                        //

-                        // OtherPrimeInfo ::= SEQUENCE {

-                        //     prime             INTEGER,  -- ri

-                        //     exponent          INTEGER,  -- di

-                        //     coefficient       INTEGER   -- ti

-                        // }

-                        $OtherPrimeInfo = pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($primes[$i]->toBytes(true))), $primes[$i]->toBytes(true));

-                        $OtherPrimeInfo.= pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($exponents[$i]->toBytes(true))), $exponents[$i]->toBytes(true));

-                        $OtherPrimeInfo.= pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($coefficients[$i]->toBytes(true))), $coefficients[$i]->toBytes(true));

-                        $OtherPrimeInfos.= pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfo)), $OtherPrimeInfo);

-                    }

-                    $RSAPrivateKey.= pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfos)), $OtherPrimeInfos);

-                }

-

-                $RSAPrivateKey = pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($RSAPrivateKey)), $RSAPrivateKey);

-

-                if (!empty($this->password)) {

-                    $iv = $this->_random(8);

-                    $symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key

-                    $symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);

-                    if (!class_exists('Crypt_TripleDES')) {

-                        require_once('Crypt/TripleDES.php');

-                    }

-                    $des = new Crypt_TripleDES();

-                    $des->setKey($symkey);

-                    $des->setIV($iv);

-                    $iv = strtoupper(bin2hex($iv));

-                    $RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .

-                                     "Proc-Type: 4,ENCRYPTED\r\n" .

-                                     "DEK-Info: DES-EDE3-CBC,$iv\r\n" .

-                                     "\r\n" .

-                                     chunk_split(base64_encode($des->encrypt($RSAPrivateKey))) .

-                                     '-----END RSA PRIVATE KEY-----';

-                } else {

-                    $RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .

-                                     chunk_split(base64_encode($RSAPrivateKey)) .

-                                     '-----END RSA PRIVATE KEY-----';

-                }

-

-                return $RSAPrivateKey;

-        }

-    }

-

-    /**

-     * Convert a public key to the appropriate format

-     *

-     * @access private

-     * @see setPublicKeyFormat()

-     * @param String $RSAPrivateKey

-     * @return String

-     */

-    function _convertPublicKey($n, $e)

-    {

-        $modulus = $n->toBytes(true);

-        $publicExponent = $e->toBytes(true);

-

-        switch ($this->publicKeyFormat) {

-            case CRYPT_RSA_PUBLIC_FORMAT_RAW:

-                return array('e' => $e->copy(), 'n' => $n->copy());

-            case CRYPT_RSA_PUBLIC_FORMAT_OPENSSH:

-                // from <http://tools.ietf.org/html/rfc4253#page-15>:

-                // string    "ssh-rsa"

-                // mpint     e

-                // mpint     n

-                $RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);

-                $RSAPublicKey = 'ssh-rsa ' . base64_encode($RSAPublicKey) . ' ' . CRYPT_RSA_COMMENT;

-

-                return $RSAPublicKey;

-            default: // eg. CRYPT_RSA_PUBLIC_FORMAT_PKCS1

-                // from <http://tools.ietf.org/html/rfc3447#appendix-A.1.1>:

-                // RSAPublicKey ::= SEQUENCE {

-                //     modulus           INTEGER,  -- n

-                //     publicExponent    INTEGER   -- e

-                // }

-                $components = array(

-                    'modulus' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($modulus)), $modulus),

-                    'publicExponent' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($publicExponent)), $publicExponent)

-                );

-

-                $RSAPublicKey = pack('Ca*a*a*',

-                    CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($components['modulus']) + strlen($components['publicExponent'])),

-                    $components['modulus'], $components['publicExponent']

-                );

-

-                $RSAPublicKey = "-----BEGIN PUBLIC KEY-----\r\n" .

-                                 chunk_split(base64_encode($RSAPublicKey)) .

-                                 '-----END PUBLIC KEY-----';

-

-                return $RSAPublicKey;

-        }

-    }

-

-    /**

-     * Break a public or private key down into its constituant components

-     *

-     * @access private

-     * @see _convertPublicKey()

-     * @see _convertPrivateKey()

-     * @param String $key

-     * @param Integer $type

-     * @return Array

-     */

-    function _parseKey($key, $type)

-    {

-        switch ($type) {

-            case CRYPT_RSA_PUBLIC_FORMAT_RAW:

-                if (!is_array($key)) {

-                    return false;

-                }

-                $components = array();

-                switch (true) {

-                    case isset($key['e']):

-                        $components['publicExponent'] = $key['e']->copy();

-                        break;

-                    case isset($key['exponent']):

-                        $components['publicExponent'] = $key['exponent']->copy();

-                        break;

-                    case isset($key['publicExponent']):

-                        $components['publicExponent'] = $key['publicExponent']->copy();

-                        break;

-                    case isset($key[0]):

-                        $components['publicExponent'] = $key[0]->copy();

-                }

-                switch (true) {

-                    case isset($key['n']):

-                        $components['modulus'] = $key['n']->copy();

-                        break;

-                    case isset($key['modulo']):

-                        $components['modulus'] = $key['modulo']->copy();

-                        break;

-                    case isset($key['modulus']):

-                        $components['modulus'] = $key['modulus']->copy();

-                        break;

-                    case isset($key[1]):

-                        $components['modulus'] = $key[1]->copy();

-                }

-                return $components;

-            case CRYPT_RSA_PRIVATE_FORMAT_PKCS1:

-            case CRYPT_RSA_PUBLIC_FORMAT_PKCS1:

-                /* Although PKCS#1 proposes a format that public and private keys can use, encrypting them is

-                   "outside the scope" of PKCS#1.  PKCS#1 then refers you to PKCS#12 and PKCS#15 if you're wanting to

-                   protect private keys, however, that's not what OpenSSL* does.  OpenSSL protects private keys by adding

-                   two new "fields" to the key - DEK-Info and Proc-Type.  These fields are discussed here:

-

-                   http://tools.ietf.org/html/rfc1421#section-4.6.1.1

-                   http://tools.ietf.org/html/rfc1421#section-4.6.1.3

-

-                   DES-EDE3-CBC as an algorithm, however, is not discussed anywhere, near as I can tell.

-                   DES-CBC and DES-EDE are discussed in RFC1423, however, DES-EDE3-CBC isn't, nor is its key derivation

-                   function.  As is, the definitive authority on this encoding scheme isn't the IETF but rather OpenSSL's

-                   own implementation.  ie. the implementation *is* the standard and any bugs that may exist in that 

-                   implementation are part of the standard, as well.

-

-                   * OpenSSL is the de facto standard.  It's utilized by OpenSSH and other projects */

-                if (preg_match('#DEK-Info: DES-EDE3-CBC,(.+)#', $key, $matches)) {

-                    $iv = pack('H*', trim($matches[1]));

-                    $symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key

-                    $symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);

-                    $ciphertext = base64_decode(preg_replace('#.+(\r|\n|\r\n)\1|[\r\n]|-.+-#s', '', $key));

-                    if ($ciphertext === false) {

-                        return false;

-                    }

-                    if (!class_exists('Crypt_TripleDES')) {

-                        require_once('Crypt/TripleDES.php');

-                    }

-                    $des = new Crypt_TripleDES();

-                    $des->setKey($symkey);

-                    $des->setIV($iv);

-                    $key = $des->decrypt($ciphertext);

-                } else {

-                    $key = base64_decode(preg_replace('#-.+-|[\r\n]#', '', $key));

-                    if ($key === false) {

-                        return false;

-                    }

-                }

-

-                $private = false;

-                $components = array();

-

-                $this->_string_shift($key); // skip over CRYPT_RSA_ASN1_SEQUENCE

-                $this->_decodeLength($key); // skip over the length of the above sequence

-                $this->_string_shift($key); // skip over CRYPT_RSA_ASN1_INTEGER

-                $length = $this->_decodeLength($key);

-                $temp = $this->_string_shift($key, $length);

-                if (strlen($temp) != 1 || ord($temp) > 2) {

-                    $components['modulus'] = new Math_BigInteger($temp, -256);

-                    $this->_string_shift($key); // skip over CRYPT_RSA_ASN1_INTEGER

-                    $length = $this->_decodeLength($key);

-                    $components[$type == CRYPT_RSA_PUBLIC_FORMAT_PKCS1 ? 'publicExponent' : 'privateExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-

-                    return $components;

-                }

-                $this->_string_shift($key); // skip over CRYPT_RSA_ASN1_INTEGER

-                $length = $this->_decodeLength($key);

-                $components['modulus'] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['publicExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['privateExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['primes'] = array(1 => new Math_BigInteger($this->_string_shift($key, $length), -256));

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['primes'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['exponents'] = array(1 => new Math_BigInteger($this->_string_shift($key, $length), -256));

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['exponents'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                $this->_string_shift($key);

-                $length = $this->_decodeLength($key);

-                $components['coefficients'] = array(2 => new Math_BigInteger($this->_string_shift($key, $length), -256));

-                if (!empty($key)) {

-                    $key = substr($key, 1); // skip over CRYPT_RSA_ASN1_SEQUENCE

-                    $this->_decodeLength($key);

-                    while (!empty($key)) {

-                        $key = substr($key, 1); // skip over CRYPT_RSA_ASN1_SEQUENCE

-                        $this->_decodeLength($key);

-                        $key = substr($key, 1);

-                        $length = $this->_decodeLength($key);

-                        $components['primes'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                        $this->_string_shift($key);

-                        $length = $this->_decodeLength($key);

-                        $components['exponents'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                        $this->_string_shift($key);

-                        $length = $this->_decodeLength($key);

-                        $components['coefficients'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                    }

-                }

-

-                return $components;

-            case CRYPT_RSA_PUBLIC_FORMAT_OPENSSH:

-                $key = base64_decode(preg_replace('#^ssh-rsa | .+$#', '', $key));

-                if ($key === false) {

-                    return false;

-                }

-

-                $components = array();

-                extract(unpack('Nlength', $this->_string_shift($key, 4)));

-                $components['modulus'] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-                extract(unpack('Nlength', $this->_string_shift($key, 4)));

-                $components['publicExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);

-

-                return $components;

-        }

-    }

-

-    /**

-     * Loads a public or private key

-     *

-     * @access public

-     * @param String $key

-     * @param Integer $type optional

-     */

-    function loadKey($key, $type = CRYPT_RSA_PRIVATE_FORMAT_PKCS1)

-    {

-        $components = $this->_parseKey($key, $type);

-        $this->modulus = $components['modulus'];

-        $this->k = strlen($this->modulus->toBytes());

-        $this->exponent = isset($components['privateExponent']) ? $components['privateExponent'] : $components['publicExponent'];

-        if (isset($components['primes'])) {

-            $this->primes = $components['primes'];

-            $this->exponents = $components['exponents'];

-            $this->coefficients = $components['coefficients'];

-            $this->publicExponent = $components['publicExponent'];

-        } else {

-            $this->primes = array();

-            $this->exponents = array();

-            $this->coefficients = array();

-            $this->publicExponent = false;

-        }

-    }

-

-    /**

-     * Sets the password

-     *

-     * Private keys can be encrypted with a password.  To unset the password, pass in the empty string or false.

-     * Or rather, pass in $password such that empty($password) is true.

-     *

-     * @see createKey()

-     * @see loadKey()

-     * @access public

-     * @param String $password

-     */

-    function setPassword($password)

-    {

-        $this->password = $password;

-    }

-

-    /**

-     * Defines the public key

-     *

-     * Some private key formats define the public exponent and some don't.  Those that don't define it are problematic when

-     * used in certain contexts.  For example, in SSH-2, RSA authentication works by sending the public key along with a

-     * message signed by the private key to the server.  The SSH-2 server looks the public key up in an index of public keys

-     * and if it's present then proceeds to verify the signature.  Problem is, if your private key doesn't include the public

-     * exponent this won't work unless you manually add the public exponent.

-     *

-     * Do note that when a new key is loaded the index will be cleared.

-     *

-     * Returns true on success, false on failure

-     *

-     * @see getPublicKey()

-     * @access public

-     * @param String $key

-     * @param Integer $type optional

-     * @return Boolean

-     */

-    function setPublicKey($key, $type = CRYPT_RSA_PUBLIC_FORMAT_PKCS1)

-    {

-        $components = $this->_parseKey($key, $type);

-        if (!$this->modulus->equals($components['modulus'])) {

-            return false;

-        }

-        $this->publicExponent = $components['publicExponent'];

-    }

-

-    /**

-     * Returns the public key

-     *

-     * The public key is only returned under two circumstances - if the private key had the public key embedded within it

-     * or if the public key was set via setPublicKey().  If the currently loaded key is supposed to be the public key this

-     * function won't return it since this library, for the most part, doesn't distinguish between public and private keys.

-     *

-     * @see getPublicKey()

-     * @access public

-     * @param String $key

-     * @param Integer $type optional

-     */

-    function getPublicKey($type = CRYPT_RSA_PUBLIC_FORMAT_PKCS1)

-    {

-        $oldFormat = $this->publicKeyFormat;

-        $this->publicKeyFormat = $type;

-        $temp = $this->_convertPublicKey($this->modulus, $this->publicExponent);

-        $this->publicKeyFormat = $oldFormat;

-        return $temp;

-    }

-

-    /**

-     * Generates the smallest and largest numbers requiring $bits bits

-     *

-     * @access private

-     * @param Integer $bits

-     * @return Array

-     */

-    function _generateMinMax($bits)

-    {

-        $bytes = $bits >> 3;

-        $min = str_repeat(chr(0), $bytes);

-        $max = str_repeat(chr(0xFF), $bytes);

-        $msb = $num_bits & 7;

-        if ($msb) {

-            $min = chr(1 << ($msb - 1)) . $min;

-            $max = chr((1 << $msb) - 1) . $max;

-        } else {

-            $min[0] = chr(0x80);

-        }

-

-        return array(

-            'min' => new Math_BigInteger($min, 256),

-            'max' => new Math_BigInteger($max, 256)

-        );

-    }

-

-    /**

-     * DER-decode the length

-     *

-     * DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4.  See

-     * {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 § 8.1.3} for more information.

-     *

-     * @access private

-     * @param String $string

-     * @return Integer

-     */

-    function _decodeLength(&$string)

-    {

-        $length = ord($this->_string_shift($string));

-        if ( $length & 0x80 ) { // definite length, long form

-            $length&= 0x7F;

-            $temp = $this->_string_shift($string, $length);

-            $start+= $length;

-            list(, $length) = unpack('N', substr(str_pad($temp, 4, chr(0), STR_PAD_LEFT), -4));

-        }

-        return $length;

-    }

-

-    /**

-     * DER-encode the length

-     *

-     * DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4.  See

-     * {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 § 8.1.3} for more information.

-     *

-     * @access private

-     * @param Integer $length

-     * @return String

-     */

-    function _encodeLength($length)

-    {

-        if ($length <= 0x7F) {

-            return chr($length);

-        }

-

-        $temp = ltrim(pack('N', $length), chr(0));

-        return pack('Ca*', 0x80 | strlen($temp), $temp);

-    }

-

-    /**

-     * String Shift

-     *

-     * Inspired by array_shift

-     *

-     * @param String $string

-     * @param optional Integer $index

-     * @return String

-     * @access private

-     */

-    function _string_shift(&$string, $index = 1)

-    {

-        $substr = substr($string, 0, $index);

-        $string = substr($string, $index);

-        return $substr;

-    }

-

-    /**

-     * Determines the private key format

-     *

-     * @see createKey()

-     * @access public

-     * @param Integer $format

-     */

-    function setPrivateKeyFormat($format)

-    {

-        $this->privateKeyFormat = $format;

-    }

-

-    /**

-     * Determines the public key format

-     *

-     * @see createKey()

-     * @access public

-     * @param Integer $format

-     */

-    function setPublicKeyFormat($format)

-    {

-        $this->publicKeyFormat = $format;

-    }

-

-    /**

-     * Determines which hashing function should be used

-     *

-     * Used with signature production / verification and (if the encryption mode is CRYPT_RSA_ENCRYPTION_OAEP) encryption and

-     * decryption.  If $hash isn't supported, sha1 is used.

-     *

-     * @access public

-     * @param String $hash

-     */

-    function setHash($hash)

-    {

-        // Crypt_Hash supports algorithms that PKCS#1 doesn't support.  md5-96 and sha1-96, for example.

-        switch ($hash) {

-            case 'md2':

-            case 'md5':

-            case 'sha1':

-            case 'sha256':

-            case 'sha384':

-            case 'sha512':

-                $this->hash = new Crypt_Hash($hash);

-                $this->hLen = $this->hash->getLength();

-                $this->hashName = $hash;

-                break;

-            default:

-                $this->hash = new Crypt_Hash('sha1');

-                $this->hLen = $this->hash->getLength();

-                $this->hashName = 'sha1';

-        }

-    }

-

-    /**

-     * Determines which hashing function should be used for the mask generation function

-     *

-     * The mask generation function is used by CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_SIGNATURE_PSS and although it's

-     * best if Hash and MGFHash are set to the same thing this is not a requirement.

-     *

-     * @access public

-     * @param String $hash

-     */

-    function setMGFHash($hash)

-    {

-        // Crypt_Hash supports algorithms that PKCS#1 doesn't support.  md5-96 and sha1-96, for example.

-        switch ($hash) {

-            case 'md2':

-            case 'md5':

-            case 'sha1':

-            case 'sha256':

-            case 'sha384':

-            case 'sha512':

-                $this->mgfHash = new Crypt_Hash($hash);

-                break;

-            default:

-                $this->mgfHash = new Crypt_Hash('sha1');

-        }

-    }

-

-    /**

-     * Determines the salt length

-     *

-     * To quote from {@link http://tools.ietf.org/html/rfc3447#page-38 RFC3447#page-38}:

-     *

-     *    Typical salt lengths in octets are hLen (the length of the output

-     *    of the hash function Hash) and 0.

-     *

-     * @access public

-     * @param Integer $format

-     */

-    function setSaltLength($sLen)

-    {

-        $this->sLen = $sLen;

-    }

-

-    /**

-     * Generates a random string x bytes long

-     *

-     * @access public

-     * @param Integer $bytes

-     * @param optional Integer $nonzero

-     * @return String

-     */

-    function _random($bytes, $nonzero = false)

-    {

-        $temp = '';

-        if ($nonzero) {

-            for ($i = 0; $i < $bytes; $i++) {

-                $temp.= chr(crypt_random(1, 255));

-            }

-        } else {

-            $ints = ($bytes + 1) >> 2;

-            for ($i = 0; $i < $ints; $i++) {

-                $temp.= pack('N', crypt_random());

-            }

-            $temp = substr($temp, 0, $bytes);

-        }

-        return $temp;

-    }

-

-    /**

-     * Integer-to-Octet-String primitive

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-4.1 RFC3447#section-4.1}.

-     *

-     * @access private

-     * @param Math_BigInteger $x

-     * @param Integer $xLen

-     * @return String

-     */

-    function _i2osp($x, $xLen)

-    {

-        $x = $x->toBytes();

-        if (strlen($x) > $xLen) {

-            user_error('Integer too large', E_USER_NOTICE);

-            return false;

-        }

-        return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);

-    }

-

-    /**

-     * Octet-String-to-Integer primitive

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-4.2 RFC3447#section-4.2}.

-     *

-     * @access private

-     * @param String $x

-     * @return Math_BigInteger

-     */

-    function _os2ip($x)

-    {

-        return new Math_BigInteger($x, 256);

-    }

-

-    /**

-     * Exponentiate with or without Chinese Remainder Theorem

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.2}.

-     *

-     * @access private

-     * @param Math_BigInteger $x

-     * @return Math_BigInteger

-     */

-    function _exponentiate($x)

-    {

-        if (empty($this->primes) || empty($this->coefficients) || empty($this->exponents)) {

-            return $x->modPow($this->exponent, $this->modulus);

-        }

-

-        $num_primes = count($this->primes);

-        $m_i = array(

-            1 => $x->modPow($this->exponents[1], $this->primes[1]),

-            2 => $x->modPow($this->exponents[2], $this->primes[2])

-        );

-        $h = $m_i[1]->subtract($m_i[2]);

-        $h = $h->multiply($this->coefficients[2]);

-        list(, $h) = $h->divide($this->primes[1]);

-        $m = $m_i[2]->add($h->multiply($this->primes[2]));

-

-        $r = $this->primes[1];

-        for ($i = 3; $i <= $num_primes; $i++) {

-            $m_i = $x->modPow($this->exponents[$i], $this->primes[$i]);

-

-            $r = $r->multiply($this->primes[$i - 1]);

-

-            $h = $m_i->subtract($m);

-            $h = $h->multiply($this->coefficients[$i]);

-            list(, $h) = $h->divide($this->primes[$i]);

-

-            $m = $m->add($r->multiply($h));

-        }

-

-        return $m;

-    }

-

-    /**

-     * RSAEP

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.1}.

-     *

-     * @access private

-     * @param Math_BigInteger $m

-     * @return Math_BigInteger

-     */

-    function _rsaep($m)

-    {

-        if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {

-            user_error('Message representative out of range', E_USER_NOTICE);

-            return false;

-        }

-        return $this->_exponentiate($m);

-    }

-

-    /**

-     * RSADP

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.2 RFC3447#section-5.1.2}.

-     *

-     * @access private

-     * @param Math_BigInteger $c

-     * @return Math_BigInteger

-     */

-    function _rsadp($c)

-    {

-        if ($c->compare($this->zero) < 0 || $c->compare($this->modulus) > 0) {

-            user_error('Ciphertext representative out of range', E_USER_NOTICE);

-            return false;

-        }

-        return $this->_exponentiate($c);

-    }

-

-    /**

-     * RSASP1

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.1 RFC3447#section-5.2.1}.

-     *

-     * @access private

-     * @param Math_BigInteger $m

-     * @return Math_BigInteger

-     */

-    function _rsasp1($m)

-    {

-        if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {

-            user_error('Message representative out of range', E_USER_NOTICE);

-            return false;

-        }

-        return $this->_exponentiate($m);

-    }

-

-    /**

-     * RSAVP1

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.2 RFC3447#section-5.2.2}.

-     *

-     * @access private

-     * @param Math_BigInteger $s

-     * @return Math_BigInteger

-     */

-    function _rsavp1($s)

-    {

-        if ($s->compare($this->zero) < 0 || $s->compare($this->modulus) > 0) {

-            user_error('Signature representative out of range', E_USER_NOTICE);

-            return false;

-        }

-        return $this->_exponentiate($s);

-    }

-

-    /**

-     * MGF1

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-B.2.1 RFC3447#section-B.2.1}.

-     *

-     * @access private

-     * @param String $mgfSeed

-     * @param Integer $mgfLen

-     * @return String

-     */

-    function _mgf1($mgfSeed, $maskLen)

-    {

-        // if $maskLen would yield strings larger than 4GB, PKCS#1 suggests a "Mask too long" error be output.

-

-        $t = '';

-        $count = ceil($maskLen / $this->hLen);

-        for ($i = 0; $i < $count; $i++) {

-            $c = pack('N', $i);

-            $t.= $this->mgfHash->hash($mgfSeed . $c);

-        }

-

-        return substr($t, 0, $maskLen);

-    }

-

-    /**

-     * RSAES-OAEP-ENCRYPT

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.1 RFC3447#section-7.1.1} and

-     * {http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding OAES}.

-     *

-     * @access private

-     * @param String $m

-     * @param String $l

-     * @return String

-     */

-    function _rsaes_oaep_encrypt($m, $l = '')

-    {

-        $mLen = strlen($m);

-

-        // Length checking

-

-        // if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error

-        // be output.

-

-        if ($mLen > $this->k - 2 * $this->hLen - 2) {

-            user_error('Message too long', E_USER_NOTICE);

-            return false;

-        }

-

-        // EME-OAEP encoding

-

-        $lHash = $this->hash->hash($l);

-        $ps = str_repeat(chr(0), $this->k - $mLen - 2 * $this->hLen - 2);

-        $db = $lHash . $ps . chr(1) . $m;

-        $seed = $this->_random($this->hLen);

-        $dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);

-        $maskedDB = $db ^ $dbMask;

-        $seedMask = $this->_mgf1($maskedDB, $this->hLen);

-        $maskedSeed = $seed ^ $seedMask;

-        $em = chr(0) . $maskedSeed . $maskedDB;

-

-        // RSA encryption

-

-        $m = $this->_os2ip($em);

-        $c = $this->_rsaep($m);

-        $c = $this->_i2osp($c, $this->k);

-

-        // Output the ciphertext C

-

-        return $c;

-    }

-

-    /**

-     * RSAES-OAEP-DECRYPT

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.2 RFC3447#section-7.1.2}.  The fact that the error

-     * messages aren't distinguishable from one another hinders debugging, but, to quote from RFC3447#section-7.1.2:

-     * 

-     *    Note.  Care must be taken to ensure that an opponent cannot

-     *    distinguish the different error conditions in Step 3.g, whether by

-     *    error message or timing, or, more generally, learn partial

-     *    information about the encoded message EM.  Otherwise an opponent may

-     *    be able to obtain useful information about the decryption of the

-     *    ciphertext C, leading to a chosen-ciphertext attack such as the one

-     *    observed by Manger [36].

-     *

-     * As for $l...  to quote from {@link http://tools.ietf.org/html/rfc3447#page-17 RFC3447#page-17}:

-     *

-     *    Both the encryption and the decryption operations of RSAES-OAEP take

-     *    the value of a label L as input.  In this version of PKCS #1, L is

-     *    the empty string; other uses of the label are outside the scope of

-     *    this document.

-     *

-     * @access private

-     * @param String $c

-     * @param String $l

-     * @return String

-     */

-    function _rsaes_oaep_decrypt($c, $l = '')

-    {

-        // Length checking

-

-        // if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error

-        // be output.

-

-        if (strlen($c) != $this->k || $this->k < 2 * $this->hLen + 2) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-

-        // RSA decryption

-

-        $c = $this->_os2ip($c);

-        $m = $this->_rsadp($c);

-        if ($m === false) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-        $em = $this->_i2osp($m, $this->k);

-

-        // EME-OAEP decoding

-

-        $lHash = $this->hash->hash($l);

-        $y = ord($em[0]);

-        $maskedSeed = substr($em, 1, $this->hLen);

-        $maskedDB = substr($em, $this->hLen + 1);

-        $seedMask = $this->_mgf1($maskedDB, $this->hLen);

-        $seed = $maskedSeed ^ $seedMask;

-        $dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);

-        $db = $maskedDB ^ $dbMask;

-        $lHash2 = substr($db, 0, $this->hLen);

-        $m = substr($db, $this->hLen);

-        if ($lHash != $lHash2) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-        $m = ltrim($m, chr(0));

-        if (ord($m[0]) != 1) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-

-        // Output the message M

-

-        return substr($m, 1);

-    }

-

-    /**

-     * RSAES-PKCS1-V1_5-ENCRYPT

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.1 RFC3447#section-7.2.1}.

-     *

-     * @access private

-     * @param String $m

-     * @return String

-     */

-    function _rsaes_pkcs1_v1_5_encrypt($m)

-    {

-        $mLen = strlen($m);

-

-        // Length checking

-

-        if ($mLen > $this->k - 11) {

-            user_error('Message too long', E_USER_NOTICE);

-            return false;

-        }

-

-        // EME-PKCS1-v1_5 encoding

-

-        $ps = $this->_random($this->k - $mLen - 3, true);

-        $em = chr(0) . chr(2) . $ps . chr(0) . $m;

-

-        // RSA encryption

-        $m = $this->_os2ip($em);

-        $c = $this->_rsaep($m);

-        $c = $this->_i2osp($c, $this->k);

-

-        // Output the ciphertext C

-

-        return $c;

-    }

-

-    /**

-     * RSAES-PKCS1-V1_5-DECRYPT

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.2 RFC3447#section-7.2.2}.

-     *

-     * @access private

-     * @param String $c

-     * @return String

-     */

-    function _rsaes_pkcs1_v1_5_decrypt($c)

-    {

-        // Length checking

-

-        if (strlen($c) != $this->k) { // or if k < 11

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-

-        // RSA decryption

-

-        $c = $this->_os2ip($c);

-        $m = $this->_rsadp($c);

-        if ($m === false) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-        $em = $this->_i2osp($m, $this->k);

-

-        // EME-PKCS1-v1_5 decoding

-

-        if (ord($em[0]) != 0 || ord($em[1]) != 2) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-

-        $ps = substr($em, 2, strpos($em, chr(0), 2) - 2);

-        $m = substr($em, strlen($ps) + 3);

-

-        if (strlen($ps) < 8) {

-            user_error('Decryption error', E_USER_NOTICE);

-            return false;

-        }

-

-        // Output M

-

-        return $m;

-    }

-

-    /**

-     * EMSA-PSS-ENCODE

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.1 RFC3447#section-9.1.1}.

-     *

-     * @access private

-     * @param String $m

-     * @param Integer $emBits

-     */

-    function _emsa_pss_encode($m, $emBits)

-    {

-        // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error

-        // be output.

-

-        $emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8)

-        $sLen = $this->sLen == false ? $this->hLen : $this->sLen;

-

-        $mHash = $this->hash->hash($m);

-        if ($emLen < $this->hLen + $sLen + 2) {

-            user_error('Encoding error', E_USER_NOTICE);

-            return false;

-        }

-

-        $salt = $this->_random($sLen);

-        $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;

-        $h = $this->hash->hash($m2);

-        $ps = str_repeat(chr(0), $emLen - $sLen - $this->hLen - 2);

-        $db = $ps . chr(1) . $salt;

-        $dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);

-        $maskedDB = $db ^ $dbMask;

-        $maskedDB[0] = ~chr(0xFF << ($emBits & 7)) & $maskedDB[0];

-        $em = $maskedDB . $h . chr(0xBC);

-

-        return $em;

-    }

-

-    /**

-     * EMSA-PSS-VERIFY

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.2 RFC3447#section-9.1.2}.

-     *

-     * @access private

-     * @param String $m

-     * @param String $em

-     * @param Integer $emBits

-     * @return String

-     */

-    function _emsa_pss_verify($m, $em, $emBits)

-    {

-        // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error

-        // be output.

-

-        $emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8);

-        $sLen = $this->sLen == false ? $this->hLen : $this->sLen;

-

-        $mHash = $this->hash->hash($m);

-        if ($emLen < $this->hLen + $sLen + 2) {

-            return false;

-        }

-

-        if ($em[strlen($em) - 1] != chr(0xBC)) {

-            return false;

-        }

-

-        $maskedDB = substr($em, 0, $em - $this->hLen - 1);

-        $h = substr($em, $em - $this->hLen - 1, $this->hLen);

-        $temp = chr(0xFF << ($emBits & 7));

-        if ((~$maskedDB[0] & $temp) != $temp) {

-            return false;

-        }

-        $dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);

-        $db = $maskedDB ^ $dbMask;

-        $db[0] = ~chr(0xFF << ($emBits & 7)) & $db[0];

-        $temp = $emLen - $this->hLen - $sLen - 2;

-        if (substr($db, 0, $temp) != str_repeat(chr(0), $temp) || ord($db[$temp]) != 1) {

-            return false;

-        }

-        $salt = substr($db, $temp + 1); // should be $sLen long

-        $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;

-        $h2 = $this->hash->hash($m2);

-        return $h == $h2;

-    }

-

-    /**

-     * RSASSA-PSS-SIGN

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.1 RFC3447#section-8.1.1}.

-     *

-     * @access private

-     * @param String $m

-     * @return String

-     */

-    function _rsassa_pss_sign($m)

-    {

-        // EMSA-PSS encoding

-

-        $em = $this->_emsa_pss_encode($m, 8 * $this->k - 1);

-

-        // RSA signature

-

-        $m = $this->_os2ip($em);

-        $s = $this->_rsasp1($m);

-        $s = $this->_i2osp($s, $this->k);

-

-        // Output the signature S

-

-        return $s;

-    }

-

-    /**

-     * RSASSA-PSS-VERIFY

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.2 RFC3447#section-8.1.2}.

-     *

-     * @access private

-     * @param String $m

-     * @param String $s

-     * @return String

-     */

-    function _rsassa_pss_verify($m, $s)

-    {

-        // Length checking

-

-        if (strlen($s) != $this->k) {

-            user_error('Invalid signature', E_USER_NOTICE);

-            return false;

-        }

-

-        // RSA verification

-

-        $modBits = 8 * $this->k;

-

-        $s2 = $this->_os2ip($s);

-        $m2 = $this->_rsavp1($s2);

-        if ($m2 === false) {

-            user_error('Invalid signature', E_USER_NOTICE);

-            return false;

-        }

-        $em = $this->_i2osp($m2, $modBits >> 3);

-        if ($em === false) {

-            user_error('Invalid signature', E_USER_NOTICE);

-            return false;

-        }

-

-        // EMSA-PSS verification

-

-        return $this->_emsa_pss_verify($m, $em, $modBits - 1);

-    }

-

-    /**

-     * EMSA-PKCS1-V1_5-ENCODE

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-9.2 RFC3447#section-9.2}.

-     *

-     * @access private

-     * @param String $m

-     * @param Integer $emLen

-     * @return String

-     */

-    function _emsa_pkcs1_v1_5_encode($m, $emLen)

-    {

-        $h = $this->hash->hash($m);

-        if ($h === false) {

-            return false;

-        }

-

-        // see http://tools.ietf.org/html/rfc3447#page-43

-        switch ($this->hashName) {

-            case 'md2':

-                $t = pack('H*', '3020300c06082a864886f70d020205000410');

-                break;

-            case 'md5':

-                $t = pack('H*', '3020300c06082a864886f70d020505000410');

-                break;

-            case 'sha1':

-                $t = pack('H*', '3021300906052b0e03021a05000414');

-                break;

-            case 'sha256':

-                $t = pack('H*', '3031300d060960864801650304020105000420');

-                break;

-            case 'sha384':

-                $t = pack('H*', '3041300d060960864801650304020205000430');

-                break;

-            case 'sha512':

-                $t = pack('H*', '3051300d060960864801650304020305000440');

-        }

-        $t.= $h;

-        $tLen = strlen($t);

-

-        if ($emLen < $tLen + 11) {

-            user_error('Intended encoded message length too short', E_USER_NOTICE);

-            return false;

-        }

-

-        $ps = str_repeat(chr(0xFF), $emLen - $tLen - 3);

-

-        $em = "\0\1$ps\0$t";

-

-        return $em;

-    }

-

-    /**

-     * RSASSA-PKCS1-V1_5-SIGN

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.1 RFC3447#section-8.2.1}.

-     *

-     * @access private

-     * @param String $m

-     * @return String

-     */

-    function _rsassa_pkcs1_v1_5_sign($m)

-    {

-        // EMSA-PKCS1-v1_5 encoding

-

-        $em = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);

-        if ($em === false) {

-            user_error('RSA modulus too short', E_USER_NOTICE);

-            return false;

-        }

-

-        // RSA signature

-

-        $m = $this->_os2ip($em);

-        $s = $this->_rsasp1($m);

-        $s = $this->_i2osp($s, $this->k);

-

-        // Output the signature S

-

-        return $s;

-    }

-

-    /**

-     * RSASSA-PKCS1-V1_5-VERIFY

-     *

-     * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.2 RFC3447#section-8.2.2}.

-     *

-     * @access private

-     * @param String $m

-     * @return String

-     */

-    function _rsassa_pkcs1_v1_5_verify($m, $s)

-    {

-        // Length checking

-

-        if (strlen($s) != $this->k) {

-            user_error('Invalid signature', E_USER_NOTICE);

-            return false;

-        }

-

-        // RSA verification

-

-        $s = $this->_os2ip($s);

-        $m2 = $this->_rsavp1($s);

-        if ($m2 === false) {

-            user_error('Invalid signature', E_USER_NOTICE);

-            return false;

-        }

-        $em = $this->_i2osp($m2, $this->k);

-        if ($em === false) {

-            user_error('Invalid signature', E_USER_NOTICE);

-            return false;

-        }

-

-        // EMSA-PKCS1-v1_5 encoding

-

-        $em2 = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);

-        if ($em2 === false) {

-            user_error('RSA modulus too short', E_USER_NOTICE);

-            return false;

-        }

-

-        // Compare

-

-        return $em == $em2;

-    }

-

-    /**

-     * Set Encryption Mode

-     *

-     * Valid values include CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_ENCRYPTION_PKCS1.

-     *

-     * @access public

-     * @param Integer $mode

-     */

-    function setEncryptionMode($mode)

-    {

-        $this->encryptionMode = $mode;

-    }

-

-    /**

-     * Set Signature Mode

-     *

-     * Valid values include CRYPT_RSA_SIGNATURE_PSS and CRYPT_RSA_SIGNATURE_PKCS1

-     *

-     * @access public

-     * @param Integer $mode

-     */

-    function setSignatureMode($mode)

-    {

-        $this->signatureMode = $mode;

-    }

-

-    /**

-     * Encryption

-     *

-     * Both CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_ENCRYPTION_PKCS1 both place limits on how long $plaintext can be.

-     * If $plaintext exceeds those limits it will be broken up so that it does and the resultant ciphertext's will

-     * be concatenated together.

-     *

-     * @see decrypt()

-     * @access public

-     * @param String $plaintext

-     * @return String

-     */

-    function encrypt($plaintext)

-    {

-        switch ($this->encryptionMode) {

-            case CRYPT_RSA_ENCRYPTION_PKCS1:

-                $plaintext = str_split($plaintext, $this->k - 11);

-                $ciphertext = '';

-                foreach ($plaintext as $m) {

-                    $ciphertext.= $this->_rsaes_pkcs1_v1_5_encrypt($m);

-                }

-                return $ciphertext;

-            //case CRYPT_RSA_ENCRYPTION_OAEP:

-            default:

-                $plaintext = str_split($plaintext, $this->k - 2 * $this->hLen - 2);

-                $ciphertext = '';

-                foreach ($plaintext as $m) {

-                    $ciphertext.= $this->_rsaes_oaep_encrypt($m);

-                }

-                return $ciphertext;

-        }

-    }

-

-    /**

-     * Decryption

-     *

-     * @see encrypt()

-     * @access public

-     * @param String $plaintext

-     * @return String

-     */

-    function decrypt($ciphertext)

-    {

-        switch ($this->encryptionMode) {

-            case CRYPT_RSA_ENCRYPTION_PKCS1:

-                $ciphertext = str_split($ciphertext, $this->k);

-                $plaintext = '';

-                foreach ($ciphertext as $c) {

-                    $temp = $this->_rsaes_pkcs1_v1_5_decrypt($c);

-                    if ($temp === false) {

-                        return false;

-                    }

-                    $plaintext.= $temp;

-                }

-                return $plaintext;

-            //case CRYPT_RSA_ENCRYPTION_OAEP:

-            default:

-                $ciphertext = str_split($ciphertext, $this->k);

-                $plaintext = '';

-                foreach ($ciphertext as $c) {

-                    $temp = $this->_rsaes_oaep_decrypt($c);

-                    if ($temp === false) {

-                        return false;

-                    }

-                    $plaintext.= $temp;

-                }

-                return $plaintext;

-        }

-    }

-

-    /**

-     * Create a signature

-     *

-     * @see verify()

-     * @access public

-     * @param String $message

-     * @return String

-     */

-    function sign($message)

-    {

-        switch ($this->signatureMode) {

-            case CRYPT_RSA_SIGNATURE_PKCS1:

-                return $this->_rsassa_pkcs1_v1_5_sign($message);

-            //case CRYPT_RSA_SIGNATURE_PSS:

-            default:

-                return $this->_rsassa_pss_sign($message);

-        }

-    }

-

-    /**

-     * Verifies a signature

-     *

-     * @see sign()

-     * @access public

-     * @param String $message

-     * @param String $signature

-     * @return Boolean

-     */

-    function verify($message, $signature)

-    {

-        switch ($this->signatureMode) {

-            case CRYPT_RSA_SIGNATURE_PKCS1:

-                return $this->_rsassa_pkcs1_v1_5_verify($message, $signature);

-            //case CRYPT_RSA_SIGNATURE_PSS:

-            default:

-                return $this->_rsassa_pss_verify($message, $signature);

-        }

-    }

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP PKCS#1 (v2.1) compliant implementation of RSA.
+ *
+ * PHP versions 4 and 5
+ *
+ * Here's an example of how to encrypt and decrypt text with this library:
+ * <code>
+ * <?php
+ *    include('Crypt/RSA.php');
+ *
+ *    $rsa = new Crypt_RSA();
+ *    extract($rsa->createKey());
+ *
+ *    $plaintext = 'terrafrost';
+ *
+ *    $rsa->loadKey($privatekey);
+ *    $ciphertext = $rsa->encrypt($plaintext);
+ *
+ *    $rsa->loadKey($publickey);
+ *    echo $rsa->decrypt($ciphertext);
+ * ?>
+ * </code>
+ *
+ * Here's an example of how to create signatures and verify signatures with this library:
+ * <code>
+ * <?php
+ *    include('Crypt/RSA.php');
+ *
+ *    $rsa = new Crypt_RSA();
+ *    extract($rsa->createKey());
+ *
+ *    $plaintext = 'terrafrost';
+ *
+ *    $rsa->loadKey($privatekey);
+ *    $signature = $rsa->sign($plaintext);
+ *
+ *    $rsa->loadKey($publickey);
+ *    echo $rsa->verify($plaintext, $signature) ? 'verified' : 'unverified';
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_RSA
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMIX Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: RSA.php,v 1.14 2010/03/01 17:28:19 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**
+ * Include Math_BigInteger
+ */
+require_once('Math/BigInteger.php');
+
+/**
+ * Include Crypt_Random
+ */
+require_once('Crypt/Random.php');
+
+/**
+ * Include Crypt_Hash
+ */
+require_once('Crypt/Hash.php');
+
+/**#@+
+ * @access public
+ * @see Crypt_RSA::encrypt()
+ * @see Crypt_RSA::decrypt()
+ */
+/**
+ * Use {@link http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding Optimal Asymmetric Encryption Padding}
+ * (OAEP) for encryption / decryption.
+ *
+ * Uses sha1 by default.
+ *
+ * @see Crypt_RSA::setHash()
+ * @see Crypt_RSA::setMGFHash()
+ */
+define('CRYPT_RSA_ENCRYPTION_OAEP',  1);
+/**
+ * Use PKCS#1 padding.
+ *
+ * Although CRYPT_RSA_ENCRYPTION_OAEP offers more security, including PKCS#1 padding is necessary for purposes of backwards
+ * compatability with protocols (like SSH-1) written before OAEP's introduction.
+ */
+define('CRYPT_RSA_ENCRYPTION_PKCS1', 2);
+/**#@-*/
+
+/**#@+
+ * @access public
+ * @see Crypt_RSA::sign()
+ * @see Crypt_RSA::verify()
+ * @see Crypt_RSA::setHash()
+ */
+/**
+ * Use the Probabilistic Signature Scheme for signing
+ *
+ * Uses sha1 by default.
+ *
+ * @see Crypt_RSA::setSaltLength()
+ * @see Crypt_RSA::setMGFHash()
+ */
+define('CRYPT_RSA_SIGNATURE_PSS',  1);
+/**
+ * Use the PKCS#1 scheme by default.
+ *
+ * Although CRYPT_RSA_SIGNATURE_PSS offers more security, including PKCS#1 signing is necessary for purposes of backwards
+ * compatability with protocols (like SSH-2) written before PSS's introduction.
+ */
+define('CRYPT_RSA_SIGNATURE_PKCS1', 2);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_RSA::createKey()
+ */
+/**
+ * ASN1 Integer
+ */
+define('CRYPT_RSA_ASN1_INTEGER',   2);
+/**
+ * ASN1 Sequence (with the constucted bit set)
+ */
+define('CRYPT_RSA_ASN1_SEQUENCE', 48);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_RSA::Crypt_RSA()
+ */
+/**
+ * To use the pure-PHP implementation
+ */
+define('CRYPT_RSA_MODE_INTERNAL', 1);
+/**
+ * To use the OpenSSL library
+ *
+ * (if enabled; otherwise, the internal implementation will be used)
+ */
+define('CRYPT_RSA_MODE_OPENSSL', 2);
+/**#@-*/
+
+/**#@+
+ * @access public
+ * @see Crypt_RSA::createKey()
+ * @see Crypt_RSA::setPrivateKeyFormat()
+ */
+/**
+ * PKCS#1 formatted private key
+ *
+ * Used by OpenSSH
+ */
+define('CRYPT_RSA_PRIVATE_FORMAT_PKCS1', 0);
+/**#@-*/
+
+/**#@+
+ * @access public
+ * @see Crypt_RSA::createKey()
+ * @see Crypt_RSA::setPublicKeyFormat()
+ */
+/**
+ * Raw public key
+ *
+ * An array containing two Math_BigInteger objects.
+ *
+ * The exponent can be indexed with any of the following:
+ *
+ * 0, e, exponent, publicExponent
+ *
+ * The modulus can be indexed with any of the following:
+ *
+ * 1, n, modulo, modulus
+ */
+define('CRYPT_RSA_PUBLIC_FORMAT_RAW', 1);
+/**
+ * PKCS#1 formatted public key
+ */
+define('CRYPT_RSA_PUBLIC_FORMAT_PKCS1', 2);
+/**
+ * OpenSSH formatted public key
+ *
+ * Place in $HOME/.ssh/authorized_keys
+ */
+define('CRYPT_RSA_PUBLIC_FORMAT_OPENSSH', 3);
+/**#@-*/
+
+/**
+ * Pure-PHP PKCS#1 compliant implementation of RSA.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_RSA
+ */
+class Crypt_RSA {
+    /**
+     * Precomputed Zero
+     *
+     * @var Array
+     * @access private
+     */
+    var $zero;
+
+    /**
+     * Precomputed One
+     *
+     * @var Array
+     * @access private
+     */
+    var $one;
+
+    /**
+     * Private Key Format
+     *
+     * @var Integer
+     * @access private
+     */
+    var $privateKeyFormat = CRYPT_RSA_PRIVATE_FORMAT_PKCS1;
+
+    /**
+     * Public Key Format
+     *
+     * @var Integer
+     * @access public
+     */
+    var $publicKeyFormat = CRYPT_RSA_PUBLIC_FORMAT_PKCS1;
+
+    /**
+     * Modulus (ie. n)
+     *
+     * @var Math_BigInteger
+     * @access private
+     */
+    var $modulus;
+
+    /**
+     * Modulus length
+     *
+     * @var Math_BigInteger
+     * @access private
+     */
+    var $k;
+
+    /**
+     * Exponent (ie. e or d)
+     *
+     * @var Math_BigInteger
+     * @access private
+     */
+    var $exponent;
+
+    /**
+     * Primes for Chinese Remainder Theorem (ie. p and q)
+     *
+     * @var Array
+     * @access private
+     */
+    var $primes;
+
+    /**
+     * Exponents for Chinese Remainder Theorem (ie. dP and dQ)
+     *
+     * @var Array
+     * @access private
+     */
+    var $exponents;
+
+    /**
+     * Coefficients for Chinese Remainder Theorem (ie. qInv)
+     *
+     * @var Array
+     * @access private
+     */
+    var $coefficients;
+
+    /**
+     * Hash name
+     *
+     * @var String
+     * @access private
+     */
+    var $hashName;
+
+    /**
+     * Hash function
+     *
+     * @var Crypt_Hash
+     * @access private
+     */
+    var $hash;
+
+    /**
+     * Length of hash function output
+     *
+     * @var Integer
+     * @access private
+     */
+    var $hLen;
+
+    /**
+     * Length of salt
+     *
+     * @var Integer
+     * @access private
+     */
+    var $sLen;
+
+    /**
+     * Hash function for the Mask Generation Function
+     *
+     * @var Crypt_Hash
+     * @access private
+     */
+    var $mgfHash;
+
+    /**
+     * Length of MGF hash function output
+     *
+     * @var Integer
+     * @access private
+     */
+    var $mgfHLen;
+
+    /**
+     * Encryption mode
+     *
+     * @var Integer
+     * @access private
+     */
+    var $encryptionMode = CRYPT_RSA_ENCRYPTION_OAEP;
+
+    /**
+     * Signature mode
+     *
+     * @var Integer
+     * @access private
+     */
+    var $signatureMode = CRYPT_RSA_SIGNATURE_PSS;
+
+    /**
+     * Public Exponent
+     *
+     * @var Mixed
+     * @access private
+     */
+    var $publicExponent = false;
+
+    /**
+     * Password
+     *
+     * @var String
+     * @access private
+     */
+    var $password = '';
+
+    /**
+     * The constructor
+     *
+     * If you want to make use of the openssl extension, you'll need to set the mode manually, yourself.  The reason
+     * Crypt_RSA doesn't do it is because OpenSSL doesn't fail gracefully.  openssl_pkey_new(), in particular, requires
+     * openssl.cnf be present somewhere and, unfortunately, the only real way to find out is too late.
+     *
+     * @return Crypt_RSA
+     * @access public
+     */
+    function Crypt_RSA()
+    {
+        if ( !defined('CRYPT_RSA_MODE') ) {
+            switch (true) {
+                //case extension_loaded('openssl') && version_compare(PHP_VERSION, '4.2.0', '>='):
+                //    define('CRYPT_RSA_MODE', CRYPT_RSA_MODE_OPENSSL);
+                //    break;
+                default:
+                    define('CRYPT_RSA_MODE', CRYPT_RSA_MODE_INTERNAL);
+            }
+        }
+
+        $this->zero = new Math_BigInteger();
+        $this->one = new Math_BigInteger(1);
+
+        $this->hash = new Crypt_Hash('sha1');
+        $this->hLen = $this->hash->getLength();
+        $this->hashName = 'sha1';
+        $this->mgfHash = new Crypt_Hash('sha1');
+        $this->mgfHLen = $this->mgfHash->getLength();
+    }
+
+    /**
+     * Create public / private key pair
+     *
+     * Returns an array with the following three elements:
+     *  - 'privatekey': The private key.
+     *  - 'publickey':  The public key.
+     *  - 'partialkey': A partially computed key (if the execution time exceeded $timeout).
+     *                  Will need to be passed back to Crypt_RSA::createKey() as the third parameter for further processing.
+     *
+     * @access public
+     * @param optional Integer $bits
+     * @param optional Integer $timeout
+     * @param optional Math_BigInteger $p
+     */
+    function createKey($bits = 1024, $timeout = false, $partial = array())
+    {
+        if ( CRYPT_RSA_MODE == CRYPT_RSA_MODE_OPENSSL ) {
+            $rsa = openssl_pkey_new(array('private_key_bits' => $bits));
+            openssl_pkey_export($rsa, $privatekey);
+            $publickey = openssl_pkey_get_details($rsa);
+            $publickey = $publickey['key'];
+
+            if ($this->privateKeyFormat != CRYPT_RSA_PRIVATE_FORMAT_PKCS1) {
+                $privatekey = call_user_func_array(array($this, '_convertPrivateKey'), array_values($this->_parseKey($privatekey, CRYPT_RSA_PRIVATE_FORMAT_PKCS1)));
+                $publickey = call_user_func_array(array($this, '_convertPublicKey'), array_values($this->_parseKey($publickey, CRYPT_RSA_PUBLIC_FORMAT_PKCS1)));
+            }
+
+            return array(
+                'privatekey' => $privatekey,
+                'publickey' => $publickey,
+                'partialkey' => false
+            );
+        }
+
+        static $e;
+        if (!isset($e)) {
+            if (!defined('CRYPT_RSA_EXPONENT')) {
+                // http://en.wikipedia.org/wiki/65537_%28number%29
+                define('CRYPT_RSA_EXPONENT', '65537');
+            }
+            if (!defined('CRYPT_RSA_COMMENT')) {
+                define('CRYPT_RSA_COMMENT', 'phpseclib-generated-key');
+            }
+            // per <http://cseweb.ucsd.edu/~hovav/dist/survey.pdf#page=5>, this number ought not result in primes smaller
+            // than 256 bits.
+            if (!defined('CRYPT_RSA_SMALLEST_PRIME')) {
+                define('CRYPT_RSA_SMALLEST_PRIME', 4096);
+            }
+
+            $e = new Math_BigInteger(CRYPT_RSA_EXPONENT);
+        }
+
+        extract($this->_generateMinMax($bits));
+        $absoluteMin = $min;
+        $temp = $bits >> 1;
+        if ($temp > CRYPT_RSA_SMALLEST_PRIME) {
+            $num_primes = floor($bits / CRYPT_RSA_SMALLEST_PRIME);
+            $temp = CRYPT_RSA_SMALLEST_PRIME;
+        } else {
+            $num_primes = 2;
+        }
+        extract($this->_generateMinMax($temp + $bits % $temp));
+        $finalMax = $max;
+        extract($this->_generateMinMax($temp));
+
+        $generator = new Math_BigInteger();
+        $generator->setRandomGenerator('crypt_random');
+
+        $n = $this->one->copy();
+        if (!empty($partial)) {
+            extract(unserialize($partial));
+        } else {
+            $exponents = $coefficients = $primes = array();
+            $lcm = array(
+                'top' => $this->one->copy(),
+                'bottom' => false
+            );
+        }
+
+        $start = time();
+        $i0 = count($primes) + 1;
+
+        do {
+            for ($i = $i0; $i <= $num_primes; $i++) {
+                if ($timeout !== false) {
+                    $timeout-= time() - $start;
+                    $start = time();
+                    if ($timeout <= 0) {
+                        return serialize(array(
+                            'privatekey' => '',
+                            'publickey'  => '',
+                            'partialkey' => array(
+                                'primes' => $primes,
+                                'coefficients' => $coefficients,
+                                'lcm' => $lcm,
+                                'exponents' => $exponents
+                            )
+                        ));
+                    }
+                }
+
+                if ($i == $num_primes) {
+                    list($min, $temp) = $absoluteMin->divide($n);
+                    if (!$temp->equals($this->zero)) {
+                        $min = $min->add($this->one); // ie. ceil()
+                    }
+                    $primes[$i] = $generator->randomPrime($min, $finalMax, $timeout);
+                } else {
+                    $primes[$i] = $generator->randomPrime($min, $max, $timeout);
+                }
+
+                if ($primes[$i] === false) { // if we've reached the timeout
+                    return array(
+                        'privatekey' => '',
+                        'publickey'  => '',
+                        'partialkey' => empty($primes) ? '' : serialize(array(
+                            'primes' => array_slice($primes, 0, $i - 1),
+                            'coefficients' => $coefficients,
+                            'lcm' => $lcm,
+                            'exponents' => $exponents
+                        ))
+                    );
+                }
+
+                // the first coefficient is calculated differently from the rest
+                // ie. instead of being $primes[1]->modInverse($primes[2]), it's $primes[2]->modInverse($primes[1])
+                if ($i > 2) {
+                    $coefficients[$i] = $n->modInverse($primes[$i]);
+                }
+
+                $n = $n->multiply($primes[$i]);
+
+                $temp = $primes[$i]->subtract($this->one);
+
+                // textbook RSA implementations use Euler's totient function instead of the least common multiple.
+                // see http://en.wikipedia.org/wiki/Euler%27s_totient_function
+                $lcm['top'] = $lcm['top']->multiply($temp);
+                $lcm['bottom'] = $lcm['bottom'] === false ? $temp : $lcm['bottom']->gcd($temp);
+
+                $exponents[$i] = $e->modInverse($temp);
+            }
+
+            list($lcm) = $lcm['top']->divide($lcm['bottom']);
+            $gcd = $lcm->gcd($e);
+            $i0 = 1;
+        } while (!$gcd->equals($this->one));
+
+        $d = $e->modInverse($lcm);
+
+        $coefficients[2] = $primes[2]->modInverse($primes[1]);
+
+        // from <http://tools.ietf.org/html/rfc3447#appendix-A.1.2>:
+        // RSAPrivateKey ::= SEQUENCE {
+        //     version           Version,
+        //     modulus           INTEGER,  -- n
+        //     publicExponent    INTEGER,  -- e
+        //     privateExponent   INTEGER,  -- d
+        //     prime1            INTEGER,  -- p
+        //     prime2            INTEGER,  -- q
+        //     exponent1         INTEGER,  -- d mod (p-1)
+        //     exponent2         INTEGER,  -- d mod (q-1)
+        //     coefficient       INTEGER,  -- (inverse of q) mod p
+        //     otherPrimeInfos   OtherPrimeInfos OPTIONAL
+        // }
+
+        return array(
+            'privatekey' => $this->_convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients),
+            'publickey'  => $this->_convertPublicKey($n, $e),
+            'partialkey' => false
+        );
+    }
+
+    /**
+     * Convert a private key to the appropriate format.
+     *
+     * @access private
+     * @see setPrivateKeyFormat()
+     * @param String $RSAPrivateKey
+     * @return String
+     */
+    function _convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients)
+    {
+        $num_primes = count($primes);
+        $raw = array(
+            'version' => $num_primes == 2 ? chr(0) : chr(1), // two-prime vs. multi
+            'modulus' => $n->toBytes(true),
+            'publicExponent' => $e->toBytes(true),
+            'privateExponent' => $d->toBytes(true),
+            'prime1' => $primes[1]->toBytes(true),
+            'prime2' => $primes[2]->toBytes(true),
+            'exponent1' => $exponents[1]->toBytes(true),
+            'exponent2' => $exponents[2]->toBytes(true),
+            'coefficient' => $coefficients[2]->toBytes(true)
+        );
+
+        // if the format in question does not support multi-prime rsa and multi-prime rsa was used,
+        // call _convertPublicKey() instead.
+        switch ($this->privateKeyFormat) {
+            default: // eg. CRYPT_RSA_PRIVATE_FORMAT_PKCS1
+                $components = array();
+                foreach ($raw as $name => $value) {
+                    $components[$name] = pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($value)), $value);
+                }
+
+                $RSAPrivateKey = implode('', $components);
+
+                if ($num_primes > 2) {
+                    $OtherPrimeInfos = '';
+                    for ($i = 3; $i <= $num_primes; $i++) {
+                        // OtherPrimeInfos ::= SEQUENCE SIZE(1..MAX) OF OtherPrimeInfo
+                        //
+                        // OtherPrimeInfo ::= SEQUENCE {
+                        //     prime             INTEGER,  -- ri
+                        //     exponent          INTEGER,  -- di
+                        //     coefficient       INTEGER   -- ti
+                        // }
+                        $OtherPrimeInfo = pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($primes[$i]->toBytes(true))), $primes[$i]->toBytes(true));
+                        $OtherPrimeInfo.= pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($exponents[$i]->toBytes(true))), $exponents[$i]->toBytes(true));
+                        $OtherPrimeInfo.= pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($coefficients[$i]->toBytes(true))), $coefficients[$i]->toBytes(true));
+                        $OtherPrimeInfos.= pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfo)), $OtherPrimeInfo);
+                    }
+                    $RSAPrivateKey.= pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfos)), $OtherPrimeInfos);
+                }
+
+                $RSAPrivateKey = pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($RSAPrivateKey)), $RSAPrivateKey);
+
+                if (!empty($this->password)) {
+                    $iv = $this->_random(8);
+                    $symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key
+                    $symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);
+                    if (!class_exists('Crypt_TripleDES')) {
+                        require_once('Crypt/TripleDES.php');
+                    }
+                    $des = new Crypt_TripleDES();
+                    $des->setKey($symkey);
+                    $des->setIV($iv);
+                    $iv = strtoupper(bin2hex($iv));
+                    $RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .
+                                     "Proc-Type: 4,ENCRYPTED\r\n" .
+                                     "DEK-Info: DES-EDE3-CBC,$iv\r\n" .
+                                     "\r\n" .
+                                     chunk_split(base64_encode($des->encrypt($RSAPrivateKey))) .
+                                     '-----END RSA PRIVATE KEY-----';
+                } else {
+                    $RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .
+                                     chunk_split(base64_encode($RSAPrivateKey)) .
+                                     '-----END RSA PRIVATE KEY-----';
+                }
+
+                return $RSAPrivateKey;
+        }
+    }
+
+    /**
+     * Convert a public key to the appropriate format
+     *
+     * @access private
+     * @see setPublicKeyFormat()
+     * @param String $RSAPrivateKey
+     * @return String
+     */
+    function _convertPublicKey($n, $e)
+    {
+        $modulus = $n->toBytes(true);
+        $publicExponent = $e->toBytes(true);
+
+        switch ($this->publicKeyFormat) {
+            case CRYPT_RSA_PUBLIC_FORMAT_RAW:
+                return array('e' => $e->copy(), 'n' => $n->copy());
+            case CRYPT_RSA_PUBLIC_FORMAT_OPENSSH:
+                // from <http://tools.ietf.org/html/rfc4253#page-15>:
+                // string    "ssh-rsa"
+                // mpint     e
+                // mpint     n
+                $RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);
+                $RSAPublicKey = 'ssh-rsa ' . base64_encode($RSAPublicKey) . ' ' . CRYPT_RSA_COMMENT;
+
+                return $RSAPublicKey;
+            default: // eg. CRYPT_RSA_PUBLIC_FORMAT_PKCS1
+                // from <http://tools.ietf.org/html/rfc3447#appendix-A.1.1>:
+                // RSAPublicKey ::= SEQUENCE {
+                //     modulus           INTEGER,  -- n
+                //     publicExponent    INTEGER   -- e
+                // }
+                $components = array(
+                    'modulus' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($modulus)), $modulus),
+                    'publicExponent' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($publicExponent)), $publicExponent)
+                );
+
+                $RSAPublicKey = pack('Ca*a*a*',
+                    CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($components['modulus']) + strlen($components['publicExponent'])),
+                    $components['modulus'], $components['publicExponent']
+                );
+
+                $RSAPublicKey = "-----BEGIN PUBLIC KEY-----\r\n" .
+                                 chunk_split(base64_encode($RSAPublicKey)) .
+                                 '-----END PUBLIC KEY-----';
+
+                return $RSAPublicKey;
+        }
+    }
+
+    /**
+     * Break a public or private key down into its constituant components
+     *
+     * @access private
+     * @see _convertPublicKey()
+     * @see _convertPrivateKey()
+     * @param String $key
+     * @param Integer $type
+     * @return Array
+     */
+    function _parseKey($key, $type)
+    {
+        switch ($type) {
+            case CRYPT_RSA_PUBLIC_FORMAT_RAW:
+                if (!is_array($key)) {
+                    return false;
+                }
+                $components = array();
+                switch (true) {
+                    case isset($key['e']):
+                        $components['publicExponent'] = $key['e']->copy();
+                        break;
+                    case isset($key['exponent']):
+                        $components['publicExponent'] = $key['exponent']->copy();
+                        break;
+                    case isset($key['publicExponent']):
+                        $components['publicExponent'] = $key['publicExponent']->copy();
+                        break;
+                    case isset($key[0]):
+                        $components['publicExponent'] = $key[0]->copy();
+                }
+                switch (true) {
+                    case isset($key['n']):
+                        $components['modulus'] = $key['n']->copy();
+                        break;
+                    case isset($key['modulo']):
+                        $components['modulus'] = $key['modulo']->copy();
+                        break;
+                    case isset($key['modulus']):
+                        $components['modulus'] = $key['modulus']->copy();
+                        break;
+                    case isset($key[1]):
+                        $components['modulus'] = $key[1]->copy();
+                }
+                return $components;
+            case CRYPT_RSA_PRIVATE_FORMAT_PKCS1:
+            case CRYPT_RSA_PUBLIC_FORMAT_PKCS1:
+                /* Although PKCS#1 proposes a format that public and private keys can use, encrypting them is
+                   "outside the scope" of PKCS#1.  PKCS#1 then refers you to PKCS#12 and PKCS#15 if you're wanting to
+                   protect private keys, however, that's not what OpenSSL* does.  OpenSSL protects private keys by adding
+                   two new "fields" to the key - DEK-Info and Proc-Type.  These fields are discussed here:
+
+                   http://tools.ietf.org/html/rfc1421#section-4.6.1.1
+                   http://tools.ietf.org/html/rfc1421#section-4.6.1.3
+
+                   DES-EDE3-CBC as an algorithm, however, is not discussed anywhere, near as I can tell.
+                   DES-CBC and DES-EDE are discussed in RFC1423, however, DES-EDE3-CBC isn't, nor is its key derivation
+                   function.  As is, the definitive authority on this encoding scheme isn't the IETF but rather OpenSSL's
+                   own implementation.  ie. the implementation *is* the standard and any bugs that may exist in that 
+                   implementation are part of the standard, as well.
+
+                   * OpenSSL is the de facto standard.  It's utilized by OpenSSH and other projects */
+                if (preg_match('#DEK-Info: (.+),(.+)#', $key, $matches)) {
+                    $iv = pack('H*', trim($matches[2]));
+                    $symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key
+                    $symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);
+                    $ciphertext = preg_replace('#.+(\r|\n|\r\n)\1|[\r\n]|-.+-#s', '', $key);
+                    $ciphertext = preg_match('#^[a-zA-Z\d/+]*={0,2}$#', $ciphertext) ? base64_decode($ciphertext) : false;
+                    if ($ciphertext === false) {
+                        $ciphertext = $key;
+                    }
+                    switch ($matches[1]) {
+                        case 'DES-EDE3-CBC':
+                            if (!class_exists('Crypt_TripleDES')) {
+                                require_once('Crypt/TripleDES.php');
+                            }
+                            $crypto = new Crypt_TripleDES();
+                            break;
+                        case 'DES-CBC':
+                            if (!class_exists('Crypt_DES')) {
+                                require_once('Crypt/DES.php');
+                            }
+                            $crypto = new Crypt_DES();
+                            break;
+                        default:
+                            return false;
+                    }
+                    $crypto->setKey($symkey);
+                    $crypto->setIV($iv);
+                    $decoded = $crypto->decrypt($ciphertext);
+                } else {
+                    $decoded = preg_replace('#-.+-|[\r\n]#', '', $key);
+                    $decoded = preg_match('#^[a-zA-Z\d/+]*={0,2}$#', $decoded) ? base64_decode($decoded) : false;
+                }
+
+                if ($decoded !== false) {
+                    $key = $decoded;
+                }
+
+                $components = array();
+
+                if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
+                    return false;
+                }
+                if ($this->_decodeLength($key) != strlen($key)) {
+                    return false;
+                }
+
+                $tag = ord($this->_string_shift($key));
+                if ($tag == CRYPT_RSA_ASN1_SEQUENCE) {
+                    /* intended for keys for which OpenSSL's asn1parse returns the following:
+
+                        0:d=0  hl=4 l= 290 cons: SEQUENCE
+                        4:d=1  hl=2 l=  13 cons:  SEQUENCE
+                        6:d=2  hl=2 l=   9 prim:   OBJECT            :rsaEncryption
+                       17:d=2  hl=2 l=   0 prim:   NULL
+                       19:d=1  hl=4 l= 271 prim:  BIT STRING */
+                    $this->_string_shift($key, $this->_decodeLength($key));
+                    $this->_string_shift($key); // skip over the BIT STRING tag
+                    $this->_decodeLength($key); // skip over the BIT STRING length
+                    // "The initial octet shall encode, as an unsigned binary integer wtih bit 1 as the least significant bit, the number of
+                    //  unused bits in teh final subsequent octet. The number shall be in the range zero to seven."
+                    //  -- http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf (section 8.6.2.2)
+                    $this->_string_shift($key);
+                    if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
+                        return false;
+                    }
+                    if ($this->_decodeLength($key) != strlen($key)) {
+                        return false;
+                    }
+                    $tag = ord($this->_string_shift($key));
+                }
+                if ($tag != CRYPT_RSA_ASN1_INTEGER) {
+                    return false;
+                }
+
+                $length = $this->_decodeLength($key);
+                $temp = $this->_string_shift($key, $length);
+                if (strlen($temp) != 1 || ord($temp) > 2) {
+                    $components['modulus'] = new Math_BigInteger($temp, -256);
+                    $this->_string_shift($key); // skip over CRYPT_RSA_ASN1_INTEGER
+                    $length = $this->_decodeLength($key);
+                    $components[$type == CRYPT_RSA_PUBLIC_FORMAT_PKCS1 ? 'publicExponent' : 'privateExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+
+                    return $components;
+                }
+                if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_INTEGER) {
+                    return false;
+                }
+                $length = $this->_decodeLength($key);
+                $components['modulus'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['publicExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['privateExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['primes'] = array(1 => new Math_BigInteger($this->_string_shift($key, $length), -256));
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['primes'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['exponents'] = array(1 => new Math_BigInteger($this->_string_shift($key, $length), -256));
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['exponents'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                $this->_string_shift($key);
+                $length = $this->_decodeLength($key);
+                $components['coefficients'] = array(2 => new Math_BigInteger($this->_string_shift($key, $length), -256));
+
+                if (!empty($key)) {
+                    if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
+                        return false;
+                    }
+                    $this->_decodeLength($key);
+                    while (!empty($key)) {
+                        if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
+                            return false;
+                        }
+                        $this->_decodeLength($key);
+                        $key = substr($key, 1);
+                        $length = $this->_decodeLength($key);
+                        $components['primes'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                        $this->_string_shift($key);
+                        $length = $this->_decodeLength($key);
+                        $components['exponents'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                        $this->_string_shift($key);
+                        $length = $this->_decodeLength($key);
+                        $components['coefficients'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                    }
+                }
+
+                return $components;
+            case CRYPT_RSA_PUBLIC_FORMAT_OPENSSH:
+                $key = base64_decode(preg_replace('#^ssh-rsa | .+$#', '', $key));
+                if ($key === false) {
+                    return false;
+                }
+
+                $cleanup = substr($key, 0, 11) == "\0\0\0\7ssh-rsa";
+
+                extract(unpack('Nlength', $this->_string_shift($key, 4)));
+                $publicExponent = new Math_BigInteger($this->_string_shift($key, $length), -256);
+                extract(unpack('Nlength', $this->_string_shift($key, 4)));
+                $modulus = new Math_BigInteger($this->_string_shift($key, $length), -256);
+
+                if ($cleanup && strlen($key)) {
+                    extract(unpack('Nlength', $this->_string_shift($key, 4)));
+                    return array(
+                        'modulus' => new Math_BigInteger($this->_string_shift($key, $length), -256),
+                        'publicExponent' => $modulus
+                    );
+                } else {
+                    return array(
+                        'modulus' => $modulus,
+                        'publicExponent' => $publicExponent
+                    );
+                }
+        }
+    }
+
+    /**
+     * Loads a public or private key
+     *
+     * Returns true on success and false on failure (ie. an incorrect password was provided or the key was malformed)
+     *
+     * @access public
+     * @param String $key
+     * @param Integer $type optional
+     */
+    function loadKey($key, $type = CRYPT_RSA_PRIVATE_FORMAT_PKCS1)
+    {
+        $components = $this->_parseKey($key, $type);
+        if ($components === false) {
+            return false;
+        }
+
+        $this->modulus = $components['modulus'];
+        $this->k = strlen($this->modulus->toBytes());
+        $this->exponent = isset($components['privateExponent']) ? $components['privateExponent'] : $components['publicExponent'];
+        if (isset($components['primes'])) {
+            $this->primes = $components['primes'];
+            $this->exponents = $components['exponents'];
+            $this->coefficients = $components['coefficients'];
+            $this->publicExponent = $components['publicExponent'];
+        } else {
+            $this->primes = array();
+            $this->exponents = array();
+            $this->coefficients = array();
+            $this->publicExponent = false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Sets the password
+     *
+     * Private keys can be encrypted with a password.  To unset the password, pass in the empty string or false.
+     * Or rather, pass in $password such that empty($password) is true.
+     *
+     * @see createKey()
+     * @see loadKey()
+     * @access public
+     * @param String $password
+     */
+    function setPassword($password)
+    {
+        $this->password = $password;
+    }
+
+    /**
+     * Defines the public key
+     *
+     * Some private key formats define the public exponent and some don't.  Those that don't define it are problematic when
+     * used in certain contexts.  For example, in SSH-2, RSA authentication works by sending the public key along with a
+     * message signed by the private key to the server.  The SSH-2 server looks the public key up in an index of public keys
+     * and if it's present then proceeds to verify the signature.  Problem is, if your private key doesn't include the public
+     * exponent this won't work unless you manually add the public exponent.
+     *
+     * Do note that when a new key is loaded the index will be cleared.
+     *
+     * Returns true on success, false on failure
+     *
+     * @see getPublicKey()
+     * @access public
+     * @param String $key
+     * @param Integer $type optional
+     * @return Boolean
+     */
+    function setPublicKey($key, $type = CRYPT_RSA_PUBLIC_FORMAT_PKCS1)
+    {
+        $components = $this->_parseKey($key, $type);
+        if (empty($this->modulus) || !$this->modulus->equals($components['modulus'])) {
+            return false;
+        }
+        $this->publicExponent = $components['publicExponent'];
+    }
+
+    /**
+     * Returns the public key
+     *
+     * The public key is only returned under two circumstances - if the private key had the public key embedded within it
+     * or if the public key was set via setPublicKey().  If the currently loaded key is supposed to be the public key this
+     * function won't return it since this library, for the most part, doesn't distinguish between public and private keys.
+     *
+     * @see getPublicKey()
+     * @access public
+     * @param String $key
+     * @param Integer $type optional
+     */
+    function getPublicKey($type = CRYPT_RSA_PUBLIC_FORMAT_PKCS1)
+    {
+        if (empty($this->modulus) || empty($this->publicExponent)) {
+            return false;
+        }
+
+        $oldFormat = $this->publicKeyFormat;
+        $this->publicKeyFormat = $type;
+        $temp = $this->_convertPublicKey($this->modulus, $this->publicExponent);
+        $this->publicKeyFormat = $oldFormat;
+        return $temp;
+    }
+
+    /**
+     * Generates the smallest and largest numbers requiring $bits bits
+     *
+     * @access private
+     * @param Integer $bits
+     * @return Array
+     */
+    function _generateMinMax($bits)
+    {
+        $bytes = $bits >> 3;
+        $min = str_repeat(chr(0), $bytes);
+        $max = str_repeat(chr(0xFF), $bytes);
+        $msb = $bits & 7;
+        if ($msb) {
+            $min = chr(1 << ($msb - 1)) . $min;
+            $max = chr((1 << $msb) - 1) . $max;
+        } else {
+            $min[0] = chr(0x80);
+        }
+
+        return array(
+            'min' => new Math_BigInteger($min, 256),
+            'max' => new Math_BigInteger($max, 256)
+        );
+    }
+
+    /**
+     * DER-decode the length
+     *
+     * DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4.  See
+     * {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 § 8.1.3} for more information.
+     *
+     * @access private
+     * @param String $string
+     * @return Integer
+     */
+    function _decodeLength(&$string)
+    {
+        $length = ord($this->_string_shift($string));
+        if ( $length & 0x80 ) { // definite length, long form
+            $length&= 0x7F;
+            $temp = $this->_string_shift($string, $length);
+            list(, $length) = unpack('N', substr(str_pad($temp, 4, chr(0), STR_PAD_LEFT), -4));
+        }
+        return $length;
+    }
+
+    /**
+     * DER-encode the length
+     *
+     * DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4.  See
+     * {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 § 8.1.3} for more information.
+     *
+     * @access private
+     * @param Integer $length
+     * @return String
+     */
+    function _encodeLength($length)
+    {
+        if ($length <= 0x7F) {
+            return chr($length);
+        }
+
+        $temp = ltrim(pack('N', $length), chr(0));
+        return pack('Ca*', 0x80 | strlen($temp), $temp);
+    }
+
+    /**
+     * String Shift
+     *
+     * Inspired by array_shift
+     *
+     * @param String $string
+     * @param optional Integer $index
+     * @return String
+     * @access private
+     */
+    function _string_shift(&$string, $index = 1)
+    {
+        $substr = substr($string, 0, $index);
+        $string = substr($string, $index);
+        return $substr;
+    }
+
+    /**
+     * Determines the private key format
+     *
+     * @see createKey()
+     * @access public
+     * @param Integer $format
+     */
+    function setPrivateKeyFormat($format)
+    {
+        $this->privateKeyFormat = $format;
+    }
+
+    /**
+     * Determines the public key format
+     *
+     * @see createKey()
+     * @access public
+     * @param Integer $format
+     */
+    function setPublicKeyFormat($format)
+    {
+        $this->publicKeyFormat = $format;
+    }
+
+    /**
+     * Determines which hashing function should be used
+     *
+     * Used with signature production / verification and (if the encryption mode is CRYPT_RSA_ENCRYPTION_OAEP) encryption and
+     * decryption.  If $hash isn't supported, sha1 is used.
+     *
+     * @access public
+     * @param String $hash
+     */
+    function setHash($hash)
+    {
+        // Crypt_Hash supports algorithms that PKCS#1 doesn't support.  md5-96 and sha1-96, for example.
+        switch ($hash) {
+            case 'md2':
+            case 'md5':
+            case 'sha1':
+            case 'sha256':
+            case 'sha384':
+            case 'sha512':
+                $this->hash = new Crypt_Hash($hash);
+                $this->hashName = $hash;
+                break;
+            default:
+                $this->hash = new Crypt_Hash('sha1');
+                $this->hashName = 'sha1';
+        }
+        $this->hLen = $this->hash->getLength();
+    }
+
+    /**
+     * Determines which hashing function should be used for the mask generation function
+     *
+     * The mask generation function is used by CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_SIGNATURE_PSS and although it's
+     * best if Hash and MGFHash are set to the same thing this is not a requirement.
+     *
+     * @access public
+     * @param String $hash
+     */
+    function setMGFHash($hash)
+    {
+        // Crypt_Hash supports algorithms that PKCS#1 doesn't support.  md5-96 and sha1-96, for example.
+        switch ($hash) {
+            case 'md2':
+            case 'md5':
+            case 'sha1':
+            case 'sha256':
+            case 'sha384':
+            case 'sha512':
+                $this->mgfHash = new Crypt_Hash($hash);
+                break;
+            default:
+                $this->mgfHash = new Crypt_Hash('sha1');
+        }
+        $this->mgfHLen = $this->mgfHash->getLength();
+    }
+
+    /**
+     * Determines the salt length
+     *
+     * To quote from {@link http://tools.ietf.org/html/rfc3447#page-38 RFC3447#page-38}:
+     *
+     *    Typical salt lengths in octets are hLen (the length of the output
+     *    of the hash function Hash) and 0.
+     *
+     * @access public
+     * @param Integer $format
+     */
+    function setSaltLength($sLen)
+    {
+        $this->sLen = $sLen;
+    }
+
+    /**
+     * Generates a random string x bytes long
+     *
+     * @access public
+     * @param Integer $bytes
+     * @param optional Integer $nonzero
+     * @return String
+     */
+    function _random($bytes, $nonzero = false)
+    {
+        $temp = '';
+        if ($nonzero) {
+            for ($i = 0; $i < $bytes; $i++) {
+                $temp.= chr(crypt_random(1, 255));
+            }
+        } else {
+            $ints = ($bytes + 1) >> 2;
+            for ($i = 0; $i < $ints; $i++) {
+                $temp.= pack('N', crypt_random());
+            }
+            $temp = substr($temp, 0, $bytes);
+        }
+        return $temp;
+    }
+
+    /**
+     * Integer-to-Octet-String primitive
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-4.1 RFC3447#section-4.1}.
+     *
+     * @access private
+     * @param Math_BigInteger $x
+     * @param Integer $xLen
+     * @return String
+     */
+    function _i2osp($x, $xLen)
+    {
+        $x = $x->toBytes();
+        if (strlen($x) > $xLen) {
+            user_error('Integer too large', E_USER_NOTICE);
+            return false;
+        }
+        return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);
+    }
+
+    /**
+     * Octet-String-to-Integer primitive
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-4.2 RFC3447#section-4.2}.
+     *
+     * @access private
+     * @param String $x
+     * @return Math_BigInteger
+     */
+    function _os2ip($x)
+    {
+        return new Math_BigInteger($x, 256);
+    }
+
+    /**
+     * Exponentiate with or without Chinese Remainder Theorem
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.2}.
+     *
+     * @access private
+     * @param Math_BigInteger $x
+     * @return Math_BigInteger
+     */
+    function _exponentiate($x)
+    {
+        if (empty($this->primes) || empty($this->coefficients) || empty($this->exponents)) {
+            return $x->modPow($this->exponent, $this->modulus);
+        }
+
+        $num_primes = count($this->primes);
+
+        if (defined('CRYPT_RSA_DISABLE_BLINDING')) {
+            $m_i = array(
+                1 => $x->modPow($this->exponents[1], $this->primes[1]),
+                2 => $x->modPow($this->exponents[2], $this->primes[2])
+            );
+            $h = $m_i[1]->subtract($m_i[2]);
+            $h = $h->multiply($this->coefficients[2]);
+            list(, $h) = $h->divide($this->primes[1]);
+            $m = $m_i[2]->add($h->multiply($this->primes[2]));
+
+            $r = $this->primes[1];
+            for ($i = 3; $i <= $num_primes; $i++) {
+                $m_i = $x->modPow($this->exponents[$i], $this->primes[$i]);
+
+                $r = $r->multiply($this->primes[$i - 1]);
+
+                $h = $m_i->subtract($m);
+                $h = $h->multiply($this->coefficients[$i]);
+                list(, $h) = $h->divide($this->primes[$i]);
+
+                $m = $m->add($r->multiply($h));
+            }
+        } else {
+            $smallest = $this->primes[1];
+            for ($i = 2; $i <= $num_primes; $i++) {
+                if ($smallest->compare($this->primes[$i]) > 0) {
+                    $smallest = $this->primes[$i];
+                }
+            }
+
+            $one = new Math_BigInteger(1);
+            $one->setRandomGenerator('crypt_random');
+
+            $r = $one->random($one, $smallest->subtract($one));
+
+            $m_i = array(
+                1 => $this->_blind($x, $r, 1),
+                2 => $this->_blind($x, $r, 2)
+            );
+            $h = $m_i[1]->subtract($m_i[2]);
+            $h = $h->multiply($this->coefficients[2]);
+            list(, $h) = $h->divide($this->primes[1]);
+            $m = $m_i[2]->add($h->multiply($this->primes[2]));
+
+            $r = $this->primes[1];
+            for ($i = 3; $i <= $num_primes; $i++) {
+                $m_i = $this->_blind($x, $r, $i);
+
+                $r = $r->multiply($this->primes[$i - 1]);
+
+                $h = $m_i->subtract($m);
+                $h = $h->multiply($this->coefficients[$i]);
+                list(, $h) = $h->divide($this->primes[$i]);
+
+                $m = $m->add($r->multiply($h));
+            }
+        }
+
+        return $m;
+    }
+
+    /**
+     * Performs RSA Blinding
+     *
+     * Protects against timing attacks by employing RSA Blinding.
+     * Returns $x->modPow($this->exponents[$i], $this->primes[$i])
+     *
+     * @access private
+     * @param Math_BigInteger $x
+     * @param Math_BigInteger $r
+     * @param Integer $i
+     * @return Math_BigInteger
+     */
+    function _blind($x, $r, $i)
+    {
+        $x = $x->multiply($r->modPow($this->publicExponent, $this->primes[$i]));
+
+        $x = $x->modPow($this->exponents[$i], $this->primes[$i]);
+
+        $r = $r->modInverse($this->primes[$i]);
+        $x = $x->multiply($r);
+        list(, $x) = $x->divide($this->primes[$i]);
+
+        return $x;
+    }
+
+    /**
+     * RSAEP
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.1}.
+     *
+     * @access private
+     * @param Math_BigInteger $m
+     * @return Math_BigInteger
+     */
+    function _rsaep($m)
+    {
+        if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
+            user_error('Message representative out of range', E_USER_NOTICE);
+            return false;
+        }
+        return $this->_exponentiate($m);
+    }
+
+    /**
+     * RSADP
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.2 RFC3447#section-5.1.2}.
+     *
+     * @access private
+     * @param Math_BigInteger $c
+     * @return Math_BigInteger
+     */
+    function _rsadp($c)
+    {
+        if ($c->compare($this->zero) < 0 || $c->compare($this->modulus) > 0) {
+            user_error('Ciphertext representative out of range', E_USER_NOTICE);
+            return false;
+        }
+        return $this->_exponentiate($c);
+    }
+
+    /**
+     * RSASP1
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.1 RFC3447#section-5.2.1}.
+     *
+     * @access private
+     * @param Math_BigInteger $m
+     * @return Math_BigInteger
+     */
+    function _rsasp1($m)
+    {
+        if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
+            user_error('Message representative out of range', E_USER_NOTICE);
+            return false;
+        }
+        return $this->_exponentiate($m);
+    }
+
+    /**
+     * RSAVP1
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.2 RFC3447#section-5.2.2}.
+     *
+     * @access private
+     * @param Math_BigInteger $s
+     * @return Math_BigInteger
+     */
+    function _rsavp1($s)
+    {
+        if ($s->compare($this->zero) < 0 || $s->compare($this->modulus) > 0) {
+            user_error('Signature representative out of range', E_USER_NOTICE);
+            return false;
+        }
+        return $this->_exponentiate($s);
+    }
+
+    /**
+     * MGF1
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#appendix-B.2.1 RFC3447#appendix-B.2.1}.
+     *
+     * @access private
+     * @param String $mgfSeed
+     * @param Integer $mgfLen
+     * @return String
+     */
+    function _mgf1($mgfSeed, $maskLen)
+    {
+        // if $maskLen would yield strings larger than 4GB, PKCS#1 suggests a "Mask too long" error be output.
+
+        $t = '';
+        $count = ceil($maskLen / $this->mgfHLen);
+        for ($i = 0; $i < $count; $i++) {
+            $c = pack('N', $i);
+            $t.= $this->mgfHash->hash($mgfSeed . $c);
+        }
+
+        return substr($t, 0, $maskLen);
+    }
+
+    /**
+     * RSAES-OAEP-ENCRYPT
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.1 RFC3447#section-7.1.1} and
+     * {http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding OAES}.
+     *
+     * @access private
+     * @param String $m
+     * @param String $l
+     * @return String
+     */
+    function _rsaes_oaep_encrypt($m, $l = '')
+    {
+        $mLen = strlen($m);
+
+        // Length checking
+
+        // if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
+        // be output.
+
+        if ($mLen > $this->k - 2 * $this->hLen - 2) {
+            user_error('Message too long', E_USER_NOTICE);
+            return false;
+        }
+
+        // EME-OAEP encoding
+
+        $lHash = $this->hash->hash($l);
+        $ps = str_repeat(chr(0), $this->k - $mLen - 2 * $this->hLen - 2);
+        $db = $lHash . $ps . chr(1) . $m;
+        $seed = $this->_random($this->hLen);
+        $dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);
+        $maskedDB = $db ^ $dbMask;
+        $seedMask = $this->_mgf1($maskedDB, $this->hLen);
+        $maskedSeed = $seed ^ $seedMask;
+        $em = chr(0) . $maskedSeed . $maskedDB;
+
+        // RSA encryption
+
+        $m = $this->_os2ip($em);
+        $c = $this->_rsaep($m);
+        $c = $this->_i2osp($c, $this->k);
+
+        // Output the ciphertext C
+
+        return $c;
+    }
+
+    /**
+     * RSAES-OAEP-DECRYPT
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.2 RFC3447#section-7.1.2}.  The fact that the error
+     * messages aren't distinguishable from one another hinders debugging, but, to quote from RFC3447#section-7.1.2:
+     * 
+     *    Note.  Care must be taken to ensure that an opponent cannot
+     *    distinguish the different error conditions in Step 3.g, whether by
+     *    error message or timing, or, more generally, learn partial
+     *    information about the encoded message EM.  Otherwise an opponent may
+     *    be able to obtain useful information about the decryption of the
+     *    ciphertext C, leading to a chosen-ciphertext attack such as the one
+     *    observed by Manger [36].
+     *
+     * As for $l...  to quote from {@link http://tools.ietf.org/html/rfc3447#page-17 RFC3447#page-17}:
+     *
+     *    Both the encryption and the decryption operations of RSAES-OAEP take
+     *    the value of a label L as input.  In this version of PKCS #1, L is
+     *    the empty string; other uses of the label are outside the scope of
+     *    this document.
+     *
+     * @access private
+     * @param String $c
+     * @param String $l
+     * @return String
+     */
+    function _rsaes_oaep_decrypt($c, $l = '')
+    {
+        // Length checking
+
+        // if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
+        // be output.
+
+        if (strlen($c) != $this->k || $this->k < 2 * $this->hLen + 2) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+
+        // RSA decryption
+
+        $c = $this->_os2ip($c);
+        $m = $this->_rsadp($c);
+        if ($m === false) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+        $em = $this->_i2osp($m, $this->k);
+
+        // EME-OAEP decoding
+
+        $lHash = $this->hash->hash($l);
+        $y = ord($em[0]);
+        $maskedSeed = substr($em, 1, $this->hLen);
+        $maskedDB = substr($em, $this->hLen + 1);
+        $seedMask = $this->_mgf1($maskedDB, $this->hLen);
+        $seed = $maskedSeed ^ $seedMask;
+        $dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);
+        $db = $maskedDB ^ $dbMask;
+        $lHash2 = substr($db, 0, $this->hLen);
+        $m = substr($db, $this->hLen);
+        if ($lHash != $lHash2) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+        $m = ltrim($m, chr(0));
+        if (ord($m[0]) != 1) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+
+        // Output the message M
+
+        return substr($m, 1);
+    }
+
+    /**
+     * RSAES-PKCS1-V1_5-ENCRYPT
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.1 RFC3447#section-7.2.1}.
+     *
+     * @access private
+     * @param String $m
+     * @return String
+     */
+    function _rsaes_pkcs1_v1_5_encrypt($m)
+    {
+        $mLen = strlen($m);
+
+        // Length checking
+
+        if ($mLen > $this->k - 11) {
+            user_error('Message too long', E_USER_NOTICE);
+            return false;
+        }
+
+        // EME-PKCS1-v1_5 encoding
+
+        $ps = $this->_random($this->k - $mLen - 3, true);
+        $em = chr(0) . chr(2) . $ps . chr(0) . $m;
+
+        // RSA encryption
+        $m = $this->_os2ip($em);
+        $c = $this->_rsaep($m);
+        $c = $this->_i2osp($c, $this->k);
+
+        // Output the ciphertext C
+
+        return $c;
+    }
+
+    /**
+     * RSAES-PKCS1-V1_5-DECRYPT
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.2 RFC3447#section-7.2.2}.
+     *
+     * @access private
+     * @param String $c
+     * @return String
+     */
+    function _rsaes_pkcs1_v1_5_decrypt($c)
+    {
+        // Length checking
+
+        if (strlen($c) != $this->k) { // or if k < 11
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+
+        // RSA decryption
+
+        $c = $this->_os2ip($c);
+        $m = $this->_rsadp($c);
+        if ($m === false) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+        $em = $this->_i2osp($m, $this->k);
+
+        // EME-PKCS1-v1_5 decoding
+
+        if (ord($em[0]) != 0 || ord($em[1]) != 2) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+
+        $ps = substr($em, 2, strpos($em, chr(0), 2) - 2);
+        $m = substr($em, strlen($ps) + 3);
+
+        if (strlen($ps) < 8) {
+            user_error('Decryption error', E_USER_NOTICE);
+            return false;
+        }
+
+        // Output M
+
+        return $m;
+    }
+
+    /**
+     * EMSA-PSS-ENCODE
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.1 RFC3447#section-9.1.1}.
+     *
+     * @access private
+     * @param String $m
+     * @param Integer $emBits
+     */
+    function _emsa_pss_encode($m, $emBits)
+    {
+        // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
+        // be output.
+
+        $emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8)
+        $sLen = $this->sLen == false ? $this->hLen : $this->sLen;
+
+        $mHash = $this->hash->hash($m);
+        if ($emLen < $this->hLen + $sLen + 2) {
+            user_error('Encoding error', E_USER_NOTICE);
+            return false;
+        }
+
+        $salt = $this->_random($sLen);
+        $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
+        $h = $this->hash->hash($m2);
+        $ps = str_repeat(chr(0), $emLen - $sLen - $this->hLen - 2);
+        $db = $ps . chr(1) . $salt;
+        $dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);
+        $maskedDB = $db ^ $dbMask;
+        $maskedDB[0] = ~chr(0xFF << ($emBits & 7)) & $maskedDB[0];
+        $em = $maskedDB . $h . chr(0xBC);
+
+        return $em;
+    }
+
+    /**
+     * EMSA-PSS-VERIFY
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.2 RFC3447#section-9.1.2}.
+     *
+     * @access private
+     * @param String $m
+     * @param String $em
+     * @param Integer $emBits
+     * @return String
+     */
+    function _emsa_pss_verify($m, $em, $emBits)
+    {
+        // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
+        // be output.
+
+        $emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8);
+        $sLen = $this->sLen == false ? $this->hLen : $this->sLen;
+
+        $mHash = $this->hash->hash($m);
+        if ($emLen < $this->hLen + $sLen + 2) {
+            return false;
+        }
+
+        if ($em[strlen($em) - 1] != chr(0xBC)) {
+            return false;
+        }
+
+        $maskedDB = substr($em, 0, $em - $this->hLen - 1);
+        $h = substr($em, $em - $this->hLen - 1, $this->hLen);
+        $temp = chr(0xFF << ($emBits & 7));
+        if ((~$maskedDB[0] & $temp) != $temp) {
+            return false;
+        }
+        $dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);
+        $db = $maskedDB ^ $dbMask;
+        $db[0] = ~chr(0xFF << ($emBits & 7)) & $db[0];
+        $temp = $emLen - $this->hLen - $sLen - 2;
+        if (substr($db, 0, $temp) != str_repeat(chr(0), $temp) || ord($db[$temp]) != 1) {
+            return false;
+        }
+        $salt = substr($db, $temp + 1); // should be $sLen long
+        $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
+        $h2 = $this->hash->hash($m2);
+        return $h == $h2;
+    }
+
+    /**
+     * RSASSA-PSS-SIGN
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.1 RFC3447#section-8.1.1}.
+     *
+     * @access private
+     * @param String $m
+     * @return String
+     */
+    function _rsassa_pss_sign($m)
+    {
+        // EMSA-PSS encoding
+
+        $em = $this->_emsa_pss_encode($m, 8 * $this->k - 1);
+
+        // RSA signature
+
+        $m = $this->_os2ip($em);
+        $s = $this->_rsasp1($m);
+        $s = $this->_i2osp($s, $this->k);
+
+        // Output the signature S
+
+        return $s;
+    }
+
+    /**
+     * RSASSA-PSS-VERIFY
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.2 RFC3447#section-8.1.2}.
+     *
+     * @access private
+     * @param String $m
+     * @param String $s
+     * @return String
+     */
+    function _rsassa_pss_verify($m, $s)
+    {
+        // Length checking
+
+        if (strlen($s) != $this->k) {
+            user_error('Invalid signature', E_USER_NOTICE);
+            return false;
+        }
+
+        // RSA verification
+
+        $modBits = 8 * $this->k;
+
+        $s2 = $this->_os2ip($s);
+        $m2 = $this->_rsavp1($s2);
+        if ($m2 === false) {
+            user_error('Invalid signature', E_USER_NOTICE);
+            return false;
+        }
+        $em = $this->_i2osp($m2, $modBits >> 3);
+        if ($em === false) {
+            user_error('Invalid signature', E_USER_NOTICE);
+            return false;
+        }
+
+        // EMSA-PSS verification
+
+        return $this->_emsa_pss_verify($m, $em, $modBits - 1);
+    }
+
+    /**
+     * EMSA-PKCS1-V1_5-ENCODE
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-9.2 RFC3447#section-9.2}.
+     *
+     * @access private
+     * @param String $m
+     * @param Integer $emLen
+     * @return String
+     */
+    function _emsa_pkcs1_v1_5_encode($m, $emLen)
+    {
+        $h = $this->hash->hash($m);
+        if ($h === false) {
+            return false;
+        }
+
+        // see http://tools.ietf.org/html/rfc3447#page-43
+        switch ($this->hashName) {
+            case 'md2':
+                $t = pack('H*', '3020300c06082a864886f70d020205000410');
+                break;
+            case 'md5':
+                $t = pack('H*', '3020300c06082a864886f70d020505000410');
+                break;
+            case 'sha1':
+                $t = pack('H*', '3021300906052b0e03021a05000414');
+                break;
+            case 'sha256':
+                $t = pack('H*', '3031300d060960864801650304020105000420');
+                break;
+            case 'sha384':
+                $t = pack('H*', '3041300d060960864801650304020205000430');
+                break;
+            case 'sha512':
+                $t = pack('H*', '3051300d060960864801650304020305000440');
+        }
+        $t.= $h;
+        $tLen = strlen($t);
+
+        if ($emLen < $tLen + 11) {
+            user_error('Intended encoded message length too short', E_USER_NOTICE);
+            return false;
+        }
+
+        $ps = str_repeat(chr(0xFF), $emLen - $tLen - 3);
+
+        $em = "\0\1$ps\0$t";
+
+        return $em;
+    }
+
+    /**
+     * RSASSA-PKCS1-V1_5-SIGN
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.1 RFC3447#section-8.2.1}.
+     *
+     * @access private
+     * @param String $m
+     * @return String
+     */
+    function _rsassa_pkcs1_v1_5_sign($m)
+    {
+        // EMSA-PKCS1-v1_5 encoding
+
+        $em = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
+        if ($em === false) {
+            user_error('RSA modulus too short', E_USER_NOTICE);
+            return false;
+        }
+
+        // RSA signature
+
+        $m = $this->_os2ip($em);
+        $s = $this->_rsasp1($m);
+        $s = $this->_i2osp($s, $this->k);
+
+        // Output the signature S
+
+        return $s;
+    }
+
+    /**
+     * RSASSA-PKCS1-V1_5-VERIFY
+     *
+     * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.2 RFC3447#section-8.2.2}.
+     *
+     * @access private
+     * @param String $m
+     * @return String
+     */
+    function _rsassa_pkcs1_v1_5_verify($m, $s)
+    {
+        // Length checking
+
+        if (strlen($s) != $this->k) {
+            user_error('Invalid signature', E_USER_NOTICE);
+            return false;
+        }
+
+        // RSA verification
+
+        $s = $this->_os2ip($s);
+        $m2 = $this->_rsavp1($s);
+        if ($m2 === false) {
+            user_error('Invalid signature', E_USER_NOTICE);
+            return false;
+        }
+        $em = $this->_i2osp($m2, $this->k);
+        if ($em === false) {
+            user_error('Invalid signature', E_USER_NOTICE);
+            return false;
+        }
+
+        // EMSA-PKCS1-v1_5 encoding
+
+        $em2 = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
+        if ($em2 === false) {
+            user_error('RSA modulus too short', E_USER_NOTICE);
+            return false;
+        }
+
+        // Compare
+
+        return $em === $em2;
+    }
+
+    /**
+     * Set Encryption Mode
+     *
+     * Valid values include CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_ENCRYPTION_PKCS1.
+     *
+     * @access public
+     * @param Integer $mode
+     */
+    function setEncryptionMode($mode)
+    {
+        $this->encryptionMode = $mode;
+    }
+
+    /**
+     * Set Signature Mode
+     *
+     * Valid values include CRYPT_RSA_SIGNATURE_PSS and CRYPT_RSA_SIGNATURE_PKCS1
+     *
+     * @access public
+     * @param Integer $mode
+     */
+    function setSignatureMode($mode)
+    {
+        $this->signatureMode = $mode;
+    }
+
+    /**
+     * Encryption
+     *
+     * Both CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_ENCRYPTION_PKCS1 both place limits on how long $plaintext can be.
+     * If $plaintext exceeds those limits it will be broken up so that it does and the resultant ciphertext's will
+     * be concatenated together.
+     *
+     * @see decrypt()
+     * @access public
+     * @param String $plaintext
+     * @return String
+     */
+    function encrypt($plaintext)
+    {
+        switch ($this->encryptionMode) {
+            case CRYPT_RSA_ENCRYPTION_PKCS1:
+                $length = $this->k - 11;
+                if ($length <= 0) {
+                    return false;
+                }
+
+                $plaintext = str_split($plaintext, $length);
+                $ciphertext = '';
+                foreach ($plaintext as $m) {
+                    $ciphertext.= $this->_rsaes_pkcs1_v1_5_encrypt($m);
+                }
+                return $ciphertext;
+            //case CRYPT_RSA_ENCRYPTION_OAEP:
+            default:
+                $length = $this->k - 2 * $this->hLen - 2;
+                if ($length <= 0) {
+                    return false;
+                }
+
+                $plaintext = str_split($plaintext, $length);
+                $ciphertext = '';
+                foreach ($plaintext as $m) {
+                    $ciphertext.= $this->_rsaes_oaep_encrypt($m);
+                }
+                return $ciphertext;
+        }
+    }
+
+    /**
+     * Decryption
+     *
+     * @see encrypt()
+     * @access public
+     * @param String $plaintext
+     * @return String
+     */
+    function decrypt($ciphertext)
+    {
+        if ($this->k <= 0) {
+            return false;
+        }
+
+        $ciphertext = str_split($ciphertext, $this->k);
+        $plaintext = '';
+
+        switch ($this->encryptionMode) {
+            case CRYPT_RSA_ENCRYPTION_PKCS1:
+                $decrypt = '_rsaes_pkcs1_v1_5_decrypt';
+                break;
+            //case CRYPT_RSA_ENCRYPTION_OAEP:
+            default:
+                $decrypt = '_rsaes_oaep_decrypt';
+        }
+
+        foreach ($ciphertext as $c) {
+            $temp = $this->$decrypt($c);
+            if ($temp === false) {
+                return false;
+            }
+            $plaintext.= $temp;
+        }
+
+        return $plaintext;
+    }
+
+    /**
+     * Create a signature
+     *
+     * @see verify()
+     * @access public
+     * @param String $message
+     * @return String
+     */
+    function sign($message)
+    {
+        if (empty($this->modulus) || empty($this->exponent)) {
+            return false;
+        }
+
+        switch ($this->signatureMode) {
+            case CRYPT_RSA_SIGNATURE_PKCS1:
+                return $this->_rsassa_pkcs1_v1_5_sign($message);
+            //case CRYPT_RSA_SIGNATURE_PSS:
+            default:
+                return $this->_rsassa_pss_sign($message);
+        }
+    }
+
+    /**
+     * Verifies a signature
+     *
+     * @see sign()
+     * @access public
+     * @param String $message
+     * @param String $signature
+     * @return Boolean
+     */
+    function verify($message, $signature)
+    {
+        if (empty($this->modulus) || empty($this->exponent)) {
+            return false;
+        }
+
+        switch ($this->signatureMode) {
+            case CRYPT_RSA_SIGNATURE_PKCS1:
+                return $this->_rsassa_pkcs1_v1_5_verify($message, $signature);
+            //case CRYPT_RSA_SIGNATURE_PSS:
+            default:
+                return $this->_rsassa_pss_verify($message, $signature);
+        }
+    }
 }
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/Random.php b/plugins/OStatus/extlib/Crypt/Random.php
index fbb41074e..bfc24ca62 100644
--- a/plugins/OStatus/extlib/Crypt/Random.php
+++ b/plugins/OStatus/extlib/Crypt/Random.php
@@ -1,70 +1,125 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Random Number Generator

- *

- * PHP versions 4 and 5

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/Random.php');

- *

- *    echo crypt_random();

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_Random

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: Random.php,v 1.4 2008/05/21 05:15:32 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**

- * Generate a random value.  Feel free to replace this function with a cryptographically secure PRNG.

- *

- * @param optional Integer $min

- * @param optional Integer $max

- * @param optional String $randomness_path

- * @return Integer

- * @access public

- */

-function crypt_random($min = 0, $max = 0x7FFFFFFF, $randomness_path = '/dev/urandom')

-{

-    static $seeded = false;

-

-    if (!$seeded) {

-        $seeded = true;

-        if (file_exists($randomness_path)) {

-            $fp = fopen($randomness_path, 'r');

-            $temp = unpack('Nint', fread($fp, 4));

-            mt_srand($temp['int']);

-            fclose($fp);

-        } else {

-            list($sec, $usec) = explode(' ', microtime());

-            mt_srand((float) $sec + ((float) $usec * 100000));

-        }

-    }

-

-    return mt_rand($min, $max);

-}

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Random Number Generator
+ *
+ * PHP versions 4 and 5
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/Random.php');
+ *
+ *    echo crypt_random();
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_Random
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: Random.php,v 1.6 2010/02/28 05:28:38 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**
+ * Generate a random value.
+ *
+ * On 32-bit machines, the largest distance that can exist between $min and $max is 2**31.
+ * If $min and $max are farther apart than that then the last ($max - range) numbers.
+ *
+ * Depending on how this is being used, it may be worth while to write a replacement.  For example,
+ * a PHP-based web app that stores its data in an SQL database can collect more entropy than this function
+ * can.
+ *
+ * @param optional Integer $min
+ * @param optional Integer $max
+ * @return Integer
+ * @access public
+ */
+function crypt_random($min = 0, $max = 0x7FFFFFFF)
+{
+    if ($min == $max) {
+        return $min;
+    }
+
+    // see http://en.wikipedia.org/wiki//dev/random
+    if (file_exists('/dev/urandom')) {
+        $fp = fopen('/dev/urandom', 'rb');
+        extract(unpack('Nrandom', fread($fp, 4)));
+        fclose($fp);
+
+        // say $min = 0 and $max = 3.  if we didn't do abs() then we could have stuff like this:
+        // -4 % 3 + 0 = -1, even though -1 < $min
+        return abs($random) % ($max - $min) + $min;
+    }
+
+    /* Prior to PHP 4.2.0, mt_srand() had to be called before mt_rand() could be called.
+       Prior to PHP 5.2.6, mt_rand()'s automatic seeding was subpar, as elaborated here:
+
+       http://www.suspekt.org/2008/08/17/mt_srand-and-not-so-random-numbers/
+
+       The seeding routine is pretty much ripped from PHP's own internal GENERATE_SEED() macro:
+
+       http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3_2/ext/standard/php_rand.h?view=markup */
+    if (version_compare(PHP_VERSION, '5.2.5', '<=')) { 
+        static $seeded;
+        if (!isset($seeded)) {
+            $seeded = true;
+            mt_srand(fmod(time() * getmypid(), 0x7FFFFFFF) ^ fmod(1000000 * lcg_value(), 0x7FFFFFFF));
+        }
+    }
+
+    static $crypto;
+
+    // The CSPRNG's Yarrow and Fortuna periodically reseed.  This function can be reseeded by hitting F5
+    // in the browser and reloading the page.
+
+    if (!isset($crypto)) {
+        $key = $iv = '';
+        for ($i = 0; $i < 8; $i++) {
+            $key.= pack('n', mt_rand(0, 0xFFFF));
+            $iv .= pack('n', mt_rand(0, 0xFFFF));
+        }
+        switch (true) {
+            case class_exists('Crypt_AES'):
+                $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR);
+                break;
+            case class_exists('Crypt_TripleDES'):
+                $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
+                break;
+            case class_exists('Crypt_DES'):
+                $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
+                break;
+            case class_exists('Crypt_RC4'):
+                $crypto = new Crypt_RC4();
+                break;
+            default:
+                extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7FFFFFFF)))));
+                return abs($random) % ($max - $min) + $min;
+        }
+        $crypto->setKey($key);
+        $crypto->setIV($iv);
+    }
+
+    extract(unpack('Nrandom', $crypto->encrypt("\0\0\0\0")));
+    return abs($random) % ($max - $min) + $min;
+}
 ?>
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/Rijndael.php b/plugins/OStatus/extlib/Crypt/Rijndael.php
index 19bba83f3..3b5fd6a7d 100644
--- a/plugins/OStatus/extlib/Crypt/Rijndael.php
+++ b/plugins/OStatus/extlib/Crypt/Rijndael.php
@@ -1,1135 +1,1242 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP implementation of Rijndael.

- *

- * Does not use mcrypt, even when available, for reasons that are explained below.

- *

- * PHP versions 4 and 5

- *

- * If {@link Crypt_Rijndael::setBlockLength() setBlockLength()} isn't called, it'll be assumed to be 128 bits.  If 

- * {@link Crypt_Rijndael::setKeyLength() setKeyLength()} isn't called, it'll be calculated from 

- * {@link Crypt_Rijndael::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 

- * 136-bits it'll be null-padded to 160-bits and 160 bits will be the key length until 

- * {@link Crypt_Rijndael::setKey() setKey()} is called, again, at which point, it'll be recalculated.

- *

- * Not all Rijndael implementations may support 160-bits or 224-bits as the block length / key length.  mcrypt, for example,

- * does not.  AES, itself, only supports block lengths of 128 and key lengths of 128, 192, and 256.

- * {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=10 Rijndael-ammended.pdf#page=10} defines the

- * algorithm for block lengths of 192 and 256 but not for block lengths / key lengths of 160 and 224.  Indeed, 160 and 224

- * are first defined as valid key / block lengths in 

- * {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=44 Rijndael-ammended.pdf#page=44}: 

- * Extensions: Other block and Cipher Key lengths.

- *

- * {@internal The variable names are the same as those in 

- * {@link http://www.csrc.nist.gov/publications/fips/fips197/fips-197.pdf#page=10 fips-197.pdf#page=10}.}}

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/Rijndael.php');

- *

- *    $rijndael = new Crypt_Rijndael();

- *

- *    $rijndael->setKey('abcdefghijklmnop');

- *

- *    $size = 10 * 1024;

- *    $plaintext = '';

- *    for ($i = 0; $i < $size; $i++) {

- *        $plaintext.= 'a';

- *    }

- *

- *    echo $rijndael->decrypt($rijndael->encrypt($plaintext));

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_Rijndael

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVIII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: Rijndael.php,v 1.8 2009/11/23 19:06:07 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**#@+

- * @access public

- * @see Crypt_Rijndael::encrypt()

- * @see Crypt_Rijndael::decrypt()

- */

-/**

- * Encrypt / decrypt using the Electronic Code Book mode.

- *

- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29

- */

-define('CRYPT_RIJNDAEL_MODE_ECB', 1);

-/**

- * Encrypt / decrypt using the Code Book Chaining mode.

- *

- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29

- */

-define('CRYPT_RIJNDAEL_MODE_CBC', 2);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Crypt_Rijndael::Crypt_Rijndael()

- */

-/**

- * Toggles the internal implementation

- */

-define('CRYPT_RIJNDAEL_MODE_INTERNAL', 1);

-/**

- * Toggles the mcrypt implementation

- */

-define('CRYPT_RIJNDAEL_MODE_MCRYPT', 2);

-/**#@-*/

-

-/**

- * Pure-PHP implementation of Rijndael.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_Rijndael

- */

-class Crypt_Rijndael {

-    /**

-     * The Encryption Mode

-     *

-     * @see Crypt_Rijndael::Crypt_Rijndael()

-     * @var Integer

-     * @access private

-     */

-    var $mode;

-

-    /**

-     * The Key

-     *

-     * @see Crypt_Rijndael::setKey()

-     * @var String

-     * @access private

-     */

-    var $key = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";

-

-    /**

-     * The Initialization Vector

-     *

-     * @see Crypt_Rijndael::setIV()

-     * @var String

-     * @access private

-     */

-    var $iv = '';

-

-    /**

-     * A "sliding" Initialization Vector

-     *

-     * @see Crypt_Rijndael::enableContinuousBuffer()

-     * @var String

-     * @access private

-     */

-    var $encryptIV = '';

-

-    /**

-     * A "sliding" Initialization Vector

-     *

-     * @see Crypt_Rijndael::enableContinuousBuffer()

-     * @var String

-     * @access private

-     */

-    var $decryptIV = '';

-

-    /**

-     * Continuous Buffer status

-     *

-     * @see Crypt_Rijndael::enableContinuousBuffer()

-     * @var Boolean

-     * @access private

-     */

-    var $continuousBuffer = false;

-

-    /**

-     * Padding status

-     *

-     * @see Crypt_Rijndael::enablePadding()

-     * @var Boolean

-     * @access private

-     */

-    var $padding = true;

-

-    /**

-     * Does the key schedule need to be (re)calculated?

-     *

-     * @see setKey()

-     * @see setBlockLength()

-     * @see setKeyLength()

-     * @var Boolean

-     * @access private

-     */

-    var $changed = true;

-

-    /**

-     * Has the key length explicitly been set or should it be derived from the key, itself?

-     *

-     * @see setKeyLength()

-     * @var Boolean

-     * @access private

-     */

-    var $explicit_key_length = false;

-

-    /**

-     * The Key Schedule

-     *

-     * @see _setup()

-     * @var Array

-     * @access private

-     */

-    var $w;

-

-    /**

-     * The Inverse Key Schedule

-     *

-     * @see _setup()

-     * @var Array

-     * @access private

-     */

-    var $dw;

-

-    /**

-     * The Block Length

-     *

-     * @see setBlockLength()

-     * @var Integer

-     * @access private

-     * @internal The max value is 32, the min value is 16.  All valid values are multiples of 4.  Exists in conjunction with

-     *     $Nb because we need this value and not $Nb to pad strings appropriately.  

-     */

-    var $block_size = 16;

-

-    /**

-     * The Block Length divided by 32

-     *

-     * @see setBlockLength()

-     * @var Integer

-     * @access private

-     * @internal The max value is 256 / 32 = 8, the min value is 128 / 32 = 4.  Exists in conjunction with $block_size 

-     *    because the encryption / decryption / key schedule creation requires this number and not $block_size.  We could 

-     *    derive this from $block_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu

-     *    of that, we'll just precompute it once.

-     *

-     */

-    var $Nb = 4;

-

-    /**

-     * The Key Length

-     *

-     * @see setKeyLength()

-     * @var Integer

-     * @access private

-     * @internal The max value is 256 / 8 = 32, the min value is 128 / 8 = 16.  Exists in conjunction with $key_size

-     *    because the encryption / decryption / key schedule creation requires this number and not $key_size.  We could 

-     *    derive this from $key_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu

-     *    of that, we'll just precompute it once.

-     */

-    var $key_size = 16;

-

-    /**

-     * The Key Length divided by 32

-     *

-     * @see setKeyLength()

-     * @var Integer

-     * @access private

-     * @internal The max value is 256 / 32 = 8, the min value is 128 / 32 = 4

-     */

-    var $Nk = 4;

-

-    /**

-     * The Number of Rounds

-     *

-     * @var Integer

-     * @access private

-     * @internal The max value is 14, the min value is 10.

-     */

-    var $Nr;

-

-    /**

-     * Shift offsets

-     *

-     * @var Array

-     * @access private

-     */

-    var $c;

-

-    /**

-     * Precomputed mixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $t0;

-

-    /**

-     * Precomputed mixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $t1;

-

-    /**

-     * Precomputed mixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $t2;

-

-    /**

-     * Precomputed mixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $t3;

-

-    /**

-     * Precomputed invMixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $dt0;

-

-    /**

-     * Precomputed invMixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $dt1;

-

-    /**

-     * Precomputed invMixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $dt2;

-

-    /**

-     * Precomputed invMixColumns table

-     *

-     * @see Crypt_Rijndael()

-     * @var Array

-     * @access private

-     */

-    var $dt3;

-

-    /**

-     * Default Constructor.

-     *

-     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be

-     * CRYPT_RIJNDAEL_MODE_ECB or CRYPT_RIJNDAEL_MODE_CBC.  If not explictly set, CRYPT_RIJNDAEL_MODE_CBC will be used.

-     *

-     * @param optional Integer $mode

-     * @return Crypt_Rijndael

-     * @access public

-     */

-    function Crypt_Rijndael($mode = CRYPT_RIJNDAEL_MODE_CBC)

-    {

-        switch ($mode) {

-            case CRYPT_RIJNDAEL_MODE_ECB:

-            case CRYPT_RIJNDAEL_MODE_CBC:

-                $this->mode = $mode;

-                break;

-            default:

-                $this->mode = CRYPT_RIJNDAEL_MODE_CBC;

-        }

-

-        // according to <http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=19> (section 5.2.1), 

-        // precomputed tables can be used in the mixColumns phase.  in that example, they're assigned t0...t3, so

-        // those are the names we'll use.

-        $this->t3 = array(

-            0x6363A5C6, 0x7C7C84F8, 0x777799EE, 0x7B7B8DF6, 0xF2F20DFF, 0x6B6BBDD6, 0x6F6FB1DE, 0xC5C55491, 

-            0x30305060, 0x01010302, 0x6767A9CE, 0x2B2B7D56, 0xFEFE19E7, 0xD7D762B5, 0xABABE64D, 0x76769AEC, 

-            0xCACA458F, 0x82829D1F, 0xC9C94089, 0x7D7D87FA, 0xFAFA15EF, 0x5959EBB2, 0x4747C98E, 0xF0F00BFB, 

-            0xADADEC41, 0xD4D467B3, 0xA2A2FD5F, 0xAFAFEA45, 0x9C9CBF23, 0xA4A4F753, 0x727296E4, 0xC0C05B9B, 

-            0xB7B7C275, 0xFDFD1CE1, 0x9393AE3D, 0x26266A4C, 0x36365A6C, 0x3F3F417E, 0xF7F702F5, 0xCCCC4F83, 

-            0x34345C68, 0xA5A5F451, 0xE5E534D1, 0xF1F108F9, 0x717193E2, 0xD8D873AB, 0x31315362, 0x15153F2A, 

-            0x04040C08, 0xC7C75295, 0x23236546, 0xC3C35E9D, 0x18182830, 0x9696A137, 0x05050F0A, 0x9A9AB52F, 

-            0x0707090E, 0x12123624, 0x80809B1B, 0xE2E23DDF, 0xEBEB26CD, 0x2727694E, 0xB2B2CD7F, 0x75759FEA, 

-            0x09091B12, 0x83839E1D, 0x2C2C7458, 0x1A1A2E34, 0x1B1B2D36, 0x6E6EB2DC, 0x5A5AEEB4, 0xA0A0FB5B, 

-            0x5252F6A4, 0x3B3B4D76, 0xD6D661B7, 0xB3B3CE7D, 0x29297B52, 0xE3E33EDD, 0x2F2F715E, 0x84849713, 

-            0x5353F5A6, 0xD1D168B9, 0x00000000, 0xEDED2CC1, 0x20206040, 0xFCFC1FE3, 0xB1B1C879, 0x5B5BEDB6, 

-            0x6A6ABED4, 0xCBCB468D, 0xBEBED967, 0x39394B72, 0x4A4ADE94, 0x4C4CD498, 0x5858E8B0, 0xCFCF4A85, 

-            0xD0D06BBB, 0xEFEF2AC5, 0xAAAAE54F, 0xFBFB16ED, 0x4343C586, 0x4D4DD79A, 0x33335566, 0x85859411, 

-            0x4545CF8A, 0xF9F910E9, 0x02020604, 0x7F7F81FE, 0x5050F0A0, 0x3C3C4478, 0x9F9FBA25, 0xA8A8E34B, 

-            0x5151F3A2, 0xA3A3FE5D, 0x4040C080, 0x8F8F8A05, 0x9292AD3F, 0x9D9DBC21, 0x38384870, 0xF5F504F1, 

-            0xBCBCDF63, 0xB6B6C177, 0xDADA75AF, 0x21216342, 0x10103020, 0xFFFF1AE5, 0xF3F30EFD, 0xD2D26DBF, 

-            0xCDCD4C81, 0x0C0C1418, 0x13133526, 0xECEC2FC3, 0x5F5FE1BE, 0x9797A235, 0x4444CC88, 0x1717392E, 

-            0xC4C45793, 0xA7A7F255, 0x7E7E82FC, 0x3D3D477A, 0x6464ACC8, 0x5D5DE7BA, 0x19192B32, 0x737395E6, 

-            0x6060A0C0, 0x81819819, 0x4F4FD19E, 0xDCDC7FA3, 0x22226644, 0x2A2A7E54, 0x9090AB3B, 0x8888830B, 

-            0x4646CA8C, 0xEEEE29C7, 0xB8B8D36B, 0x14143C28, 0xDEDE79A7, 0x5E5EE2BC, 0x0B0B1D16, 0xDBDB76AD, 

-            0xE0E03BDB, 0x32325664, 0x3A3A4E74, 0x0A0A1E14, 0x4949DB92, 0x06060A0C, 0x24246C48, 0x5C5CE4B8, 

-            0xC2C25D9F, 0xD3D36EBD, 0xACACEF43, 0x6262A6C4, 0x9191A839, 0x9595A431, 0xE4E437D3, 0x79798BF2, 

-            0xE7E732D5, 0xC8C8438B, 0x3737596E, 0x6D6DB7DA, 0x8D8D8C01, 0xD5D564B1, 0x4E4ED29C, 0xA9A9E049, 

-            0x6C6CB4D8, 0x5656FAAC, 0xF4F407F3, 0xEAEA25CF, 0x6565AFCA, 0x7A7A8EF4, 0xAEAEE947, 0x08081810, 

-            0xBABAD56F, 0x787888F0, 0x25256F4A, 0x2E2E725C, 0x1C1C2438, 0xA6A6F157, 0xB4B4C773, 0xC6C65197, 

-            0xE8E823CB, 0xDDDD7CA1, 0x74749CE8, 0x1F1F213E, 0x4B4BDD96, 0xBDBDDC61, 0x8B8B860D, 0x8A8A850F, 

-            0x707090E0, 0x3E3E427C, 0xB5B5C471, 0x6666AACC, 0x4848D890, 0x03030506, 0xF6F601F7, 0x0E0E121C, 

-            0x6161A3C2, 0x35355F6A, 0x5757F9AE, 0xB9B9D069, 0x86869117, 0xC1C15899, 0x1D1D273A, 0x9E9EB927, 

-            0xE1E138D9, 0xF8F813EB, 0x9898B32B, 0x11113322, 0x6969BBD2, 0xD9D970A9, 0x8E8E8907, 0x9494A733, 

-            0x9B9BB62D, 0x1E1E223C, 0x87879215, 0xE9E920C9, 0xCECE4987, 0x5555FFAA, 0x28287850, 0xDFDF7AA5, 

-            0x8C8C8F03, 0xA1A1F859, 0x89898009, 0x0D0D171A, 0xBFBFDA65, 0xE6E631D7, 0x4242C684, 0x6868B8D0, 

-            0x4141C382, 0x9999B029, 0x2D2D775A, 0x0F0F111E, 0xB0B0CB7B, 0x5454FCA8, 0xBBBBD66D, 0x16163A2C

-        );

-

-        $this->dt3 = array(

-            0xF4A75051, 0x4165537E, 0x17A4C31A, 0x275E963A, 0xAB6BCB3B, 0x9D45F11F, 0xFA58ABAC, 0xE303934B, 

-            0x30FA5520, 0x766DF6AD, 0xCC769188, 0x024C25F5, 0xE5D7FC4F, 0x2ACBD7C5, 0x35448026, 0x62A38FB5, 

-            0xB15A49DE, 0xBA1B6725, 0xEA0E9845, 0xFEC0E15D, 0x2F7502C3, 0x4CF01281, 0x4697A38D, 0xD3F9C66B, 

-            0x8F5FE703, 0x929C9515, 0x6D7AEBBF, 0x5259DA95, 0xBE832DD4, 0x7421D358, 0xE0692949, 0xC9C8448E, 

-            0xC2896A75, 0x8E7978F4, 0x583E6B99, 0xB971DD27, 0xE14FB6BE, 0x88AD17F0, 0x20AC66C9, 0xCE3AB47D, 

-            0xDF4A1863, 0x1A3182E5, 0x51336097, 0x537F4562, 0x6477E0B1, 0x6BAE84BB, 0x81A01CFE, 0x082B94F9, 

-            0x48685870, 0x45FD198F, 0xDE6C8794, 0x7BF8B752, 0x73D323AB, 0x4B02E272, 0x1F8F57E3, 0x55AB2A66, 

-            0xEB2807B2, 0xB5C2032F, 0xC57B9A86, 0x3708A5D3, 0x2887F230, 0xBFA5B223, 0x036ABA02, 0x16825CED, 

-            0xCF1C2B8A, 0x79B492A7, 0x07F2F0F3, 0x69E2A14E, 0xDAF4CD65, 0x05BED506, 0x34621FD1, 0xA6FE8AC4, 

-            0x2E539D34, 0xF355A0A2, 0x8AE13205, 0xF6EB75A4, 0x83EC390B, 0x60EFAA40, 0x719F065E, 0x6E1051BD, 

-            0x218AF93E, 0xDD063D96, 0x3E05AEDD, 0xE6BD464D, 0x548DB591, 0xC45D0571, 0x06D46F04, 0x5015FF60, 

-            0x98FB2419, 0xBDE997D6, 0x4043CC89, 0xD99E7767, 0xE842BDB0, 0x898B8807, 0x195B38E7, 0xC8EEDB79, 

-            0x7C0A47A1, 0x420FE97C, 0x841EC9F8, 0x00000000, 0x80868309, 0x2BED4832, 0x1170AC1E, 0x5A724E6C, 

-            0x0EFFFBFD, 0x8538560F, 0xAED51E3D, 0x2D392736, 0x0FD9640A, 0x5CA62168, 0x5B54D19B, 0x362E3A24, 

-            0x0A67B10C, 0x57E70F93, 0xEE96D2B4, 0x9B919E1B, 0xC0C54F80, 0xDC20A261, 0x774B695A, 0x121A161C, 

-            0x93BA0AE2, 0xA02AE5C0, 0x22E0433C, 0x1B171D12, 0x090D0B0E, 0x8BC7ADF2, 0xB6A8B92D, 0x1EA9C814, 

-            0xF1198557, 0x75074CAF, 0x99DDBBEE, 0x7F60FDA3, 0x01269FF7, 0x72F5BC5C, 0x663BC544, 0xFB7E345B, 

-            0x4329768B, 0x23C6DCCB, 0xEDFC68B6, 0xE4F163B8, 0x31DCCAD7, 0x63851042, 0x97224013, 0xC6112084, 

-            0x4A247D85, 0xBB3DF8D2, 0xF93211AE, 0x29A16DC7, 0x9E2F4B1D, 0xB230F3DC, 0x8652EC0D, 0xC1E3D077, 

-            0xB3166C2B, 0x70B999A9, 0x9448FA11, 0xE9642247, 0xFC8CC4A8, 0xF03F1AA0, 0x7D2CD856, 0x3390EF22, 

-            0x494EC787, 0x38D1C1D9, 0xCAA2FE8C, 0xD40B3698, 0xF581CFA6, 0x7ADE28A5, 0xB78E26DA, 0xADBFA43F, 

-            0x3A9DE42C, 0x78920D50, 0x5FCC9B6A, 0x7E466254, 0x8D13C2F6, 0xD8B8E890, 0x39F75E2E, 0xC3AFF582, 

-            0x5D80BE9F, 0xD0937C69, 0xD52DA96F, 0x2512B3CF, 0xAC993BC8, 0x187DA710, 0x9C636EE8, 0x3BBB7BDB, 

-            0x267809CD, 0x5918F46E, 0x9AB701EC, 0x4F9AA883, 0x956E65E6, 0xFFE67EAA, 0xBCCF0821, 0x15E8E6EF, 

-            0xE79BD9BA, 0x6F36CE4A, 0x9F09D4EA, 0xB07CD629, 0xA4B2AF31, 0x3F23312A, 0xA59430C6, 0xA266C035, 

-            0x4EBC3774, 0x82CAA6FC, 0x90D0B0E0, 0xA7D81533, 0x04984AF1, 0xECDAF741, 0xCD500E7F, 0x91F62F17, 

-            0x4DD68D76, 0xEFB04D43, 0xAA4D54CC, 0x9604DFE4, 0xD1B5E39E, 0x6A881B4C, 0x2C1FB8C1, 0x65517F46, 

-            0x5EEA049D, 0x8C355D01, 0x877473FA, 0x0B412EFB, 0x671D5AB3, 0xDBD25292, 0x105633E9, 0xD647136D, 

-            0xD7618C9A, 0xA10C7A37, 0xF8148E59, 0x133C89EB, 0xA927EECE, 0x61C935B7, 0x1CE5EDE1, 0x47B13C7A, 

-            0xD2DF599C, 0xF2733F55, 0x14CE7918, 0xC737BF73, 0xF7CDEA53, 0xFDAA5B5F, 0x3D6F14DF, 0x44DB8678, 

-            0xAFF381CA, 0x68C43EB9, 0x24342C38, 0xA3405FC2, 0x1DC37216, 0xE2250CBC, 0x3C498B28, 0x0D9541FF, 

-            0xA8017139, 0x0CB3DE08, 0xB4E49CD8, 0x56C19064, 0xCB84617B, 0x32B670D5, 0x6C5C7448, 0xB85742D0

-        );

-

-        for ($i = 0; $i < 256; $i++) {

-            $this->t2[$i <<  8] = (($this->t3[$i] <<  8) & 0xFFFFFF00) | (($this->t3[$i] >> 24) & 0x000000FF);

-            $this->t1[$i << 16] = (($this->t3[$i] << 16) & 0xFFFF0000) | (($this->t3[$i] >> 16) & 0x0000FFFF);

-            $this->t0[$i << 24] = (($this->t3[$i] << 24) & 0xFF000000) | (($this->t3[$i] >>  8) & 0x00FFFFFF);

-

-            $this->dt2[$i <<  8] = (($this->dt3[$i] <<  8) & 0xFFFFFF00) | (($this->dt3[$i] >> 24) & 0x000000FF);

-            $this->dt1[$i << 16] = (($this->dt3[$i] << 16) & 0xFFFF0000) | (($this->dt3[$i] >> 16) & 0x0000FFFF);

-            $this->dt0[$i << 24] = (($this->dt3[$i] << 24) & 0xFF000000) | (($this->dt3[$i] >>  8) & 0x00FFFFFF);

-        }

-    }

-

-    /**

-     * Sets the key.

-     *

-     * Keys can be of any length.  Rijndael, itself, requires the use of a key that's between 128-bits and 256-bits long and

-     * whose length is a multiple of 32.  If the key is less than 256-bits and the key length isn't set, we round the length

-     * up to the closest valid key length, padding $key with null bytes.  If the key is more than 256-bits, we trim the

-     * excess bits.

-     *

-     * If the key is not explicitly set, it'll be assumed to be all null bytes.

-     *

-     * @access public

-     * @param String $key

-     */

-    function setKey($key)

-    {

-        $this->key = $key;

-        $this->changed = true;

-    }

-

-    /**

-     * Sets the initialization vector. (optional)

-     *

-     * SetIV is not required when CRYPT_RIJNDAEL_MODE_ECB is being used.  If not explictly set, it'll be assumed

-     * to be all zero's.

-     *

-     * @access public

-     * @param String $iv

-     */

-    function setIV($iv)

-    {

-        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, $this->block_size), $this->block_size, chr(0));;

-    }

-

-    /**

-     * Sets the key length

-     *

-     * Valid key lengths are 128, 160, 192, 224, and 256.  If the length is less than 128, it will be rounded up to

-     * 128.  If the length is greater then 128 and invalid, it will be rounded down to the closest valid amount.

-     *

-     * @access public

-     * @param Integer $length

-     */

-    function setKeyLength($length)

-    {

-        $length >>= 5;

-        if ($length > 8) {

-            $length = 8;

-        } else if ($length < 4) {

-            $length = 4;

-        }

-        $this->Nk = $length;

-        $this->key_size = $length << 2;

-

-        $this->explicit_key_length = true;

-        $this->changed = true;

-    }

-

-    /**

-     * Sets the block length

-     *

-     * Valid block lengths are 128, 160, 192, 224, and 256.  If the length is less than 128, it will be rounded up to

-     * 128.  If the length is greater then 128 and invalid, it will be rounded down to the closest valid amount.

-     *

-     * @access public

-     * @param Integer $length

-     */

-    function setBlockLength($length)

-    {

-        $length >>= 5;

-        if ($length > 8) {

-            $length = 8;

-        } else if ($length < 4) {

-            $length = 4;

-        }

-        $this->Nb = $length;

-        $this->block_size = $length << 2;

-        $this->changed = true;

-    }

-

-    /**

-     * Encrypts a message.

-     *

-     * $plaintext will be padded with additional bytes such that it's length is a multiple of the block size.  Other Rjindael

-     * implementations may or may not pad in the same manner.  Other common approaches to padding and the reasons why it's

-     * necessary are discussed in the following

-     * URL:

-     *

-     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}

-     *

-     * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.

-     * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that

-     * length.

-     *

-     * @see Crypt_Rijndael::decrypt()

-     * @access public

-     * @param String $plaintext

-     */

-    function encrypt($plaintext)

-    {

-        $this->_setup();

-        $plaintext = $this->_pad($plaintext);

-

-        $ciphertext = '';

-        switch ($this->mode) {

-            case CRYPT_RIJNDAEL_MODE_ECB:

-                for ($i = 0; $i < strlen($plaintext); $i+=$this->block_size) {

-                    $ciphertext.= $this->_encryptBlock(substr($plaintext, $i, $this->block_size));

-                }

-                break;

-            case CRYPT_RIJNDAEL_MODE_CBC:

-                $xor = $this->encryptIV;

-                for ($i = 0; $i < strlen($plaintext); $i+=$this->block_size) {

-                    $block = substr($plaintext, $i, $this->block_size);

-                    $block = $this->_encryptBlock($block ^ $xor);

-                    $xor = $block;

-                    $ciphertext.= $block;

-                }

-                if ($this->continuousBuffer) {

-                    $this->encryptIV = $xor;

-                }

-        }

-

-        return $ciphertext;

-    }

-

-    /**

-     * Decrypts a message.

-     *

-     * If strlen($ciphertext) is not a multiple of the block size, null bytes will be added to the end of the string until

-     * it is.

-     *

-     * @see Crypt_Rijndael::encrypt()

-     * @access public

-     * @param String $ciphertext

-     */

-    function decrypt($ciphertext)

-    {

-        $this->_setup();

-        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :

-        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."

-        $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + $this->block_size - 1) % $this->block_size, chr(0));

-

-        $plaintext = '';

-        switch ($this->mode) {

-            case CRYPT_RIJNDAEL_MODE_ECB:

-                for ($i = 0; $i < strlen($ciphertext); $i+=$this->block_size) {

-                    $plaintext.= $this->_decryptBlock(substr($ciphertext, $i, $this->block_size));

-                }

-                break;

-            case CRYPT_RIJNDAEL_MODE_CBC:

-                $xor = $this->decryptIV;

-                for ($i = 0; $i < strlen($ciphertext); $i+=$this->block_size) {

-                    $block = substr($ciphertext, $i, $this->block_size);

-                    $plaintext.= $this->_decryptBlock($block) ^ $xor;

-                    $xor = $block;

-                }

-                if ($this->continuousBuffer) {

-                    $this->decryptIV = $xor;

-                }

-        }

-

-        return $this->_unpad($plaintext);

-    }

-

-    /**

-     * Encrypts a block

-     *

-     * @access private

-     * @param String $in

-     * @return String

-     */

-    function _encryptBlock($in)

-    {

-        $state = array();

-        $words = unpack('N*word', $in);

-

-        // addRoundKey

-        foreach ($words as $word) {

-            $state[] = $word ^ $this->w[0][count($state)];

-        }

-

-        // fips-197.pdf#page=19, "Figure 5. Pseudo Code for the Cipher", states that this loop has four components - 

-        // subBytes, shiftRows, mixColumns, and addRoundKey. fips-197.pdf#page=30, "Implementation Suggestions Regarding 

-        // Various Platforms" suggests that performs enhanced implementations are described in Rijndael-ammended.pdf.

-        // Rijndael-ammended.pdf#page=20, "Implementation aspects / 32-bit processor", discusses such an optimization.

-        // Unfortunately, the description given there is not quite correct.  Per aes.spec.v316.pdf#page=19 [1], 

-        // equation (7.4.7) is supposed to use addition instead of subtraction, so we'll do that here, as well.

-

-        // [1] http://fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.v316.pdf

-        $temp = array();

-        for ($round = 1; $round < $this->Nr; $round++) {

-            $i = 0; // $this->c[0] == 0

-            $j = $this->c[1];

-            $k = $this->c[2];

-            $l = $this->c[3];

-

-            while ($i < $this->Nb) {

-                $temp[$i] = $this->t0[$state[$i] & 0xFF000000] ^ 

-                            $this->t1[$state[$j] & 0x00FF0000] ^ 

-                            $this->t2[$state[$k] & 0x0000FF00] ^ 

-                            $this->t3[$state[$l] & 0x000000FF] ^ 

-                            $this->w[$round][$i];

-                $i++;

-                $j = ($j + 1) % $this->Nb;

-                $k = ($k + 1) % $this->Nb;

-                $l = ($l + 1) % $this->Nb;

-            }

-

-            for ($i = 0; $i < $this->Nb; $i++) {

-                $state[$i] = $temp[$i];

-            }

-        }

-

-        // subWord

-        for ($i = 0; $i < $this->Nb; $i++) {

-            $state[$i] = $this->_subWord($state[$i]);

-        }

-

-        // shiftRows + addRoundKey

-        $i = 0; // $this->c[0] == 0

-        $j = $this->c[1];

-        $k = $this->c[2];

-        $l = $this->c[3];

-        while ($i < $this->Nb) {

-            $temp[$i] = ($state[$i] & 0xFF000000) ^ 

-                        ($state[$j] & 0x00FF0000) ^ 

-                        ($state[$k] & 0x0000FF00) ^ 

-                        ($state[$l] & 0x000000FF) ^

-                         $this->w[$this->Nr][$i];

-            $i++;

-            $j = ($j + 1) % $this->Nb;

-            $k = ($k + 1) % $this->Nb;

-            $l = ($l + 1) % $this->Nb;

-        }

-        $state = $temp;

-

-        array_unshift($state, 'N*');

-

-        return call_user_func_array('pack', $state);

-    }

-

-    /**

-     * Decrypts a block

-     *

-     * @access private

-     * @param String $in

-     * @return String

-     */

-    function _decryptBlock($in)

-    {

-        $state = array();

-        $words = unpack('N*word', $in);

-

-        // addRoundKey

-        foreach ($words as $word) {

-            $state[] = $word ^ $this->dw[0][count($state)];

-        }

-

-        $temp = array();

-        for ($round = $this->Nr - 1; $round > 0; $round--) {

-            $i = 0; // $this->c[0] == 0

-            $j = $this->Nb - $this->c[1];

-            $k = $this->Nb - $this->c[2];

-            $l = $this->Nb - $this->c[3];

-

-            while ($i < $this->Nb) {

-                $temp[$i] = $this->dt0[$state[$i] & 0xFF000000] ^ 

-                            $this->dt1[$state[$j] & 0x00FF0000] ^ 

-                            $this->dt2[$state[$k] & 0x0000FF00] ^ 

-                            $this->dt3[$state[$l] & 0x000000FF] ^ 

-                            $this->dw[$round][$i];

-                $i++;

-                $j = ($j + 1) % $this->Nb;

-                $k = ($k + 1) % $this->Nb;

-                $l = ($l + 1) % $this->Nb;

-            }

-

-            for ($i = 0; $i < $this->Nb; $i++) {

-                $state[$i] = $temp[$i];

-            }

-        }

-

-        // invShiftRows + invSubWord + addRoundKey

-        $i = 0; // $this->c[0] == 0

-        $j = $this->Nb - $this->c[1];

-        $k = $this->Nb - $this->c[2];

-        $l = $this->Nb - $this->c[3];

-

-        while ($i < $this->Nb) {

-            $temp[$i] = $this->dw[0][$i] ^ 

-                        $this->_invSubWord(($state[$i] & 0xFF000000) | 

-                                           ($state[$j] & 0x00FF0000) | 

-                                           ($state[$k] & 0x0000FF00) | 

-                                           ($state[$l] & 0x000000FF));

-            $i++;

-            $j = ($j + 1) % $this->Nb;

-            $k = ($k + 1) % $this->Nb;

-            $l = ($l + 1) % $this->Nb;

-        }

-

-        $state = $temp;

-

-        array_unshift($state, 'N*');

-

-        return call_user_func_array('pack', $state);

-    }

-

-    /**

-     * Setup Rijndael

-     *

-     * Validates all the variables and calculates $Nr - the number of rounds that need to be performed - and $w - the key

-     * key schedule.

-     *

-     * @access private

-     */

-    function _setup()

-    {

-        // Each number in $rcon is equal to the previous number multiplied by two in Rijndael's finite field.

-        // See http://en.wikipedia.org/wiki/Finite_field_arithmetic#Multiplicative_inverse

-        static $rcon = array(0,

-            0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000,

-            0x20000000, 0x40000000, 0x80000000, 0x1B000000, 0x36000000,

-            0x6C000000, 0xD8000000, 0xAB000000, 0x4D000000, 0x9A000000,

-            0x2F000000, 0x5E000000, 0xBC000000, 0x63000000, 0xC6000000,

-            0x97000000, 0x35000000, 0x6A000000, 0xD4000000, 0xB3000000,

-            0x7D000000, 0xFA000000, 0xEF000000, 0xC5000000, 0x91000000

-        );

-

-        if (!$this->changed) {

-            return;

-        }

-

-        if (!$this->explicit_key_length) {

-            // we do >> 2, here, and not >> 5, as we do above, since strlen($this->key) tells us the number of bytes - not bits

-            $length = strlen($this->key) >> 2;

-            if ($length > 8) {

-                $length = 8;

-            } else if ($length < 4) {

-                $length = 4;

-            }

-            $this->Nk = $length;

-            $this->key_size = $length << 2;

-        }

-

-        $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, chr(0));

-        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, $this->block_size), $this->block_size, chr(0));

-

-        // see Rijndael-ammended.pdf#page=44

-        $this->Nr = max($this->Nk, $this->Nb) + 6;

-

-        // shift offsets for Nb = 5, 7 are defined in Rijndael-ammended.pdf#page=44,

-        //     "Table 8: Shift offsets in Shiftrow for the alternative block lengths"

-        // shift offsets for Nb = 4, 6, 8 are defined in Rijndael-ammended.pdf#page=14,

-        //     "Table 2: Shift offsets for different block lengths"

-        switch ($this->Nb) {

-            case 4:

-            case 5:

-            case 6:

-                $this->c = array(0, 1, 2, 3);

-                break;

-            case 7:

-                $this->c = array(0, 1, 2, 4);

-                break;

-            case 8:

-                $this->c = array(0, 1, 3, 4);

-        }

-

-        $key = $this->key;

-

-        $w = array_values(unpack('N*words', $key));

-

-        $length = $this->Nb * ($this->Nr + 1);

-        for ($i = $this->Nk; $i < $length; $i++) {

-            $temp = $w[$i - 1];

-            if ($i % $this->Nk == 0) {

-                // according to <http://php.net/language.types.integer>, "the size of an integer is platform-dependent".

-                // on a 32-bit machine, it's 32-bits, and on a 64-bit machine, it's 64-bits. on a 32-bit machine,

-                // 0xFFFFFFFF << 8 == 0xFFFFFF00, but on a 64-bit machine, it equals 0xFFFFFFFF00. as such, doing 'and'

-                // with 0xFFFFFFFF (or 0xFFFFFF00) on a 32-bit machine is unnecessary, but on a 64-bit machine, it is.

-                $temp = (($temp << 8) & 0xFFFFFF00) | (($temp >> 24) & 0x000000FF); // rotWord

-                $temp = $this->_subWord($temp) ^ $rcon[$i / $this->Nk];

-            } else if ($this->Nk > 6 && $i % $this->Nk == 4) {

-                $temp = $this->_subWord($temp);

-            }

-            $w[$i] = $w[$i - $this->Nk] ^ $temp;

-        }

-

-        // convert the key schedule from a vector of $Nb * ($Nr + 1) length to a matrix with $Nr + 1 rows and $Nb columns

-        // and generate the inverse key schedule.  more specifically,

-        // according to <http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=23> (section 5.3.3), 

-        // "The key expansion for the Inverse Cipher is defined as follows:

-        //        1. Apply the Key Expansion.

-        //        2. Apply InvMixColumn to all Round Keys except the first and the last one."

-        // also, see fips-197.pdf#page=27, "5.3.5 Equivalent Inverse Cipher"

-        $temp = array();

-        for ($i = $row = $col = 0; $i < $length; $i++, $col++) {

-            if ($col == $this->Nb) {

-                if ($row == 0) {

-                    $this->dw[0] = $this->w[0];

-                } else {

-                    // subWord + invMixColumn + invSubWord = invMixColumn

-                    $j = 0;

-                    while ($j < $this->Nb) {

-                        $dw = $this->_subWord($this->w[$row][$j]);

-                        $temp[$j] = $this->dt0[$dw & 0xFF000000] ^ 

-                                    $this->dt1[$dw & 0x00FF0000] ^ 

-                                    $this->dt2[$dw & 0x0000FF00] ^ 

-                                    $this->dt3[$dw & 0x000000FF];

-                        $j++;

-                    }

-                    $this->dw[$row] = $temp;

-                }

-

-                $col = 0;

-                $row++;

-            }

-            $this->w[$row][$col] = $w[$i];

-        }

-

-        $this->dw[$row] = $this->w[$row];

-

-        $this->changed = false;

-    }

-

-    /**

-     * Performs S-Box substitutions

-     *

-     * @access private

-     */

-    function _subWord($word)

-    {

-        static $sbox0, $sbox1, $sbox2, $sbox3;

-

-        if (empty($sbox0)) {

-            $sbox0 = array(

-                0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,

-                0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,

-                0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,

-                0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,

-                0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,

-                0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,

-                0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,

-                0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,

-                0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,

-                0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,

-                0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,

-                0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,

-                0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,

-                0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,

-                0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,

-                0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16

-            );

-

-            $sbox1 = array();

-            $sbox2 = array();

-            $sbox3 = array();

-

-            for ($i = 0; $i < 256; $i++) {

-                $sbox1[$i <<  8] = $sbox0[$i] <<  8;

-                $sbox2[$i << 16] = $sbox0[$i] << 16;

-                $sbox3[$i << 24] = $sbox0[$i] << 24;

-            }

-        }

-

-        return $sbox0[$word & 0x000000FF] | 

-               $sbox1[$word & 0x0000FF00] | 

-               $sbox2[$word & 0x00FF0000] | 

-               $sbox3[$word & 0xFF000000];

-    }

-

-    /**

-     * Performs inverse S-Box substitutions

-     *

-     * @access private

-     */

-    function _invSubWord($word)

-    {

-        static $sbox0, $sbox1, $sbox2, $sbox3;

-

-        if (empty($sbox0)) {

-            $sbox0 = array(

-                0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,

-                0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,

-                0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,

-                0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,

-                0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,

-                0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,

-                0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,

-                0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,

-                0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,

-                0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,

-                0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,

-                0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,

-                0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,

-                0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,

-                0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,

-                0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D

-            );

-

-            $sbox1 = array();

-            $sbox2 = array();

-            $sbox3 = array();

-

-            for ($i = 0; $i < 256; $i++) {

-                $sbox1[$i <<  8] = $sbox0[$i] <<  8;

-                $sbox2[$i << 16] = $sbox0[$i] << 16;

-                $sbox3[$i << 24] = $sbox0[$i] << 24;

-            }

-        }

-

-        return $sbox0[$word & 0x000000FF] | 

-               $sbox1[$word & 0x0000FF00] | 

-               $sbox2[$word & 0x00FF0000] | 

-               $sbox3[$word & 0xFF000000];

-    }

-

-    /**

-     * Pad "packets".

-     *

-     * Rijndael works by encrypting between sixteen and thirty-two bytes at a time, provided that number is also a multiple

-     * of four.  If you ever need to encrypt or decrypt something that isn't of the proper length, it becomes necessary to

-     * pad the input so that it is of the proper length.

-     *

-     * Padding is enabled by default.  Sometimes, however, it is undesirable to pad strings.  Such is the case in SSH,

-     * where "packets" are padded with random bytes before being encrypted.  Unpad these packets and you risk stripping

-     * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is

-     * transmitted separately)

-     *

-     * @see Crypt_Rijndael::disablePadding()

-     * @access public

-     */

-    function enablePadding()

-    {

-        $this->padding = true;

-    }

-

-    /**

-     * Do not pad packets.

-     *

-     * @see Crypt_Rijndael::enablePadding()

-     * @access public

-     */

-    function disablePadding()

-    {

-        $this->padding = false;

-    }

-

-    /**

-     * Pads a string

-     *

-     * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize.

-     * $block_size - (strlen($text) % $block_size) bytes are added, each of which is equal to 

-     * chr($block_size - (strlen($text) % $block_size)

-     *

-     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless

-     * and padding will, hence forth, be enabled.

-     *

-     * @see Crypt_Rijndael::_unpad()

-     * @access private

-     */

-    function _pad($text)

-    {

-        $length = strlen($text);

-

-        if (!$this->padding) {

-            if ($length % $this->block_size == 0) {

-                return $text;

-            } else {

-                user_error("The plaintext's length ($length) is not a multiple of the block size ({$this->block_size})", E_USER_NOTICE);

-                $this->padding = true;

-            }

-        }

-

-        $pad = $this->block_size - ($length % $this->block_size);

-

-        return str_pad($text, $length + $pad, chr($pad));

-    }

-

-    /**

-     * Unpads a string.

-     *

-     * If padding is enabled and the reported padding length is invalid, padding will be, hence forth, disabled.

-     *

-     * @see Crypt_Rijndael::_pad()

-     * @access private

-     */

-    function _unpad($text)

-    {

-        if (!$this->padding) {

-            return $text;

-        }

-

-        $length = ord($text[strlen($text) - 1]);

-

-        if (!$length || $length > $this->block_size) {

-            user_error("The number of bytes reported as being padded ($length) is invalid (block size = {$this->block_size})", E_USER_NOTICE);

-            $this->padding = false;

-            return $text;

-        }

-

-        return substr($text, 0, -$length);

-    }

-

-    /**

-     * Treat consecutive "packets" as if they are a continuous buffer.

-     *

-     * Say you have a 32-byte plaintext $plaintext.  Using the default behavior, the two following code snippets

-     * will yield different outputs:

-     *

-     * <code>

-     *    echo $rijndael->encrypt(substr($plaintext,  0, 16));

-     *    echo $rijndael->encrypt(substr($plaintext, 16, 16));

-     * </code>

-     * <code>

-     *    echo $rijndael->encrypt($plaintext);

-     * </code>

-     *

-     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates

-     * another, as demonstrated with the following:

-     *

-     * <code>

-     *    $rijndael->encrypt(substr($plaintext, 0, 16));

-     *    echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16)));

-     * </code>

-     * <code>

-     *    echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16)));

-     * </code>

-     *

-     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different

-     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /

-     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.

-     *

-     * Put another way, when the continuous buffer is enabled, the state of the Crypt_Rijndael() object changes after each

-     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that

-     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),

-     * however, they are also less intuitive and more likely to cause you problems.

-     *

-     * @see Crypt_Rijndael::disableContinuousBuffer()

-     * @access public

-     */

-    function enableContinuousBuffer()

-    {

-        $this->continuousBuffer = true;

-    }

-

-    /**

-     * Treat consecutive packets as if they are a discontinuous buffer.

-     *

-     * The default behavior.

-     *

-     * @see Crypt_Rijndael::enableContinuousBuffer()

-     * @access public

-     */

-    function disableContinuousBuffer()

-    {

-        $this->continuousBuffer = false;

-        $this->encryptIV = $this->iv;

-        $this->decryptIV = $this->iv;

-    }

-

-    /**

-     * String Shift

-     *

-     * Inspired by array_shift

-     *

-     * @param String $string

-     * @param optional Integer $index

-     * @return String

-     * @access private

-     */

-    function _string_shift(&$string, $index = 1)

-    {

-        $substr = substr($string, 0, $index);

-        $string = substr($string, $index);

-        return $substr;

-    }

-}

-

-// vim: ts=4:sw=4:et:

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementation of Rijndael.
+ *
+ * Does not use mcrypt, even when available, for reasons that are explained below.
+ *
+ * PHP versions 4 and 5
+ *
+ * If {@link Crypt_Rijndael::setBlockLength() setBlockLength()} isn't called, it'll be assumed to be 128 bits.  If 
+ * {@link Crypt_Rijndael::setKeyLength() setKeyLength()} isn't called, it'll be calculated from 
+ * {@link Crypt_Rijndael::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 
+ * 136-bits it'll be null-padded to 160-bits and 160 bits will be the key length until 
+ * {@link Crypt_Rijndael::setKey() setKey()} is called, again, at which point, it'll be recalculated.
+ *
+ * Not all Rijndael implementations may support 160-bits or 224-bits as the block length / key length.  mcrypt, for example,
+ * does not.  AES, itself, only supports block lengths of 128 and key lengths of 128, 192, and 256.
+ * {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=10 Rijndael-ammended.pdf#page=10} defines the
+ * algorithm for block lengths of 192 and 256 but not for block lengths / key lengths of 160 and 224.  Indeed, 160 and 224
+ * are first defined as valid key / block lengths in 
+ * {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=44 Rijndael-ammended.pdf#page=44}: 
+ * Extensions: Other block and Cipher Key lengths.
+ *
+ * {@internal The variable names are the same as those in 
+ * {@link http://www.csrc.nist.gov/publications/fips/fips197/fips-197.pdf#page=10 fips-197.pdf#page=10}.}}
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/Rijndael.php');
+ *
+ *    $rijndael = new Crypt_Rijndael();
+ *
+ *    $rijndael->setKey('abcdefghijklmnop');
+ *
+ *    $size = 10 * 1024;
+ *    $plaintext = '';
+ *    for ($i = 0; $i < $size; $i++) {
+ *        $plaintext.= 'a';
+ *    }
+ *
+ *    echo $rijndael->decrypt($rijndael->encrypt($plaintext));
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_Rijndael
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVIII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: Rijndael.php,v 1.12 2010/02/09 06:10:26 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**#@+
+ * @access public
+ * @see Crypt_Rijndael::encrypt()
+ * @see Crypt_Rijndael::decrypt()
+ */
+/**
+ * Encrypt / decrypt using the Counter mode.
+ *
+ * Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
+ */
+define('CRYPT_RIJNDAEL_MODE_CTR', -1);
+/**
+ * Encrypt / decrypt using the Electronic Code Book mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
+ */
+define('CRYPT_RIJNDAEL_MODE_ECB', 1);
+/**
+ * Encrypt / decrypt using the Code Book Chaining mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
+ */
+define('CRYPT_RIJNDAEL_MODE_CBC', 2);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_Rijndael::Crypt_Rijndael()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_RIJNDAEL_MODE_INTERNAL', 1);
+/**
+ * Toggles the mcrypt implementation
+ */
+define('CRYPT_RIJNDAEL_MODE_MCRYPT', 2);
+/**#@-*/
+
+/**
+ * Pure-PHP implementation of Rijndael.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_Rijndael
+ */
+class Crypt_Rijndael {
+    /**
+     * The Encryption Mode
+     *
+     * @see Crypt_Rijndael::Crypt_Rijndael()
+     * @var Integer
+     * @access private
+     */
+    var $mode;
+
+    /**
+     * The Key
+     *
+     * @see Crypt_Rijndael::setKey()
+     * @var String
+     * @access private
+     */
+    var $key = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
+
+    /**
+     * The Initialization Vector
+     *
+     * @see Crypt_Rijndael::setIV()
+     * @var String
+     * @access private
+     */
+    var $iv = '';
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_Rijndael::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $encryptIV = '';
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_Rijndael::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $decryptIV = '';
+
+    /**
+     * Continuous Buffer status
+     *
+     * @see Crypt_Rijndael::enableContinuousBuffer()
+     * @var Boolean
+     * @access private
+     */
+    var $continuousBuffer = false;
+
+    /**
+     * Padding status
+     *
+     * @see Crypt_Rijndael::enablePadding()
+     * @var Boolean
+     * @access private
+     */
+    var $padding = true;
+
+    /**
+     * Does the key schedule need to be (re)calculated?
+     *
+     * @see setKey()
+     * @see setBlockLength()
+     * @see setKeyLength()
+     * @var Boolean
+     * @access private
+     */
+    var $changed = true;
+
+    /**
+     * Has the key length explicitly been set or should it be derived from the key, itself?
+     *
+     * @see setKeyLength()
+     * @var Boolean
+     * @access private
+     */
+    var $explicit_key_length = false;
+
+    /**
+     * The Key Schedule
+     *
+     * @see _setup()
+     * @var Array
+     * @access private
+     */
+    var $w;
+
+    /**
+     * The Inverse Key Schedule
+     *
+     * @see _setup()
+     * @var Array
+     * @access private
+     */
+    var $dw;
+
+    /**
+     * The Block Length
+     *
+     * @see setBlockLength()
+     * @var Integer
+     * @access private
+     * @internal The max value is 32, the min value is 16.  All valid values are multiples of 4.  Exists in conjunction with
+     *     $Nb because we need this value and not $Nb to pad strings appropriately.  
+     */
+    var $block_size = 16;
+
+    /**
+     * The Block Length divided by 32
+     *
+     * @see setBlockLength()
+     * @var Integer
+     * @access private
+     * @internal The max value is 256 / 32 = 8, the min value is 128 / 32 = 4.  Exists in conjunction with $block_size 
+     *    because the encryption / decryption / key schedule creation requires this number and not $block_size.  We could 
+     *    derive this from $block_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu
+     *    of that, we'll just precompute it once.
+     *
+     */
+    var $Nb = 4;
+
+    /**
+     * The Key Length
+     *
+     * @see setKeyLength()
+     * @var Integer
+     * @access private
+     * @internal The max value is 256 / 8 = 32, the min value is 128 / 8 = 16.  Exists in conjunction with $key_size
+     *    because the encryption / decryption / key schedule creation requires this number and not $key_size.  We could 
+     *    derive this from $key_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu
+     *    of that, we'll just precompute it once.
+     */
+    var $key_size = 16;
+
+    /**
+     * The Key Length divided by 32
+     *
+     * @see setKeyLength()
+     * @var Integer
+     * @access private
+     * @internal The max value is 256 / 32 = 8, the min value is 128 / 32 = 4
+     */
+    var $Nk = 4;
+
+    /**
+     * The Number of Rounds
+     *
+     * @var Integer
+     * @access private
+     * @internal The max value is 14, the min value is 10.
+     */
+    var $Nr;
+
+    /**
+     * Shift offsets
+     *
+     * @var Array
+     * @access private
+     */
+    var $c;
+
+    /**
+     * Precomputed mixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $t0;
+
+    /**
+     * Precomputed mixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $t1;
+
+    /**
+     * Precomputed mixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $t2;
+
+    /**
+     * Precomputed mixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $t3;
+
+    /**
+     * Precomputed invMixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $dt0;
+
+    /**
+     * Precomputed invMixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $dt1;
+
+    /**
+     * Precomputed invMixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $dt2;
+
+    /**
+     * Precomputed invMixColumns table
+     *
+     * @see Crypt_Rijndael()
+     * @var Array
+     * @access private
+     */
+    var $dt3;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be
+     * CRYPT_RIJNDAEL_MODE_ECB or CRYPT_RIJNDAEL_MODE_CBC.  If not explictly set, CRYPT_RIJNDAEL_MODE_CBC will be used.
+     *
+     * @param optional Integer $mode
+     * @return Crypt_Rijndael
+     * @access public
+     */
+    function Crypt_Rijndael($mode = CRYPT_RIJNDAEL_MODE_CBC)
+    {
+        switch ($mode) {
+            case CRYPT_RIJNDAEL_MODE_ECB:
+            case CRYPT_RIJNDAEL_MODE_CBC:
+            case CRYPT_RIJNDAEL_MODE_CTR:
+                $this->mode = $mode;
+                break;
+            default:
+                $this->mode = CRYPT_RIJNDAEL_MODE_CBC;
+        }
+
+        $t3 = &$this->t3;
+        $t2 = &$this->t2;
+        $t1 = &$this->t1;
+        $t0 = &$this->t0;
+
+        $dt3 = &$this->dt3;
+        $dt2 = &$this->dt2;
+        $dt1 = &$this->dt1;
+        $dt0 = &$this->dt0;
+
+        // according to <http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=19> (section 5.2.1), 
+        // precomputed tables can be used in the mixColumns phase.  in that example, they're assigned t0...t3, so
+        // those are the names we'll use.
+        $t3 = array(
+            0x6363A5C6, 0x7C7C84F8, 0x777799EE, 0x7B7B8DF6, 0xF2F20DFF, 0x6B6BBDD6, 0x6F6FB1DE, 0xC5C55491, 
+            0x30305060, 0x01010302, 0x6767A9CE, 0x2B2B7D56, 0xFEFE19E7, 0xD7D762B5, 0xABABE64D, 0x76769AEC, 
+            0xCACA458F, 0x82829D1F, 0xC9C94089, 0x7D7D87FA, 0xFAFA15EF, 0x5959EBB2, 0x4747C98E, 0xF0F00BFB, 
+            0xADADEC41, 0xD4D467B3, 0xA2A2FD5F, 0xAFAFEA45, 0x9C9CBF23, 0xA4A4F753, 0x727296E4, 0xC0C05B9B, 
+            0xB7B7C275, 0xFDFD1CE1, 0x9393AE3D, 0x26266A4C, 0x36365A6C, 0x3F3F417E, 0xF7F702F5, 0xCCCC4F83, 
+            0x34345C68, 0xA5A5F451, 0xE5E534D1, 0xF1F108F9, 0x717193E2, 0xD8D873AB, 0x31315362, 0x15153F2A, 
+            0x04040C08, 0xC7C75295, 0x23236546, 0xC3C35E9D, 0x18182830, 0x9696A137, 0x05050F0A, 0x9A9AB52F, 
+            0x0707090E, 0x12123624, 0x80809B1B, 0xE2E23DDF, 0xEBEB26CD, 0x2727694E, 0xB2B2CD7F, 0x75759FEA, 
+            0x09091B12, 0x83839E1D, 0x2C2C7458, 0x1A1A2E34, 0x1B1B2D36, 0x6E6EB2DC, 0x5A5AEEB4, 0xA0A0FB5B, 
+            0x5252F6A4, 0x3B3B4D76, 0xD6D661B7, 0xB3B3CE7D, 0x29297B52, 0xE3E33EDD, 0x2F2F715E, 0x84849713, 
+            0x5353F5A6, 0xD1D168B9, 0x00000000, 0xEDED2CC1, 0x20206040, 0xFCFC1FE3, 0xB1B1C879, 0x5B5BEDB6, 
+            0x6A6ABED4, 0xCBCB468D, 0xBEBED967, 0x39394B72, 0x4A4ADE94, 0x4C4CD498, 0x5858E8B0, 0xCFCF4A85, 
+            0xD0D06BBB, 0xEFEF2AC5, 0xAAAAE54F, 0xFBFB16ED, 0x4343C586, 0x4D4DD79A, 0x33335566, 0x85859411, 
+            0x4545CF8A, 0xF9F910E9, 0x02020604, 0x7F7F81FE, 0x5050F0A0, 0x3C3C4478, 0x9F9FBA25, 0xA8A8E34B, 
+            0x5151F3A2, 0xA3A3FE5D, 0x4040C080, 0x8F8F8A05, 0x9292AD3F, 0x9D9DBC21, 0x38384870, 0xF5F504F1, 
+            0xBCBCDF63, 0xB6B6C177, 0xDADA75AF, 0x21216342, 0x10103020, 0xFFFF1AE5, 0xF3F30EFD, 0xD2D26DBF, 
+            0xCDCD4C81, 0x0C0C1418, 0x13133526, 0xECEC2FC3, 0x5F5FE1BE, 0x9797A235, 0x4444CC88, 0x1717392E, 
+            0xC4C45793, 0xA7A7F255, 0x7E7E82FC, 0x3D3D477A, 0x6464ACC8, 0x5D5DE7BA, 0x19192B32, 0x737395E6, 
+            0x6060A0C0, 0x81819819, 0x4F4FD19E, 0xDCDC7FA3, 0x22226644, 0x2A2A7E54, 0x9090AB3B, 0x8888830B, 
+            0x4646CA8C, 0xEEEE29C7, 0xB8B8D36B, 0x14143C28, 0xDEDE79A7, 0x5E5EE2BC, 0x0B0B1D16, 0xDBDB76AD, 
+            0xE0E03BDB, 0x32325664, 0x3A3A4E74, 0x0A0A1E14, 0x4949DB92, 0x06060A0C, 0x24246C48, 0x5C5CE4B8, 
+            0xC2C25D9F, 0xD3D36EBD, 0xACACEF43, 0x6262A6C4, 0x9191A839, 0x9595A431, 0xE4E437D3, 0x79798BF2, 
+            0xE7E732D5, 0xC8C8438B, 0x3737596E, 0x6D6DB7DA, 0x8D8D8C01, 0xD5D564B1, 0x4E4ED29C, 0xA9A9E049, 
+            0x6C6CB4D8, 0x5656FAAC, 0xF4F407F3, 0xEAEA25CF, 0x6565AFCA, 0x7A7A8EF4, 0xAEAEE947, 0x08081810, 
+            0xBABAD56F, 0x787888F0, 0x25256F4A, 0x2E2E725C, 0x1C1C2438, 0xA6A6F157, 0xB4B4C773, 0xC6C65197, 
+            0xE8E823CB, 0xDDDD7CA1, 0x74749CE8, 0x1F1F213E, 0x4B4BDD96, 0xBDBDDC61, 0x8B8B860D, 0x8A8A850F, 
+            0x707090E0, 0x3E3E427C, 0xB5B5C471, 0x6666AACC, 0x4848D890, 0x03030506, 0xF6F601F7, 0x0E0E121C, 
+            0x6161A3C2, 0x35355F6A, 0x5757F9AE, 0xB9B9D069, 0x86869117, 0xC1C15899, 0x1D1D273A, 0x9E9EB927, 
+            0xE1E138D9, 0xF8F813EB, 0x9898B32B, 0x11113322, 0x6969BBD2, 0xD9D970A9, 0x8E8E8907, 0x9494A733, 
+            0x9B9BB62D, 0x1E1E223C, 0x87879215, 0xE9E920C9, 0xCECE4987, 0x5555FFAA, 0x28287850, 0xDFDF7AA5, 
+            0x8C8C8F03, 0xA1A1F859, 0x89898009, 0x0D0D171A, 0xBFBFDA65, 0xE6E631D7, 0x4242C684, 0x6868B8D0, 
+            0x4141C382, 0x9999B029, 0x2D2D775A, 0x0F0F111E, 0xB0B0CB7B, 0x5454FCA8, 0xBBBBD66D, 0x16163A2C
+        );
+
+        $dt3 = array(
+            0xF4A75051, 0x4165537E, 0x17A4C31A, 0x275E963A, 0xAB6BCB3B, 0x9D45F11F, 0xFA58ABAC, 0xE303934B, 
+            0x30FA5520, 0x766DF6AD, 0xCC769188, 0x024C25F5, 0xE5D7FC4F, 0x2ACBD7C5, 0x35448026, 0x62A38FB5, 
+            0xB15A49DE, 0xBA1B6725, 0xEA0E9845, 0xFEC0E15D, 0x2F7502C3, 0x4CF01281, 0x4697A38D, 0xD3F9C66B, 
+            0x8F5FE703, 0x929C9515, 0x6D7AEBBF, 0x5259DA95, 0xBE832DD4, 0x7421D358, 0xE0692949, 0xC9C8448E, 
+            0xC2896A75, 0x8E7978F4, 0x583E6B99, 0xB971DD27, 0xE14FB6BE, 0x88AD17F0, 0x20AC66C9, 0xCE3AB47D, 
+            0xDF4A1863, 0x1A3182E5, 0x51336097, 0x537F4562, 0x6477E0B1, 0x6BAE84BB, 0x81A01CFE, 0x082B94F9, 
+            0x48685870, 0x45FD198F, 0xDE6C8794, 0x7BF8B752, 0x73D323AB, 0x4B02E272, 0x1F8F57E3, 0x55AB2A66, 
+            0xEB2807B2, 0xB5C2032F, 0xC57B9A86, 0x3708A5D3, 0x2887F230, 0xBFA5B223, 0x036ABA02, 0x16825CED, 
+            0xCF1C2B8A, 0x79B492A7, 0x07F2F0F3, 0x69E2A14E, 0xDAF4CD65, 0x05BED506, 0x34621FD1, 0xA6FE8AC4, 
+            0x2E539D34, 0xF355A0A2, 0x8AE13205, 0xF6EB75A4, 0x83EC390B, 0x60EFAA40, 0x719F065E, 0x6E1051BD, 
+            0x218AF93E, 0xDD063D96, 0x3E05AEDD, 0xE6BD464D, 0x548DB591, 0xC45D0571, 0x06D46F04, 0x5015FF60, 
+            0x98FB2419, 0xBDE997D6, 0x4043CC89, 0xD99E7767, 0xE842BDB0, 0x898B8807, 0x195B38E7, 0xC8EEDB79, 
+            0x7C0A47A1, 0x420FE97C, 0x841EC9F8, 0x00000000, 0x80868309, 0x2BED4832, 0x1170AC1E, 0x5A724E6C, 
+            0x0EFFFBFD, 0x8538560F, 0xAED51E3D, 0x2D392736, 0x0FD9640A, 0x5CA62168, 0x5B54D19B, 0x362E3A24, 
+            0x0A67B10C, 0x57E70F93, 0xEE96D2B4, 0x9B919E1B, 0xC0C54F80, 0xDC20A261, 0x774B695A, 0x121A161C, 
+            0x93BA0AE2, 0xA02AE5C0, 0x22E0433C, 0x1B171D12, 0x090D0B0E, 0x8BC7ADF2, 0xB6A8B92D, 0x1EA9C814, 
+            0xF1198557, 0x75074CAF, 0x99DDBBEE, 0x7F60FDA3, 0x01269FF7, 0x72F5BC5C, 0x663BC544, 0xFB7E345B, 
+            0x4329768B, 0x23C6DCCB, 0xEDFC68B6, 0xE4F163B8, 0x31DCCAD7, 0x63851042, 0x97224013, 0xC6112084, 
+            0x4A247D85, 0xBB3DF8D2, 0xF93211AE, 0x29A16DC7, 0x9E2F4B1D, 0xB230F3DC, 0x8652EC0D, 0xC1E3D077, 
+            0xB3166C2B, 0x70B999A9, 0x9448FA11, 0xE9642247, 0xFC8CC4A8, 0xF03F1AA0, 0x7D2CD856, 0x3390EF22, 
+            0x494EC787, 0x38D1C1D9, 0xCAA2FE8C, 0xD40B3698, 0xF581CFA6, 0x7ADE28A5, 0xB78E26DA, 0xADBFA43F, 
+            0x3A9DE42C, 0x78920D50, 0x5FCC9B6A, 0x7E466254, 0x8D13C2F6, 0xD8B8E890, 0x39F75E2E, 0xC3AFF582, 
+            0x5D80BE9F, 0xD0937C69, 0xD52DA96F, 0x2512B3CF, 0xAC993BC8, 0x187DA710, 0x9C636EE8, 0x3BBB7BDB, 
+            0x267809CD, 0x5918F46E, 0x9AB701EC, 0x4F9AA883, 0x956E65E6, 0xFFE67EAA, 0xBCCF0821, 0x15E8E6EF, 
+            0xE79BD9BA, 0x6F36CE4A, 0x9F09D4EA, 0xB07CD629, 0xA4B2AF31, 0x3F23312A, 0xA59430C6, 0xA266C035, 
+            0x4EBC3774, 0x82CAA6FC, 0x90D0B0E0, 0xA7D81533, 0x04984AF1, 0xECDAF741, 0xCD500E7F, 0x91F62F17, 
+            0x4DD68D76, 0xEFB04D43, 0xAA4D54CC, 0x9604DFE4, 0xD1B5E39E, 0x6A881B4C, 0x2C1FB8C1, 0x65517F46, 
+            0x5EEA049D, 0x8C355D01, 0x877473FA, 0x0B412EFB, 0x671D5AB3, 0xDBD25292, 0x105633E9, 0xD647136D, 
+            0xD7618C9A, 0xA10C7A37, 0xF8148E59, 0x133C89EB, 0xA927EECE, 0x61C935B7, 0x1CE5EDE1, 0x47B13C7A, 
+            0xD2DF599C, 0xF2733F55, 0x14CE7918, 0xC737BF73, 0xF7CDEA53, 0xFDAA5B5F, 0x3D6F14DF, 0x44DB8678, 
+            0xAFF381CA, 0x68C43EB9, 0x24342C38, 0xA3405FC2, 0x1DC37216, 0xE2250CBC, 0x3C498B28, 0x0D9541FF, 
+            0xA8017139, 0x0CB3DE08, 0xB4E49CD8, 0x56C19064, 0xCB84617B, 0x32B670D5, 0x6C5C7448, 0xB85742D0
+        );
+
+        for ($i = 0; $i < 256; $i++) {
+            $t2[$i <<  8] = (($t3[$i] <<  8) & 0xFFFFFF00) | (($t3[$i] >> 24) & 0x000000FF);
+            $t1[$i << 16] = (($t3[$i] << 16) & 0xFFFF0000) | (($t3[$i] >> 16) & 0x0000FFFF);
+            $t0[$i << 24] = (($t3[$i] << 24) & 0xFF000000) | (($t3[$i] >>  8) & 0x00FFFFFF);
+
+            $dt2[$i <<  8] = (($this->dt3[$i] <<  8) & 0xFFFFFF00) | (($dt3[$i] >> 24) & 0x000000FF);
+            $dt1[$i << 16] = (($this->dt3[$i] << 16) & 0xFFFF0000) | (($dt3[$i] >> 16) & 0x0000FFFF);
+            $dt0[$i << 24] = (($this->dt3[$i] << 24) & 0xFF000000) | (($dt3[$i] >>  8) & 0x00FFFFFF);
+        }
+    }
+
+    /**
+     * Sets the key.
+     *
+     * Keys can be of any length.  Rijndael, itself, requires the use of a key that's between 128-bits and 256-bits long and
+     * whose length is a multiple of 32.  If the key is less than 256-bits and the key length isn't set, we round the length
+     * up to the closest valid key length, padding $key with null bytes.  If the key is more than 256-bits, we trim the
+     * excess bits.
+     *
+     * If the key is not explicitly set, it'll be assumed to be all null bytes.
+     *
+     * @access public
+     * @param String $key
+     */
+    function setKey($key)
+    {
+        $this->key = $key;
+        $this->changed = true;
+    }
+
+    /**
+     * Sets the initialization vector. (optional)
+     *
+     * SetIV is not required when CRYPT_RIJNDAEL_MODE_ECB is being used.  If not explictly set, it'll be assumed
+     * to be all zero's.
+     *
+     * @access public
+     * @param String $iv
+     */
+    function setIV($iv)
+    {
+        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, $this->block_size), $this->block_size, chr(0));;
+    }
+
+    /**
+     * Sets the key length
+     *
+     * Valid key lengths are 128, 160, 192, 224, and 256.  If the length is less than 128, it will be rounded up to
+     * 128.  If the length is greater then 128 and invalid, it will be rounded down to the closest valid amount.
+     *
+     * @access public
+     * @param Integer $length
+     */
+    function setKeyLength($length)
+    {
+        $length >>= 5;
+        if ($length > 8) {
+            $length = 8;
+        } else if ($length < 4) {
+            $length = 4;
+        }
+        $this->Nk = $length;
+        $this->key_size = $length << 2;
+
+        $this->explicit_key_length = true;
+        $this->changed = true;
+    }
+
+    /**
+     * Sets the block length
+     *
+     * Valid block lengths are 128, 160, 192, 224, and 256.  If the length is less than 128, it will be rounded up to
+     * 128.  If the length is greater then 128 and invalid, it will be rounded down to the closest valid amount.
+     *
+     * @access public
+     * @param Integer $length
+     */
+    function setBlockLength($length)
+    {
+        $length >>= 5;
+        if ($length > 8) {
+            $length = 8;
+        } else if ($length < 4) {
+            $length = 4;
+        }
+        $this->Nb = $length;
+        $this->block_size = $length << 2;
+        $this->changed = true;
+    }
+
+    /**
+     * Generate CTR XOR encryption key
+     *
+     * Encrypt the output of this and XOR it against the ciphertext / plaintext to get the
+     * plaintext / ciphertext in CTR mode.
+     *
+     * @see Crypt_Rijndael::decrypt()
+     * @see Crypt_Rijndael::encrypt()
+     * @access public
+     * @param Integer $length
+     * @param String $iv
+     */
+    function _generate_xor($length, &$iv)
+    {
+        $xor = '';
+        $block_size = $this->block_size;
+        $num_blocks = floor(($length + ($block_size - 1)) / $block_size);
+        for ($i = 0; $i < $num_blocks; $i++) {
+            $xor.= $iv;
+            for ($j = 4; $j <= $block_size; $j+=4) {
+                $temp = substr($iv, -$j, 4);
+                switch ($temp) {
+                    case "\xFF\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x00\x00\x00\x00", -$j, 4);
+                        break;
+                    case "\x7F\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x80\x00\x00\x00", -$j, 4);
+                        break 2;
+                    default:
+                        extract(unpack('Ncount', $temp));
+                        $iv = substr_replace($iv, pack('N', $count + 1), -$j, 4);
+                        break 2;
+                }
+            }
+        }
+
+        return $xor;
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * $plaintext will be padded with additional bytes such that it's length is a multiple of the block size.  Other Rjindael
+     * implementations may or may not pad in the same manner.  Other common approaches to padding and the reasons why it's
+     * necessary are discussed in the following
+     * URL:
+     *
+     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
+     *
+     * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.
+     * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that
+     * length.
+     *
+     * @see Crypt_Rijndael::decrypt()
+     * @access public
+     * @param String $plaintext
+     */
+    function encrypt($plaintext)
+    {
+        $this->_setup();
+        if ($this->mode != CRYPT_RIJNDAEL_MODE_CTR) {
+            $plaintext = $this->_pad($plaintext);
+        }
+
+        $block_size = $this->block_size;
+        $ciphertext = '';
+        switch ($this->mode) {
+            case CRYPT_RIJNDAEL_MODE_ECB:
+                for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                    $ciphertext.= $this->_encryptBlock(substr($plaintext, $i, $block_size));
+                }
+                break;
+            case CRYPT_RIJNDAEL_MODE_CBC:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                    $block = substr($plaintext, $i, $block_size);
+                    $block = $this->_encryptBlock($block ^ $xor);
+                    $xor = $block;
+                    $ciphertext.= $block;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+                break;
+            case CRYPT_RIJNDAEL_MODE_CTR:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                    $block = substr($plaintext, $i, $block_size);
+                    $key = $this->_encryptBlock($this->_generate_xor($block_size, $xor));
+                    $ciphertext.= $block ^ $key;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+        }
+
+        return $ciphertext;
+    }
+
+    /**
+     * Decrypts a message.
+     *
+     * If strlen($ciphertext) is not a multiple of the block size, null bytes will be added to the end of the string until
+     * it is.
+     *
+     * @see Crypt_Rijndael::encrypt()
+     * @access public
+     * @param String $ciphertext
+     */
+    function decrypt($ciphertext)
+    {
+        $this->_setup();
+
+        if ($this->mode != CRYPT_RIJNDAEL_MODE_CTR) {
+            // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :
+            // "The data is padded with "\0" to make sure the length of the data is n * blocksize."
+            $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + $this->block_size - 1) % $this->block_size, chr(0));
+        }
+
+        $block_size = $this->block_size;
+        $plaintext = '';
+        switch ($this->mode) {
+            case CRYPT_RIJNDAEL_MODE_ECB:
+                for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
+                    $plaintext.= $this->_decryptBlock(substr($ciphertext, $i, $block_size));
+                }
+                break;
+            case CRYPT_RIJNDAEL_MODE_CBC:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
+                    $block = substr($ciphertext, $i, $block_size);
+                    $plaintext.= $this->_decryptBlock($block) ^ $xor;
+                    $xor = $block;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+                break;
+            case CRYPT_RIJNDAEL_MODE_CTR:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
+                    $block = substr($ciphertext, $i, $block_size);
+                    $key = $this->_encryptBlock($this->_generate_xor($block_size, $xor));
+                    $plaintext.= $block ^ $key;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+        }
+
+        return $this->mode != CRYPT_RIJNDAEL_MODE_CTR ? $this->_unpad($plaintext) : $plaintext;
+    }
+
+    /**
+     * Encrypts a block
+     *
+     * @access private
+     * @param String $in
+     * @return String
+     */
+    function _encryptBlock($in)
+    {
+        $state = array();
+        $words = unpack('N*word', $in);
+
+        $w = $this->w;
+        $t0 = $this->t0;
+        $t1 = $this->t1;
+        $t2 = $this->t2;
+        $t3 = $this->t3;
+        $Nb = $this->Nb;
+        $Nr = $this->Nr;
+        $c = $this->c;
+
+        // addRoundKey
+        $i = 0;
+        foreach ($words as $word) {
+            $state[] = $word ^ $w[0][$i++];
+        }
+
+        // fips-197.pdf#page=19, "Figure 5. Pseudo Code for the Cipher", states that this loop has four components - 
+        // subBytes, shiftRows, mixColumns, and addRoundKey. fips-197.pdf#page=30, "Implementation Suggestions Regarding 
+        // Various Platforms" suggests that performs enhanced implementations are described in Rijndael-ammended.pdf.
+        // Rijndael-ammended.pdf#page=20, "Implementation aspects / 32-bit processor", discusses such an optimization.
+        // Unfortunately, the description given there is not quite correct.  Per aes.spec.v316.pdf#page=19 [1], 
+        // equation (7.4.7) is supposed to use addition instead of subtraction, so we'll do that here, as well.
+
+        // [1] http://fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.v316.pdf
+        $temp = array();
+        for ($round = 1; $round < $Nr; $round++) {
+            $i = 0; // $c[0] == 0
+            $j = $c[1];
+            $k = $c[2];
+            $l = $c[3];
+
+            while ($i < $this->Nb) {
+                $temp[$i] = $t0[$state[$i] & 0xFF000000] ^ 
+                            $t1[$state[$j] & 0x00FF0000] ^ 
+                            $t2[$state[$k] & 0x0000FF00] ^ 
+                            $t3[$state[$l] & 0x000000FF] ^ 
+                            $w[$round][$i];
+                $i++;
+                $j = ($j + 1) % $Nb;
+                $k = ($k + 1) % $Nb;
+                $l = ($l + 1) % $Nb;
+            }
+
+            for ($i = 0; $i < $Nb; $i++) {
+                $state[$i] = $temp[$i];
+            }
+        }
+
+        // subWord
+        for ($i = 0; $i < $Nb; $i++) {
+            $state[$i] = $this->_subWord($state[$i]);
+        }
+
+        // shiftRows + addRoundKey
+        $i = 0; // $c[0] == 0
+        $j = $c[1];
+        $k = $c[2];
+        $l = $c[3];
+        while ($i < $this->Nb) {
+            $temp[$i] = ($state[$i] & 0xFF000000) ^ 
+                        ($state[$j] & 0x00FF0000) ^ 
+                        ($state[$k] & 0x0000FF00) ^ 
+                        ($state[$l] & 0x000000FF) ^
+                         $w[$Nr][$i];
+            $i++;
+            $j = ($j + 1) % $Nb;
+            $k = ($k + 1) % $Nb;
+            $l = ($l + 1) % $Nb;
+        }
+        $state = $temp;
+
+        array_unshift($state, 'N*');
+
+        return call_user_func_array('pack', $state);
+    }
+
+    /**
+     * Decrypts a block
+     *
+     * @access private
+     * @param String $in
+     * @return String
+     */
+    function _decryptBlock($in)
+    {
+        $state = array();
+        $words = unpack('N*word', $in);
+
+        $num_states = count($state);
+        $dw = $this->dw;
+        $dt0 = $this->dt0;
+        $dt1 = $this->dt1;
+        $dt2 = $this->dt2;
+        $dt3 = $this->dt3;
+        $Nb = $this->Nb;
+        $Nr = $this->Nr;
+        $c = $this->c;
+
+        // addRoundKey
+        $i = 0;
+        foreach ($words as $word) {
+            $state[] = $word ^ $dw[$Nr][$i++];
+        }
+
+        $temp = array();
+        for ($round = $Nr - 1; $round > 0; $round--) {
+            $i = 0; // $c[0] == 0
+            $j = $Nb - $c[1];
+            $k = $Nb - $c[2];
+            $l = $Nb - $c[3];
+
+            while ($i < $Nb) {
+                $temp[$i] = $dt0[$state[$i] & 0xFF000000] ^ 
+                            $dt1[$state[$j] & 0x00FF0000] ^ 
+                            $dt2[$state[$k] & 0x0000FF00] ^ 
+                            $dt3[$state[$l] & 0x000000FF] ^ 
+                            $dw[$round][$i];
+                $i++;
+                $j = ($j + 1) % $Nb;
+                $k = ($k + 1) % $Nb;
+                $l = ($l + 1) % $Nb;
+            }
+
+            for ($i = 0; $i < $Nb; $i++) {
+                $state[$i] = $temp[$i];
+            }
+        }
+
+        // invShiftRows + invSubWord + addRoundKey
+        $i = 0; // $c[0] == 0
+        $j = $Nb - $c[1];
+        $k = $Nb - $c[2];
+        $l = $Nb - $c[3];
+
+        while ($i < $Nb) {
+            $temp[$i] = $dw[0][$i] ^ 
+                        $this->_invSubWord(($state[$i] & 0xFF000000) | 
+                                           ($state[$j] & 0x00FF0000) | 
+                                           ($state[$k] & 0x0000FF00) | 
+                                           ($state[$l] & 0x000000FF));
+            $i++;
+            $j = ($j + 1) % $Nb;
+            $k = ($k + 1) % $Nb;
+            $l = ($l + 1) % $Nb;
+        }
+
+        $state = $temp;
+
+        array_unshift($state, 'N*');
+
+        return call_user_func_array('pack', $state);
+    }
+
+    /**
+     * Setup Rijndael
+     *
+     * Validates all the variables and calculates $Nr - the number of rounds that need to be performed - and $w - the key
+     * key schedule.
+     *
+     * @access private
+     */
+    function _setup()
+    {
+        // Each number in $rcon is equal to the previous number multiplied by two in Rijndael's finite field.
+        // See http://en.wikipedia.org/wiki/Finite_field_arithmetic#Multiplicative_inverse
+        static $rcon = array(0,
+            0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000,
+            0x20000000, 0x40000000, 0x80000000, 0x1B000000, 0x36000000,
+            0x6C000000, 0xD8000000, 0xAB000000, 0x4D000000, 0x9A000000,
+            0x2F000000, 0x5E000000, 0xBC000000, 0x63000000, 0xC6000000,
+            0x97000000, 0x35000000, 0x6A000000, 0xD4000000, 0xB3000000,
+            0x7D000000, 0xFA000000, 0xEF000000, 0xC5000000, 0x91000000
+        );
+
+        if (!$this->changed) {
+            return;
+        }
+
+        if (!$this->explicit_key_length) {
+            // we do >> 2, here, and not >> 5, as we do above, since strlen($this->key) tells us the number of bytes - not bits
+            $length = strlen($this->key) >> 2;
+            if ($length > 8) {
+                $length = 8;
+            } else if ($length < 4) {
+                $length = 4;
+            }
+            $this->Nk = $length;
+            $this->key_size = $length << 2;
+        }
+
+        $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, chr(0));
+        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, $this->block_size), $this->block_size, chr(0));
+
+        // see Rijndael-ammended.pdf#page=44
+        $this->Nr = max($this->Nk, $this->Nb) + 6;
+
+        // shift offsets for Nb = 5, 7 are defined in Rijndael-ammended.pdf#page=44,
+        //     "Table 8: Shift offsets in Shiftrow for the alternative block lengths"
+        // shift offsets for Nb = 4, 6, 8 are defined in Rijndael-ammended.pdf#page=14,
+        //     "Table 2: Shift offsets for different block lengths"
+        switch ($this->Nb) {
+            case 4:
+            case 5:
+            case 6:
+                $this->c = array(0, 1, 2, 3);
+                break;
+            case 7:
+                $this->c = array(0, 1, 2, 4);
+                break;
+            case 8:
+                $this->c = array(0, 1, 3, 4);
+        }
+
+        $key = $this->key;
+
+        $w = array_values(unpack('N*words', $key));
+
+        $length = $this->Nb * ($this->Nr + 1);
+        for ($i = $this->Nk; $i < $length; $i++) {
+            $temp = $w[$i - 1];
+            if ($i % $this->Nk == 0) {
+                // according to <http://php.net/language.types.integer>, "the size of an integer is platform-dependent".
+                // on a 32-bit machine, it's 32-bits, and on a 64-bit machine, it's 64-bits. on a 32-bit machine,
+                // 0xFFFFFFFF << 8 == 0xFFFFFF00, but on a 64-bit machine, it equals 0xFFFFFFFF00. as such, doing 'and'
+                // with 0xFFFFFFFF (or 0xFFFFFF00) on a 32-bit machine is unnecessary, but on a 64-bit machine, it is.
+                $temp = (($temp << 8) & 0xFFFFFF00) | (($temp >> 24) & 0x000000FF); // rotWord
+                $temp = $this->_subWord($temp) ^ $rcon[$i / $this->Nk];
+            } else if ($this->Nk > 6 && $i % $this->Nk == 4) {
+                $temp = $this->_subWord($temp);
+            }
+            $w[$i] = $w[$i - $this->Nk] ^ $temp;
+        }
+
+        // convert the key schedule from a vector of $Nb * ($Nr + 1) length to a matrix with $Nr + 1 rows and $Nb columns
+        // and generate the inverse key schedule.  more specifically,
+        // according to <http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=23> (section 5.3.3), 
+        // "The key expansion for the Inverse Cipher is defined as follows:
+        //        1. Apply the Key Expansion.
+        //        2. Apply InvMixColumn to all Round Keys except the first and the last one."
+        // also, see fips-197.pdf#page=27, "5.3.5 Equivalent Inverse Cipher"
+        $temp = array();
+        for ($i = $row = $col = 0; $i < $length; $i++, $col++) {
+            if ($col == $this->Nb) {
+                if ($row == 0) {
+                    $this->dw[0] = $this->w[0];
+                } else {
+                    // subWord + invMixColumn + invSubWord = invMixColumn
+                    $j = 0;
+                    while ($j < $this->Nb) {
+                        $dw = $this->_subWord($this->w[$row][$j]);
+                        $temp[$j] = $this->dt0[$dw & 0xFF000000] ^ 
+                                    $this->dt1[$dw & 0x00FF0000] ^ 
+                                    $this->dt2[$dw & 0x0000FF00] ^ 
+                                    $this->dt3[$dw & 0x000000FF];
+                        $j++;
+                    }
+                    $this->dw[$row] = $temp;
+                }
+
+                $col = 0;
+                $row++;
+            }
+            $this->w[$row][$col] = $w[$i];
+        }
+
+        $this->dw[$row] = $this->w[$row];
+
+        $this->changed = false;
+    }
+
+    /**
+     * Performs S-Box substitutions
+     *
+     * @access private
+     */
+    function _subWord($word)
+    {
+        static $sbox0, $sbox1, $sbox2, $sbox3;
+
+        if (empty($sbox0)) {
+            $sbox0 = array(
+                0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
+                0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
+                0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
+                0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
+                0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
+                0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
+                0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
+                0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
+                0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
+                0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
+                0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
+                0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
+                0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
+                0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
+                0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
+                0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
+            );
+
+            $sbox1 = array();
+            $sbox2 = array();
+            $sbox3 = array();
+
+            for ($i = 0; $i < 256; $i++) {
+                $sbox1[$i <<  8] = $sbox0[$i] <<  8;
+                $sbox2[$i << 16] = $sbox0[$i] << 16;
+                $sbox3[$i << 24] = $sbox0[$i] << 24;
+            }
+        }
+
+        return $sbox0[$word & 0x000000FF] | 
+               $sbox1[$word & 0x0000FF00] | 
+               $sbox2[$word & 0x00FF0000] | 
+               $sbox3[$word & 0xFF000000];
+    }
+
+    /**
+     * Performs inverse S-Box substitutions
+     *
+     * @access private
+     */
+    function _invSubWord($word)
+    {
+        static $sbox0, $sbox1, $sbox2, $sbox3;
+
+        if (empty($sbox0)) {
+            $sbox0 = array(
+                0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
+                0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
+                0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
+                0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
+                0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
+                0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
+                0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
+                0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
+                0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
+                0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
+                0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
+                0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
+                0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
+                0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
+                0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
+                0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
+            );
+
+            $sbox1 = array();
+            $sbox2 = array();
+            $sbox3 = array();
+
+            for ($i = 0; $i < 256; $i++) {
+                $sbox1[$i <<  8] = $sbox0[$i] <<  8;
+                $sbox2[$i << 16] = $sbox0[$i] << 16;
+                $sbox3[$i << 24] = $sbox0[$i] << 24;
+            }
+        }
+
+        return $sbox0[$word & 0x000000FF] | 
+               $sbox1[$word & 0x0000FF00] | 
+               $sbox2[$word & 0x00FF0000] | 
+               $sbox3[$word & 0xFF000000];
+    }
+
+    /**
+     * Pad "packets".
+     *
+     * Rijndael works by encrypting between sixteen and thirty-two bytes at a time, provided that number is also a multiple
+     * of four.  If you ever need to encrypt or decrypt something that isn't of the proper length, it becomes necessary to
+     * pad the input so that it is of the proper length.
+     *
+     * Padding is enabled by default.  Sometimes, however, it is undesirable to pad strings.  Such is the case in SSH,
+     * where "packets" are padded with random bytes before being encrypted.  Unpad these packets and you risk stripping
+     * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is
+     * transmitted separately)
+     *
+     * @see Crypt_Rijndael::disablePadding()
+     * @access public
+     */
+    function enablePadding()
+    {
+        $this->padding = true;
+    }
+
+    /**
+     * Do not pad packets.
+     *
+     * @see Crypt_Rijndael::enablePadding()
+     * @access public
+     */
+    function disablePadding()
+    {
+        $this->padding = false;
+    }
+
+    /**
+     * Pads a string
+     *
+     * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize.
+     * $block_size - (strlen($text) % $block_size) bytes are added, each of which is equal to 
+     * chr($block_size - (strlen($text) % $block_size)
+     *
+     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless
+     * and padding will, hence forth, be enabled.
+     *
+     * @see Crypt_Rijndael::_unpad()
+     * @access private
+     */
+    function _pad($text)
+    {
+        $length = strlen($text);
+
+        if (!$this->padding) {
+            if ($length % $this->block_size == 0) {
+                return $text;
+            } else {
+                user_error("The plaintext's length ($length) is not a multiple of the block size ({$this->block_size})", E_USER_NOTICE);
+                $this->padding = true;
+            }
+        }
+
+        $pad = $this->block_size - ($length % $this->block_size);
+
+        return str_pad($text, $length + $pad, chr($pad));
+    }
+
+    /**
+     * Unpads a string.
+     *
+     * If padding is enabled and the reported padding length is invalid the encryption key will be assumed to be wrong
+     * and false will be returned.
+     *
+     * @see Crypt_Rijndael::_pad()
+     * @access private
+     */
+    function _unpad($text)
+    {
+        if (!$this->padding) {
+            return $text;
+        }
+
+        $length = ord($text[strlen($text) - 1]);
+
+        if (!$length || $length > $this->block_size) {
+            return false;
+        }
+
+        return substr($text, 0, -$length);
+    }
+
+    /**
+     * Treat consecutive "packets" as if they are a continuous buffer.
+     *
+     * Say you have a 32-byte plaintext $plaintext.  Using the default behavior, the two following code snippets
+     * will yield different outputs:
+     *
+     * <code>
+     *    echo $rijndael->encrypt(substr($plaintext,  0, 16));
+     *    echo $rijndael->encrypt(substr($plaintext, 16, 16));
+     * </code>
+     * <code>
+     *    echo $rijndael->encrypt($plaintext);
+     * </code>
+     *
+     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates
+     * another, as demonstrated with the following:
+     *
+     * <code>
+     *    $rijndael->encrypt(substr($plaintext, 0, 16));
+     *    echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16)));
+     * </code>
+     * <code>
+     *    echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16)));
+     * </code>
+     *
+     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different
+     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /
+     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.
+     *
+     * Put another way, when the continuous buffer is enabled, the state of the Crypt_Rijndael() object changes after each
+     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that
+     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),
+     * however, they are also less intuitive and more likely to cause you problems.
+     *
+     * @see Crypt_Rijndael::disableContinuousBuffer()
+     * @access public
+     */
+    function enableContinuousBuffer()
+    {
+        $this->continuousBuffer = true;
+    }
+
+    /**
+     * Treat consecutive packets as if they are a discontinuous buffer.
+     *
+     * The default behavior.
+     *
+     * @see Crypt_Rijndael::enableContinuousBuffer()
+     * @access public
+     */
+    function disableContinuousBuffer()
+    {
+        $this->continuousBuffer = false;
+        $this->encryptIV = $this->iv;
+        $this->decryptIV = $this->iv;
+    }
+
+    /**
+     * String Shift
+     *
+     * Inspired by array_shift
+     *
+     * @param String $string
+     * @param optional Integer $index
+     * @return String
+     * @access private
+     */
+    function _string_shift(&$string, $index = 1)
+    {
+        $substr = substr($string, 0, $index);
+        $string = substr($string, $index);
+        return $substr;
+    }
+}
+
+// vim: ts=4:sw=4:et:
 // vim6: fdl=1:
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Crypt/TripleDES.php b/plugins/OStatus/extlib/Crypt/TripleDES.php
index 03050e5d6..9d054086a 100644
--- a/plugins/OStatus/extlib/Crypt/TripleDES.php
+++ b/plugins/OStatus/extlib/Crypt/TripleDES.php
@@ -1,603 +1,690 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP implementation of Triple DES.

- *

- * Uses mcrypt, if available, and an internal implementation, otherwise.  Operates in the EDE3 mode (encrypt-decrypt-encrypt).

- *

- * PHP versions 4 and 5

- *

- * Here's a short example of how to use this library:

- * <code>

- * <?php

- *    include('Crypt/TripleDES.php');

- *

- *    $des = new Crypt_TripleDES();

- *

- *    $des->setKey('abcdefghijklmnopqrstuvwx');

- *

- *    $size = 10 * 1024;

- *    $plaintext = '';

- *    for ($i = 0; $i < $size; $i++) {

- *        $plaintext.= 'a';

- *    }

- *

- *    echo $des->decrypt($des->encrypt($plaintext));

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Crypt

- * @package    Crypt_TripleDES

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVII Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: TripleDES.php,v 1.9 2009/11/23 19:06:07 terrafrost Exp $

- * @link       http://phpseclib.sourceforge.net

- */

-

-/**

- * Include Crypt_DES

- */

-require_once 'DES.php';

-

-/**

- * Encrypt / decrypt using inner chaining

- *

- * Inner chaining is used by SSH-1 and is generally considered to be less secure then outer chaining (CRYPT_DES_MODE_CBC3).

- */

-define('CRYPT_DES_MODE_3CBC', 3);

-

-/**

- * Encrypt / decrypt using outer chaining

- *

- * Outer chaining is used by SSH-2 and when the mode is set to CRYPT_DES_MODE_CBC.

- */

-define('CRYPT_DES_MODE_CBC3', CRYPT_DES_MODE_CBC);

-

-/**

- * Pure-PHP implementation of Triple DES.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 0.1.0

- * @access  public

- * @package Crypt_TerraDES

- */

-class Crypt_TripleDES {

-    /**

-     * The Three Keys

-     *

-     * @see Crypt_TripleDES::setKey()

-     * @var String

-     * @access private

-     */

-    var $key = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * The Encryption Mode

-     *

-     * @see Crypt_TripleDES::Crypt_TripleDES()

-     * @var Integer

-     * @access private

-     */

-    var $mode = CRYPT_DES_MODE_CBC;

-

-    /**

-     * Continuous Buffer status

-     *

-     * @see Crypt_TripleDES::enableContinuousBuffer()

-     * @var Boolean

-     * @access private

-     */

-    var $continuousBuffer = false;

-

-    /**

-     * Padding status

-     *

-     * @see Crypt_TripleDES::enablePadding()

-     * @var Boolean

-     * @access private

-     */

-    var $padding = true;

-

-    /**

-     * The Initialization Vector

-     *

-     * @see Crypt_TripleDES::setIV()

-     * @var String

-     * @access private

-     */

-    var $iv = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * A "sliding" Initialization Vector

-     *

-     * @see Crypt_TripleDES::enableContinuousBuffer()

-     * @var String

-     * @access private

-     */

-    var $encryptIV = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * A "sliding" Initialization Vector

-     *

-     * @see Crypt_TripleDES::enableContinuousBuffer()

-     * @var String

-     * @access private

-     */

-    var $decryptIV = "\0\0\0\0\0\0\0\0";

-

-    /**

-     * MCrypt parameters

-     *

-     * @see Crypt_TripleDES::setMCrypt()

-     * @var Array

-     * @access private

-     */

-    var $mcrypt = array('', '');

-

-    /**

-     * The Crypt_DES objects

-     *

-     * @var Array

-     * @access private

-     */

-    var $des;

-

-    /**

-     * Default Constructor.

-     *

-     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be

-     * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC.  If not explictly set, CRYPT_DES_MODE_CBC will be used.

-     *

-     * @param optional Integer $mode

-     * @return Crypt_TripleDES

-     * @access public

-     */

-    function Crypt_TripleDES($mode = CRYPT_DES_MODE_CBC)

-    {

-        if ( !defined('CRYPT_DES_MODE') ) {

-            switch (true) {

-                case extension_loaded('mcrypt'):

-                    // i'd check to see if des was supported, by doing in_array('des', mcrypt_list_algorithms('')),

-                    // but since that can be changed after the object has been created, there doesn't seem to be

-                    // a lot of point...

-                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT);

-                    break;

-                default:

-                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL);

-            }

-        }

-

-        if ( $mode == CRYPT_DES_MODE_3CBC ) {

-            $this->mode = CRYPT_DES_MODE_3CBC;

-            $this->des = array(

-                new Crypt_DES(CRYPT_DES_MODE_CBC),

-                new Crypt_DES(CRYPT_DES_MODE_CBC),

-                new Crypt_DES(CRYPT_DES_MODE_CBC)

-            );

-

-            // we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects

-            $this->des[0]->disablePadding();

-            $this->des[1]->disablePadding();

-            $this->des[2]->disablePadding();

-

-            return;

-        }

-

-        switch ( CRYPT_DES_MODE ) {

-            case CRYPT_DES_MODE_MCRYPT:

-                switch ($mode) {

-                    case CRYPT_DES_MODE_ECB:

-                        $this->mode = MCRYPT_MODE_ECB;    break;

-                    case CRYPT_DES_MODE_CBC:

-                    default:

-                        $this->mode = MCRYPT_MODE_CBC;

-                }

-

-                break;

-            default:

-                $this->des = array(

-                    new Crypt_DES(CRYPT_DES_MODE_ECB),

-                    new Crypt_DES(CRYPT_DES_MODE_ECB),

-                    new Crypt_DES(CRYPT_DES_MODE_ECB)

-                );

- 

-                // we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects

-                $this->des[0]->disablePadding();

-                $this->des[1]->disablePadding();

-                $this->des[2]->disablePadding();

-

-                switch ($mode) {

-                    case CRYPT_DES_MODE_ECB:

-                    case CRYPT_DES_MODE_CBC:

-                        $this->mode = $mode;

-                        break;

-                    default:

-                        $this->mode = CRYPT_DES_MODE_CBC;

-                }

-        }

-    }

-

-    /**

-     * Sets the key.

-     *

-     * Keys can be of any length.  Triple DES, itself, can use 128-bit (eg. strlen($key) == 16) or

-     * 192-bit (eg. strlen($key) == 24) keys.  This function pads and truncates $key as appropriate.

-     *

-     * DES also requires that every eighth bit be a parity bit, however, we'll ignore that.

-     *

-     * If the key is not explicitly set, it'll be assumed to be all zero's.

-     *

-     * @access public

-     * @param String $key

-     */

-    function setKey($key)

-    {

-        $length = strlen($key);

-        if ($length > 8) {

-            $key = str_pad($key, 24, chr(0));

-            // if $key is between 64 and 128-bits, use the first 64-bits as the last, per this:

-            // http://php.net/function.mcrypt-encrypt#47973

-            $key = $length <= 16 ? substr_replace($key, substr($key, 0, 8), 16) : substr($key, 0, 24);

-        }

-        $this->key = $key;

-        switch (true) {

-            case CRYPT_DES_MODE == CRYPT_DES_MODE_INTERNAL:

-            case $this->mode == CRYPT_DES_MODE_3CBC:

-                $this->des[0]->setKey(substr($key,  0, 8));

-                $this->des[1]->setKey(substr($key,  8, 8));

-                $this->des[2]->setKey(substr($key, 16, 8));

-        }

-    }

-

-    /**

-     * Sets the initialization vector. (optional)

-     *

-     * SetIV is not required when CRYPT_DES_MODE_ECB is being used.  If not explictly set, it'll be assumed

-     * to be all zero's.

-     *

-     * @access public

-     * @param String $iv

-     */

-    function setIV($iv)

-    {

-        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));

-        if ($this->mode == CRYPT_DES_MODE_3CBC) {

-            $this->des[0]->setIV($iv);

-            $this->des[1]->setIV($iv);

-            $this->des[2]->setIV($iv);

-        }

-    }

-

-    /**

-     * Sets MCrypt parameters. (optional)

-     *

-     * If MCrypt is being used, empty strings will be used, unless otherwise specified.

-     *

-     * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open

-     * @access public

-     * @param optional Integer $algorithm_directory

-     * @param optional Integer $mode_directory

-     */

-    function setMCrypt($algorithm_directory = '', $mode_directory = '')

-    {

-        $this->mcrypt = array($algorithm_directory, $mode_directory);

-        if ( $this->mode == CRYPT_DES_MODE_3CBC ) {

-            $this->des[0]->setMCrypt($algorithm_directory, $mode_directory);

-            $this->des[1]->setMCrypt($algorithm_directory, $mode_directory);

-            $this->des[2]->setMCrypt($algorithm_directory, $mode_directory);

-        }

-    }

-

-    /**

-     * Encrypts a message.

-     *

-     * @access public

-     * @param String $plaintext

-     */

-    function encrypt($plaintext)

-    {

-        $plaintext = $this->_pad($plaintext);

-

-        // if the key is smaller then 8, do what we'd normally do

-        if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {

-            $ciphertext = $this->des[2]->encrypt($this->des[1]->decrypt($this->des[0]->encrypt($plaintext)));

-

-            return $ciphertext;

-        }

-

-        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {

-            $td = mcrypt_module_open(MCRYPT_3DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);

-            mcrypt_generic_init($td, $this->key, $this->encryptIV);

-

-            $ciphertext = mcrypt_generic($td, $plaintext);

-

-            mcrypt_generic_deinit($td);

-            mcrypt_module_close($td);

-

-            if ($this->continuousBuffer) {

-                $this->encryptIV = substr($ciphertext, -8);

-            }

-

-            return $ciphertext;

-        }

-

-        if (strlen($this->key) <= 8) {

-            $this->des[0]->mode = $this->mode;

-

-            return $this->des[0]->encrypt($plaintext);

-        }

-

-        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :

-        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."

-        $plaintext = str_pad($plaintext, ceil(strlen($plaintext) / 8) * 8, chr(0));

-

-        $ciphertext = '';

-        switch ($this->mode) {

-            case CRYPT_DES_MODE_ECB:

-                for ($i = 0; $i < strlen($plaintext); $i+=8) {

-                    $block = substr($plaintext, $i, 8);

-                    $block = $this->des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);

-                    $block = $this->des[1]->_processBlock($block, CRYPT_DES_DECRYPT);

-                    $block = $this->des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);

-                    $ciphertext.= $block;

-                }

-                break;

-            case CRYPT_DES_MODE_CBC:

-                $xor = $this->encryptIV;

-                for ($i = 0; $i < strlen($plaintext); $i+=8) {

-                    $block = substr($plaintext, $i, 8) ^ $xor;

-                    $block = $this->des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);

-                    $block = $this->des[1]->_processBlock($block, CRYPT_DES_DECRYPT);

-                    $block = $this->des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);

-                    $xor = $block;

-                    $ciphertext.= $block;

-                }

-                if ($this->continuousBuffer) {

-                    $this->encryptIV = $xor;

-                }

-        }

-

-        return $ciphertext;

-    }

-

-    /**

-     * Decrypts a message.

-     *

-     * @access public

-     * @param String $ciphertext

-     */

-    function decrypt($ciphertext)

-    {

-        if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {

-            $plaintext = $this->des[0]->decrypt($this->des[1]->encrypt($this->des[2]->decrypt($ciphertext)));

-

-            return $this->_unpad($plaintext);

-        }

-

-        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :

-        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."

-        $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 0xFFFFFFF8, chr(0));

-

-        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {

-            $td = mcrypt_module_open(MCRYPT_3DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);

-            mcrypt_generic_init($td, $this->key, $this->decryptIV);

-

-            $plaintext = mdecrypt_generic($td, $ciphertext);

-

-            mcrypt_generic_deinit($td);

-            mcrypt_module_close($td);

-

-            if ($this->continuousBuffer) {

-                $this->decryptIV = substr($ciphertext, -8);

-            }

-

-            return $this->_unpad($plaintext);

-        }

-

-        if (strlen($this->key) <= 8) {

-            $this->des[0]->mode = $this->mode;

-

-            return $this->_unpad($this->des[0]->decrypt($plaintext));

-        }

-

-        $plaintext = '';

-        switch ($this->mode) {

-            case CRYPT_DES_MODE_ECB:

-                for ($i = 0; $i < strlen($ciphertext); $i+=8) {

-                    $block = substr($ciphertext, $i, 8);

-                    $block = $this->des[2]->_processBlock($block, CRYPT_DES_DECRYPT);

-                    $block = $this->des[1]->_processBlock($block, CRYPT_DES_ENCRYPT);

-                    $block = $this->des[0]->_processBlock($block, CRYPT_DES_DECRYPT);

-                    $plaintext.= $block;

-                }

-                break;

-            case CRYPT_DES_MODE_CBC:

-                $xor = $this->decryptIV;

-                for ($i = 0; $i < strlen($ciphertext); $i+=8) {

-                    $orig = $block = substr($ciphertext, $i, 8);

-                    $block = $this->des[2]->_processBlock($block, CRYPT_DES_DECRYPT);

-                    $block = $this->des[1]->_processBlock($block, CRYPT_DES_ENCRYPT);

-                    $block = $this->des[0]->_processBlock($block, CRYPT_DES_DECRYPT);

-                    $plaintext.= $block ^ $xor;

-                    $xor = $orig;

-                }

-                if ($this->continuousBuffer) {

-                    $this->decryptIV = $xor;

-                }

-        }

-

-        return $this->_unpad($plaintext);

-    }

-

-    /**

-     * Treat consecutive "packets" as if they are a continuous buffer.

-     *

-     * Say you have a 16-byte plaintext $plaintext.  Using the default behavior, the two following code snippets

-     * will yield different outputs:

-     *

-     * <code>

-     *    echo $des->encrypt(substr($plaintext, 0, 8));

-     *    echo $des->encrypt(substr($plaintext, 8, 8));

-     * </code>

-     * <code>

-     *    echo $des->encrypt($plaintext);

-     * </code>

-     *

-     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates

-     * another, as demonstrated with the following:

-     *

-     * <code>

-     *    $des->encrypt(substr($plaintext, 0, 8));

-     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));

-     * </code>

-     * <code>

-     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));

-     * </code>

-     *

-     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different

-     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /

-     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.

-     *

-     * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each

-     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that

-     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),

-     * however, they are also less intuitive and more likely to cause you problems.

-     *

-     * @see Crypt_TripleDES::disableContinuousBuffer()

-     * @access public

-     */

-    function enableContinuousBuffer()

-    {

-        $this->continuousBuffer = true;

-        if ($this->mode == CRYPT_DES_MODE_3CBC) {

-            $this->des[0]->enableContinuousBuffer();

-            $this->des[1]->enableContinuousBuffer();

-            $this->des[2]->enableContinuousBuffer();

-        }

-    }

-

-    /**

-     * Treat consecutive packets as if they are a discontinuous buffer.

-     *

-     * The default behavior.

-     *

-     * @see Crypt_TripleDES::enableContinuousBuffer()

-     * @access public

-     */

-    function disableContinuousBuffer()

-    {

-        $this->continuousBuffer = false;

-        $this->encryptIV = $this->iv;

-        $this->decryptIV = $this->iv;

-

-        if ($this->mode == CRYPT_DES_MODE_3CBC) {

-            $this->des[0]->disableContinuousBuffer();

-            $this->des[1]->disableContinuousBuffer();

-            $this->des[2]->disableContinuousBuffer();

-        }

-    }

-

-    /**

-     * Pad "packets".

-     *

-     * DES works by encrypting eight bytes at a time.  If you ever need to encrypt or decrypt something that's not

-     * a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight.

-     *

-     * Padding is enabled by default.  Sometimes, however, it is undesirable to pad strings.  Such is the case in SSH1,

-     * where "packets" are padded with random bytes before being encrypted.  Unpad these packets and you risk stripping

-     * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is

-     * transmitted separately)

-     *

-     * @see Crypt_TripleDES::disablePadding()

-     * @access public

-     */

-    function enablePadding()

-    {

-        $this->padding = true;

-    }

-

-    /**

-     * Do not pad packets.

-     *

-     * @see Crypt_TripleDES::enablePadding()

-     * @access public

-     */

-    function disablePadding()

-    {

-        $this->padding = false;

-    }

-

-    /**

-     * Pads a string

-     *

-     * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8).

-     * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7)

-     *

-     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless

-     * and padding will, hence forth, be enabled.

-     *

-     * @see Crypt_TripleDES::_unpad()

-     * @access private

-     */

-    function _pad($text)

-    {

-        $length = strlen($text);

-

-        if (!$this->padding) {

-            if (($length & 7) == 0) {

-                return $text;

-            } else {

-                user_error("The plaintext's length ($length) is not a multiple of the block size (8)", E_USER_NOTICE);

-                $this->padding = true;

-            }

-        }

-

-        $pad = 8 - ($length & 7);

-        return str_pad($text, $length + $pad, chr($pad));

-    }

-

-    /**

-     * Unpads a string

-     *

-     * If padding is enabled and the reported padding length is invalid, padding will be, hence forth, disabled.

-     *

-     * @see Crypt_TripleDES::_pad()

-     * @access private

-     */

-    function _unpad($text)

-    {

-        if (!$this->padding) {

-            return $text;

-        }

-

-        $length = ord($text[strlen($text) - 1]);

-

-        if (!$length || $length > 8) {

-            user_error("The number of bytes reported as being padded ($length) is invalid (block size = 8)", E_USER_NOTICE);

-            $this->padding = false;

-            return $text;

-        }

-

-        return substr($text, 0, -$length);

-    }

-}

-

-// vim: ts=4:sw=4:et:

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementation of Triple DES.
+ *
+ * Uses mcrypt, if available, and an internal implementation, otherwise.  Operates in the EDE3 mode (encrypt-decrypt-encrypt).
+ *
+ * PHP versions 4 and 5
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/TripleDES.php');
+ *
+ *    $des = new Crypt_TripleDES();
+ *
+ *    $des->setKey('abcdefghijklmnopqrstuvwx');
+ *
+ *    $size = 10 * 1024;
+ *    $plaintext = '';
+ *    for ($i = 0; $i < $size; $i++) {
+ *        $plaintext.= 'a';
+ *    }
+ *
+ *    echo $des->decrypt($des->encrypt($plaintext));
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Crypt
+ * @package    Crypt_TripleDES
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVII Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: TripleDES.php,v 1.13 2010/02/26 03:40:25 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**
+ * Include Crypt_DES
+ */
+require_once 'DES.php';
+
+/**
+ * Encrypt / decrypt using inner chaining
+ *
+ * Inner chaining is used by SSH-1 and is generally considered to be less secure then outer chaining (CRYPT_DES_MODE_CBC3).
+ */
+define('CRYPT_DES_MODE_3CBC', 3);
+
+/**
+ * Encrypt / decrypt using outer chaining
+ *
+ * Outer chaining is used by SSH-2 and when the mode is set to CRYPT_DES_MODE_CBC.
+ */
+define('CRYPT_DES_MODE_CBC3', CRYPT_DES_MODE_CBC);
+
+/**
+ * Pure-PHP implementation of Triple DES.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_TerraDES
+ */
+class Crypt_TripleDES {
+    /**
+     * The Three Keys
+     *
+     * @see Crypt_TripleDES::setKey()
+     * @var String
+     * @access private
+     */
+    var $key = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * The Encryption Mode
+     *
+     * @see Crypt_TripleDES::Crypt_TripleDES()
+     * @var Integer
+     * @access private
+     */
+    var $mode = CRYPT_DES_MODE_CBC;
+
+    /**
+     * Continuous Buffer status
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @var Boolean
+     * @access private
+     */
+    var $continuousBuffer = false;
+
+    /**
+     * Padding status
+     *
+     * @see Crypt_TripleDES::enablePadding()
+     * @var Boolean
+     * @access private
+     */
+    var $padding = true;
+
+    /**
+     * The Initialization Vector
+     *
+     * @see Crypt_TripleDES::setIV()
+     * @var String
+     * @access private
+     */
+    var $iv = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $encryptIV = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $decryptIV = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * The Crypt_DES objects
+     *
+     * @var Array
+     * @access private
+     */
+    var $des;
+
+    /**
+     * mcrypt resource for encryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
+     *
+     * @see Crypt_AES::encrypt()
+     * @var String
+     * @access private
+     */
+    var $enmcrypt;
+
+    /**
+     * mcrypt resource for decryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
+     *
+     * @see Crypt_AES::decrypt()
+     * @var String
+     * @access private
+     */
+    var $demcrypt;
+
+    /**
+     * Does the (en|de)mcrypt resource need to be (re)initialized?
+     *
+     * @see setKey()
+     * @see setIV()
+     * @var Boolean
+     * @access private
+     */
+    var $changed = true;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.  $mode should only, at present, be
+     * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC.  If not explictly set, CRYPT_DES_MODE_CBC will be used.
+     *
+     * @param optional Integer $mode
+     * @return Crypt_TripleDES
+     * @access public
+     */
+    function Crypt_TripleDES($mode = CRYPT_DES_MODE_CBC)
+    {
+        if ( !defined('CRYPT_DES_MODE') ) {
+            switch (true) {
+                case extension_loaded('mcrypt'):
+                    // i'd check to see if des was supported, by doing in_array('des', mcrypt_list_algorithms('')),
+                    // but since that can be changed after the object has been created, there doesn't seem to be
+                    // a lot of point...
+                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT);
+                    break;
+                default:
+                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL);
+            }
+        }
+
+        if ( $mode == CRYPT_DES_MODE_3CBC ) {
+            $this->mode = CRYPT_DES_MODE_3CBC;
+            $this->des = array(
+                new Crypt_DES(CRYPT_DES_MODE_CBC),
+                new Crypt_DES(CRYPT_DES_MODE_CBC),
+                new Crypt_DES(CRYPT_DES_MODE_CBC)
+            );
+
+            // we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects
+            $this->des[0]->disablePadding();
+            $this->des[1]->disablePadding();
+            $this->des[2]->disablePadding();
+
+            return;
+        }
+
+        switch ( CRYPT_DES_MODE ) {
+            case CRYPT_DES_MODE_MCRYPT:
+                switch ($mode) {
+                    case CRYPT_DES_MODE_ECB:
+                        $this->mode = MCRYPT_MODE_ECB;
+                        break;
+                    case CRYPT_DES_MODE_CTR:
+                        $this->mode = 'ctr';
+                        break;
+                    case CRYPT_DES_MODE_CBC:
+                    default:
+                        $this->mode = MCRYPT_MODE_CBC;
+                }
+
+                break;
+            default:
+                $this->des = array(
+                    new Crypt_DES(CRYPT_DES_MODE_ECB),
+                    new Crypt_DES(CRYPT_DES_MODE_ECB),
+                    new Crypt_DES(CRYPT_DES_MODE_ECB)
+                );
+ 
+                // we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects
+                $this->des[0]->disablePadding();
+                $this->des[1]->disablePadding();
+                $this->des[2]->disablePadding();
+
+                switch ($mode) {
+                    case CRYPT_DES_MODE_ECB:
+                    case CRYPT_DES_MODE_CTR:
+                    case CRYPT_DES_MODE_CBC:
+                        $this->mode = $mode;
+                        break;
+                    default:
+                        $this->mode = CRYPT_DES_MODE_CBC;
+                }
+        }
+    }
+
+    /**
+     * Sets the key.
+     *
+     * Keys can be of any length.  Triple DES, itself, can use 128-bit (eg. strlen($key) == 16) or
+     * 192-bit (eg. strlen($key) == 24) keys.  This function pads and truncates $key as appropriate.
+     *
+     * DES also requires that every eighth bit be a parity bit, however, we'll ignore that.
+     *
+     * If the key is not explicitly set, it'll be assumed to be all zero's.
+     *
+     * @access public
+     * @param String $key
+     */
+    function setKey($key)
+    {
+        $length = strlen($key);
+        if ($length > 8) {
+            $key = str_pad($key, 24, chr(0));
+            // if $key is between 64 and 128-bits, use the first 64-bits as the last, per this:
+            // http://php.net/function.mcrypt-encrypt#47973
+            //$key = $length <= 16 ? substr_replace($key, substr($key, 0, 8), 16) : substr($key, 0, 24);
+        }
+        $this->key = $key;
+        switch (true) {
+            case CRYPT_DES_MODE == CRYPT_DES_MODE_INTERNAL:
+            case $this->mode == CRYPT_DES_MODE_3CBC:
+                $this->des[0]->setKey(substr($key,  0, 8));
+                $this->des[1]->setKey(substr($key,  8, 8));
+                $this->des[2]->setKey(substr($key, 16, 8));
+        }
+        $this->changed = true;
+    }
+
+    /**
+     * Sets the initialization vector. (optional)
+     *
+     * SetIV is not required when CRYPT_DES_MODE_ECB is being used.  If not explictly set, it'll be assumed
+     * to be all zero's.
+     *
+     * @access public
+     * @param String $iv
+     */
+    function setIV($iv)
+    {
+        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));
+        if ($this->mode == CRYPT_DES_MODE_3CBC) {
+            $this->des[0]->setIV($iv);
+            $this->des[1]->setIV($iv);
+            $this->des[2]->setIV($iv);
+        }
+        $this->changed = true;
+    }
+
+    /**
+     * Generate CTR XOR encryption key
+     *
+     * Encrypt the output of this and XOR it against the ciphertext / plaintext to get the
+     * plaintext / ciphertext in CTR mode.
+     *
+     * @see Crypt_DES::decrypt()
+     * @see Crypt_DES::encrypt()
+     * @access public
+     * @param Integer $length
+     * @param String $iv
+     */
+    function _generate_xor($length, &$iv)
+    {
+        $xor = '';
+        $num_blocks = ($length + 7) >> 3;
+        for ($i = 0; $i < $num_blocks; $i++) {
+            $xor.= $iv;
+            for ($j = 4; $j <= 8; $j+=4) {
+                $temp = substr($iv, -$j, 4);
+                switch ($temp) {
+                    case "\xFF\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x00\x00\x00\x00", -$j, 4);
+                        break;
+                    case "\x7F\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x80\x00\x00\x00", -$j, 4);
+                        break 2;
+                    default:
+                        extract(unpack('Ncount', $temp));
+                        $iv = substr_replace($iv, pack('N', $count + 1), -$j, 4);
+                        break 2;
+                }
+            }
+        }
+
+        return $xor;
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * @access public
+     * @param String $plaintext
+     */
+    function encrypt($plaintext)
+    {
+        if ($this->mode != CRYPT_DES_MODE_CTR && $this->mode != 'ctr') {
+            $plaintext = $this->_pad($plaintext);
+        }
+
+        // if the key is smaller then 8, do what we'd normally do
+        if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {
+            $ciphertext = $this->des[2]->encrypt($this->des[1]->decrypt($this->des[0]->encrypt($plaintext)));
+
+            return $ciphertext;
+        }
+
+        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
+            if ($this->changed) {
+                if (!isset($this->enmcrypt)) {
+                    $this->enmcrypt = mcrypt_module_open(MCRYPT_3DES, '', $this->mode, '');
+                }
+                mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
+                $this->changed = false;
+            }
+
+            $ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
+            }
+
+            return $ciphertext;
+        }
+
+        if (strlen($this->key) <= 8) {
+            $this->des[0]->mode = $this->mode;
+
+            return $this->des[0]->encrypt($plaintext);
+        }
+
+        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :
+        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."
+        $plaintext = str_pad($plaintext, ceil(strlen($plaintext) / 8) * 8, chr(0));
+
+        $des = $this->des;
+
+        $ciphertext = '';
+        switch ($this->mode) {
+            case CRYPT_DES_MODE_ECB:
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8);
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $ciphertext.= $block;
+                }
+                break;
+            case CRYPT_DES_MODE_CBC:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8) ^ $xor;
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $xor = $block;
+                    $ciphertext.= $block;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+                break;
+            case CRYPT_DES_MODE_CTR:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $key = $this->_generate_xor(8, $xor);
+                    $key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                    $key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
+                    $key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                    $block = substr($plaintext, $i, 8);
+                    $ciphertext.= $block ^ $key;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+        }
+
+        return $ciphertext;
+    }
+
+    /**
+     * Decrypts a message.
+     *
+     * @access public
+     * @param String $ciphertext
+     */
+    function decrypt($ciphertext)
+    {
+        if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {
+            $plaintext = $this->des[0]->decrypt($this->des[1]->encrypt($this->des[2]->decrypt($ciphertext)));
+
+            return $this->_unpad($plaintext);
+        }
+
+        // we pad with chr(0) since that's what mcrypt_generic does.  to quote from http://php.net/function.mcrypt-generic :
+        // "The data is padded with "\0" to make sure the length of the data is n * blocksize."
+        $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 0xFFFFFFF8, chr(0));
+
+        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
+            if ($this->changed) {
+                if (!isset($this->demcrypt)) {
+                    $this->demcrypt = mcrypt_module_open(MCRYPT_3DES, '', $this->mode, '');
+                }
+                mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV);
+                $this->changed = false;
+            }
+
+            $plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV);
+            }
+
+            return $this->mode != 'ctr' ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        if (strlen($this->key) <= 8) {
+            $this->des[0]->mode = $this->mode;
+
+            return $this->_unpad($this->des[0]->decrypt($plaintext));
+        }
+
+        $des = $this->des;
+
+        $plaintext = '';
+        switch ($this->mode) {
+            case CRYPT_DES_MODE_ECB:
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $block = substr($ciphertext, $i, 8);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $plaintext.= $block;
+                }
+                break;
+            case CRYPT_DES_MODE_CBC:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $orig = $block = substr($ciphertext, $i, 8);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $plaintext.= $block ^ $xor;
+                    $xor = $orig;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+                break;
+            case CRYPT_DES_MODE_CTR:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $key = $this->_generate_xor(8, $xor);
+                    $key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                    $key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
+                    $key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                    $block = substr($ciphertext, $i, 8);
+                    $plaintext.= $block ^ $key;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+        }
+
+        return $this->mode != CRYPT_DES_MODE_CTR ? $this->_unpad($plaintext) : $plaintext;
+    }
+
+    /**
+     * Treat consecutive "packets" as if they are a continuous buffer.
+     *
+     * Say you have a 16-byte plaintext $plaintext.  Using the default behavior, the two following code snippets
+     * will yield different outputs:
+     *
+     * <code>
+     *    echo $des->encrypt(substr($plaintext, 0, 8));
+     *    echo $des->encrypt(substr($plaintext, 8, 8));
+     * </code>
+     * <code>
+     *    echo $des->encrypt($plaintext);
+     * </code>
+     *
+     * The solution is to enable the continuous buffer.  Although this will resolve the above discrepancy, it creates
+     * another, as demonstrated with the following:
+     *
+     * <code>
+     *    $des->encrypt(substr($plaintext, 0, 8));
+     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     * <code>
+     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     *
+     * With the continuous buffer disabled, these would yield the same output.  With it enabled, they yield different
+     * outputs.  The reason is due to the fact that the initialization vector's change after every encryption /
+     * decryption round when the continuous buffer is enabled.  When it's disabled, they remain constant.
+     *
+     * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each
+     * encryption / decryption round, whereas otherwise, it'd remain constant.  For this reason, it's recommended that
+     * continuous buffers not be used.  They do offer better security and are, in fact, sometimes required (SSH uses them),
+     * however, they are also less intuitive and more likely to cause you problems.
+     *
+     * @see Crypt_TripleDES::disableContinuousBuffer()
+     * @access public
+     */
+    function enableContinuousBuffer()
+    {
+        $this->continuousBuffer = true;
+        if ($this->mode == CRYPT_DES_MODE_3CBC) {
+            $this->des[0]->enableContinuousBuffer();
+            $this->des[1]->enableContinuousBuffer();
+            $this->des[2]->enableContinuousBuffer();
+        }
+    }
+
+    /**
+     * Treat consecutive packets as if they are a discontinuous buffer.
+     *
+     * The default behavior.
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @access public
+     */
+    function disableContinuousBuffer()
+    {
+        $this->continuousBuffer = false;
+        $this->encryptIV = $this->iv;
+        $this->decryptIV = $this->iv;
+
+        if ($this->mode == CRYPT_DES_MODE_3CBC) {
+            $this->des[0]->disableContinuousBuffer();
+            $this->des[1]->disableContinuousBuffer();
+            $this->des[2]->disableContinuousBuffer();
+        }
+    }
+
+    /**
+     * Pad "packets".
+     *
+     * DES works by encrypting eight bytes at a time.  If you ever need to encrypt or decrypt something that's not
+     * a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight.
+     *
+     * Padding is enabled by default.  Sometimes, however, it is undesirable to pad strings.  Such is the case in SSH1,
+     * where "packets" are padded with random bytes before being encrypted.  Unpad these packets and you risk stripping
+     * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is
+     * transmitted separately)
+     *
+     * @see Crypt_TripleDES::disablePadding()
+     * @access public
+     */
+    function enablePadding()
+    {
+        $this->padding = true;
+    }
+
+    /**
+     * Do not pad packets.
+     *
+     * @see Crypt_TripleDES::enablePadding()
+     * @access public
+     */
+    function disablePadding()
+    {
+        $this->padding = false;
+    }
+
+    /**
+     * Pads a string
+     *
+     * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8).
+     * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7)
+     *
+     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless
+     * and padding will, hence forth, be enabled.
+     *
+     * @see Crypt_TripleDES::_unpad()
+     * @access private
+     */
+    function _pad($text)
+    {
+        $length = strlen($text);
+
+        if (!$this->padding) {
+            if (($length & 7) == 0) {
+                return $text;
+            } else {
+                user_error("The plaintext's length ($length) is not a multiple of the block size (8)", E_USER_NOTICE);
+                $this->padding = true;
+            }
+        }
+
+        $pad = 8 - ($length & 7);
+        return str_pad($text, $length + $pad, chr($pad));
+    }
+
+    /**
+     * Unpads a string
+     *
+     * If padding is enabled and the reported padding length is invalid the encryption key will be assumed to be wrong
+     * and false will be returned.
+     *
+     * @see Crypt_TripleDES::_pad()
+     * @access private
+     */
+    function _unpad($text)
+    {
+        if (!$this->padding) {
+            return $text;
+        }
+
+        $length = ord($text[strlen($text) - 1]);
+
+        if (!$length || $length > 8) {
+            return false;
+        }
+
+        return substr($text, 0, -$length);
+    }
+}
+
+// vim: ts=4:sw=4:et:
 // vim6: fdl=1:
\ No newline at end of file
diff --git a/plugins/OStatus/extlib/Math/BigInteger.php b/plugins/OStatus/extlib/Math/BigInteger.php
index ce0e08354..9733351d4 100644
--- a/plugins/OStatus/extlib/Math/BigInteger.php
+++ b/plugins/OStatus/extlib/Math/BigInteger.php
@@ -1,3060 +1,3545 @@
-<?php

-/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

-

-/**

- * Pure-PHP arbitrary precision integer arithmetic library.

- *

- * Supports base-2, base-10, base-16, and base-256 numbers.  Uses the GMP or BCMath extensions, if available,

- * and an internal implementation, otherwise.

- *

- * PHP versions 4 and 5

- *

- * {@internal (all DocBlock comments regarding implementation - such as the one that follows - refer to the 

- * {@link MATH_BIGINTEGER_MODE_INTERNAL MATH_BIGINTEGER_MODE_INTERNAL} mode)

- *

- * Math_BigInteger uses base-2**26 to perform operations such as multiplication and division and

- * base-2**52 (ie. two base 2**26 digits) to perform addition and subtraction.  Because the largest possible

- * value when multiplying two base-2**26 numbers together is a base-2**52 number, double precision floating

- * point numbers - numbers that should be supported on most hardware and whose significand is 53 bits - are

- * used.  As a consequence, bitwise operators such as >> and << cannot be used, nor can the modulo operator %,

- * which only supports integers.  Although this fact will slow this library down, the fact that such a high

- * base is being used should more than compensate.

- *

- * When PHP version 6 is officially released, we'll be able to use 64-bit integers.  This should, once again,

- * allow bitwise operators, and will increase the maximum possible base to 2**31 (or 2**62 for addition /

- * subtraction).

- *

- * Useful resources are as follows:

- *

- *  - {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf Handbook of Applied Cryptography (HAC)}

- *  - {@link http://math.libtomcrypt.com/files/tommath.pdf Multi-Precision Math (MPM)}

- *  - Java's BigInteger classes.  See /j2se/src/share/classes/java/math in jdk-1_5_0-src-jrl.zip

- *

- * One idea for optimization is to use the comba method to reduce the number of operations performed.

- * MPM uses this quite extensively.  The following URL elaborates:

- *

- * {@link http://www.everything2.com/index.pl?node_id=1736418}}}

- *

- * Here's an example of how to use this library:

- * <code>

- * <?php

- *    include('Math/BigInteger.php');

- *

- *    $a = new Math_BigInteger(2);

- *    $b = new Math_BigInteger(3);

- *

- *    $c = $a->add($b);

- *

- *    echo $c->toString(); // outputs 5

- * ?>

- * </code>

- *

- * LICENSE: This library is free software; you can redistribute it and/or

- * modify it under the terms of the GNU Lesser General Public

- * License as published by the Free Software Foundation; either

- * version 2.1 of the License, or (at your option) any later version.

- *

- * This library is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- * Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser General Public

- * License along with this library; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,

- * MA  02111-1307  USA

- *

- * @category   Math

- * @package    Math_BigInteger

- * @author     Jim Wigginton <terrafrost@php.net>

- * @copyright  MMVI Jim Wigginton

- * @license    http://www.gnu.org/licenses/lgpl.txt

- * @version    $Id: BigInteger.php,v 1.18 2009/12/04 19:12:18 terrafrost Exp $

- * @link       http://pear.php.net/package/Math_BigInteger

- */

-

-/**#@+

- * @access private

- * @see Math_BigInteger::_slidingWindow()

- */

-/**

- * @see Math_BigInteger::_montgomery()

- * @see Math_BigInteger::_prepMontgomery()

- */

-define('MATH_BIGINTEGER_MONTGOMERY', 0);

-/**

- * @see Math_BigInteger::_barrett()

- */

-define('MATH_BIGINTEGER_BARRETT', 1);

-/**

- * @see Math_BigInteger::_mod2()

- */

-define('MATH_BIGINTEGER_POWEROF2', 2);

-/**

- * @see Math_BigInteger::_remainder()

- */

-define('MATH_BIGINTEGER_CLASSIC', 3);

-/**

- * @see Math_BigInteger::__clone()

- */

-define('MATH_BIGINTEGER_NONE', 4);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Math_BigInteger::_montgomery()

- * @see Math_BigInteger::_barrett()

- */

-/**

- * $cache[MATH_BIGINTEGER_VARIABLE] tells us whether or not the cached data is still valid.

- */

-define('MATH_BIGINTEGER_VARIABLE', 0);

-/**

- * $cache[MATH_BIGINTEGER_DATA] contains the cached data.

- */

-define('MATH_BIGINTEGER_DATA', 1);

-/**#@-*/

-

-/**#@+

- * @access private

- * @see Math_BigInteger::Math_BigInteger()

- */

-/**

- * To use the pure-PHP implementation

- */

-define('MATH_BIGINTEGER_MODE_INTERNAL', 1);

-/**

- * To use the BCMath library

- *

- * (if enabled; otherwise, the internal implementation will be used)

- */

-define('MATH_BIGINTEGER_MODE_BCMATH', 2);

-/**

- * To use the GMP library

- *

- * (if present; otherwise, either the BCMath or the internal implementation will be used)

- */

-define('MATH_BIGINTEGER_MODE_GMP', 3);

-/**#@-*/

-

-/**

- * The largest digit that may be used in addition / subtraction

- *

- * (we do pow(2, 52) instead of using 4503599627370496, directly, because some PHP installations

- *  will truncate 4503599627370496)

- *

- * @access private

- */

-define('MATH_BIGINTEGER_MAX_DIGIT52', pow(2, 52));

-

-/**

- * Karatsuba Cutoff

- *

- * At what point do we switch between Karatsuba multiplication and schoolbook long multiplication?

- *

- * @access private

- */

-define('MATH_BIGINTEGER_KARATSUBA_CUTOFF', 15);

-

-/**

- * Pure-PHP arbitrary precision integer arithmetic library. Supports base-2, base-10, base-16, and base-256

- * numbers.

- *

- * @author  Jim Wigginton <terrafrost@php.net>

- * @version 1.0.0RC3

- * @access  public

- * @package Math_BigInteger

- */

-class Math_BigInteger {

-    /**

-     * Holds the BigInteger's value.

-     *

-     * @var Array

-     * @access private

-     */

-    var $value;

-

-    /**

-     * Holds the BigInteger's magnitude.

-     *

-     * @var Boolean

-     * @access private

-     */

-    var $is_negative = false;

-

-    /**

-     * Random number generator function

-     *

-     * @see setRandomGenerator()

-     * @access private

-     */

-    var $generator = 'mt_rand';

-

-    /**

-     * Precision

-     *

-     * @see setPrecision()

-     * @access private

-     */

-    var $precision = -1;

-

-    /**

-     * Precision Bitmask

-     *

-     * @see setPrecision()

-     * @access private

-     */

-    var $bitmask = false;

-

-    /**

-     * Converts base-2, base-10, base-16, and binary strings (eg. base-256) to BigIntegers.

-     *

-     * If the second parameter - $base - is negative, then it will be assumed that the number's are encoded using

-     * two's compliment.  The sole exception to this is -10, which is treated the same as 10 is.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('0x32', 16); // 50 in base-16

-     *

-     *    echo $a->toString(); // outputs 50

-     * ?>

-     * </code>

-     *

-     * @param optional $x base-10 number or base-$base number if $base set.

-     * @param optional integer $base

-     * @return Math_BigInteger

-     * @access public

-     */

-    function Math_BigInteger($x = 0, $base = 10)

-    {

-        if ( !defined('MATH_BIGINTEGER_MODE') ) {

-            switch (true) {

-                case extension_loaded('gmp'):

-                    define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_GMP);

-                    break;

-                case extension_loaded('bcmath'):

-                    define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_BCMATH);

-                    break;

-                default:

-                    define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_INTERNAL);

-            }

-        }

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                if (is_resource($x) && get_resource_type($x) == 'GMP integer') {

-                    $this->value = $x;

-                    return;

-                }

-                $this->value = gmp_init(0);

-                break;

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $this->value = '0';

-                break;

-            default:

-                $this->value = array();

-        }

-

-        if ($x === 0) {

-            return;

-        }

-

-        switch ($base) {

-            case -256:

-                if (ord($x[0]) & 0x80) {

-                    $x = ~$x;

-                    $this->is_negative = true;

-                }

-            case  256:

-                switch ( MATH_BIGINTEGER_MODE ) {

-                    case MATH_BIGINTEGER_MODE_GMP:

-                        $sign = $this->is_negative ? '-' : '';

-                        $this->value = gmp_init($sign . '0x' . bin2hex($x));

-                        break;

-                    case MATH_BIGINTEGER_MODE_BCMATH:

-                        // round $len to the nearest 4 (thanks, DavidMJ!)

-                        $len = (strlen($x) + 3) & 0xFFFFFFFC;

-

-                        $x = str_pad($x, $len, chr(0), STR_PAD_LEFT);

-

-                        for ($i = 0; $i < $len; $i+= 4) {

-                            $this->value = bcmul($this->value, '4294967296'); // 4294967296 == 2**32

-                            $this->value = bcadd($this->value, 0x1000000 * ord($x[$i]) + ((ord($x[$i + 1]) << 16) | (ord($x[$i + 2]) << 8) | ord($x[$i + 3])));

-                        }

-

-                        if ($this->is_negative) {

-                            $this->value = '-' . $this->value;

-                        }

-

-                        break;

-                    // converts a base-2**8 (big endian / msb) number to base-2**26 (little endian / lsb)

-                    default:

-                        while (strlen($x)) {

-                            $this->value[] = $this->_bytes2int($this->_base256_rshift($x, 26));

-                        }

-                }

-

-                if ($this->is_negative) {

-                    if (MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_INTERNAL) {

-                        $this->is_negative = false;

-                    }

-                    $temp = $this->add(new Math_BigInteger('-1'));

-                    $this->value = $temp->value;

-                }

-                break;

-            case  16:

-            case -16:

-                if ($base > 0 && $x[0] == '-') {

-                    $this->is_negative = true;

-                    $x = substr($x, 1);

-                }

-

-                $x = preg_replace('#^(?:0x)?([A-Fa-f0-9]*).*#', '$1', $x);

-

-                $is_negative = false;

-                if ($base < 0 && hexdec($x[0]) >= 8) {

-                    $this->is_negative = $is_negative = true;

-                    $x = bin2hex(~pack('H*', $x));

-                }

-

-                switch ( MATH_BIGINTEGER_MODE ) {

-                    case MATH_BIGINTEGER_MODE_GMP:

-                        $temp = $this->is_negative ? '-0x' . $x : '0x' . $x;

-                        $this->value = gmp_init($temp);

-                        $this->is_negative = false;

-                        break;

-                    case MATH_BIGINTEGER_MODE_BCMATH:

-                        $x = ( strlen($x) & 1 ) ? '0' . $x : $x;

-                        $temp = new Math_BigInteger(pack('H*', $x), 256);

-                        $this->value = $this->is_negative ? '-' . $temp->value : $temp->value;

-                        $this->is_negative = false;

-                        break;

-                    default:

-                        $x = ( strlen($x) & 1 ) ? '0' . $x : $x;

-                        $temp = new Math_BigInteger(pack('H*', $x), 256);

-                        $this->value = $temp->value;

-                }

-

-                if ($is_negative) {

-                    $temp = $this->add(new Math_BigInteger('-1'));

-                    $this->value = $temp->value;

-                }

-                break;

-            case  10:

-            case -10:

-                $x = preg_replace('#^(-?[0-9]*).*#', '$1', $x);

-

-                switch ( MATH_BIGINTEGER_MODE ) {

-                    case MATH_BIGINTEGER_MODE_GMP:

-                        $this->value = gmp_init($x);

-                        break;

-                    case MATH_BIGINTEGER_MODE_BCMATH:

-                        // explicitly casting $x to a string is necessary, here, since doing $x[0] on -1 yields different

-                        // results then doing it on '-1' does (modInverse does $x[0])

-                        $this->value = (string) $x;

-                        break;

-                    default:

-                        $temp = new Math_BigInteger();

-

-                        // array(10000000) is 10**7 in base-2**26.  10**7 is the closest to 2**26 we can get without passing it.

-                        $multiplier = new Math_BigInteger();

-                        $multiplier->value = array(10000000);

-

-                        if ($x[0] == '-') {

-                            $this->is_negative = true;

-                            $x = substr($x, 1);

-                        }

-

-                        $x = str_pad($x, strlen($x) + (6 * strlen($x)) % 7, 0, STR_PAD_LEFT);

-

-                        while (strlen($x)) {

-                            $temp = $temp->multiply($multiplier);

-                            $temp = $temp->add(new Math_BigInteger($this->_int2bytes(substr($x, 0, 7)), 256));

-                            $x = substr($x, 7);

-                        }

-

-                        $this->value = $temp->value;

-                }

-                break;

-            case  2: // base-2 support originally implemented by Lluis Pamies - thanks!

-            case -2:

-                if ($base > 0 && $x[0] == '-') {

-                    $this->is_negative = true;

-                    $x = substr($x, 1);

-                }

-

-                $x = preg_replace('#^([01]*).*#', '$1', $x);

-                $x = str_pad($x, strlen($x) + (3 * strlen($x)) % 4, 0, STR_PAD_LEFT);

-

-                $str = '0x';

-                while (strlen($x)) {

-                    $part = substr($x, 0, 4);

-                    $str.= dechex(bindec($part));

-                    $x = substr($x, 4);

-                }

-

-                if ($this->is_negative) {

-                    $str = '-' . $str;

-                }

-

-                $temp = new Math_BigInteger($str, 8 * $base); // ie. either -16 or +16

-                $this->value = $temp->value;

-                $this->is_negative = $temp->is_negative;

-

-                break;

-            default:

-                // base not supported, so we'll let $this == 0

-        }

-    }

-

-    /**

-     * Converts a BigInteger to a byte string (eg. base-256).

-     *

-     * Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're

-     * saved as two's compliment.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('65');

-     *

-     *    echo $a->toBytes(); // outputs chr(65)

-     * ?>

-     * </code>

-     *

-     * @param Boolean $twos_compliment

-     * @return String

-     * @access public

-     * @internal Converts a base-2**26 number to base-2**8

-     */

-    function toBytes($twos_compliment = false)

-    {

-        if ($twos_compliment) {

-            $comparison = $this->compare(new Math_BigInteger());

-            if ($comparison == 0) {

-                return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';

-            }

-

-            $temp = $comparison < 0 ? $this->add(new Math_BigInteger(1)) : $this->copy();

-            $bytes = $temp->toBytes();

-

-            if (empty($bytes)) { // eg. if the number we're trying to convert is -1

-                $bytes = chr(0);

-            }

-

-            if (ord($bytes[0]) & 0x80) {

-                $bytes = chr(0) . $bytes;

-            }

-

-            return $comparison < 0 ? ~$bytes : $bytes;

-        }

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                if (gmp_cmp($this->value, gmp_init(0)) == 0) {

-                    return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';

-                }

-

-                $temp = gmp_strval(gmp_abs($this->value), 16);

-                $temp = ( strlen($temp) & 1 ) ? '0' . $temp : $temp;

-                $temp = pack('H*', $temp);

-

-                return $this->precision > 0 ?

-                    substr(str_pad($temp, $this->precision >> 3, chr(0), STR_PAD_LEFT), -($this->precision >> 3)) :

-                    ltrim($temp, chr(0));

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                if ($this->value === '0') {

-                    return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';

-                }

-

-                $value = '';

-                $current = $this->value;

-

-                if ($current[0] == '-') {

-                    $current = substr($current, 1);

-                }

-

-                // we don't do four bytes at a time because then numbers larger than 1<<31 would be negative

-                // two's complimented numbers, which would break chr.

-                while (bccomp($current, '0') > 0) {

-                    $temp = bcmod($current, 0x1000000);

-                    $value = chr($temp >> 16) . chr($temp >> 8) . chr($temp) . $value;

-                    $current = bcdiv($current, 0x1000000);

-                }

-

-                return $this->precision > 0 ?

-                    substr(str_pad($value, $this->precision >> 3, chr(0), STR_PAD_LEFT), -($this->precision >> 3)) :

-                    ltrim($value, chr(0));

-        }

-

-        if (!count($this->value)) {

-            return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';

-        }

-        $result = $this->_int2bytes($this->value[count($this->value) - 1]);

-

-        $temp = $this->copy();

-

-        for ($i = count($temp->value) - 2; $i >= 0; $i--) {

-            $temp->_base256_lshift($result, 26);

-            $result = $result | str_pad($temp->_int2bytes($temp->value[$i]), strlen($result), chr(0), STR_PAD_LEFT);

-        }

-

-        return $this->precision > 0 ?

-            substr(str_pad($result, $this->precision >> 3, chr(0), STR_PAD_LEFT), -($this->precision >> 3)) :

-            $result;

-    }

-

-    /**

-     * Converts a BigInteger to a hex string (eg. base-16)).

-     *

-     * Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're

-     * saved as two's compliment.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('65');

-     *

-     *    echo $a->toHex(); // outputs '41'

-     * ?>

-     * </code>

-     *

-     * @param Boolean $twos_compliment

-     * @return String

-     * @access public

-     * @internal Converts a base-2**26 number to base-2**8

-     */

-    function toHex($twos_compliment = false)

-    {

-        return bin2hex($this->toBytes($twos_compliment));

-    }

-

-    /**

-     * Converts a BigInteger to a bit string (eg. base-2).

-     *

-     * Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're

-     * saved as two's compliment.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('65');

-     *

-     *    echo $a->toBits(); // outputs '1000001'

-     * ?>

-     * </code>

-     *

-     * @param Boolean $twos_compliment

-     * @return String

-     * @access public

-     * @internal Converts a base-2**26 number to base-2**2

-     */

-    function toBits($twos_compliment = false)

-    {

-        $hex = $this->toHex($twos_compliment);

-        $bits = '';

-        for ($i = 0; $i < strlen($hex); $i+=8) {

-            $bits.= str_pad(decbin(hexdec(substr($hex, $i, 8))), 32, '0', STR_PAD_LEFT);

-        }

-        return $this->precision > 0 ? substr($bits, -$this->precision) : ltrim($bits, '0');

-    }

-

-    /**

-     * Converts a BigInteger to a base-10 number.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('50');

-     *

-     *    echo $a->toString(); // outputs 50

-     * ?>

-     * </code>

-     *

-     * @return String

-     * @access public

-     * @internal Converts a base-2**26 number to base-10**7 (which is pretty much base-10)

-     */

-    function toString()

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                return gmp_strval($this->value);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                if ($this->value === '0') {

-                    return '0';

-                }

-

-                return ltrim($this->value, '0');

-        }

-

-        if (!count($this->value)) {

-            return '0';

-        }

-

-        $temp = $this->copy();

-        $temp->is_negative = false;

-

-        $divisor = new Math_BigInteger();

-        $divisor->value = array(10000000); // eg. 10**7

-        $result = '';

-        while (count($temp->value)) {

-            list($temp, $mod) = $temp->divide($divisor);

-            $result = str_pad($mod->value[0], 7, '0', STR_PAD_LEFT) . $result;

-        }

-        $result = ltrim($result, '0');

-

-        if ($this->is_negative) {

-            $result = '-' . $result;

-        }

-

-        return $result;

-    }

-

-    /**

-     * Copy an object

-     *

-     * PHP5 passes objects by reference while PHP4 passes by value.  As such, we need a function to guarantee

-     * that all objects are passed by value, when appropriate.  More information can be found here:

-     *

-     * {@link http://php.net/language.oop5.basic#51624}

-     *

-     * @access public

-     * @see __clone()

-     * @return Math_BigInteger

-     */

-    function copy()

-    {

-        $temp = new Math_BigInteger();

-        $temp->value = $this->value;

-        $temp->is_negative = $this->is_negative;

-        $temp->generator = $this->generator;

-        $temp->precision = $this->precision;

-        $temp->bitmask = $this->bitmask;

-        return $temp;

-    }

-

-    /**

-     *  __toString() magic method

-     *

-     * Will be called, automatically, if you're supporting just PHP5.  If you're supporting PHP4, you'll need to call

-     * toString().

-     *

-     * @access public

-     * @internal Implemented per a suggestion by Techie-Michael - thanks!

-     */

-    function __toString()

-    {

-        return $this->toString();

-    }

-

-    /**

-     * __clone() magic method

-     *

-     * Although you can call Math_BigInteger::__toString() directly in PHP5, you cannot call Math_BigInteger::__clone()

-     * directly in PHP5.  You can in PHP4 since it's not a magic method, but in PHP5, you have to call it by using the PHP5

-     * only syntax of $y = clone $x.  As such, if you're trying to write an application that works on both PHP4 and PHP5,

-     * call Math_BigInteger::copy(), instead.

-     *

-     * @access public

-     * @see copy()

-     * @return Math_BigInteger

-     */

-    function __clone()

-    {

-        return $this->copy();

-    }

-

-    /**

-     * Adds two BigIntegers.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('10');

-     *    $b = new Math_BigInteger('20');

-     *

-     *    $c = $a->add($b);

-     *

-     *    echo $c->toString(); // outputs 30

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $y

-     * @return Math_BigInteger

-     * @access public

-     * @internal Performs base-2**52 addition

-     */

-    function add($y)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_add($this->value, $y->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp = new Math_BigInteger();

-                $temp->value = bcadd($this->value, $y->value);

-

-                return $this->_normalize($temp);

-        }

-

-        $this_size = count($this->value);

-        $y_size = count($y->value);

-

-        if ($this_size == 0) {

-            return $y->copy();

-        } else if ($y_size == 0) {

-            return $this->copy();

-        }

-

-        // subtract, if appropriate

-        if ( $this->is_negative != $y->is_negative ) {

-            // is $y the negative number?

-            $y_negative = $this->compare($y) > 0;

-

-            $temp = $this->copy();

-            $y = $y->copy();

-            $temp->is_negative = $y->is_negative = false;

-

-            $diff = $temp->compare($y);

-            if ( !$diff ) {

-                $temp = new Math_BigInteger();

-                return $this->_normalize($temp);

-            }

-

-            $temp = $temp->subtract($y);

-

-            $temp->is_negative = ($diff > 0) ? !$y_negative : $y_negative;

-

-            return $this->_normalize($temp);

-        }

-

-        $result = new Math_BigInteger();

-        $carry = 0;

-

-        $size = max($this_size, $y_size);

-        $size+= $size & 1; // rounds $size to the nearest 2.

-

-        $x = array_pad($this->value, $size, 0);

-        $y = array_pad($y->value, $size, 0);

-

-        for ($i = 0; $i < $size - 1; $i+=2) {

-            $sum = $x[$i + 1] * 0x4000000 + $x[$i] + $y[$i + 1] * 0x4000000 + $y[$i] + $carry;

-            $carry = $sum >= MATH_BIGINTEGER_MAX_DIGIT52; // eg. floor($sum / 2**52); only possible values (in any base) are 0 and 1

-            $sum = $carry ? $sum - MATH_BIGINTEGER_MAX_DIGIT52 : $sum;

-

-            $temp = floor($sum / 0x4000000);

-

-            $result->value[] = $sum - 0x4000000 * $temp; // eg. a faster alternative to fmod($sum, 0x4000000)

-            $result->value[] = $temp;

-        }

-

-        if ($carry) {

-            $result->value[] = (int) $carry;

-        }

-

-        $result->is_negative = $this->is_negative;

-

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Subtracts two BigIntegers.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('10');

-     *    $b = new Math_BigInteger('20');

-     *

-     *    $c = $a->subtract($b);

-     *

-     *    echo $c->toString(); // outputs -10

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $y

-     * @return Math_BigInteger

-     * @access public

-     * @internal Performs base-2**52 subtraction

-     */

-    function subtract($y)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_sub($this->value, $y->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp = new Math_BigInteger();

-                $temp->value = bcsub($this->value, $y->value);

-

-                return $this->_normalize($temp);

-        }

-

-        $this_size = count($this->value);

-        $y_size = count($y->value);

-

-        if ($this_size == 0) {

-            $temp = $y->copy();

-            $temp->is_negative = !$temp->is_negative;

-            return $temp;

-        } else if ($y_size == 0) {

-            return $this->copy();

-        }

-

-        // add, if appropriate (ie. -$x - +$y or +$x - -$y)

-        if ( $this->is_negative != $y->is_negative ) {

-            $is_negative = $y->compare($this) > 0;

-

-            $temp = $this->copy();

-            $y = $y->copy();

-            $temp->is_negative = $y->is_negative = false;

-

-            $temp = $temp->add($y);

-

-            $temp->is_negative = $is_negative;

-

-            return $this->_normalize($temp);

-        }

-

-        $diff = $this->compare($y);

-

-        if ( !$diff ) {

-            $temp = new Math_BigInteger();

-            return $this->_normalize($temp);

-        }

-

-        // switch $this and $y around, if appropriate.

-        if ( (!$this->is_negative && $diff < 0) || ($this->is_negative && $diff > 0) ) {

-            $is_negative = $y->is_negative;

-

-            $temp = $this->copy();

-            $y = $y->copy();

-            $temp->is_negative = $y->is_negative = false;

-

-            $temp = $y->subtract($temp);

-            $temp->is_negative = !$is_negative;

-

-            return $this->_normalize($temp);

-        }

-

-        $result = new Math_BigInteger();

-        $carry = 0;

-

-        $size = max($this_size, $y_size);

-        $size+= $size % 2;

-

-        $x = array_pad($this->value, $size, 0);

-        $y = array_pad($y->value, $size, 0);

-

-        for ($i = 0; $i < $size - 1; $i+=2) {

-            $sum = $x[$i + 1] * 0x4000000 + $x[$i] - $y[$i + 1] * 0x4000000 - $y[$i] + $carry;

-            $carry = $sum < 0 ? -1 : 0; // eg. floor($sum / 2**52); only possible values (in any base) are 0 and 1

-            $sum = $carry ? $sum + MATH_BIGINTEGER_MAX_DIGIT52 : $sum;

-

-            $temp = floor($sum / 0x4000000);

-

-            $result->value[] = $sum - 0x4000000 * $temp;

-            $result->value[] = $temp;

-        }

-

-        // $carry shouldn't be anything other than zero, at this point, since we already made sure that $this

-        // was bigger than $y.

-

-        $result->is_negative = $this->is_negative;

-

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Multiplies two BigIntegers

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('10');

-     *    $b = new Math_BigInteger('20');

-     *

-     *    $c = $a->multiply($b);

-     *

-     *    echo $c->toString(); // outputs 200

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $x

-     * @return Math_BigInteger

-     * @access public

-     */

-    function multiply($x)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_mul($this->value, $x->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp = new Math_BigInteger();

-                $temp->value = bcmul($this->value, $x->value);

-

-                return $this->_normalize($temp);

-        }

-

-        static $cutoff = false;

-        if ($cutoff === false) {

-            $cutoff = 2 * MATH_BIGINTEGER_KARATSUBA_CUTOFF;

-        }

-

-        if ( $this->equals($x) ) {

-            return $this->_square();

-        }

-

-        $this_length = count($this->value);

-        $x_length = count($x->value);

-

-        if ( !$this_length || !$x_length ) { // a 0 is being multiplied

-            $temp = new Math_BigInteger();

-            return $this->_normalize($temp);

-        }

-

-        $product = min($this_length, $x_length) < $cutoff ? $this->_multiply($x) : $this->_karatsuba($x);

-

-        $product->is_negative = $this->is_negative != $x->is_negative;

-

-        return $this->_normalize($product);

-    }

-

-    /**

-     * Performs long multiplication up to $stop digits

-     *

-     * If you're going to be doing array_slice($product->value, 0, $stop), some cycles can be saved.

-     *

-     * @see _barrett()

-     * @param Math_BigInteger $x

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _multiplyLower($x, $stop)

-    {

-        $this_length = count($this->value);

-        $x_length = count($x->value);

-

-        if ( !$this_length || !$x_length ) { // a 0 is being multiplied

-            return new Math_BigInteger();

-        }

-

-        if ( $this_length < $x_length ) {

-            return $x->_multiplyLower($this, $stop);

-        }

-

-        $product = new Math_BigInteger();

-        $product->value = $this->_array_repeat(0, $this_length + $x_length);

-

-        // the following for loop could be removed if the for loop following it

-        // (the one with nested for loops) initially set $i to 0, but

-        // doing so would also make the result in one set of unnecessary adds,

-        // since on the outermost loops first pass, $product->value[$k] is going

-        // to always be 0

-

-        $carry = 0;

-

-        for ($j = 0; $j < $this_length; $j++) { // ie. $i = 0, $k = $i

-            $temp = $this->value[$j] * $x->value[0] + $carry; // $product->value[$k] == 0

-            $carry = floor($temp / 0x4000000);

-            $product->value[$j] = $temp - 0x4000000 * $carry;

-        }

-

-        if ($j < $stop) {

-            $product->value[$j] = $carry;

-        }

-

-        // the above for loop is what the previous comment was talking about.  the

-        // following for loop is the "one with nested for loops"

-

-        for ($i = 1; $i < $x_length; $i++) {

-            $carry = 0;

-

-            for ($j = 0, $k = $i; $j < $this_length && $k < $stop; $j++, $k++) {

-                $temp = $product->value[$k] + $this->value[$j] * $x->value[$i] + $carry;

-                $carry = floor($temp / 0x4000000);

-                $product->value[$k] = $temp - 0x4000000 * $carry;

-            }

-

-            if ($k < $stop) {

-                $product->value[$k] = $carry;

-            }

-        }

-

-        $product->is_negative = $this->is_negative != $x->is_negative;

-

-        return $product;

-    }

-

-    /**

-     * Performs long multiplication on two BigIntegers

-     *

-     * Modeled after 'multiply' in MutableBigInteger.java.

-     *

-     * @param Math_BigInteger $x

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _multiply($x)

-    {

-        $this_length = count($this->value);

-        $x_length = count($x->value);

-

-        if ( !$this_length || !$x_length ) { // a 0 is being multiplied

-            return new Math_BigInteger();

-        }

-

-        if ( $this_length < $x_length ) {

-            return $x->_multiply($this);

-        }

-

-        $product = new Math_BigInteger();

-        $product->value = $this->_array_repeat(0, $this_length + $x_length);

-

-        // the following for loop could be removed if the for loop following it

-        // (the one with nested for loops) initially set $i to 0, but

-        // doing so would also make the result in one set of unnecessary adds,

-        // since on the outermost loops first pass, $product->value[$k] is going

-        // to always be 0

-

-        $carry = 0;

-

-        for ($j = 0; $j < $this_length; $j++) { // ie. $i = 0

-            $temp = $this->value[$j] * $x->value[0] + $carry; // $product->value[$k] == 0

-            $carry = floor($temp / 0x4000000);

-            $product->value[$j] = $temp - 0x4000000 * $carry;

-        }

-

-        $product->value[$j] = $carry;

-

-        // the above for loop is what the previous comment was talking about.  the

-        // following for loop is the "one with nested for loops"

-        for ($i = 1; $i < $x_length; $i++) {

-            $carry = 0;

-

-            for ($j = 0, $k = $i; $j < $this_length; $j++, $k++) {

-                $temp = $product->value[$k] + $this->value[$j] * $x->value[$i] + $carry;

-                $carry = floor($temp / 0x4000000);

-                $product->value[$k] = $temp - 0x4000000 * $carry;

-            }

-

-            $product->value[$k] = $carry;

-        }

-

-        $product->is_negative = $this->is_negative != $x->is_negative;

-

-        return $this->_normalize($product);

-    }

-

-    /**

-     * Performs Karatsuba multiplication on two BigIntegers

-     *

-     * See {@link http://en.wikipedia.org/wiki/Karatsuba_algorithm Karatsuba algorithm} and

-     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=120 MPM 5.2.3}.

-     *

-     * @param Math_BigInteger $y

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _karatsuba($y)

-    {

-        $x = $this->copy();

-

-        $m = min(count($x->value) >> 1, count($y->value) >> 1);

-

-        if ($m < MATH_BIGINTEGER_KARATSUBA_CUTOFF) {

-            return $x->_multiply($y);

-        }

-

-        $x1 = new Math_BigInteger();

-        $x0 = new Math_BigInteger();

-        $y1 = new Math_BigInteger();

-        $y0 = new Math_BigInteger();

-

-        $x1->value = array_slice($x->value, $m);

-        $x0->value = array_slice($x->value, 0, $m);

-        $y1->value = array_slice($y->value, $m);

-        $y0->value = array_slice($y->value, 0, $m);

-

-        $z2 = $x1->_karatsuba($y1);

-        $z0 = $x0->_karatsuba($y0);

-

-        $z1 = $x1->add($x0);

-        $z1 = $z1->_karatsuba($y1->add($y0));

-        $z1 = $z1->subtract($z2->add($z0));

-

-        $z2->value = array_merge(array_fill(0, 2 * $m, 0), $z2->value);

-        $z1->value = array_merge(array_fill(0,     $m, 0), $z1->value);

-

-        $xy = $z2->add($z1);

-        $xy = $xy->add($z0);

-

-        return $xy;

-    }

-

-    /**

-     * Squares a BigInteger

-     *

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _square()

-    {

-        static $cutoff = false;

-        if ($cutoff === false) {

-            $cutoff = 2 * MATH_BIGINTEGER_KARATSUBA_CUTOFF;

-        }

-

-        return count($this->value) < $cutoff ? $this->_baseSquare() : $this->_karatsubaSquare();

-    }

-

-    /**

-     * Performs traditional squaring on two BigIntegers

-     *

-     * Squaring can be done faster than multiplying a number by itself can be.  See

-     * {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=7 HAC 14.2.4} /

-     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=141 MPM 5.3} for more information.

-     *

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _baseSquare()

-    {

-        if ( empty($this->value) ) {

-            return new Math_BigInteger();

-        }

-

-        $square = new Math_BigInteger();

-        $square->value = $this->_array_repeat(0, 2 * count($this->value));

-

-        for ($i = 0, $max_index = count($this->value) - 1; $i <= $max_index; $i++) {

-            $i2 = 2 * $i;

-

-            $temp = $square->value[$i2] + $this->value[$i] * $this->value[$i];

-            $carry = floor($temp / 0x4000000);

-            $square->value[$i2] = $temp - 0x4000000 * $carry;

-

-            // note how we start from $i+1 instead of 0 as we do in multiplication.

-            for ($j = $i + 1, $k = $i2 + 1; $j <= $max_index; $j++, $k++) {

-                $temp = $square->value[$k] + 2 * $this->value[$j] * $this->value[$i] + $carry;

-                $carry = floor($temp / 0x4000000);

-                $square->value[$k] = $temp - 0x4000000 * $carry;

-            }

-

-            // the following line can yield values larger 2**15.  at this point, PHP should switch

-            // over to floats.

-            $square->value[$i + $max_index + 1] = $carry;

-        }

-

-        return $square;

-    }

-

-    /**

-     * Performs Karatsuba "squaring" on two BigIntegers

-     *

-     * See {@link http://en.wikipedia.org/wiki/Karatsuba_algorithm Karatsuba algorithm} and

-     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=151 MPM 5.3.4}.

-     *

-     * @param Math_BigInteger $y

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _karatsubaSquare()

-    {

-        $m = count($this->value) >> 1;

-

-        if ($m < MATH_BIGINTEGER_KARATSUBA_CUTOFF) {

-            return $this->_square();

-        }

-

-        $x1 = new Math_BigInteger();

-        $x0 = new Math_BigInteger();

-

-        $x1->value = array_slice($this->value, $m);

-        $x0->value = array_slice($this->value, 0, $m);

-

-        $z2 = $x1->_karatsubaSquare();

-        $z0 = $x0->_karatsubaSquare();

-

-        $z1 = $x1->add($x0);

-        $z1 = $z1->_karatsubaSquare();

-        $z1 = $z1->subtract($z2->add($z0));

-

-        $z2->value = array_merge(array_fill(0, 2 * $m, 0), $z2->value);

-        $z1->value = array_merge(array_fill(0,     $m, 0), $z1->value);

-

-        $xx = $z2->add($z1);

-        $xx = $xx->add($z0);

-

-        return $xx;

-    }

-

-    /**

-     * Divides two BigIntegers.

-     *

-     * Returns an array whose first element contains the quotient and whose second element contains the

-     * "common residue".  If the remainder would be positive, the "common residue" and the remainder are the

-     * same.  If the remainder would be negative, the "common residue" is equal to the sum of the remainder

-     * and the divisor (basically, the "common residue" is the first positive modulo).

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('10');

-     *    $b = new Math_BigInteger('20');

-     *

-     *    list($quotient, $remainder) = $a->divide($b);

-     *

-     *    echo $quotient->toString(); // outputs 0

-     *    echo "\r\n";

-     *    echo $remainder->toString(); // outputs 10

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $y

-     * @return Array

-     * @access public

-     * @internal This function is based off of {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=9 HAC 14.20}.

-     */

-    function divide($y)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $quotient = new Math_BigInteger();

-                $remainder = new Math_BigInteger();

-

-                list($quotient->value, $remainder->value) = gmp_div_qr($this->value, $y->value);

-

-                if (gmp_sign($remainder->value) < 0) {

-                    $remainder->value = gmp_add($remainder->value, gmp_abs($y->value));

-                }

-

-                return array($this->_normalize($quotient), $this->_normalize($remainder));

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $quotient = new Math_BigInteger();

-                $remainder = new Math_BigInteger();

-

-                $quotient->value = bcdiv($this->value, $y->value);

-                $remainder->value = bcmod($this->value, $y->value);

-

-                if ($remainder->value[0] == '-') {

-                    $remainder->value = bcadd($remainder->value, $y->value[0] == '-' ? substr($y->value, 1) : $y->value);

-                }

-

-                return array($this->_normalize($quotient), $this->_normalize($remainder));

-        }

-

-        if (count($y->value) == 1) {

-            $temp = $this->_divide_digit($y->value[0]);

-            $temp[0]->is_negative = $this->is_negative != $y->is_negative;

-            return array($this->_normalize($temp[0]), $this->_normalize($temp[1]));

-        }

-

-        static $zero;

-        if (!isset($zero)) {

-            $zero = new Math_BigInteger();

-        }

-

-        $x = $this->copy();

-        $y = $y->copy();

-

-        $x_sign = $x->is_negative;

-        $y_sign = $y->is_negative;

-

-        $x->is_negative = $y->is_negative = false;

-

-        $diff = $x->compare($y);

-

-        if ( !$diff ) {

-            $temp = new Math_BigInteger();

-            $temp->value = array(1);

-            $temp->is_negative = $x_sign != $y_sign;

-            return array($this->_normalize($temp), $this->_normalize(new Math_BigInteger()));

-        }

-

-        if ( $diff < 0 ) {

-            // if $x is negative, "add" $y.

-            if ( $x_sign ) {

-                $x = $y->subtract($x);

-            }

-            return array($this->_normalize(new Math_BigInteger()), $this->_normalize($x));

-        }

-

-        // normalize $x and $y as described in HAC 14.23 / 14.24

-        $msb = $y->value[count($y->value) - 1];

-        for ($shift = 0; !($msb & 0x2000000); $shift++) {

-            $msb <<= 1;

-        }

-        $x->_lshift($shift);

-        $y->_lshift($shift);

-

-        $x_max = count($x->value) - 1;

-        $y_max = count($y->value) - 1;

-

-        $quotient = new Math_BigInteger();

-        $quotient->value = $this->_array_repeat(0, $x_max - $y_max + 1);

-

-        // $temp = $y << ($x_max - $y_max-1) in base 2**26

-        $temp = new Math_BigInteger();

-        $temp->value = array_merge($this->_array_repeat(0, $x_max - $y_max), $y->value);

-

-        while ( $x->compare($temp) >= 0 ) {

-            // calculate the "common residue"

-            $quotient->value[$x_max - $y_max]++;

-            $x = $x->subtract($temp);

-            $x_max = count($x->value) - 1;

-        }

-

-        for ($i = $x_max; $i >= $y_max + 1; $i--) {

-            $x_value = array(

-                $x->value[$i],

-                ( $i > 0 ) ? $x->value[$i - 1] : 0,

-                ( $i > 1 ) ? $x->value[$i - 2] : 0

-            );

-            $y_value = array(

-                $y->value[$y_max],

-                ( $y_max > 0 ) ? $y->value[$y_max - 1] : 0

-            );

-

-            $q_index = $i - $y_max - 1;

-            if ($x_value[0] == $y_value[0]) {

-                $quotient->value[$q_index] = 0x3FFFFFF;

-            } else {

-                $quotient->value[$q_index] = floor(

-                    ($x_value[0] * 0x4000000 + $x_value[1])

-                    /

-                    $y_value[0]

-                );

-            }

-

-            $temp = new Math_BigInteger();

-            $temp->value = array($y_value[1], $y_value[0]);

-

-            $lhs = new Math_BigInteger();

-            $lhs->value = array($quotient->value[$q_index]);

-            $lhs = $lhs->multiply($temp);

-

-            $rhs = new Math_BigInteger();

-            $rhs->value = array($x_value[2], $x_value[1], $x_value[0]);

-

-            while ( $lhs->compare($rhs) > 0 ) {

-                $quotient->value[$q_index]--;

-

-                $lhs = new Math_BigInteger();

-                $lhs->value = array($quotient->value[$q_index]);

-                $lhs = $lhs->multiply($temp);

-            }

-

-            $adjust = $this->_array_repeat(0, $q_index);

-            $temp = new Math_BigInteger();

-            $temp->value = array($quotient->value[$q_index]);

-            $temp = $temp->multiply($y);

-            $temp->value = array_merge($adjust, $temp->value);

-

-            $x = $x->subtract($temp);

-

-            if ($x->compare($zero) < 0) {

-                $temp->value = array_merge($adjust, $y->value);

-                $x = $x->add($temp);

-

-                $quotient->value[$q_index]--;

-            }

-

-            $x_max = count($x->value) - 1;

-        }

-

-        // unnormalize the remainder

-        $x->_rshift($shift);

-

-        $quotient->is_negative = $x_sign != $y_sign;

-

-        // calculate the "common residue", if appropriate

-        if ( $x_sign ) {

-            $y->_rshift($shift);

-            $x = $y->subtract($x);

-        }

-

-        return array($this->_normalize($quotient), $this->_normalize($x));

-    }

-

-    /**

-     * Divides a BigInteger by a regular integer

-     *

-     * abc / x = a00 / x + b0 / x + c / x

-     *

-     * @param Math_BigInteger $divisor

-     * @return Array

-     * @access public

-     */

-    function _divide_digit($divisor)

-    {

-        $carry = 0;

-        $result = new Math_BigInteger();

-

-        for ($i = count($this->value) - 1; $i >= 0; $i--) {

-            $temp = 0x4000000 * $carry + $this->value[$i];

-            $result->value[$i] = floor($temp / $divisor);

-            $carry = fmod($temp, $divisor);

-        }

-

-        $remainder = new Math_BigInteger();

-        $remainder->value = array($carry);

-

-        return array($result, $remainder);

-    }

-

-    /**

-     * Performs modular exponentiation.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger('10');

-     *    $b = new Math_BigInteger('20');

-     *    $c = new Math_BigInteger('30');

-     *

-     *    $c = $a->modPow($b, $c);

-     *

-     *    echo $c->toString(); // outputs 10

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $e

-     * @param Math_BigInteger $n

-     * @return Math_BigInteger

-     * @access public

-     * @internal The most naive approach to modular exponentiation has very unreasonable requirements, and

-     *    and although the approach involving repeated squaring does vastly better, it, too, is impractical

-     *    for our purposes.  The reason being that division - by far the most complicated and time-consuming

-     *    of the basic operations (eg. +,-,*,/) - occurs multiple times within it.

-     *

-     *    Modular reductions resolve this issue.  Although an individual modular reduction takes more time

-     *    then an individual division, when performed in succession (with the same modulo), they're a lot faster.

-     *

-     *    The two most commonly used modular reductions are Barrett and Montgomery reduction.  Montgomery reduction,

-     *    although faster, only works when the gcd of the modulo and of the base being used is 1.  In RSA, when the

-     *    base is a power of two, the modulo - a product of two primes - is always going to have a gcd of 1 (because

-     *    the product of two odd numbers is odd), but what about when RSA isn't used?

-     *

-     *    In contrast, Barrett reduction has no such constraint.  As such, some bigint implementations perform a

-     *    Barrett reduction after every operation in the modpow function.  Others perform Barrett reductions when the

-     *    modulo is even and Montgomery reductions when the modulo is odd.  BigInteger.java's modPow method, however,

-     *    uses a trick involving the Chinese Remainder Theorem to factor the even modulo into two numbers - one odd and

-     *    the other, a power of two - and recombine them, later.  This is the method that this modPow function uses.

-     *    {@link http://islab.oregonstate.edu/papers/j34monex.pdf Montgomery Reduction with Even Modulus} elaborates.

-     */

-    function modPow($e, $n)

-    {

-        $n = $this->bitmask !== false && $this->bitmask->compare($n) < 0 ? $this->bitmask : $n->abs();

-

-        if ($e->compare(new Math_BigInteger()) < 0) {

-            $e = $e->abs();

-

-            $temp = $this->modInverse($n);

-            if ($temp === false) {

-                return false;

-            }

-

-            return $this->_normalize($temp->modPow($e, $n));

-        }

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_powm($this->value, $e->value, $n->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp = new Math_BigInteger();

-                $temp->value = bcpowmod($this->value, $e->value, $n->value);

-

-                return $this->_normalize($temp);

-        }

-

-        if ( empty($e->value) ) {

-            $temp = new Math_BigInteger();

-            $temp->value = array(1);

-            return $this->_normalize($temp);

-        }

-

-        if ( $e->value == array(1) ) {

-            list(, $temp) = $this->divide($n);

-            return $this->_normalize($temp);

-        }

-

-        if ( $e->value == array(2) ) {

-            $temp = $this->_square();

-            list(, $temp) = $temp->divide($n);

-            return $this->_normalize($temp);

-        }

-

-        return $this->_normalize($this->_slidingWindow($e, $n, MATH_BIGINTEGER_BARRETT));

-

-        // is the modulo odd?

-        if ( $n->value[0] & 1 ) {

-            return $this->_normalize($this->_slidingWindow($e, $n, MATH_BIGINTEGER_MONTGOMERY));

-        }

-        // if it's not, it's even

-

-        // find the lowest set bit (eg. the max pow of 2 that divides $n)

-        for ($i = 0; $i < count($n->value); $i++) {

-            if ( $n->value[$i] ) {

-                $temp = decbin($n->value[$i]);

-                $j = strlen($temp) - strrpos($temp, '1') - 1;

-                $j+= 26 * $i;

-                break;

-            }

-        }

-        // at this point, 2^$j * $n/(2^$j) == $n

-

-        $mod1 = $n->copy();

-        $mod1->_rshift($j);

-        $mod2 = new Math_BigInteger();

-        $mod2->value = array(1);

-        $mod2->_lshift($j);

-

-        $part1 = ( $mod1->value != array(1) ) ? $this->_slidingWindow($e, $mod1, MATH_BIGINTEGER_MONTGOMERY) : new Math_BigInteger();

-        $part2 = $this->_slidingWindow($e, $mod2, MATH_BIGINTEGER_POWEROF2);

-

-        $y1 = $mod2->modInverse($mod1);

-        $y2 = $mod1->modInverse($mod2);

-

-        $result = $part1->multiply($mod2);

-        $result = $result->multiply($y1);

-

-        $temp = $part2->multiply($mod1);

-        $temp = $temp->multiply($y2);

-

-        $result = $result->add($temp);

-        list(, $result) = $result->divide($n);

-

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Performs modular exponentiation.

-     *

-     * Alias for Math_BigInteger::modPow()

-     *

-     * @param Math_BigInteger $e

-     * @param Math_BigInteger $n

-     * @return Math_BigInteger

-     * @access public

-     */

-    function powMod($e, $n)

-    {

-        return $this->modPow($e, $n);

-    }

-

-    /**

-     * Sliding Window k-ary Modular Exponentiation

-     *

-     * Based on {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=27 HAC 14.85} /

-     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=210 MPM 7.7}.  In a departure from those algorithims,

-     * however, this function performs a modular reduction after every multiplication and squaring operation.

-     * As such, this function has the same preconditions that the reductions being used do.

-     *

-     * @param Math_BigInteger $e

-     * @param Math_BigInteger $n

-     * @param Integer $mode

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _slidingWindow($e, $n, $mode)

-    {

-        static $window_ranges = array(7, 25, 81, 241, 673, 1793); // from BigInteger.java's oddModPow function

-        //static $window_ranges = array(0, 7, 36, 140, 450, 1303, 3529); // from MPM 7.3.1

-

-        $e_length = count($e->value) - 1;

-        $e_bits = decbin($e->value[$e_length]);

-        for ($i = $e_length - 1; $i >= 0; $i--) {

-            $e_bits.= str_pad(decbin($e->value[$i]), 26, '0', STR_PAD_LEFT);

-        }

-

-        $e_length = strlen($e_bits);

-

-        // calculate the appropriate window size.

-        // $window_size == 3 if $window_ranges is between 25 and 81, for example.

-        for ($i = 0, $window_size = 1; $e_length > $window_ranges[$i] && $i < count($window_ranges); $window_size++, $i++);

-        switch ($mode) {

-            case MATH_BIGINTEGER_MONTGOMERY:

-                $reduce = '_montgomery';

-                $prep = '_prepMontgomery';

-                break;

-            case MATH_BIGINTEGER_BARRETT:

-                $reduce = '_barrett';

-                $prep = '_barrett';

-                break;

-            case MATH_BIGINTEGER_POWEROF2:

-                $reduce = '_mod2';

-                $prep = '_mod2';

-                break;

-            case MATH_BIGINTEGER_CLASSIC:

-                $reduce = '_remainder';

-                $prep = '_remainder';

-                break;

-            case MATH_BIGINTEGER_NONE:

-                // ie. do no modular reduction.  useful if you want to just do pow as opposed to modPow.

-                $reduce = 'copy';

-                $prep = 'copy';

-                break;

-            default:

-                // an invalid $mode was provided

-        }

-

-        // precompute $this^0 through $this^$window_size

-        $powers = array();

-        $powers[1] = $this->$prep($n);

-        $powers[2] = $powers[1]->_square();

-        $powers[2] = $powers[2]->$reduce($n);

-

-        // we do every other number since substr($e_bits, $i, $j+1) (see below) is supposed to end

-        // in a 1.  ie. it's supposed to be odd.

-        $temp = 1 << ($window_size - 1);

-        for ($i = 1; $i < $temp; $i++) {

-            $powers[2 * $i + 1] = $powers[2 * $i - 1]->multiply($powers[2]);

-            $powers[2 * $i + 1] = $powers[2 * $i + 1]->$reduce($n);

-        }

-

-        $result = new Math_BigInteger();

-        $result->value = array(1);

-        $result = $result->$prep($n);

-

-        for ($i = 0; $i < $e_length; ) {

-            if ( !$e_bits[$i] ) {

-                $result = $result->_square();

-                $result = $result->$reduce($n);

-                $i++;

-            } else {

-                for ($j = $window_size - 1; $j > 0; $j--) {

-                    if ( !empty($e_bits[$i + $j]) ) {

-                        break;

-                    }

-                }

-

-                for ($k = 0; $k <= $j; $k++) {// eg. the length of substr($e_bits, $i, $j+1)

-                    $result = $result->_square();

-                    $result = $result->$reduce($n);

-                }

-

-                $result = $result->multiply($powers[bindec(substr($e_bits, $i, $j + 1))]);

-                $result = $result->$reduce($n);

-

-                $i+=$j + 1;

-            }

-        }

-

-        $result = $result->$reduce($n);

-

-        return $result;

-    }

-

-    /**

-     * Remainder

-     *

-     * A wrapper for the divide function.

-     *

-     * @see divide()

-     * @see _slidingWindow()

-     * @access private

-     * @param Math_BigInteger

-     * @return Math_BigInteger

-     */

-    function _remainder($n)

-    {

-        list(, $temp) = $this->divide($n);

-        return $temp;

-    }

-

-    /**

-     * Modulos for Powers of Two

-     *

-     * Calculates $x%$n, where $n = 2**$e, for some $e.  Since this is basically the same as doing $x & ($n-1),

-     * we'll just use this function as a wrapper for doing that.

-     *

-     * @see _slidingWindow()

-     * @access private

-     * @param Math_BigInteger

-     * @return Math_BigInteger

-     */

-    function _mod2($n)

-    {

-        $temp = new Math_BigInteger();

-        $temp->value = array(1);

-        return $this->bitwise_and($n->subtract($temp));

-    }

-

-    /**

-     * Barrett Modular Reduction

-     *

-     * See {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=14 HAC 14.3.3} /

-     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=165 MPM 6.2.5} for more information.  Modified slightly,

-     * so as not to require negative numbers (initially, this script didn't support negative numbers).

-     *

-     * @see _slidingWindow()

-     * @access private

-     * @param Math_BigInteger

-     * @return Math_BigInteger

-     */

-    function _barrett($n)

-    {

-        static $cache = array(

-            MATH_BIGINTEGER_VARIABLE => array(),

-            MATH_BIGINTEGER_DATA => array()

-        );

-

-        $n_length = count($n->value);

-

-        if (count($this->value) > 2 * $n_length) {

-            list(, $temp) = $this->divide($n);

-            return $temp;

-        }

-

-        if ( ($key = array_search($n->value, $cache[MATH_BIGINTEGER_VARIABLE])) === false ) {

-            $key = count($cache[MATH_BIGINTEGER_VARIABLE]);

-            $cache[MATH_BIGINTEGER_VARIABLE][] = $n->value;

-            $temp = new Math_BigInteger();

-            $temp->value = $this->_array_repeat(0, 2 * $n_length);

-            $temp->value[] = 1;

-            list($cache[MATH_BIGINTEGER_DATA][], ) = $temp->divide($n);

-        }

-

-        $temp = new Math_BigInteger();

-        $temp->value = array_slice($this->value, $n_length - 1);

-        $temp = $temp->multiply($cache[MATH_BIGINTEGER_DATA][$key]);

-        $temp->value = array_slice($temp->value, $n_length + 1);

-

-        $result = new Math_BigInteger();

-        $result->value = array_slice($this->value, 0, $n_length + 1);

-        $temp = $temp->_multiplyLower($n, $n_length + 1);

-        // $temp->value == array_slice($temp->multiply($n)->value, 0, $n_length + 1)

-

-        if ($result->compare($temp) < 0) {

-            $corrector = new Math_BigInteger();

-            $corrector->value = $this->_array_repeat(0, $n_length + 1);

-            $corrector->value[] = 1;

-            $result = $result->add($corrector);

-        }

-

-        $result = $result->subtract($temp);

-        while ($result->compare($n) > 0) {

-            $result = $result->subtract($n);

-        }

-

-        return $result;

-    }

-

-    /**

-     * Montgomery Modular Reduction

-     *

-     * ($this->_prepMontgomery($n))->_montgomery($n) yields $x%$n.

-     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=170 MPM 6.3} provides insights on how this can be

-     * improved upon (basically, by using the comba method).  gcd($n, 2) must be equal to one for this function

-     * to work correctly.

-     *

-     * @see _prepMontgomery()

-     * @see _slidingWindow()

-     * @access private

-     * @param Math_BigInteger

-     * @return Math_BigInteger

-     */

-    function _montgomery($n)

-    {

-        static $cache = array(

-            MATH_BIGINTEGER_VARIABLE => array(),

-            MATH_BIGINTEGER_DATA => array()

-        );

-

-        if ( ($key = array_search($n->value, $cache[MATH_BIGINTEGER_VARIABLE])) === false ) {

-            $key = count($cache[MATH_BIGINTEGER_VARIABLE]);

-            $cache[MATH_BIGINTEGER_VARIABLE][] = $n->value;

-            $cache[MATH_BIGINTEGER_DATA][] = $n->_modInverse67108864();

-        }

-

-        $k = count($n->value);

-

-        $result = $this->copy();

-

-        for ($i = 0; $i < $k; $i++) {

-            $temp = new Math_BigInteger();

-            $temp->value = array(

-                ($result->value[$i] * $cache[MATH_BIGINTEGER_DATA][$key]) & 0x3FFFFFF

-            );

-

-            $temp = $temp->multiply($n);

-            $temp->value = array_merge($this->_array_repeat(0, $i), $temp->value);

-            $result = $result->add($temp);

-        }

-

-        $result->value = array_slice($result->value, $k);

-

-        if ($result->compare($n) >= 0) {

-            $result = $result->subtract($n);

-        }

-

-        return $result;

-    }

-

-    /**

-     * Prepare a number for use in Montgomery Modular Reductions

-     *

-     * @see _montgomery()

-     * @see _slidingWindow()

-     * @access private

-     * @param Math_BigInteger

-     * @return Math_BigInteger

-     */

-    function _prepMontgomery($n)

-    {

-        $k = count($n->value);

-

-        $temp = new Math_BigInteger();

-        $temp->value = array_merge($this->_array_repeat(0, $k), $this->value);

-

-        list(, $temp) = $temp->divide($n);

-        return $temp;

-    }

-

-    /**

-     * Modular Inverse of a number mod 2**26 (eg. 67108864)

-     *

-     * Based off of the bnpInvDigit function implemented and justified in the following URL:

-     *

-     * {@link http://www-cs-students.stanford.edu/~tjw/jsbn/jsbn.js}

-     *

-     * The following URL provides more info:

-     *

-     * {@link http://groups.google.com/group/sci.crypt/msg/7a137205c1be7d85}

-     *

-     * As for why we do all the bitmasking...  strange things can happen when converting from floats to ints. For

-     * instance, on some computers, var_dump((int) -4294967297) yields int(-1) and on others, it yields 

-     * int(-2147483648).  To avoid problems stemming from this, we use bitmasks to guarantee that ints aren't

-     * auto-converted to floats.  The outermost bitmask is present because without it, there's no guarantee that

-     * the "residue" returned would be the so-called "common residue".  We use fmod, in the last step, because the

-     * maximum possible $x is 26 bits and the maximum $result is 16 bits.  Thus, we have to be able to handle up to

-     * 40 bits, which only 64-bit floating points will support.

-     *

-     * Thanks to Pedro Gimeno Fortea for input!

-     *

-     * @see _montgomery()

-     * @access private

-     * @return Integer

-     */

-    function _modInverse67108864() // 2**26 == 67108864

-    {

-        $x = -$this->value[0];

-        $result = $x & 0x3; // x**-1 mod 2**2

-        $result = ($result * (2 - $x * $result)) & 0xF; // x**-1 mod 2**4

-        $result = ($result * (2 - ($x & 0xFF) * $result))  & 0xFF; // x**-1 mod 2**8

-        $result = ($result * ((2 - ($x & 0xFFFF) * $result) & 0xFFFF)) & 0xFFFF; // x**-1 mod 2**16

-        $result = fmod($result * (2 - fmod($x * $result, 0x4000000)), 0x4000000); // x**-1 mod 2**26

-        return $result & 0x3FFFFFF;

-    }

-

-    /**

-     * Calculates modular inverses.

-     *

-     * Say you have (30 mod 17 * x mod 17) mod 17 == 1.  x can be found using modular inverses.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger(30);

-     *    $b = new Math_BigInteger(17);

-     *

-     *    $c = $a->modInverse($b);

-     *    echo $c->toString(); // outputs 4

-     *

-     *    echo "\r\n";

-     *

-     *    $d = $a->multiply($c);

-     *    list(, $d) = $d->divide($b);

-     *    echo $d; // outputs 1 (as per the definition of modular inverse)

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $n

-     * @return mixed false, if no modular inverse exists, Math_BigInteger, otherwise.

-     * @access public

-     * @internal See {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=21 HAC 14.64} for more information.

-     */

-    function modInverse($n)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_invert($this->value, $n->value);

-

-                return ( $temp->value === false ) ? false : $this->_normalize($temp);

-        }

-

-        static $zero, $one;

-        if (!isset($zero)) {

-            $zero = new Math_BigInteger();

-            $one = new Math_BigInteger(1);

-        }

-

-        // $x mod $n == $x mod -$n.

-        $n = $n->abs();

-

-        if ($this->compare($zero) < 0) {

-            $temp = $this->abs();

-            $temp = $temp->modInverse($n);

-            return $negated === false ? false : $this->_normalize($n->subtract($temp));

-        }

-

-        extract($this->extendedGCD($n));

-

-        if (!$gcd->equals($one)) {

-            return false;

-        }

-

-        $x = $x->compare($zero) < 0 ? $x->add($n) : $x;

-

-        return $this->compare($zero) < 0 ? $this->_normalize($n->subtract($x)) : $this->_normalize($x);

-    }

-

-    /**

-     * Calculates the greatest common divisor and Bézout's identity.

-     *

-     * Say you have 693 and 609.  The GCD is 21.  Bézout's identity states that there exist integers x and y such that

-     * 693*x + 609*y == 21.  In point of fact, there are actually an infinite number of x and y combinations and which

-     * combination is returned is dependant upon which mode is in use.  See

-     * {@link http://en.wikipedia.org/wiki/B%C3%A9zout%27s_identity Bézout's identity - Wikipedia} for more information.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger(693);

-     *    $b = new Math_BigInteger(609);

-     *

-     *    extract($a->extendedGCD($b));

-     *

-     *    echo $gcd->toString() . "\r\n"; // outputs 21

-     *    echo $a->toString() * $x->toString() + $b->toString() * $y->toString(); // outputs 21

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $n

-     * @return Math_BigInteger

-     * @access public

-     * @internal Calculates the GCD using the binary xGCD algorithim described in

-     *    {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=19 HAC 14.61}.  As the text above 14.61 notes,

-     *    the more traditional algorithim requires "relatively costly multiple-precision divisions".

-     */

-    function extendedGCD($n) {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                extract(gmp_gcdext($this->value, $n->value));

-

-                return array(

-                    'gcd' => $this->_normalize(new Math_BigInteger($g)),

-                    'x'   => $this->_normalize(new Math_BigInteger($s)),

-                    'y'   => $this->_normalize(new Math_BigInteger($t))

-                );

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                // it might be faster to use the binary xGCD algorithim here, as well, but (1) that algorithim works

-                // best when the base is a power of 2 and (2) i don't think it'd make much difference, anyway.  as is,

-                // the basic extended euclidean algorithim is what we're using.

-

-                $u = $this->value;

-                $v = $n->value;

-

-                $a = '1';

-                $b = '0';

-                $c = '0';

-                $d = '1';

-

-                while (bccomp($v, '0') != 0) {

-                    $q = bcdiv($u, $v);

-

-                    $temp = $u;

-                    $u = $v;

-                    $v = bcsub($temp, bcmul($v, $q));

-

-                    $temp = $a;

-                    $a = $c;

-                    $c = bcsub($temp, bcmul($a, $q));

-

-                    $temp = $b;

-                    $b = $d;

-                    $d = bcsub($temp, bcmul($b, $q));

-                }

-

-                return array(

-                    'gcd' => $this->_normalize(new Math_BigInteger($u)),

-                    'x'   => $this->_normalize(new Math_BigInteger($a)),

-                    'y'   => $this->_normalize(new Math_BigInteger($b))

-                );

-        }

-

-        $y = $n->copy();

-        $x = $this->copy();

-        $g = new Math_BigInteger();

-        $g->value = array(1);

-

-        while ( !(($x->value[0] & 1)|| ($y->value[0] & 1)) ) {

-            $x->_rshift(1);

-            $y->_rshift(1);

-            $g->_lshift(1);

-        }

-

-        $u = $x->copy();

-        $v = $y->copy();

-

-        $a = new Math_BigInteger();

-        $b = new Math_BigInteger();

-        $c = new Math_BigInteger();

-        $d = new Math_BigInteger();

-

-        $a->value = $d->value = $g->value = array(1);

-

-        while ( !empty($u->value) ) {

-            while ( !($u->value[0] & 1) ) {

-                $u->_rshift(1);

-                if ( ($a->value[0] & 1) || ($b->value[0] & 1) ) {

-                    $a = $a->add($y);

-                    $b = $b->subtract($x);

-                }

-                $a->_rshift(1);

-                $b->_rshift(1);

-            }

-

-            while ( !($v->value[0] & 1) ) {

-                $v->_rshift(1);

-                if ( ($c->value[0] & 1) || ($d->value[0] & 1) ) {

-                    $c = $c->add($y);

-                    $d = $d->subtract($x);

-                }

-                $c->_rshift(1);

-                $d->_rshift(1);

-            }

-

-            if ($u->compare($v) >= 0) {

-                $u = $u->subtract($v);

-                $a = $a->subtract($c);

-                $b = $b->subtract($d);

-            } else {

-                $v = $v->subtract($u);

-                $c = $c->subtract($a);

-                $d = $d->subtract($b);

-            }

-        }

-

-        return array(

-            'gcd' => $this->_normalize($g->multiply($v)),

-            'x'   => $this->_normalize($c),

-            'y'   => $this->_normalize($d)

-        );

-    }

-

-    /**

-     * Calculates the greatest common divisor

-     *

-     * Say you have 693 and 609.  The GCD is 21.

-     *

-     * Here's an example:

-     * <code>

-     * <?php

-     *    include('Math/BigInteger.php');

-     *

-     *    $a = new Math_BigInteger(693);

-     *    $b = new Math_BigInteger(609);

-     *

-     *    $gcd = a->extendedGCD($b);

-     *

-     *    echo $gcd->toString() . "\r\n"; // outputs 21

-     * ?>

-     * </code>

-     *

-     * @param Math_BigInteger $n

-     * @return Math_BigInteger

-     * @access public

-     */

-    function gcd($n)

-    {

-        extract($this->extendedGCD($n));

-        return $gcd;

-    }

-

-    /**

-     * Absolute value.

-     *

-     * @return Math_BigInteger

-     * @access public

-     */

-    function abs()

-    {

-        $temp = new Math_BigInteger();

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp->value = gmp_abs($this->value);

-                break;

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp->value = (bccomp($this->value, '0') < 0) ? substr($this->value, 1) : $this->value;

-                break;

-            default:

-                $temp->value = $this->value;

-        }

-

-        return $temp;

-    }

-

-    /**

-     * Compares two numbers.

-     *

-     * Although one might think !$x->compare($y) means $x != $y, it, in fact, means the opposite.  The reason for this is

-     * demonstrated thusly:

-     *

-     * $x  > $y: $x->compare($y)  > 0

-     * $x  < $y: $x->compare($y)  < 0

-     * $x == $y: $x->compare($y) == 0

-     *

-     * Note how the same comparison operator is used.  If you want to test for equality, use $x->equals($y).

-     *

-     * @param Math_BigInteger $x

-     * @return Integer < 0 if $this is less than $x; > 0 if $this is greater than $x, and 0 if they are equal.

-     * @access public

-     * @see equals()

-     * @internal Could return $this->sub($x), but that's not as fast as what we do do.

-     */

-    function compare($y)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                return gmp_cmp($this->value, $y->value);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                return bccomp($this->value, $y->value);

-        }

-

-        $x = $this->_normalize($this->copy());

-        $y = $this->_normalize($y);

-

-        if ( $x->is_negative != $y->is_negative ) {

-            return ( !$x->is_negative && $y->is_negative ) ? 1 : -1;

-        }

-

-        $result = $x->is_negative ? -1 : 1;

-

-        if ( count($x->value) != count($y->value) ) {

-            return ( count($x->value) > count($y->value) ) ? $result : -$result;

-        }

-

-        for ($i = count($x->value) - 1; $i >= 0; $i--) {

-            if ($x->value[$i] != $y->value[$i]) {

-                return ( $x->value[$i] > $y->value[$i] ) ? $result : -$result;

-            }

-        }

-

-        return 0;

-    }

-

-    /**

-     * Tests the equality of two numbers.

-     *

-     * If you need to see if one number is greater than or less than another number, use Math_BigInteger::compare()

-     *

-     * @param Math_BigInteger $x

-     * @return Boolean

-     * @access public

-     * @see compare()

-     */

-    function equals($x)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                return gmp_cmp($this->value, $x->value) == 0;

-            default:

-                return $this->value == $x->value && $this->is_negative == $x->is_negative;

-        }

-    }         

-

-    /**

-     * Set Precision

-     *

-     * Some bitwise operations give different results depending on the precision being used.  Examples include left

-     * shift, not, and rotates.

-     *

-     * @param Math_BigInteger $x

-     * @access public

-     * @return Math_BigInteger

-     */

-    function setPrecision($bits)

-    {

-        $this->precision = $bits;

-        if ( MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_BCMATH ) {

-            $this->bitmask = new Math_BigInteger(chr((1 << ($bits & 0x7)) - 1) . str_repeat(chr(0xFF), $bits >> 3), 256);

-        } else {

-            $this->bitmask = new Math_BigInteger(bcpow('2', $bits));

-        }

-    }

-

-    /**

-     * Logical And

-     *

-     * @param Math_BigInteger $x

-     * @access public

-     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>

-     * @return Math_BigInteger

-     */

-    function bitwise_and($x)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_and($this->value, $x->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $left = $this->toBytes();

-                $right = $x->toBytes();

-

-                $length = max(strlen($left), strlen($right));

-

-                $left = str_pad($left, $length, chr(0), STR_PAD_LEFT);

-                $right = str_pad($right, $length, chr(0), STR_PAD_LEFT);

-

-                return $this->_normalize(new Math_BigInteger($left & $right, 256));

-        }

-

-        $result = $this->copy();

-

-        $length = min(count($x->value), count($this->value));

-

-        $result->value = array_slice($result->value, 0, $length);

-

-        for ($i = 0; $i < $length; $i++) {

-            $result->value[$i] = $result->value[$i] & $x->value[$i];

-        }

-

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Logical Or

-     *

-     * @param Math_BigInteger $x

-     * @access public

-     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>

-     * @return Math_BigInteger

-     */

-    function bitwise_or($x)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_or($this->value, $x->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $left = $this->toBytes();

-                $right = $x->toBytes();

-

-                $length = max(strlen($left), strlen($right));

-

-                $left = str_pad($left, $length, chr(0), STR_PAD_LEFT);

-                $right = str_pad($right, $length, chr(0), STR_PAD_LEFT);

-

-                return $this->_normalize(new Math_BigInteger($left | $right, 256));

-        }

-

-        $length = max(count($this->value), count($x->value));

-        $result = $this->copy();

-        $result->value = array_pad($result->value, 0, $length);

-        $x->value = array_pad($x->value, 0, $length);

-

-        for ($i = 0; $i < $length; $i++) {

-            $result->value[$i] = $this->value[$i] | $x->value[$i];

-        }

-

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Logical Exclusive-Or

-     *

-     * @param Math_BigInteger $x

-     * @access public

-     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>

-     * @return Math_BigInteger

-     */

-    function bitwise_xor($x)

-    {

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                $temp = new Math_BigInteger();

-                $temp->value = gmp_xor($this->value, $x->value);

-

-                return $this->_normalize($temp);

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $left = $this->toBytes();

-                $right = $x->toBytes();

-

-                $length = max(strlen($left), strlen($right));

-

-                $left = str_pad($left, $length, chr(0), STR_PAD_LEFT);

-                $right = str_pad($right, $length, chr(0), STR_PAD_LEFT);

-

-                return $this->_normalize(new Math_BigInteger($left ^ $right, 256));

-        }

-

-        $length = max(count($this->value), count($x->value));

-        $result = $this->copy();

-        $result->value = array_pad($result->value, 0, $length);

-        $x->value = array_pad($x->value, 0, $length);

-

-        for ($i = 0; $i < $length; $i++) {

-            $result->value[$i] = $this->value[$i] ^ $x->value[$i];

-        }

-

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Logical Not

-     *

-     * @access public

-     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>

-     * @return Math_BigInteger

-     */

-    function bitwise_not()

-    {

-        // calculuate "not" without regard to $this->precision

-        // (will always result in a smaller number.  ie. ~1 isn't 1111 1110 - it's 0)

-        $temp = $this->toBytes();

-        $pre_msb = decbin(ord($temp[0]));

-        $temp = ~$temp;

-        $msb = decbin(ord($temp[0]));

-        if (strlen($msb) == 8) {

-            $msb = substr($msb, strpos($msb, '0'));

-        }

-        $temp[0] = chr(bindec($msb));

-

-        // see if we need to add extra leading 1's

-        $current_bits = strlen($pre_msb) + 8 * strlen($temp) - 8;

-        $new_bits = $this->precision - $current_bits;

-        if ($new_bits <= 0) {

-            return $this->_normalize(new Math_BigInteger($temp, 256));

-        }

-

-        // generate as many leading 1's as we need to.

-        $leading_ones = chr((1 << ($new_bits & 0x7)) - 1) . str_repeat(chr(0xFF), $new_bits >> 3);

-        $this->_base256_lshift($leading_ones, $current_bits);

-

-        $temp = str_pad($temp, ceil($this->bits / 8), chr(0), STR_PAD_LEFT);

-

-        return $this->_normalize(new Math_BigInteger($leading_ones | $temp, 256));

-    }

-

-    /**

-     * Logical Right Shift

-     *

-     * Shifts BigInteger's by $shift bits, effectively dividing by 2**$shift.

-     *

-     * @param Integer $shift

-     * @return Math_BigInteger

-     * @access public

-     * @internal The only version that yields any speed increases is the internal version.

-     */

-    function bitwise_rightShift($shift)

-    {

-        $temp = new Math_BigInteger();

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                static $two;

-

-                if (empty($two)) {

-                    $two = gmp_init('2');

-                }

-

-                $temp->value = gmp_div_q($this->value, gmp_pow($two, $shift));

-

-                break;

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp->value = bcdiv($this->value, bcpow('2', $shift));

-

-                break;

-            default: // could just replace _lshift with this, but then all _lshift() calls would need to be rewritten

-                     // and I don't want to do that...

-                $temp->value = $this->value;

-                $temp->_rshift($shift);

-        }

-

-        return $this->_normalize($temp);

-    }

-

-    /**

-     * Logical Left Shift

-     *

-     * Shifts BigInteger's by $shift bits, effectively multiplying by 2**$shift.

-     *

-     * @param Integer $shift

-     * @return Math_BigInteger

-     * @access public

-     * @internal The only version that yields any speed increases is the internal version.

-     */

-    function bitwise_leftShift($shift)

-    {

-        $temp = new Math_BigInteger();

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                static $two;

-

-                if (empty($two)) {

-                    $two = gmp_init('2');

-                }

-

-                $temp->value = gmp_mul($this->value, gmp_pow($two, $shift));

-

-                break;

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                $temp->value = bcmul($this->value, bcpow('2', $shift));

-

-                break;

-            default: // could just replace _rshift with this, but then all _lshift() calls would need to be rewritten

-                     // and I don't want to do that...

-                $temp->value = $this->value;

-                $temp->_lshift($shift);

-        }

-

-        return $this->_normalize($temp);

-    }

-

-    /**

-     * Logical Left Rotate

-     *

-     * Instead of the top x bits being dropped they're appended to the shifted bit string.

-     *

-     * @param Integer $shift

-     * @return Math_BigInteger

-     * @access public

-     */

-    function bitwise_leftRotate($shift)

-    {

-        $bits = $this->toBytes();

-

-        if ($this->precision > 0) {

-            $precision = $this->precision;

-            if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_BCMATH ) {

-                $mask = $this->bitmask->subtract(new Math_BigInteger(1));

-                $mask = $mask->toBytes();

-            } else {

-                $mask = $this->bitmask->toBytes();

-            }

-        } else {

-            $temp = ord($bits[0]);

-            for ($i = 0; $temp >> $i; $i++);

-            $precision = 8 * strlen($bits) - 8 + $i;

-            $mask = chr((1 << ($precision & 0x7)) - 1) . str_repeat(chr(0xFF), $precision >> 3);

-        }

-

-        if ($shift < 0) {

-            $shift+= $precision;

-        }

-        $shift%= $precision;

-

-        if (!$shift) {

-            return $this->copy();

-        }

-

-        $left = $this->bitwise_leftShift($shift);

-        $left = $left->bitwise_and(new Math_BigInteger($mask, 256));

-        $right = $this->bitwise_rightShift($precision - $shift);

-        $result = MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_BCMATH ? $left->bitwise_or($right) : $left->add($right);

-        return $this->_normalize($result);

-    }

-

-    /**

-     * Logical Right Rotate

-     *

-     * Instead of the bottom x bits being dropped they're prepended to the shifted bit string.

-     *

-     * @param Integer $shift

-     * @return Math_BigInteger

-     * @access public

-     */

-    function bitwise_rightRotate($shift)

-    {

-        return $this->bitwise_leftRotate(-$shift);

-    }

-

-    /**

-     * Set random number generator function

-     *

-     * $generator should be the name of a random generating function whose first parameter is the minimum

-     * value and whose second parameter is the maximum value.  If this function needs to be seeded, it should

-     * be seeded prior to calling Math_BigInteger::random() or Math_BigInteger::randomPrime()

-     *

-     * If the random generating function is not explicitly set, it'll be assumed to be mt_rand().

-     *

-     * @see random()

-     * @see randomPrime()

-     * @param optional String $generator

-     * @access public

-     */

-    function setRandomGenerator($generator)

-    {

-        $this->generator = $generator;

-    }

-

-    /**

-     * Generate a random number

-     *

-     * @param optional Integer $min

-     * @param optional Integer $max

-     * @return Math_BigInteger

-     * @access public

-     */

-    function random($min = false, $max = false)

-    {

-        if ($min === false) {

-            $min = new Math_BigInteger(0);

-        }

-

-        if ($max === false) {

-            $max = new Math_BigInteger(0x7FFFFFFF);

-        }

-

-        $compare = $max->compare($min);

-

-        if (!$compare) {

-            return $this->_normalize($min);

-        } else if ($compare < 0) {

-            // if $min is bigger then $max, swap $min and $max

-            $temp = $max;

-            $max = $min;

-            $min = $temp;

-        }

-

-        $generator = $this->generator;

-

-        $max = $max->subtract($min);

-        $max = ltrim($max->toBytes(), chr(0));

-        $size = strlen($max) - 1;

-        $random = '';

-

-        $bytes = $size & 1;

-        for ($i = 0; $i < $bytes; $i++) {

-            $random.= chr($generator(0, 255));

-        }

-

-        $blocks = $size >> 1;

-        for ($i = 0; $i < $blocks; $i++) {

-            // mt_rand(-2147483648, 0x7FFFFFFF) always produces -2147483648 on some systems

-            $random.= pack('n', $generator(0, 0xFFFF));

-        }

-

-        $temp = new Math_BigInteger($random, 256);

-        if ($temp->compare(new Math_BigInteger(substr($max, 1), 256)) > 0) {

-            $random = chr($generator(0, ord($max[0]) - 1)) . $random;

-        } else {

-            $random = chr($generator(0, ord($max[0])    )) . $random;

-        }

-

-        $random = new Math_BigInteger($random, 256);

-

-        return $this->_normalize($random->add($min));

-    }

-

-    /**

-     * Generate a random prime number.

-     *

-     * If there's not a prime within the given range, false will be returned.  If more than $timeout seconds have elapsed,

-     * give up and return false.

-     *

-     * @param optional Integer $min

-     * @param optional Integer $max

-     * @param optional Integer $timeout

-     * @return Math_BigInteger

-     * @access public

-     * @internal See {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap4.pdf#page=15 HAC 4.44}.

-     */

-    function randomPrime($min = false, $max = false, $timeout = false)

-    {

-        // gmp_nextprime() requires PHP 5 >= 5.2.0 per <http://php.net/gmp-nextprime>.

-        if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_GMP && function_exists('gmp_nextprime') ) {

-            // we don't rely on Math_BigInteger::random()'s min / max when gmp_nextprime() is being used since this function

-            // does its own checks on $max / $min when gmp_nextprime() is used.  When gmp_nextprime() is not used, however,

-            // the same $max / $min checks are not performed.

-            if ($min === false) {

-                $min = new Math_BigInteger(0);

-            }

-

-            if ($max === false) {

-                $max = new Math_BigInteger(0x7FFFFFFF);

-            }

-

-            $compare = $max->compare($min);

-

-            if (!$compare) {

-                return $min;

-            } else if ($compare < 0) {

-                // if $min is bigger then $max, swap $min and $max

-                $temp = $max;

-                $max = $min;

-                $min = $temp;

-            }

-

-            $x = $this->random($min, $max);

-

-            $x->value = gmp_nextprime($x->value);

-

-            if ($x->compare($max) <= 0) {

-                return $x;

-            }

-

-            $x->value = gmp_nextprime($min->value);

-

-            if ($x->compare($max) <= 0) {

-                return $x;

-            }

-

-            return false;

-        }

-

-        $repeat1 = $repeat2 = array();

-

-        $one = new Math_BigInteger(1);

-        $two = new Math_BigInteger(2);

-

-        $start = time();

-

-        do {

-            if ($timeout !== false && time() - $start > $timeout) {

-                return false;

-            }

-

-            $x = $this->random($min, $max);

-            if ($x->equals($two)) {

-                return $x;

-            }

-

-            // make the number odd

-            switch ( MATH_BIGINTEGER_MODE ) {

-                case MATH_BIGINTEGER_MODE_GMP:

-                    gmp_setbit($x->value, 0);

-                    break;

-                case MATH_BIGINTEGER_MODE_BCMATH:

-                    if ($x->value[strlen($x->value) - 1] % 2 == 0) {

-                        $x = $x->add($one);

-                    }

-                    break;

-                default:

-                    $x->value[0] |= 1;

-            }

-

-            // if we've seen this number twice before, assume there are no prime numbers within the given range

-            if (in_array($x->value, $repeat1)) {

-                if (in_array($x->value, $repeat2)) {

-                    return false;

-                } else {

-                    $repeat2[] = $x->value;

-                }

-            } else {

-                $repeat1[] = $x->value;

-            }

-        } while (!$x->isPrime());

-

-        return $x;

-    }

-

-    /**

-     * Checks a numer to see if it's prime

-     *

-     * Assuming the $t parameter is not set, this functoin has an error rate of 2**-80.  The main motivation for the

-     * $t parameter is distributability.  Math_BigInteger::randomPrime() can be distributed accross multiple pageloads

-     * on a website instead of just one.

-     *

-     * @param optional Integer $t

-     * @return Boolean

-     * @access public

-     * @internal Uses the

-     *     {@link http://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test Miller–Rabin primality test}.  See 

-     *     {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap4.pdf#page=8 HAC 4.24}.

-     */

-    function isPrime($t = false)

-    {

-        $length = strlen($this->toBytes());

-

-        if (!$t) {

-            // see HAC 4.49 "Note (controlling the error probability)"

-                 if ($length >= 163) { $t =  2; } // floor(1300 / 8)

-            else if ($length >= 106) { $t =  3; } // floor( 850 / 8)

-            else if ($length >= 81 ) { $t =  4; } // floor( 650 / 8)

-            else if ($length >= 68 ) { $t =  5; } // floor( 550 / 8)

-            else if ($length >= 56 ) { $t =  6; } // floor( 450 / 8)

-            else if ($length >= 50 ) { $t =  7; } // floor( 400 / 8)

-            else if ($length >= 43 ) { $t =  8; } // floor( 350 / 8)

-            else if ($length >= 37 ) { $t =  9; } // floor( 300 / 8)

-            else if ($length >= 31 ) { $t = 12; } // floor( 250 / 8)

-            else if ($length >= 25 ) { $t = 15; } // floor( 200 / 8)

-            else if ($length >= 18 ) { $t = 18; } // floor( 150 / 8)

-            else                     { $t = 27; }

-        }

-

-        // ie. gmp_testbit($this, 0)

-        // ie. isEven() or !isOdd()

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                return gmp_prob_prime($this->value, $t) != 0;

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                if ($this->value == '2') {

-                    return true;

-                }

-                if ($this->value[strlen($this->value) - 1] % 2 == 0) {

-                    return false;

-                }

-                break;

-            default:

-                if ($this->value == array(2)) {

-                    return true;

-                }

-                if (~$this->value[0] & 1) {

-                    return false;

-                }

-        }

-

-        static $primes, $zero, $one, $two;

-

-        if (!isset($primes)) {

-            $primes = array(

-                3,    5,    7,    11,   13,   17,   19,   23,   29,   31,   37,   41,   43,   47,   53,   59,   

-                61,   67,   71,   73,   79,   83,   89,   97,   101,  103,  107,  109,  113,  127,  131,  137,  

-                139,  149,  151,  157,  163,  167,  173,  179,  181,  191,  193,  197,  199,  211,  223,  227,  

-                229,  233,  239,  241,  251,  257,  263,  269,  271,  277,  281,  283,  293,  307,  311,  313,  

-                317,  331,  337,  347,  349,  353,  359,  367,  373,  379,  383,  389,  397,  401,  409,  419,  

-                421,  431,  433,  439,  443,  449,  457,  461,  463,  467,  479,  487,  491,  499,  503,  509,  

-                521,  523,  541,  547,  557,  563,  569,  571,  577,  587,  593,  599,  601,  607,  613,  617,  

-                619,  631,  641,  643,  647,  653,  659,  661,  673,  677,  683,  691,  701,  709,  719,  727,  

-                733,  739,  743,  751,  757,  761,  769,  773,  787,  797,  809,  811,  821,  823,  827,  829,  

-                839,  853,  857,  859,  863,  877,  881,  883,  887,  907,  911,  919,  929,  937,  941,  947,  

-                953,  967,  971,  977,  983,  991,  997

-            );

-

-            for ($i = 0; $i < count($primes); $i++) {

-                $primes[$i] = new Math_BigInteger($primes[$i]);

-            }

-

-            $zero = new Math_BigInteger();

-            $one = new Math_BigInteger(1);

-            $two = new Math_BigInteger(2);

-        }

-

-        // see HAC 4.4.1 "Random search for probable primes"

-        for ($i = 0; $i < count($primes); $i++) {

-            list(, $r) = $this->divide($primes[$i]);

-            if ($r->equals($zero)) {

-                return false;

-            }

-        }

-

-        $n   = $this->copy();

-        $n_1 = $n->subtract($one);

-        $n_2 = $n->subtract($two);

-

-        $r = $n_1->copy();

-        // ie. $s = gmp_scan1($n, 0) and $r = gmp_div_q($n, gmp_pow(gmp_init('2'), $s));

-        if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_BCMATH ) {

-            $s = 0;

-            while ($r->value[strlen($r->value) - 1] % 2 == 0) {

-                $r->value = bcdiv($r->value, 2);

-                $s++;

-            }

-        } else {

-            for ($i = 0; $i < count($r->value); $i++) {

-                $temp = ~$r->value[$i] & 0xFFFFFF;

-                for ($j = 1; ($temp >> $j) & 1; $j++);

-                if ($j != 25) {

-                    break;

-                }

-            }

-            $s = 26 * $i + $j - 1;

-            $r->_rshift($s);

-        }

-

-        for ($i = 0; $i < $t; $i++) {

-            $a = new Math_BigInteger();

-            $a = $a->random($two, $n_2);

-            $y = $a->modPow($r, $n);

-

-            if (!$y->equals($one) && !$y->equals($n_1)) {

-                for ($j = 1; $j < $s && !$y->equals($n_1); $j++) {

-                    $y = $y->modPow($two, $n);

-                    if ($y->equals($one)) {

-                        return false;

-                    }

-                }

-

-                if (!$y->equals($n_1)) {

-                    return false;

-                }

-            }

-        }

-        return true;

-    }

-

-    /**

-     * Logical Left Shift

-     *

-     * Shifts BigInteger's by $shift bits.

-     *

-     * @param Integer $shift

-     * @access private

-     */

-    function _lshift($shift)

-    {

-        if ( $shift == 0 ) {

-            return;

-        }

-

-        $num_digits = floor($shift / 26);

-        $shift %= 26;

-        $shift = 1 << $shift;

-

-        $carry = 0;

-

-        for ($i = 0; $i < count($this->value); $i++) {

-            $temp = $this->value[$i] * $shift + $carry;

-            $carry = floor($temp / 0x4000000);

-            $this->value[$i] = $temp - $carry * 0x4000000;

-        }

-

-        if ( $carry ) {

-            $this->value[] = $carry;

-        }

-

-        while ($num_digits--) {

-            array_unshift($this->value, 0);

-        }

-    }

-

-    /**

-     * Logical Right Shift

-     *

-     * Shifts BigInteger's by $shift bits.

-     *

-     * @param Integer $shift

-     * @access private

-     */

-    function _rshift($shift)

-    {

-        if ($shift == 0) {

-            return;

-        }

-

-        $num_digits = floor($shift / 26);

-        $shift %= 26;

-        $carry_shift = 26 - $shift;

-        $carry_mask = (1 << $shift) - 1;

-

-        if ( $num_digits ) {

-            $this->value = array_slice($this->value, $num_digits);

-        }

-

-        $carry = 0;

-

-        for ($i = count($this->value) - 1; $i >= 0; $i--) {

-            $temp = $this->value[$i] >> $shift | $carry;

-            $carry = ($this->value[$i] & $carry_mask) << $carry_shift;

-            $this->value[$i] = $temp;

-        }

-    }

-

-    /**

-     * Normalize

-     *

-     * Deletes leading zeros and truncates (if necessary) to maintain the appropriate precision

-     *

-     * @return Math_BigInteger

-     * @access private

-     */

-    function _normalize($result)

-    {

-        $result->precision = $this->precision;

-        $result->bitmask = $this->bitmask;

-

-        switch ( MATH_BIGINTEGER_MODE ) {

-            case MATH_BIGINTEGER_MODE_GMP:

-                if (!empty($result->bitmask->value)) {

-                    $result->value = gmp_and($result->value, $result->bitmask->value);

-                }

-

-                return $result;

-            case MATH_BIGINTEGER_MODE_BCMATH:

-                if (!empty($result->bitmask->value)) {

-                    $result->value = bcmod($result->value, $result->bitmask->value);

-                }

-

-                return $result;

-        }

-

-        if ( !count($result->value) ) {

-            return $result;

-        }

-

-        for ($i = count($result->value) - 1; $i >= 0; $i--) {

-            if ( $result->value[$i] ) {

-                break;

-            }

-            unset($result->value[$i]);

-        }

-

-        if (!empty($result->bitmask->value)) {

-            $length = min(count($result->value), count($this->bitmask->value));

-            $result->value = array_slice($result->value, 0, $length);

-

-            for ($i = 0; $i < $length; $i++) {

-                $result->value[$i] = $result->value[$i] & $this->bitmask->value[$i];

-            }

-        }

-

-        return $result;

-    }

-

-    /**

-     * Array Repeat

-     *

-     * @param $input Array

-     * @param $multiplier mixed

-     * @return Array

-     * @access private

-     */

-    function _array_repeat($input, $multiplier)

-    {

-        return ($multiplier) ? array_fill(0, $multiplier, $input) : array();

-    }

-

-    /**

-     * Logical Left Shift

-     *

-     * Shifts binary strings $shift bits, essentially multiplying by 2**$shift.

-     *

-     * @param $x String

-     * @param $shift Integer

-     * @return String

-     * @access private

-     */

-    function _base256_lshift(&$x, $shift)

-    {

-        if ($shift == 0) {

-            return;

-        }

-

-        $num_bytes = $shift >> 3; // eg. floor($shift/8)

-        $shift &= 7; // eg. $shift % 8

-

-        $carry = 0;

-        for ($i = strlen($x) - 1; $i >= 0; $i--) {

-            $temp = ord($x[$i]) << $shift | $carry;

-            $x[$i] = chr($temp);

-            $carry = $temp >> 8;

-        }

-        $carry = ($carry != 0) ? chr($carry) : '';

-        $x = $carry . $x . str_repeat(chr(0), $num_bytes);

-    }

-

-    /**

-     * Logical Right Shift

-     *

-     * Shifts binary strings $shift bits, essentially dividing by 2**$shift and returning the remainder.

-     *

-     * @param $x String

-     * @param $shift Integer

-     * @return String

-     * @access private

-     */

-    function _base256_rshift(&$x, $shift)

-    {

-        if ($shift == 0) {

-            $x = ltrim($x, chr(0));

-            return '';

-        }

-

-        $num_bytes = $shift >> 3; // eg. floor($shift/8)

-        $shift &= 7; // eg. $shift % 8

-

-        $remainder = '';

-        if ($num_bytes) {

-            $start = $num_bytes > strlen($x) ? -strlen($x) : -$num_bytes;

-            $remainder = substr($x, $start);

-            $x = substr($x, 0, -$num_bytes);

-        }

-

-        $carry = 0;

-        $carry_shift = 8 - $shift;

-        for ($i = 0; $i < strlen($x); $i++) {

-            $temp = (ord($x[$i]) >> $shift) | $carry;

-            $carry = (ord($x[$i]) << $carry_shift) & 0xFF;

-            $x[$i] = chr($temp);

-        }

-        $x = ltrim($x, chr(0));

-

-        $remainder = chr($carry >> $carry_shift) . $remainder;

-

-        return ltrim($remainder, chr(0));

-    }

-

-    // one quirk about how the following functions are implemented is that PHP defines N to be an unsigned long

-    // at 32-bits, while java's longs are 64-bits.

-

-    /**

-     * Converts 32-bit integers to bytes.

-     *

-     * @param Integer $x

-     * @return String

-     * @access private

-     */

-    function _int2bytes($x)

-    {

-        return ltrim(pack('N', $x), chr(0));

-    }

-

-    /**

-     * Converts bytes to 32-bit integers

-     *

-     * @param String $x

-     * @return Integer

-     * @access private

-     */

-    function _bytes2int($x)

-    {

-        $temp = unpack('Nint', str_pad($x, 4, chr(0), STR_PAD_LEFT));

-        return $temp['int'];

-    }

+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP arbitrary precision integer arithmetic library.
+ *
+ * Supports base-2, base-10, base-16, and base-256 numbers.  Uses the GMP or BCMath extensions, if available,
+ * and an internal implementation, otherwise.
+ *
+ * PHP versions 4 and 5
+ *
+ * {@internal (all DocBlock comments regarding implementation - such as the one that follows - refer to the 
+ * {@link MATH_BIGINTEGER_MODE_INTERNAL MATH_BIGINTEGER_MODE_INTERNAL} mode)
+ *
+ * Math_BigInteger uses base-2**26 to perform operations such as multiplication and division and
+ * base-2**52 (ie. two base 2**26 digits) to perform addition and subtraction.  Because the largest possible
+ * value when multiplying two base-2**26 numbers together is a base-2**52 number, double precision floating
+ * point numbers - numbers that should be supported on most hardware and whose significand is 53 bits - are
+ * used.  As a consequence, bitwise operators such as >> and << cannot be used, nor can the modulo operator %,
+ * which only supports integers.  Although this fact will slow this library down, the fact that such a high
+ * base is being used should more than compensate.
+ *
+ * When PHP version 6 is officially released, we'll be able to use 64-bit integers.  This should, once again,
+ * allow bitwise operators, and will increase the maximum possible base to 2**31 (or 2**62 for addition /
+ * subtraction).
+ *
+ * Numbers are stored in {@link http://en.wikipedia.org/wiki/Endianness little endian} format.  ie.
+ * (new Math_BigInteger(pow(2, 26)))->value = array(0, 1)
+ *
+ * Useful resources are as follows:
+ *
+ *  - {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf Handbook of Applied Cryptography (HAC)}
+ *  - {@link http://math.libtomcrypt.com/files/tommath.pdf Multi-Precision Math (MPM)}
+ *  - Java's BigInteger classes.  See /j2se/src/share/classes/java/math in jdk-1_5_0-src-jrl.zip
+ *
+ * Here's an example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Math/BigInteger.php');
+ *
+ *    $a = new Math_BigInteger(2);
+ *    $b = new Math_BigInteger(3);
+ *
+ *    $c = $a->add($b);
+ *
+ *    echo $c->toString(); // outputs 5
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA  02111-1307  USA
+ *
+ * @category   Math
+ * @package    Math_BigInteger
+ * @author     Jim Wigginton <terrafrost@php.net>
+ * @copyright  MMVI Jim Wigginton
+ * @license    http://www.gnu.org/licenses/lgpl.txt
+ * @version    $Id: BigInteger.php,v 1.31 2010/03/01 17:28:19 terrafrost Exp $
+ * @link       http://pear.php.net/package/Math_BigInteger
+ */
+
+/**#@+
+ * Reduction constants
+ *
+ * @access private
+ * @see Math_BigInteger::_reduce()
+ */
+/**
+ * @see Math_BigInteger::_montgomery()
+ * @see Math_BigInteger::_prepMontgomery()
+ */
+define('MATH_BIGINTEGER_MONTGOMERY', 0);
+/**
+ * @see Math_BigInteger::_barrett()
+ */
+define('MATH_BIGINTEGER_BARRETT', 1);
+/**
+ * @see Math_BigInteger::_mod2()
+ */
+define('MATH_BIGINTEGER_POWEROF2', 2);
+/**
+ * @see Math_BigInteger::_remainder()
+ */
+define('MATH_BIGINTEGER_CLASSIC', 3);
+/**
+ * @see Math_BigInteger::__clone()
+ */
+define('MATH_BIGINTEGER_NONE', 4);
+/**#@-*/
+
+/**#@+
+ * Array constants
+ *
+ * Rather than create a thousands and thousands of new Math_BigInteger objects in repeated function calls to add() and
+ * multiply() or whatever, we'll just work directly on arrays, taking them in as parameters and returning them.
+ *
+ * @access private
+ */
+/**
+ * $result[MATH_BIGINTEGER_VALUE] contains the value.
+ */
+define('MATH_BIGINTEGER_VALUE', 0);
+/**
+ * $result[MATH_BIGINTEGER_SIGN] contains the sign.
+ */
+define('MATH_BIGINTEGER_SIGN', 1);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Math_BigInteger::_montgomery()
+ * @see Math_BigInteger::_barrett()
+ */
+/**
+ * Cache constants
+ *
+ * $cache[MATH_BIGINTEGER_VARIABLE] tells us whether or not the cached data is still valid.
+ */
+define('MATH_BIGINTEGER_VARIABLE', 0);
+/**
+ * $cache[MATH_BIGINTEGER_DATA] contains the cached data.
+ */
+define('MATH_BIGINTEGER_DATA', 1);
+/**#@-*/
+
+/**#@+
+ * Mode constants.
+ *
+ * @access private
+ * @see Math_BigInteger::Math_BigInteger()
+ */
+/**
+ * To use the pure-PHP implementation
+ */
+define('MATH_BIGINTEGER_MODE_INTERNAL', 1);
+/**
+ * To use the BCMath library
+ *
+ * (if enabled; otherwise, the internal implementation will be used)
+ */
+define('MATH_BIGINTEGER_MODE_BCMATH', 2);
+/**
+ * To use the GMP library
+ *
+ * (if present; otherwise, either the BCMath or the internal implementation will be used)
+ */
+define('MATH_BIGINTEGER_MODE_GMP', 3);
+/**#@-*/
+
+/**
+ * The largest digit that may be used in addition / subtraction
+ *
+ * (we do pow(2, 52) instead of using 4503599627370496, directly, because some PHP installations
+ *  will truncate 4503599627370496)
+ *
+ * @access private
+ */
+define('MATH_BIGINTEGER_MAX_DIGIT52', pow(2, 52));
+
+/**
+ * Karatsuba Cutoff
+ *
+ * At what point do we switch between Karatsuba multiplication and schoolbook long multiplication?
+ *
+ * @access private
+ */
+define('MATH_BIGINTEGER_KARATSUBA_CUTOFF', 25);
+
+/**
+ * Pure-PHP arbitrary precision integer arithmetic library. Supports base-2, base-10, base-16, and base-256
+ * numbers.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 1.0.0RC4
+ * @access  public
+ * @package Math_BigInteger
+ */
+class Math_BigInteger {
+    /**
+     * Holds the BigInteger's value.
+     *
+     * @var Array
+     * @access private
+     */
+    var $value;
+
+    /**
+     * Holds the BigInteger's magnitude.
+     *
+     * @var Boolean
+     * @access private
+     */
+    var $is_negative = false;
+
+    /**
+     * Random number generator function
+     *
+     * @see setRandomGenerator()
+     * @access private
+     */
+    var $generator = 'mt_rand';
+
+    /**
+     * Precision
+     *
+     * @see setPrecision()
+     * @access private
+     */
+    var $precision = -1;
+
+    /**
+     * Precision Bitmask
+     *
+     * @see setPrecision()
+     * @access private
+     */
+    var $bitmask = false;
+
+    /**
+     * Mode independant value used for serialization.
+     *
+     * If the bcmath or gmp extensions are installed $this->value will be a non-serializable resource, hence the need for 
+     * a variable that'll be serializable regardless of whether or not extensions are being used.  Unlike $this->value,
+     * however, $this->hex is only calculated when $this->__sleep() is called.
+     *
+     * @see __sleep()
+     * @see __wakeup()
+     * @var String
+     * @access private
+     */
+    var $hex;
+
+    /**
+     * Converts base-2, base-10, base-16, and binary strings (eg. base-256) to BigIntegers.
+     *
+     * If the second parameter - $base - is negative, then it will be assumed that the number's are encoded using
+     * two's compliment.  The sole exception to this is -10, which is treated the same as 10 is.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('0x32', 16); // 50 in base-16
+     *
+     *    echo $a->toString(); // outputs 50
+     * ?>
+     * </code>
+     *
+     * @param optional $x base-10 number or base-$base number if $base set.
+     * @param optional integer $base
+     * @return Math_BigInteger
+     * @access public
+     */
+    function Math_BigInteger($x = 0, $base = 10)
+    {
+        if ( !defined('MATH_BIGINTEGER_MODE') ) {
+            switch (true) {
+                case extension_loaded('gmp'):
+                    define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_GMP);
+                    break;
+                case extension_loaded('bcmath'):
+                    define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_BCMATH);
+                    break;
+                default:
+                    define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_INTERNAL);
+            }
+        }
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                if (is_resource($x) && get_resource_type($x) == 'GMP integer') {
+                    $this->value = $x;
+                    return;
+                }
+                $this->value = gmp_init(0);
+                break;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $this->value = '0';
+                break;
+            default:
+                $this->value = array();
+        }
+
+        if ($x === 0) {
+            return;
+        }
+
+        switch ($base) {
+            case -256:
+                if (ord($x[0]) & 0x80) {
+                    $x = ~$x;
+                    $this->is_negative = true;
+                }
+            case  256:
+                switch ( MATH_BIGINTEGER_MODE ) {
+                    case MATH_BIGINTEGER_MODE_GMP:
+                        $sign = $this->is_negative ? '-' : '';
+                        $this->value = gmp_init($sign . '0x' . bin2hex($x));
+                        break;
+                    case MATH_BIGINTEGER_MODE_BCMATH:
+                        // round $len to the nearest 4 (thanks, DavidMJ!)
+                        $len = (strlen($x) + 3) & 0xFFFFFFFC;
+
+                        $x = str_pad($x, $len, chr(0), STR_PAD_LEFT);
+
+                        for ($i = 0; $i < $len; $i+= 4) {
+                            $this->value = bcmul($this->value, '4294967296', 0); // 4294967296 == 2**32
+                            $this->value = bcadd($this->value, 0x1000000 * ord($x[$i]) + ((ord($x[$i + 1]) << 16) | (ord($x[$i + 2]) << 8) | ord($x[$i + 3])), 0);
+                        }
+
+                        if ($this->is_negative) {
+                            $this->value = '-' . $this->value;
+                        }
+
+                        break;
+                    // converts a base-2**8 (big endian / msb) number to base-2**26 (little endian / lsb)
+                    default:
+                        while (strlen($x)) {
+                            $this->value[] = $this->_bytes2int($this->_base256_rshift($x, 26));
+                        }
+                }
+
+                if ($this->is_negative) {
+                    if (MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_INTERNAL) {
+                        $this->is_negative = false;
+                    }
+                    $temp = $this->add(new Math_BigInteger('-1'));
+                    $this->value = $temp->value;
+                }
+                break;
+            case  16:
+            case -16:
+                if ($base > 0 && $x[0] == '-') {
+                    $this->is_negative = true;
+                    $x = substr($x, 1);
+                }
+
+                $x = preg_replace('#^(?:0x)?([A-Fa-f0-9]*).*#', '$1', $x);
+
+                $is_negative = false;
+                if ($base < 0 && hexdec($x[0]) >= 8) {
+                    $this->is_negative = $is_negative = true;
+                    $x = bin2hex(~pack('H*', $x));
+                }
+
+                switch ( MATH_BIGINTEGER_MODE ) {
+                    case MATH_BIGINTEGER_MODE_GMP:
+                        $temp = $this->is_negative ? '-0x' . $x : '0x' . $x;
+                        $this->value = gmp_init($temp);
+                        $this->is_negative = false;
+                        break;
+                    case MATH_BIGINTEGER_MODE_BCMATH:
+                        $x = ( strlen($x) & 1 ) ? '0' . $x : $x;
+                        $temp = new Math_BigInteger(pack('H*', $x), 256);
+                        $this->value = $this->is_negative ? '-' . $temp->value : $temp->value;
+                        $this->is_negative = false;
+                        break;
+                    default:
+                        $x = ( strlen($x) & 1 ) ? '0' . $x : $x;
+                        $temp = new Math_BigInteger(pack('H*', $x), 256);
+                        $this->value = $temp->value;
+                }
+
+                if ($is_negative) {
+                    $temp = $this->add(new Math_BigInteger('-1'));
+                    $this->value = $temp->value;
+                }
+                break;
+            case  10:
+            case -10:
+                $x = preg_replace('#^(-?[0-9]*).*#', '$1', $x);
+
+                switch ( MATH_BIGINTEGER_MODE ) {
+                    case MATH_BIGINTEGER_MODE_GMP:
+                        $this->value = gmp_init($x);
+                        break;
+                    case MATH_BIGINTEGER_MODE_BCMATH:
+                        // explicitly casting $x to a string is necessary, here, since doing $x[0] on -1 yields different
+                        // results then doing it on '-1' does (modInverse does $x[0])
+                        $this->value = (string) $x;
+                        break;
+                    default:
+                        $temp = new Math_BigInteger();
+
+                        // array(10000000) is 10**7 in base-2**26.  10**7 is the closest to 2**26 we can get without passing it.
+                        $multiplier = new Math_BigInteger();
+                        $multiplier->value = array(10000000);
+
+                        if ($x[0] == '-') {
+                            $this->is_negative = true;
+                            $x = substr($x, 1);
+                        }
+
+                        $x = str_pad($x, strlen($x) + (6 * strlen($x)) % 7, 0, STR_PAD_LEFT);
+
+                        while (strlen($x)) {
+                            $temp = $temp->multiply($multiplier);
+                            $temp = $temp->add(new Math_BigInteger($this->_int2bytes(substr($x, 0, 7)), 256));
+                            $x = substr($x, 7);
+                        }
+
+                        $this->value = $temp->value;
+                }
+                break;
+            case  2: // base-2 support originally implemented by Lluis Pamies - thanks!
+            case -2:
+                if ($base > 0 && $x[0] == '-') {
+                    $this->is_negative = true;
+                    $x = substr($x, 1);
+                }
+
+                $x = preg_replace('#^([01]*).*#', '$1', $x);
+                $x = str_pad($x, strlen($x) + (3 * strlen($x)) % 4, 0, STR_PAD_LEFT);
+
+                $str = '0x';
+                while (strlen($x)) {
+                    $part = substr($x, 0, 4);
+                    $str.= dechex(bindec($part));
+                    $x = substr($x, 4);
+                }
+
+                if ($this->is_negative) {
+                    $str = '-' . $str;
+                }
+
+                $temp = new Math_BigInteger($str, 8 * $base); // ie. either -16 or +16
+                $this->value = $temp->value;
+                $this->is_negative = $temp->is_negative;
+
+                break;
+            default:
+                // base not supported, so we'll let $this == 0
+        }
+    }
+
+    /**
+     * Converts a BigInteger to a byte string (eg. base-256).
+     *
+     * Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're
+     * saved as two's compliment.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('65');
+     *
+     *    echo $a->toBytes(); // outputs chr(65)
+     * ?>
+     * </code>
+     *
+     * @param Boolean $twos_compliment
+     * @return String
+     * @access public
+     * @internal Converts a base-2**26 number to base-2**8
+     */
+    function toBytes($twos_compliment = false)
+    {
+        if ($twos_compliment) {
+            $comparison = $this->compare(new Math_BigInteger());
+            if ($comparison == 0) {
+                return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';
+            }
+
+            $temp = $comparison < 0 ? $this->add(new Math_BigInteger(1)) : $this->copy();
+            $bytes = $temp->toBytes();
+
+            if (empty($bytes)) { // eg. if the number we're trying to convert is -1
+                $bytes = chr(0);
+            }
+
+            if (ord($bytes[0]) & 0x80) {
+                $bytes = chr(0) . $bytes;
+            }
+
+            return $comparison < 0 ? ~$bytes : $bytes;
+        }
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                if (gmp_cmp($this->value, gmp_init(0)) == 0) {
+                    return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';
+                }
+
+                $temp = gmp_strval(gmp_abs($this->value), 16);
+                $temp = ( strlen($temp) & 1 ) ? '0' . $temp : $temp;
+                $temp = pack('H*', $temp);
+
+                return $this->precision > 0 ?
+                    substr(str_pad($temp, $this->precision >> 3, chr(0), STR_PAD_LEFT), -($this->precision >> 3)) :
+                    ltrim($temp, chr(0));
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                if ($this->value === '0') {
+                    return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';
+                }
+
+                $value = '';
+                $current = $this->value;
+
+                if ($current[0] == '-') {
+                    $current = substr($current, 1);
+                }
+
+                while (bccomp($current, '0', 0) > 0) {
+                    $temp = bcmod($current, '16777216');
+                    $value = chr($temp >> 16) . chr($temp >> 8) . chr($temp) . $value;
+                    $current = bcdiv($current, '16777216', 0);
+                }
+
+                return $this->precision > 0 ?
+                    substr(str_pad($value, $this->precision >> 3, chr(0), STR_PAD_LEFT), -($this->precision >> 3)) :
+                    ltrim($value, chr(0));
+        }
+
+        if (!count($this->value)) {
+            return $this->precision > 0 ? str_repeat(chr(0), ($this->precision + 1) >> 3) : '';
+        }
+        $result = $this->_int2bytes($this->value[count($this->value) - 1]);
+
+        $temp = $this->copy();
+
+        for ($i = count($temp->value) - 2; $i >= 0; --$i) {
+            $temp->_base256_lshift($result, 26);
+            $result = $result | str_pad($temp->_int2bytes($temp->value[$i]), strlen($result), chr(0), STR_PAD_LEFT);
+        }
+
+        return $this->precision > 0 ?
+            str_pad(substr($result, -(($this->precision + 7) >> 3)), ($this->precision + 7) >> 3, chr(0), STR_PAD_LEFT) :
+            $result;
+    }
+
+    /**
+     * Converts a BigInteger to a hex string (eg. base-16)).
+     *
+     * Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're
+     * saved as two's compliment.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('65');
+     *
+     *    echo $a->toHex(); // outputs '41'
+     * ?>
+     * </code>
+     *
+     * @param Boolean $twos_compliment
+     * @return String
+     * @access public
+     * @internal Converts a base-2**26 number to base-2**8
+     */
+    function toHex($twos_compliment = false)
+    {
+        return bin2hex($this->toBytes($twos_compliment));
+    }
+
+    /**
+     * Converts a BigInteger to a bit string (eg. base-2).
+     *
+     * Negative numbers are saved as positive numbers, unless $twos_compliment is set to true, at which point, they're
+     * saved as two's compliment.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('65');
+     *
+     *    echo $a->toBits(); // outputs '1000001'
+     * ?>
+     * </code>
+     *
+     * @param Boolean $twos_compliment
+     * @return String
+     * @access public
+     * @internal Converts a base-2**26 number to base-2**2
+     */
+    function toBits($twos_compliment = false)
+    {
+        $hex = $this->toHex($twos_compliment);
+        $bits = '';
+        for ($i = 0; $i < strlen($hex); $i+=8) {
+            $bits.= str_pad(decbin(hexdec(substr($hex, $i, 8))), 32, '0', STR_PAD_LEFT);
+        }
+        return $this->precision > 0 ? substr($bits, -$this->precision) : ltrim($bits, '0');
+    }
+
+    /**
+     * Converts a BigInteger to a base-10 number.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('50');
+     *
+     *    echo $a->toString(); // outputs 50
+     * ?>
+     * </code>
+     *
+     * @return String
+     * @access public
+     * @internal Converts a base-2**26 number to base-10**7 (which is pretty much base-10)
+     */
+    function toString()
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                return gmp_strval($this->value);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                if ($this->value === '0') {
+                    return '0';
+                }
+
+                return ltrim($this->value, '0');
+        }
+
+        if (!count($this->value)) {
+            return '0';
+        }
+
+        $temp = $this->copy();
+        $temp->is_negative = false;
+
+        $divisor = new Math_BigInteger();
+        $divisor->value = array(10000000); // eg. 10**7
+        $result = '';
+        while (count($temp->value)) {
+            list($temp, $mod) = $temp->divide($divisor);
+            $result = str_pad(isset($mod->value[0]) ? $mod->value[0] : '', 7, '0', STR_PAD_LEFT) . $result;
+        }
+        $result = ltrim($result, '0');
+        if (empty($result)) {
+            $result = '0';
+        }
+
+        if ($this->is_negative) {
+            $result = '-' . $result;
+        }
+
+        return $result;
+    }
+
+    /**
+     * Copy an object
+     *
+     * PHP5 passes objects by reference while PHP4 passes by value.  As such, we need a function to guarantee
+     * that all objects are passed by value, when appropriate.  More information can be found here:
+     *
+     * {@link http://php.net/language.oop5.basic#51624}
+     *
+     * @access public
+     * @see __clone()
+     * @return Math_BigInteger
+     */
+    function copy()
+    {
+        $temp = new Math_BigInteger();
+        $temp->value = $this->value;
+        $temp->is_negative = $this->is_negative;
+        $temp->generator = $this->generator;
+        $temp->precision = $this->precision;
+        $temp->bitmask = $this->bitmask;
+        return $temp;
+    }
+
+    /**
+     *  __toString() magic method
+     *
+     * Will be called, automatically, if you're supporting just PHP5.  If you're supporting PHP4, you'll need to call
+     * toString().
+     *
+     * @access public
+     * @internal Implemented per a suggestion by Techie-Michael - thanks!
+     */
+    function __toString()
+    {
+        return $this->toString();
+    }
+
+    /**
+     * __clone() magic method
+     *
+     * Although you can call Math_BigInteger::__toString() directly in PHP5, you cannot call Math_BigInteger::__clone()
+     * directly in PHP5.  You can in PHP4 since it's not a magic method, but in PHP5, you have to call it by using the PHP5
+     * only syntax of $y = clone $x.  As such, if you're trying to write an application that works on both PHP4 and PHP5,
+     * call Math_BigInteger::copy(), instead.
+     *
+     * @access public
+     * @see copy()
+     * @return Math_BigInteger
+     */
+    function __clone()
+    {
+        return $this->copy();
+    }
+
+    /**
+     *  __sleep() magic method
+     *
+     * Will be called, automatically, when serialize() is called on a Math_BigInteger object.
+     *
+     * @see __wakeup
+     * @access public
+     */
+    function __sleep()
+    {
+        $this->hex = $this->toHex(true);
+        $vars = array('hex');
+        if ($this->generator != 'mt_rand') {
+            $vars[] = 'generator';
+        }
+        if ($this->precision > 0) {
+            $vars[] = 'precision';
+        }
+        return $vars;
+        
+    }
+
+    /**
+     *  __wakeup() magic method
+     *
+     * Will be called, automatically, when unserialize() is called on a Math_BigInteger object.
+     *
+     * @see __sleep
+     * @access public
+     */
+    function __wakeup()
+    {
+        $temp = new Math_BigInteger($this->hex, -16);
+        $this->value = $temp->value;
+        $this->is_negative = $temp->is_negative;
+        $this->setRandomGenerator($this->generator);
+        if ($this->precision > 0) {
+            // recalculate $this->bitmask
+            $this->setPrecision($this->precision);
+        }
+    }
+
+    /**
+     * Adds two BigIntegers.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('10');
+     *    $b = new Math_BigInteger('20');
+     *
+     *    $c = $a->add($b);
+     *
+     *    echo $c->toString(); // outputs 30
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $y
+     * @return Math_BigInteger
+     * @access public
+     * @internal Performs base-2**52 addition
+     */
+    function add($y)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_add($this->value, $y->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp = new Math_BigInteger();
+                $temp->value = bcadd($this->value, $y->value, 0);
+
+                return $this->_normalize($temp);
+        }
+
+        $temp = $this->_add($this->value, $this->is_negative, $y->value, $y->is_negative);
+
+        $result = new Math_BigInteger();
+        $result->value = $temp[MATH_BIGINTEGER_VALUE];
+        $result->is_negative = $temp[MATH_BIGINTEGER_SIGN];
+
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Performs addition.
+     *
+     * @param Array $x_value
+     * @param Boolean $x_negative
+     * @param Array $y_value
+     * @param Boolean $y_negative
+     * @return Array
+     * @access private
+     */
+    function _add($x_value, $x_negative, $y_value, $y_negative)
+    {
+        $x_size = count($x_value);
+        $y_size = count($y_value);
+
+        if ($x_size == 0) {
+            return array(
+                MATH_BIGINTEGER_VALUE => $y_value,
+                MATH_BIGINTEGER_SIGN => $y_negative
+            );
+        } else if ($y_size == 0) {
+            return array(
+                MATH_BIGINTEGER_VALUE => $x_value,
+                MATH_BIGINTEGER_SIGN => $x_negative
+            );
+        }
+
+        // subtract, if appropriate
+        if ( $x_negative != $y_negative ) {
+            if ( $x_value == $y_value ) {
+                return array(
+                    MATH_BIGINTEGER_VALUE => array(),
+                    MATH_BIGINTEGER_SIGN => false
+                );
+            }
+
+            $temp = $this->_subtract($x_value, false, $y_value, false);
+            $temp[MATH_BIGINTEGER_SIGN] = $this->_compare($x_value, false, $y_value, false) > 0 ?
+                                          $x_negative : $y_negative;
+
+            return $temp;
+        }
+
+        if ($x_size < $y_size) {
+            $size = $x_size;
+            $value = $y_value;
+        } else {
+            $size = $y_size;
+            $value = $x_value;
+        }
+
+        $value[] = 0; // just in case the carry adds an extra digit
+
+        $carry = 0;
+        for ($i = 0, $j = 1; $j < $size; $i+=2, $j+=2) {
+            $sum = $x_value[$j] * 0x4000000 + $x_value[$i] + $y_value[$j] * 0x4000000 + $y_value[$i] + $carry;
+            $carry = $sum >= MATH_BIGINTEGER_MAX_DIGIT52; // eg. floor($sum / 2**52); only possible values (in any base) are 0 and 1
+            $sum = $carry ? $sum - MATH_BIGINTEGER_MAX_DIGIT52 : $sum;
+
+            $temp = (int) ($sum / 0x4000000);
+
+            $value[$i] = (int) ($sum - 0x4000000 * $temp); // eg. a faster alternative to fmod($sum, 0x4000000)
+            $value[$j] = $temp;
+        }
+
+        if ($j == $size) { // ie. if $y_size is odd
+            $sum = $x_value[$i] + $y_value[$i] + $carry;
+            $carry = $sum >= 0x4000000;
+            $value[$i] = $carry ? $sum - 0x4000000 : $sum;
+            ++$i; // ie. let $i = $j since we've just done $value[$i]
+        }
+
+        if ($carry) {
+            for (; $value[$i] == 0x3FFFFFF; ++$i) {
+                $value[$i] = 0;
+            }
+            ++$value[$i];
+        }
+
+        return array(
+            MATH_BIGINTEGER_VALUE => $this->_trim($value),
+            MATH_BIGINTEGER_SIGN => $x_negative
+        );
+    }
+
+    /**
+     * Subtracts two BigIntegers.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('10');
+     *    $b = new Math_BigInteger('20');
+     *
+     *    $c = $a->subtract($b);
+     *
+     *    echo $c->toString(); // outputs -10
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $y
+     * @return Math_BigInteger
+     * @access public
+     * @internal Performs base-2**52 subtraction
+     */
+    function subtract($y)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_sub($this->value, $y->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp = new Math_BigInteger();
+                $temp->value = bcsub($this->value, $y->value, 0);
+
+                return $this->_normalize($temp);
+        }
+
+        $temp = $this->_subtract($this->value, $this->is_negative, $y->value, $y->is_negative);
+
+        $result = new Math_BigInteger();
+        $result->value = $temp[MATH_BIGINTEGER_VALUE];
+        $result->is_negative = $temp[MATH_BIGINTEGER_SIGN];
+
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Performs subtraction.
+     *
+     * @param Array $x_value
+     * @param Boolean $x_negative
+     * @param Array $y_value
+     * @param Boolean $y_negative
+     * @return Array
+     * @access private
+     */
+    function _subtract($x_value, $x_negative, $y_value, $y_negative)
+    {
+        $x_size = count($x_value);
+        $y_size = count($y_value);
+
+        if ($x_size == 0) {
+            return array(
+                MATH_BIGINTEGER_VALUE => $y_value,
+                MATH_BIGINTEGER_SIGN => !$y_negative
+            );
+        } else if ($y_size == 0) {
+            return array(
+                MATH_BIGINTEGER_VALUE => $x_value,
+                MATH_BIGINTEGER_SIGN => $x_negative
+            );
+        }
+
+        // add, if appropriate (ie. -$x - +$y or +$x - -$y)
+        if ( $x_negative != $y_negative ) {
+            $temp = $this->_add($x_value, false, $y_value, false);
+            $temp[MATH_BIGINTEGER_SIGN] = $x_negative;
+
+            return $temp;
+        }
+
+        $diff = $this->_compare($x_value, $x_negative, $y_value, $y_negative);
+
+        if ( !$diff ) {
+            return array(
+                MATH_BIGINTEGER_VALUE => array(),
+                MATH_BIGINTEGER_SIGN => false
+            );
+        }
+
+        // switch $x and $y around, if appropriate.
+        if ( (!$x_negative && $diff < 0) || ($x_negative && $diff > 0) ) {
+            $temp = $x_value;
+            $x_value = $y_value;
+            $y_value = $temp;
+
+            $x_negative = !$x_negative;
+
+            $x_size = count($x_value);
+            $y_size = count($y_value);
+        }
+
+        // at this point, $x_value should be at least as big as - if not bigger than - $y_value
+
+        $carry = 0;
+        for ($i = 0, $j = 1; $j < $y_size; $i+=2, $j+=2) {
+            $sum = $x_value[$j] * 0x4000000 + $x_value[$i] - $y_value[$j] * 0x4000000 - $y_value[$i] - $carry;
+            $carry = $sum < 0; // eg. floor($sum / 2**52); only possible values (in any base) are 0 and 1
+            $sum = $carry ? $sum + MATH_BIGINTEGER_MAX_DIGIT52 : $sum;
+
+            $temp = (int) ($sum / 0x4000000);
+
+            $x_value[$i] = (int) ($sum - 0x4000000 * $temp);
+            $x_value[$j] = $temp;
+        }
+
+        if ($j == $y_size) { // ie. if $y_size is odd
+            $sum = $x_value[$i] - $y_value[$i] - $carry;
+            $carry = $sum < 0;
+            $x_value[$i] = $carry ? $sum + 0x4000000 : $sum;
+            ++$i;
+        }
+
+        if ($carry) {
+            for (; !$x_value[$i]; ++$i) {
+                $x_value[$i] = 0x3FFFFFF;
+            }
+            --$x_value[$i];
+        }
+
+        return array(
+            MATH_BIGINTEGER_VALUE => $this->_trim($x_value),
+            MATH_BIGINTEGER_SIGN => $x_negative
+        );
+    }
+
+    /**
+     * Multiplies two BigIntegers
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('10');
+     *    $b = new Math_BigInteger('20');
+     *
+     *    $c = $a->multiply($b);
+     *
+     *    echo $c->toString(); // outputs 200
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $x
+     * @return Math_BigInteger
+     * @access public
+     */
+    function multiply($x)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_mul($this->value, $x->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp = new Math_BigInteger();
+                $temp->value = bcmul($this->value, $x->value, 0);
+
+                return $this->_normalize($temp);
+        }
+
+        $temp = $this->_multiply($this->value, $this->is_negative, $x->value, $x->is_negative);
+
+        $product = new Math_BigInteger();
+        $product->value = $temp[MATH_BIGINTEGER_VALUE];
+        $product->is_negative = $temp[MATH_BIGINTEGER_SIGN];
+
+        return $this->_normalize($product);
+    }
+
+    /**
+     * Performs multiplication.
+     *
+     * @param Array $x_value
+     * @param Boolean $x_negative
+     * @param Array $y_value
+     * @param Boolean $y_negative
+     * @return Array
+     * @access private
+     */
+    function _multiply($x_value, $x_negative, $y_value, $y_negative)
+    {
+        //if ( $x_value == $y_value ) {
+        //    return array(
+        //        MATH_BIGINTEGER_VALUE => $this->_square($x_value),
+        //        MATH_BIGINTEGER_SIGN => $x_sign != $y_value
+        //    );
+        //}
+
+        $x_length = count($x_value);
+        $y_length = count($y_value);
+
+        if ( !$x_length || !$y_length ) { // a 0 is being multiplied
+            return array(
+                MATH_BIGINTEGER_VALUE => array(),
+                MATH_BIGINTEGER_SIGN => false
+            );
+        }
+
+        return array(
+            MATH_BIGINTEGER_VALUE => min($x_length, $y_length) < 2 * MATH_BIGINTEGER_KARATSUBA_CUTOFF ?
+                $this->_trim($this->_regularMultiply($x_value, $y_value)) :
+                $this->_trim($this->_karatsuba($x_value, $y_value)),
+            MATH_BIGINTEGER_SIGN => $x_negative != $y_negative
+        );
+    }
+
+    /**
+     * Performs long multiplication on two BigIntegers
+     *
+     * Modeled after 'multiply' in MutableBigInteger.java.
+     *
+     * @param Array $x_value
+     * @param Array $y_value
+     * @return Array
+     * @access private
+     */
+    function _regularMultiply($x_value, $y_value)
+    {
+        $x_length = count($x_value);
+        $y_length = count($y_value);
+
+        if ( !$x_length || !$y_length ) { // a 0 is being multiplied
+            return array();
+        }
+
+        if ( $x_length < $y_length ) {
+            $temp = $x_value;
+            $x_value = $y_value;
+            $y_value = $temp;
+
+            $x_length = count($x_value);
+            $y_length = count($y_value);
+        }
+
+        $product_value = $this->_array_repeat(0, $x_length + $y_length);
+
+        // the following for loop could be removed if the for loop following it
+        // (the one with nested for loops) initially set $i to 0, but
+        // doing so would also make the result in one set of unnecessary adds,
+        // since on the outermost loops first pass, $product->value[$k] is going
+        // to always be 0
+
+        $carry = 0;
+
+        for ($j = 0; $j < $x_length; ++$j) { // ie. $i = 0
+            $temp = $x_value[$j] * $y_value[0] + $carry; // $product_value[$k] == 0
+            $carry = (int) ($temp / 0x4000000);
+            $product_value[$j] = (int) ($temp - 0x4000000 * $carry);
+        }
+
+        $product_value[$j] = $carry;
+
+        // the above for loop is what the previous comment was talking about.  the
+        // following for loop is the "one with nested for loops"
+        for ($i = 1; $i < $y_length; ++$i) {
+            $carry = 0;
+
+            for ($j = 0, $k = $i; $j < $x_length; ++$j, ++$k) {
+                $temp = $product_value[$k] + $x_value[$j] * $y_value[$i] + $carry;
+                $carry = (int) ($temp / 0x4000000);
+                $product_value[$k] = (int) ($temp - 0x4000000 * $carry);
+            }
+
+            $product_value[$k] = $carry;
+        }
+
+        return $product_value;
+    }
+
+    /**
+     * Performs Karatsuba multiplication on two BigIntegers
+     *
+     * See {@link http://en.wikipedia.org/wiki/Karatsuba_algorithm Karatsuba algorithm} and
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=120 MPM 5.2.3}.
+     *
+     * @param Array $x_value
+     * @param Array $y_value
+     * @return Array
+     * @access private
+     */
+    function _karatsuba($x_value, $y_value)
+    {
+        $m = min(count($x_value) >> 1, count($y_value) >> 1);
+
+        if ($m < MATH_BIGINTEGER_KARATSUBA_CUTOFF) {
+            return $this->_regularMultiply($x_value, $y_value);
+        }
+
+        $x1 = array_slice($x_value, $m);
+        $x0 = array_slice($x_value, 0, $m);
+        $y1 = array_slice($y_value, $m);
+        $y0 = array_slice($y_value, 0, $m);
+
+        $z2 = $this->_karatsuba($x1, $y1);
+        $z0 = $this->_karatsuba($x0, $y0);
+
+        $z1 = $this->_add($x1, false, $x0, false);
+        $temp = $this->_add($y1, false, $y0, false);
+        $z1 = $this->_karatsuba($z1[MATH_BIGINTEGER_VALUE], $temp[MATH_BIGINTEGER_VALUE]);
+        $temp = $this->_add($z2, false, $z0, false);
+        $z1 = $this->_subtract($z1, false, $temp[MATH_BIGINTEGER_VALUE], false);
+
+        $z2 = array_merge(array_fill(0, 2 * $m, 0), $z2);
+        $z1[MATH_BIGINTEGER_VALUE] = array_merge(array_fill(0, $m, 0), $z1[MATH_BIGINTEGER_VALUE]);
+
+        $xy = $this->_add($z2, false, $z1[MATH_BIGINTEGER_VALUE], $z1[MATH_BIGINTEGER_SIGN]);
+        $xy = $this->_add($xy[MATH_BIGINTEGER_VALUE], $xy[MATH_BIGINTEGER_SIGN], $z0, false);
+
+        return $xy[MATH_BIGINTEGER_VALUE];
+    }
+
+    /**
+     * Performs squaring
+     *
+     * @param Array $x
+     * @return Array
+     * @access private
+     */
+    function _square($x = false)
+    {
+        return count($x) < 2 * MATH_BIGINTEGER_KARATSUBA_CUTOFF ?
+            $this->_trim($this->_baseSquare($x)) :
+            $this->_trim($this->_karatsubaSquare($x));
+    }
+
+    /**
+     * Performs traditional squaring on two BigIntegers
+     *
+     * Squaring can be done faster than multiplying a number by itself can be.  See
+     * {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=7 HAC 14.2.4} /
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=141 MPM 5.3} for more information.
+     *
+     * @param Array $value
+     * @return Array
+     * @access private
+     */
+    function _baseSquare($value)
+    {
+        if ( empty($value) ) {
+            return array();
+        }
+        $square_value = $this->_array_repeat(0, 2 * count($value));
+
+        for ($i = 0, $max_index = count($value) - 1; $i <= $max_index; ++$i) {
+            $i2 = $i << 1;
+
+            $temp = $square_value[$i2] + $value[$i] * $value[$i];
+            $carry = (int) ($temp / 0x4000000);
+            $square_value[$i2] = (int) ($temp - 0x4000000 * $carry);
+
+            // note how we start from $i+1 instead of 0 as we do in multiplication.
+            for ($j = $i + 1, $k = $i2 + 1; $j <= $max_index; ++$j, ++$k) {
+                $temp = $square_value[$k] + 2 * $value[$j] * $value[$i] + $carry;
+                $carry = (int) ($temp / 0x4000000);
+                $square_value[$k] = (int) ($temp - 0x4000000 * $carry);
+            }
+
+            // the following line can yield values larger 2**15.  at this point, PHP should switch
+            // over to floats.
+            $square_value[$i + $max_index + 1] = $carry;
+        }
+
+        return $square_value;
+    }
+
+    /**
+     * Performs Karatsuba "squaring" on two BigIntegers
+     *
+     * See {@link http://en.wikipedia.org/wiki/Karatsuba_algorithm Karatsuba algorithm} and
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=151 MPM 5.3.4}.
+     *
+     * @param Array $value
+     * @return Array
+     * @access private
+     */
+    function _karatsubaSquare($value)
+    {
+        $m = count($value) >> 1;
+
+        if ($m < MATH_BIGINTEGER_KARATSUBA_CUTOFF) {
+            return $this->_baseSquare($value);
+        }
+
+        $x1 = array_slice($value, $m);
+        $x0 = array_slice($value, 0, $m);
+
+        $z2 = $this->_karatsubaSquare($x1);
+        $z0 = $this->_karatsubaSquare($x0);
+
+        $z1 = $this->_add($x1, false, $x0, false);
+        $z1 = $this->_karatsubaSquare($z1[MATH_BIGINTEGER_VALUE]);
+        $temp = $this->_add($z2, false, $z0, false);
+        $z1 = $this->_subtract($z1, false, $temp[MATH_BIGINTEGER_VALUE], false);
+
+        $z2 = array_merge(array_fill(0, 2 * $m, 0), $z2);
+        $z1[MATH_BIGINTEGER_VALUE] = array_merge(array_fill(0, $m, 0), $z1[MATH_BIGINTEGER_VALUE]);
+
+        $xx = $this->_add($z2, false, $z1[MATH_BIGINTEGER_VALUE], $z1[MATH_BIGINTEGER_SIGN]);
+        $xx = $this->_add($xx[MATH_BIGINTEGER_VALUE], $xx[MATH_BIGINTEGER_SIGN], $z0, false);
+
+        return $xx[MATH_BIGINTEGER_VALUE];
+    }
+
+    /**
+     * Divides two BigIntegers.
+     *
+     * Returns an array whose first element contains the quotient and whose second element contains the
+     * "common residue".  If the remainder would be positive, the "common residue" and the remainder are the
+     * same.  If the remainder would be negative, the "common residue" is equal to the sum of the remainder
+     * and the divisor (basically, the "common residue" is the first positive modulo).
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('10');
+     *    $b = new Math_BigInteger('20');
+     *
+     *    list($quotient, $remainder) = $a->divide($b);
+     *
+     *    echo $quotient->toString(); // outputs 0
+     *    echo "\r\n";
+     *    echo $remainder->toString(); // outputs 10
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $y
+     * @return Array
+     * @access public
+     * @internal This function is based off of {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=9 HAC 14.20}.
+     */
+    function divide($y)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $quotient = new Math_BigInteger();
+                $remainder = new Math_BigInteger();
+
+                list($quotient->value, $remainder->value) = gmp_div_qr($this->value, $y->value);
+
+                if (gmp_sign($remainder->value) < 0) {
+                    $remainder->value = gmp_add($remainder->value, gmp_abs($y->value));
+                }
+
+                return array($this->_normalize($quotient), $this->_normalize($remainder));
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $quotient = new Math_BigInteger();
+                $remainder = new Math_BigInteger();
+
+                $quotient->value = bcdiv($this->value, $y->value, 0);
+                $remainder->value = bcmod($this->value, $y->value);
+
+                if ($remainder->value[0] == '-') {
+                    $remainder->value = bcadd($remainder->value, $y->value[0] == '-' ? substr($y->value, 1) : $y->value, 0);
+                }
+
+                return array($this->_normalize($quotient), $this->_normalize($remainder));
+        }
+
+        if (count($y->value) == 1) {
+            list($q, $r) = $this->_divide_digit($this->value, $y->value[0]);
+            $quotient = new Math_BigInteger();
+            $remainder = new Math_BigInteger();
+            $quotient->value = $q;
+            $remainder->value = array($r);
+            $quotient->is_negative = $this->is_negative != $y->is_negative;
+            return array($this->_normalize($quotient), $this->_normalize($remainder));
+        }
+
+        static $zero;
+        if ( !isset($zero) ) {
+            $zero = new Math_BigInteger();
+        }
+
+        $x = $this->copy();
+        $y = $y->copy();
+
+        $x_sign = $x->is_negative;
+        $y_sign = $y->is_negative;
+
+        $x->is_negative = $y->is_negative = false;
+
+        $diff = $x->compare($y);
+
+        if ( !$diff ) {
+            $temp = new Math_BigInteger();
+            $temp->value = array(1);
+            $temp->is_negative = $x_sign != $y_sign;
+            return array($this->_normalize($temp), $this->_normalize(new Math_BigInteger()));
+        }
+
+        if ( $diff < 0 ) {
+            // if $x is negative, "add" $y.
+            if ( $x_sign ) {
+                $x = $y->subtract($x);
+            }
+            return array($this->_normalize(new Math_BigInteger()), $this->_normalize($x));
+        }
+
+        // normalize $x and $y as described in HAC 14.23 / 14.24
+        $msb = $y->value[count($y->value) - 1];
+        for ($shift = 0; !($msb & 0x2000000); ++$shift) {
+            $msb <<= 1;
+        }
+        $x->_lshift($shift);
+        $y->_lshift($shift);
+        $y_value = &$y->value;
+
+        $x_max = count($x->value) - 1;
+        $y_max = count($y->value) - 1;
+
+        $quotient = new Math_BigInteger();
+        $quotient_value = &$quotient->value;
+        $quotient_value = $this->_array_repeat(0, $x_max - $y_max + 1);
+
+        static $temp, $lhs, $rhs;
+        if (!isset($temp)) {
+            $temp = new Math_BigInteger();
+            $lhs =  new Math_BigInteger();
+            $rhs =  new Math_BigInteger();
+        }
+        $temp_value = &$temp->value;
+        $rhs_value =  &$rhs->value;
+
+        // $temp = $y << ($x_max - $y_max-1) in base 2**26
+        $temp_value = array_merge($this->_array_repeat(0, $x_max - $y_max), $y_value);
+
+        while ( $x->compare($temp) >= 0 ) {
+            // calculate the "common residue"
+            ++$quotient_value[$x_max - $y_max];
+            $x = $x->subtract($temp);
+            $x_max = count($x->value) - 1;
+        }
+
+        for ($i = $x_max; $i >= $y_max + 1; --$i) {
+            $x_value = &$x->value;
+            $x_window = array(
+                isset($x_value[$i]) ? $x_value[$i] : 0,
+                isset($x_value[$i - 1]) ? $x_value[$i - 1] : 0,
+                isset($x_value[$i - 2]) ? $x_value[$i - 2] : 0
+            );
+            $y_window = array(
+                $y_value[$y_max],
+                ( $y_max > 0 ) ? $y_value[$y_max - 1] : 0
+            );
+
+            $q_index = $i - $y_max - 1;
+            if ($x_window[0] == $y_window[0]) {
+                $quotient_value[$q_index] = 0x3FFFFFF;
+            } else {
+                $quotient_value[$q_index] = (int) (
+                    ($x_window[0] * 0x4000000 + $x_window[1])
+                    /
+                    $y_window[0]
+                );
+            }
+
+            $temp_value = array($y_window[1], $y_window[0]);
+
+            $lhs->value = array($quotient_value[$q_index]);
+            $lhs = $lhs->multiply($temp);
+
+            $rhs_value = array($x_window[2], $x_window[1], $x_window[0]);
+
+            while ( $lhs->compare($rhs) > 0 ) {
+                --$quotient_value[$q_index];
+
+                $lhs->value = array($quotient_value[$q_index]);
+                $lhs = $lhs->multiply($temp);
+            }
+
+            $adjust = $this->_array_repeat(0, $q_index);
+            $temp_value = array($quotient_value[$q_index]);
+            $temp = $temp->multiply($y);
+            $temp_value = &$temp->value;
+            $temp_value = array_merge($adjust, $temp_value);
+
+            $x = $x->subtract($temp);
+
+            if ($x->compare($zero) < 0) {
+                $temp_value = array_merge($adjust, $y_value);
+                $x = $x->add($temp);
+
+                --$quotient_value[$q_index];
+            }
+
+            $x_max = count($x_value) - 1;
+        }
+
+        // unnormalize the remainder
+        $x->_rshift($shift);
+
+        $quotient->is_negative = $x_sign != $y_sign;
+
+        // calculate the "common residue", if appropriate
+        if ( $x_sign ) {
+            $y->_rshift($shift);
+            $x = $y->subtract($x);
+        }
+
+        return array($this->_normalize($quotient), $this->_normalize($x));
+    }
+
+    /**
+     * Divides a BigInteger by a regular integer
+     *
+     * abc / x = a00 / x + b0 / x + c / x
+     *
+     * @param Array $dividend
+     * @param Array $divisor
+     * @return Array
+     * @access private
+     */
+    function _divide_digit($dividend, $divisor)
+    {
+        $carry = 0;
+        $result = array();
+
+        for ($i = count($dividend) - 1; $i >= 0; --$i) {
+            $temp = 0x4000000 * $carry + $dividend[$i];
+            $result[$i] = (int) ($temp / $divisor);
+            $carry = (int) ($temp - $divisor * $result[$i]);
+        }
+
+        return array($result, $carry);
+    }
+
+    /**
+     * Performs modular exponentiation.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger('10');
+     *    $b = new Math_BigInteger('20');
+     *    $c = new Math_BigInteger('30');
+     *
+     *    $c = $a->modPow($b, $c);
+     *
+     *    echo $c->toString(); // outputs 10
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $e
+     * @param Math_BigInteger $n
+     * @return Math_BigInteger
+     * @access public
+     * @internal The most naive approach to modular exponentiation has very unreasonable requirements, and
+     *    and although the approach involving repeated squaring does vastly better, it, too, is impractical
+     *    for our purposes.  The reason being that division - by far the most complicated and time-consuming
+     *    of the basic operations (eg. +,-,*,/) - occurs multiple times within it.
+     *
+     *    Modular reductions resolve this issue.  Although an individual modular reduction takes more time
+     *    then an individual division, when performed in succession (with the same modulo), they're a lot faster.
+     *
+     *    The two most commonly used modular reductions are Barrett and Montgomery reduction.  Montgomery reduction,
+     *    although faster, only works when the gcd of the modulo and of the base being used is 1.  In RSA, when the
+     *    base is a power of two, the modulo - a product of two primes - is always going to have a gcd of 1 (because
+     *    the product of two odd numbers is odd), but what about when RSA isn't used?
+     *
+     *    In contrast, Barrett reduction has no such constraint.  As such, some bigint implementations perform a
+     *    Barrett reduction after every operation in the modpow function.  Others perform Barrett reductions when the
+     *    modulo is even and Montgomery reductions when the modulo is odd.  BigInteger.java's modPow method, however,
+     *    uses a trick involving the Chinese Remainder Theorem to factor the even modulo into two numbers - one odd and
+     *    the other, a power of two - and recombine them, later.  This is the method that this modPow function uses.
+     *    {@link http://islab.oregonstate.edu/papers/j34monex.pdf Montgomery Reduction with Even Modulus} elaborates.
+     */
+    function modPow($e, $n)
+    {
+        $n = $this->bitmask !== false && $this->bitmask->compare($n) < 0 ? $this->bitmask : $n->abs();
+
+        if ($e->compare(new Math_BigInteger()) < 0) {
+            $e = $e->abs();
+
+            $temp = $this->modInverse($n);
+            if ($temp === false) {
+                return false;
+            }
+
+            return $this->_normalize($temp->modPow($e, $n));
+        }
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_powm($this->value, $e->value, $n->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp = new Math_BigInteger();
+                $temp->value = bcpowmod($this->value, $e->value, $n->value, 0);
+
+                return $this->_normalize($temp);
+        }
+
+        if ( empty($e->value) ) {
+            $temp = new Math_BigInteger();
+            $temp->value = array(1);
+            return $this->_normalize($temp);
+        }
+
+        if ( $e->value == array(1) ) {
+            list(, $temp) = $this->divide($n);
+            return $this->_normalize($temp);
+        }
+
+        if ( $e->value == array(2) ) {
+            $temp = new Math_BigInteger();
+            $temp->value = $this->_square($this->value);
+            list(, $temp) = $temp->divide($n);
+            return $this->_normalize($temp);
+        }
+
+        return $this->_normalize($this->_slidingWindow($e, $n, MATH_BIGINTEGER_BARRETT));
+
+        // is the modulo odd?
+        if ( $n->value[0] & 1 ) {
+            return $this->_normalize($this->_slidingWindow($e, $n, MATH_BIGINTEGER_MONTGOMERY));
+        }
+        // if it's not, it's even
+
+        // find the lowest set bit (eg. the max pow of 2 that divides $n)
+        for ($i = 0; $i < count($n->value); ++$i) {
+            if ( $n->value[$i] ) {
+                $temp = decbin($n->value[$i]);
+                $j = strlen($temp) - strrpos($temp, '1') - 1;
+                $j+= 26 * $i;
+                break;
+            }
+        }
+        // at this point, 2^$j * $n/(2^$j) == $n
+
+        $mod1 = $n->copy();
+        $mod1->_rshift($j);
+        $mod2 = new Math_BigInteger();
+        $mod2->value = array(1);
+        $mod2->_lshift($j);
+
+        $part1 = ( $mod1->value != array(1) ) ? $this->_slidingWindow($e, $mod1, MATH_BIGINTEGER_MONTGOMERY) : new Math_BigInteger();
+        $part2 = $this->_slidingWindow($e, $mod2, MATH_BIGINTEGER_POWEROF2);
+
+        $y1 = $mod2->modInverse($mod1);
+        $y2 = $mod1->modInverse($mod2);
+
+        $result = $part1->multiply($mod2);
+        $result = $result->multiply($y1);
+
+        $temp = $part2->multiply($mod1);
+        $temp = $temp->multiply($y2);
+
+        $result = $result->add($temp);
+        list(, $result) = $result->divide($n);
+
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Performs modular exponentiation.
+     *
+     * Alias for Math_BigInteger::modPow()
+     *
+     * @param Math_BigInteger $e
+     * @param Math_BigInteger $n
+     * @return Math_BigInteger
+     * @access public
+     */
+    function powMod($e, $n)
+    {
+        return $this->modPow($e, $n);
+    }
+
+    /**
+     * Sliding Window k-ary Modular Exponentiation
+     *
+     * Based on {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=27 HAC 14.85} /
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=210 MPM 7.7}.  In a departure from those algorithims,
+     * however, this function performs a modular reduction after every multiplication and squaring operation.
+     * As such, this function has the same preconditions that the reductions being used do.
+     *
+     * @param Math_BigInteger $e
+     * @param Math_BigInteger $n
+     * @param Integer $mode
+     * @return Math_BigInteger
+     * @access private
+     */
+    function _slidingWindow($e, $n, $mode)
+    {
+        static $window_ranges = array(7, 25, 81, 241, 673, 1793); // from BigInteger.java's oddModPow function
+        //static $window_ranges = array(0, 7, 36, 140, 450, 1303, 3529); // from MPM 7.3.1
+
+        $e_value = $e->value;
+        $e_length = count($e_value) - 1;
+        $e_bits = decbin($e_value[$e_length]);
+        for ($i = $e_length - 1; $i >= 0; --$i) {
+            $e_bits.= str_pad(decbin($e_value[$i]), 26, '0', STR_PAD_LEFT);
+        }
+
+        $e_length = strlen($e_bits);
+
+        // calculate the appropriate window size.
+        // $window_size == 3 if $window_ranges is between 25 and 81, for example.
+        for ($i = 0, $window_size = 1; $e_length > $window_ranges[$i] && $i < count($window_ranges); ++$window_size, ++$i);
+
+        $n_value = $n->value;
+
+        // precompute $this^0 through $this^$window_size
+        $powers = array();
+        $powers[1] = $this->_prepareReduce($this->value, $n_value, $mode);
+        $powers[2] = $this->_squareReduce($powers[1], $n_value, $mode);
+
+        // we do every other number since substr($e_bits, $i, $j+1) (see below) is supposed to end
+        // in a 1.  ie. it's supposed to be odd.
+        $temp = 1 << ($window_size - 1);
+        for ($i = 1; $i < $temp; ++$i) {
+            $i2 = $i << 1;
+            $powers[$i2 + 1] = $this->_multiplyReduce($powers[$i2 - 1], $powers[2], $n_value, $mode);
+        }
+
+        $result = array(1);
+        $result = $this->_prepareReduce($result, $n_value, $mode);
+
+        for ($i = 0; $i < $e_length; ) {
+            if ( !$e_bits[$i] ) {
+                $result = $this->_squareReduce($result, $n_value, $mode);
+                ++$i;
+            } else {
+                for ($j = $window_size - 1; $j > 0; --$j) {
+                    if ( !empty($e_bits[$i + $j]) ) {
+                        break;
+                    }
+                }
+
+                for ($k = 0; $k <= $j; ++$k) {// eg. the length of substr($e_bits, $i, $j+1)
+                    $result = $this->_squareReduce($result, $n_value, $mode);
+                }
+
+                $result = $this->_multiplyReduce($result, $powers[bindec(substr($e_bits, $i, $j + 1))], $n_value, $mode);
+
+                $i+=$j + 1;
+            }
+        }
+
+        $temp = new Math_BigInteger();
+        $temp->value = $this->_reduce($result, $n_value, $mode);
+
+        return $temp;
+    }
+
+    /**
+     * Modular reduction
+     *
+     * For most $modes this will return the remainder.
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $n
+     * @param Integer $mode
+     * @return Array
+     */
+    function _reduce($x, $n, $mode)
+    {
+        switch ($mode) {
+            case MATH_BIGINTEGER_MONTGOMERY:
+                return $this->_montgomery($x, $n);
+            case MATH_BIGINTEGER_BARRETT:
+                return $this->_barrett($x, $n);
+            case MATH_BIGINTEGER_POWEROF2:
+                $lhs = new Math_BigInteger();
+                $lhs->value = $x;
+                $rhs = new Math_BigInteger();
+                $rhs->value = $n;
+                return $x->_mod2($n);
+            case MATH_BIGINTEGER_CLASSIC:
+                $lhs = new Math_BigInteger();
+                $lhs->value = $x;
+                $rhs = new Math_BigInteger();
+                $rhs->value = $n;
+                list(, $temp) = $lhs->divide($rhs);
+                return $temp->value;
+            case MATH_BIGINTEGER_NONE:
+                return $x;
+            default:
+                // an invalid $mode was provided
+        }
+    }
+
+    /**
+     * Modular reduction preperation
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $n
+     * @param Integer $mode
+     * @return Array
+     */
+    function _prepareReduce($x, $n, $mode)
+    {
+        if ($mode == MATH_BIGINTEGER_MONTGOMERY) {
+            return $this->_prepMontgomery($x, $n);
+        }
+        return $this->_reduce($x, $n, $mode);
+    }
+
+    /**
+     * Modular multiply
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $y
+     * @param Array $n
+     * @param Integer $mode
+     * @return Array
+     */
+    function _multiplyReduce($x, $y, $n, $mode)
+    {
+        if ($mode == MATH_BIGINTEGER_MONTGOMERY) {
+            return $this->_montgomeryMultiply($x, $y, $n);
+        }
+        $temp = $this->_multiply($x, false, $y, false);
+        return $this->_reduce($temp[MATH_BIGINTEGER_VALUE], $n, $mode);
+    }
+
+    /**
+     * Modular square
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $n
+     * @param Integer $mode
+     * @return Array
+     */
+    function _squareReduce($x, $n, $mode)
+    {
+        if ($mode == MATH_BIGINTEGER_MONTGOMERY) {
+            return $this->_montgomeryMultiply($x, $x, $n);
+        }
+        return $this->_reduce($this->_square($x), $n, $mode);
+    }
+
+    /**
+     * Modulos for Powers of Two
+     *
+     * Calculates $x%$n, where $n = 2**$e, for some $e.  Since this is basically the same as doing $x & ($n-1),
+     * we'll just use this function as a wrapper for doing that.
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Math_BigInteger
+     * @return Math_BigInteger
+     */
+    function _mod2($n)
+    {
+        $temp = new Math_BigInteger();
+        $temp->value = array(1);
+        return $this->bitwise_and($n->subtract($temp));
+    }
+
+    /**
+     * Barrett Modular Reduction
+     *
+     * See {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=14 HAC 14.3.3} /
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=165 MPM 6.2.5} for more information.  Modified slightly,
+     * so as not to require negative numbers (initially, this script didn't support negative numbers).
+     *
+     * Employs "folding", as described at
+     * {@link http://www.cosic.esat.kuleuven.be/publications/thesis-149.pdf#page=66 thesis-149.pdf#page=66}.  To quote from
+     * it, "the idea [behind folding] is to find a value x' such that x (mod m) = x' (mod m), with x' being smaller than x."
+     *
+     * Unfortunately, the "Barrett Reduction with Folding" algorithm described in thesis-149.pdf is not, as written, all that
+     * usable on account of (1) its not using reasonable radix points as discussed in
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=162 MPM 6.2.2} and (2) the fact that, even with reasonable
+     * radix points, it only works when there are an even number of digits in the denominator.  The reason for (2) is that
+     * (x >> 1) + (x >> 1) != x / 2 + x / 2.  If x is even, they're the same, but if x is odd, they're not.  See the in-line
+     * comments for details.
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $n
+     * @param Array $m
+     * @return Array
+     */
+    function _barrett($n, $m)
+    {
+        static $cache = array(
+            MATH_BIGINTEGER_VARIABLE => array(),
+            MATH_BIGINTEGER_DATA => array()
+        );
+
+        $m_length = count($m);
+
+        // if ($this->_compare($n, $this->_square($m)) >= 0) {
+        if (count($n) > 2 * $m_length) {
+            $lhs = new Math_BigInteger();
+            $rhs = new Math_BigInteger();
+            $lhs->value = $n;
+            $rhs->value = $m;
+            list(, $temp) = $lhs->divide($rhs);
+            return $temp->value;
+        }
+
+        // if (m.length >> 1) + 2 <= m.length then m is too small and n can't be reduced
+        if ($m_length < 5) {
+            return $this->_regularBarrett($n, $m);
+        }
+
+        // n = 2 * m.length
+
+        if ( ($key = array_search($m, $cache[MATH_BIGINTEGER_VARIABLE])) === false ) {
+            $key = count($cache[MATH_BIGINTEGER_VARIABLE]);
+            $cache[MATH_BIGINTEGER_VARIABLE][] = $m;
+
+            $lhs = new Math_BigInteger();
+            $lhs_value = &$lhs->value;
+            $lhs_value = $this->_array_repeat(0, $m_length + ($m_length >> 1));
+            $lhs_value[] = 1;
+            $rhs = new Math_BigInteger();
+            $rhs->value = $m;
+
+            list($u, $m1) = $lhs->divide($rhs);
+            $u = $u->value;
+            $m1 = $m1->value;
+
+            $cache[MATH_BIGINTEGER_DATA][] = array(
+                'u' => $u, // m.length >> 1 (technically (m.length >> 1) + 1)
+                'm1'=> $m1 // m.length
+            );
+        } else {
+            extract($cache[MATH_BIGINTEGER_DATA][$key]);
+        }
+
+        $cutoff = $m_length + ($m_length >> 1);
+        $lsd = array_slice($n, 0, $cutoff); // m.length + (m.length >> 1)
+        $msd = array_slice($n, $cutoff);    // m.length >> 1
+        $lsd = $this->_trim($lsd);
+        $temp = $this->_multiply($msd, false, $m1, false);
+        $n = $this->_add($lsd, false, $temp[MATH_BIGINTEGER_VALUE], false); // m.length + (m.length >> 1) + 1
+
+        if ($m_length & 1) {
+            return $this->_regularBarrett($n[MATH_BIGINTEGER_VALUE], $m);
+        }
+
+        // (m.length + (m.length >> 1) + 1) - (m.length - 1) == (m.length >> 1) + 2
+        $temp = array_slice($n[MATH_BIGINTEGER_VALUE], $m_length - 1);
+        // if even: ((m.length >> 1) + 2) + (m.length >> 1) == m.length + 2
+        // if odd:  ((m.length >> 1) + 2) + (m.length >> 1) == (m.length - 1) + 2 == m.length + 1
+        $temp = $this->_multiply($temp, false, $u, false);
+        // if even: (m.length + 2) - ((m.length >> 1) + 1) = m.length - (m.length >> 1) + 1
+        // if odd:  (m.length + 1) - ((m.length >> 1) + 1) = m.length - (m.length >> 1)
+        $temp = array_slice($temp[MATH_BIGINTEGER_VALUE], ($m_length >> 1) + 1);
+        // if even: (m.length - (m.length >> 1) + 1) + m.length = 2 * m.length - (m.length >> 1) + 1
+        // if odd:  (m.length - (m.length >> 1)) + m.length     = 2 * m.length - (m.length >> 1)
+        $temp = $this->_multiply($temp, false, $m, false);
+
+        // at this point, if m had an odd number of digits, we'd be subtracting a 2 * m.length - (m.length >> 1) digit
+        // number from a m.length + (m.length >> 1) + 1 digit number.  ie. there'd be an extra digit and the while loop
+        // following this comment would loop a lot (hence our calling _regularBarrett() in that situation).
+
+        $result = $this->_subtract($n[MATH_BIGINTEGER_VALUE], false, $temp[MATH_BIGINTEGER_VALUE], false);
+
+        while ($this->_compare($result[MATH_BIGINTEGER_VALUE], $result[MATH_BIGINTEGER_SIGN], $m, false) >= 0) {
+            $result = $this->_subtract($result[MATH_BIGINTEGER_VALUE], $result[MATH_BIGINTEGER_SIGN], $m, false);
+        }
+
+        return $result[MATH_BIGINTEGER_VALUE];
+    }
+
+    /**
+     * (Regular) Barrett Modular Reduction
+     *
+     * For numbers with more than four digits Math_BigInteger::_barrett() is faster.  The difference between that and this
+     * is that this function does not fold the denominator into a smaller form.
+     *
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $n
+     * @return Array
+     */
+    function _regularBarrett($x, $n)
+    {
+        static $cache = array(
+            MATH_BIGINTEGER_VARIABLE => array(),
+            MATH_BIGINTEGER_DATA => array()
+        );
+
+        $n_length = count($n);
+
+        if (count($x) > 2 * $n_length) {
+            $lhs = new Math_BigInteger();
+            $rhs = new Math_BigInteger();
+            $lhs->value = $x;
+            $rhs->value = $n;
+            list(, $temp) = $lhs->divide($rhs);
+            return $temp->value;
+        }
+
+        if ( ($key = array_search($n, $cache[MATH_BIGINTEGER_VARIABLE])) === false ) {
+            $key = count($cache[MATH_BIGINTEGER_VARIABLE]);
+            $cache[MATH_BIGINTEGER_VARIABLE][] = $n;
+            $lhs = new Math_BigInteger();
+            $lhs_value = &$lhs->value;
+            $lhs_value = $this->_array_repeat(0, 2 * $n_length);
+            $lhs_value[] = 1;
+            $rhs = new Math_BigInteger();
+            $rhs->value = $n;
+            list($temp, ) = $lhs->divide($rhs); // m.length
+            $cache[MATH_BIGINTEGER_DATA][] = $temp->value;
+        }
+
+        // 2 * m.length - (m.length - 1) = m.length + 1
+        $temp = array_slice($x, $n_length - 1);
+        // (m.length + 1) + m.length = 2 * m.length + 1
+        $temp = $this->_multiply($temp, false, $cache[MATH_BIGINTEGER_DATA][$key], false);
+        // (2 * m.length + 1) - (m.length - 1) = m.length + 2
+        $temp = array_slice($temp[MATH_BIGINTEGER_VALUE], $n_length + 1);
+
+        // m.length + 1
+        $result = array_slice($x, 0, $n_length + 1);
+        // m.length + 1
+        $temp = $this->_multiplyLower($temp, false, $n, false, $n_length + 1);
+        // $temp == array_slice($temp->_multiply($temp, false, $n, false)->value, 0, $n_length + 1)
+
+        if ($this->_compare($result, false, $temp[MATH_BIGINTEGER_VALUE], $temp[MATH_BIGINTEGER_SIGN]) < 0) {
+            $corrector_value = $this->_array_repeat(0, $n_length + 1);
+            $corrector_value[] = 1;
+            $result = $this->_add($result, false, $corrector, false);
+            $result = $result[MATH_BIGINTEGER_VALUE];
+        }
+
+        // at this point, we're subtracting a number with m.length + 1 digits from another number with m.length + 1 digits
+        $result = $this->_subtract($result, false, $temp[MATH_BIGINTEGER_VALUE], $temp[MATH_BIGINTEGER_SIGN]);
+        while ($this->_compare($result[MATH_BIGINTEGER_VALUE], $result[MATH_BIGINTEGER_SIGN], $n, false) > 0) {
+            $result = $this->_subtract($result[MATH_BIGINTEGER_VALUE], $result[MATH_BIGINTEGER_SIGN], $n, false);
+        }
+
+        return $result[MATH_BIGINTEGER_VALUE];
+    }
+
+    /**
+     * Performs long multiplication up to $stop digits
+     *
+     * If you're going to be doing array_slice($product->value, 0, $stop), some cycles can be saved.
+     *
+     * @see _regularBarrett()
+     * @param Array $x_value
+     * @param Boolean $x_negative
+     * @param Array $y_value
+     * @param Boolean $y_negative
+     * @return Array
+     * @access private
+     */
+    function _multiplyLower($x_value, $x_negative, $y_value, $y_negative, $stop)
+    {
+        $x_length = count($x_value);
+        $y_length = count($y_value);
+
+        if ( !$x_length || !$y_length ) { // a 0 is being multiplied
+            return array(
+                MATH_BIGINTEGER_VALUE => array(),
+                MATH_BIGINTEGER_SIGN => false
+            );
+        }
+
+        if ( $x_length < $y_length ) {
+            $temp = $x_value;
+            $x_value = $y_value;
+            $y_value = $temp;
+
+            $x_length = count($x_value);
+            $y_length = count($y_value);
+        }
+
+        $product_value = $this->_array_repeat(0, $x_length + $y_length);
+
+        // the following for loop could be removed if the for loop following it
+        // (the one with nested for loops) initially set $i to 0, but
+        // doing so would also make the result in one set of unnecessary adds,
+        // since on the outermost loops first pass, $product->value[$k] is going
+        // to always be 0
+
+        $carry = 0;
+
+        for ($j = 0; $j < $x_length; ++$j) { // ie. $i = 0, $k = $i
+            $temp = $x_value[$j] * $y_value[0] + $carry; // $product_value[$k] == 0
+            $carry = (int) ($temp / 0x4000000);
+            $product_value[$j] = (int) ($temp - 0x4000000 * $carry);
+        }
+
+        if ($j < $stop) {
+            $product_value[$j] = $carry;
+        }
+
+        // the above for loop is what the previous comment was talking about.  the
+        // following for loop is the "one with nested for loops"
+
+        for ($i = 1; $i < $y_length; ++$i) {
+            $carry = 0;
+
+            for ($j = 0, $k = $i; $j < $x_length && $k < $stop; ++$j, ++$k) {
+                $temp = $product_value[$k] + $x_value[$j] * $y_value[$i] + $carry;
+                $carry = (int) ($temp / 0x4000000);
+                $product_value[$k] = (int) ($temp - 0x4000000 * $carry);
+            }
+
+            if ($k < $stop) {
+                $product_value[$k] = $carry;
+            }
+        }
+
+        return array(
+            MATH_BIGINTEGER_VALUE => $this->_trim($product_value),
+            MATH_BIGINTEGER_SIGN => $x_negative != $y_negative
+        );
+    }
+
+    /**
+     * Montgomery Modular Reduction
+     *
+     * ($x->_prepMontgomery($n))->_montgomery($n) yields $x % $n.
+     * {@link http://math.libtomcrypt.com/files/tommath.pdf#page=170 MPM 6.3} provides insights on how this can be
+     * improved upon (basically, by using the comba method).  gcd($n, 2) must be equal to one for this function
+     * to work correctly.
+     *
+     * @see _prepMontgomery()
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $n
+     * @return Array
+     */
+    function _montgomery($x, $n)
+    {
+        static $cache = array(
+            MATH_BIGINTEGER_VARIABLE => array(),
+            MATH_BIGINTEGER_DATA => array()
+        );
+
+        if ( ($key = array_search($n, $cache[MATH_BIGINTEGER_VARIABLE])) === false ) {
+            $key = count($cache[MATH_BIGINTEGER_VARIABLE]);
+            $cache[MATH_BIGINTEGER_VARIABLE][] = $x;
+            $cache[MATH_BIGINTEGER_DATA][] = $this->_modInverse67108864($n);
+        }
+
+        $k = count($n);
+
+        $result = array(MATH_BIGINTEGER_VALUE => $x);
+
+        for ($i = 0; $i < $k; ++$i) {
+            $temp = $result[MATH_BIGINTEGER_VALUE][$i] * $cache[MATH_BIGINTEGER_DATA][$key];
+            $temp = (int) ($temp - 0x4000000 * ((int) ($temp / 0x4000000)));
+            $temp = $this->_regularMultiply(array($temp), $n);
+            $temp = array_merge($this->_array_repeat(0, $i), $temp);
+            $result = $this->_add($result[MATH_BIGINTEGER_VALUE], false, $temp, false);
+        }
+
+        $result[MATH_BIGINTEGER_VALUE] = array_slice($result[MATH_BIGINTEGER_VALUE], $k);
+
+        if ($this->_compare($result, false, $n, false) >= 0) {
+            $result = $this->_subtract($result[MATH_BIGINTEGER_VALUE], false, $n, false);
+        }
+
+        return $result[MATH_BIGINTEGER_VALUE];
+    }
+
+    /**
+     * Montgomery Multiply
+     *
+     * Interleaves the montgomery reduction and long multiplication algorithms together as described in 
+     * {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=13 HAC 14.36}
+     *
+     * @see _prepMontgomery()
+     * @see _montgomery()
+     * @access private
+     * @param Array $x
+     * @param Array $y
+     * @param Array $m
+     * @return Array
+     */
+    function _montgomeryMultiply($x, $y, $m)
+    {
+        $temp = $this->_multiply($x, false, $y, false);
+        return $this->_montgomery($temp[MATH_BIGINTEGER_VALUE], $m);
+
+        static $cache = array(
+            MATH_BIGINTEGER_VARIABLE => array(),
+            MATH_BIGINTEGER_DATA => array()
+        );
+
+        if ( ($key = array_search($m, $cache[MATH_BIGINTEGER_VARIABLE])) === false ) {
+            $key = count($cache[MATH_BIGINTEGER_VARIABLE]);
+            $cache[MATH_BIGINTEGER_VARIABLE][] = $m;
+            $cache[MATH_BIGINTEGER_DATA][] = $this->_modInverse67108864($m);
+        }
+
+        $n = max(count($x), count($y), count($m));
+        $x = array_pad($x, $n, 0);
+        $y = array_pad($y, $n, 0);
+        $m = array_pad($m, $n, 0);
+        $a = array(MATH_BIGINTEGER_VALUE => $this->_array_repeat(0, $n + 1));
+        for ($i = 0; $i < $n; ++$i) {
+            $temp = $a[MATH_BIGINTEGER_VALUE][0] + $x[$i] * $y[0];
+            $temp = (int) ($temp - 0x4000000 * ((int) ($temp / 0x4000000)));
+            $temp = $temp * $cache[MATH_BIGINTEGER_DATA][$key];
+            $temp = (int) ($temp - 0x4000000 * ((int) ($temp / 0x4000000)));
+            $temp = $this->_add($this->_regularMultiply(array($x[$i]), $y), false, $this->_regularMultiply(array($temp), $m), false);
+            $a = $this->_add($a[MATH_BIGINTEGER_VALUE], false, $temp[MATH_BIGINTEGER_VALUE], false);
+            $a[MATH_BIGINTEGER_VALUE] = array_slice($a[MATH_BIGINTEGER_VALUE], 1);
+        }
+        if ($this->_compare($a[MATH_BIGINTEGER_VALUE], false, $m, false) >= 0) {
+            $a = $this->_subtract($a[MATH_BIGINTEGER_VALUE], false, $m, false);
+        }
+        return $a[MATH_BIGINTEGER_VALUE];
+    }
+
+    /**
+     * Prepare a number for use in Montgomery Modular Reductions
+     *
+     * @see _montgomery()
+     * @see _slidingWindow()
+     * @access private
+     * @param Array $x
+     * @param Array $n
+     * @return Array
+     */
+    function _prepMontgomery($x, $n)
+    {
+        $lhs = new Math_BigInteger();
+        $lhs->value = array_merge($this->_array_repeat(0, count($n)), $x);
+        $rhs = new Math_BigInteger();
+        $rhs->value = $n;
+
+        list(, $temp) = $lhs->divide($rhs);
+        return $temp->value;
+    }
+
+    /**
+     * Modular Inverse of a number mod 2**26 (eg. 67108864)
+     *
+     * Based off of the bnpInvDigit function implemented and justified in the following URL:
+     *
+     * {@link http://www-cs-students.stanford.edu/~tjw/jsbn/jsbn.js}
+     *
+     * The following URL provides more info:
+     *
+     * {@link http://groups.google.com/group/sci.crypt/msg/7a137205c1be7d85}
+     *
+     * As for why we do all the bitmasking...  strange things can happen when converting from floats to ints. For
+     * instance, on some computers, var_dump((int) -4294967297) yields int(-1) and on others, it yields 
+     * int(-2147483648).  To avoid problems stemming from this, we use bitmasks to guarantee that ints aren't
+     * auto-converted to floats.  The outermost bitmask is present because without it, there's no guarantee that
+     * the "residue" returned would be the so-called "common residue".  We use fmod, in the last step, because the
+     * maximum possible $x is 26 bits and the maximum $result is 16 bits.  Thus, we have to be able to handle up to
+     * 40 bits, which only 64-bit floating points will support.
+     *
+     * Thanks to Pedro Gimeno Fortea for input!
+     *
+     * @see _montgomery()
+     * @access private
+     * @param Array $x
+     * @return Integer
+     */
+    function _modInverse67108864($x) // 2**26 == 67108864
+    {
+        $x = -$x[0];
+        $result = $x & 0x3; // x**-1 mod 2**2
+        $result = ($result * (2 - $x * $result)) & 0xF; // x**-1 mod 2**4
+        $result = ($result * (2 - ($x & 0xFF) * $result))  & 0xFF; // x**-1 mod 2**8
+        $result = ($result * ((2 - ($x & 0xFFFF) * $result) & 0xFFFF)) & 0xFFFF; // x**-1 mod 2**16
+        $result = fmod($result * (2 - fmod($x * $result, 0x4000000)), 0x4000000); // x**-1 mod 2**26
+        return $result & 0x3FFFFFF;
+    }
+
+    /**
+     * Calculates modular inverses.
+     *
+     * Say you have (30 mod 17 * x mod 17) mod 17 == 1.  x can be found using modular inverses.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger(30);
+     *    $b = new Math_BigInteger(17);
+     *
+     *    $c = $a->modInverse($b);
+     *    echo $c->toString(); // outputs 4
+     *
+     *    echo "\r\n";
+     *
+     *    $d = $a->multiply($c);
+     *    list(, $d) = $d->divide($b);
+     *    echo $d; // outputs 1 (as per the definition of modular inverse)
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $n
+     * @return mixed false, if no modular inverse exists, Math_BigInteger, otherwise.
+     * @access public
+     * @internal See {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=21 HAC 14.64} for more information.
+     */
+    function modInverse($n)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_invert($this->value, $n->value);
+
+                return ( $temp->value === false ) ? false : $this->_normalize($temp);
+        }
+
+        static $zero, $one;
+        if (!isset($zero)) {
+            $zero = new Math_BigInteger();
+            $one = new Math_BigInteger(1);
+        }
+
+        // $x mod $n == $x mod -$n.
+        $n = $n->abs();
+
+        if ($this->compare($zero) < 0) {
+            $temp = $this->abs();
+            $temp = $temp->modInverse($n);
+            return $negated === false ? false : $this->_normalize($n->subtract($temp));
+        }
+
+        extract($this->extendedGCD($n));
+
+        if (!$gcd->equals($one)) {
+            return false;
+        }
+
+        $x = $x->compare($zero) < 0 ? $x->add($n) : $x;
+
+        return $this->compare($zero) < 0 ? $this->_normalize($n->subtract($x)) : $this->_normalize($x);
+    }
+
+    /**
+     * Calculates the greatest common divisor and Bézout's identity.
+     *
+     * Say you have 693 and 609.  The GCD is 21.  Bézout's identity states that there exist integers x and y such that
+     * 693*x + 609*y == 21.  In point of fact, there are actually an infinite number of x and y combinations and which
+     * combination is returned is dependant upon which mode is in use.  See
+     * {@link http://en.wikipedia.org/wiki/B%C3%A9zout%27s_identity Bézout's identity - Wikipedia} for more information.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger(693);
+     *    $b = new Math_BigInteger(609);
+     *
+     *    extract($a->extendedGCD($b));
+     *
+     *    echo $gcd->toString() . "\r\n"; // outputs 21
+     *    echo $a->toString() * $x->toString() + $b->toString() * $y->toString(); // outputs 21
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $n
+     * @return Math_BigInteger
+     * @access public
+     * @internal Calculates the GCD using the binary xGCD algorithim described in
+     *    {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf#page=19 HAC 14.61}.  As the text above 14.61 notes,
+     *    the more traditional algorithim requires "relatively costly multiple-precision divisions".
+     */
+    function extendedGCD($n)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                extract(gmp_gcdext($this->value, $n->value));
+
+                return array(
+                    'gcd' => $this->_normalize(new Math_BigInteger($g)),
+                    'x'   => $this->_normalize(new Math_BigInteger($s)),
+                    'y'   => $this->_normalize(new Math_BigInteger($t))
+                );
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                // it might be faster to use the binary xGCD algorithim here, as well, but (1) that algorithim works
+                // best when the base is a power of 2 and (2) i don't think it'd make much difference, anyway.  as is,
+                // the basic extended euclidean algorithim is what we're using.
+
+                $u = $this->value;
+                $v = $n->value;
+
+                $a = '1';
+                $b = '0';
+                $c = '0';
+                $d = '1';
+
+                while (bccomp($v, '0', 0) != 0) {
+                    $q = bcdiv($u, $v, 0);
+
+                    $temp = $u;
+                    $u = $v;
+                    $v = bcsub($temp, bcmul($v, $q, 0), 0);
+
+                    $temp = $a;
+                    $a = $c;
+                    $c = bcsub($temp, bcmul($a, $q, 0), 0);
+
+                    $temp = $b;
+                    $b = $d;
+                    $d = bcsub($temp, bcmul($b, $q, 0), 0);
+                }
+
+                return array(
+                    'gcd' => $this->_normalize(new Math_BigInteger($u)),
+                    'x'   => $this->_normalize(new Math_BigInteger($a)),
+                    'y'   => $this->_normalize(new Math_BigInteger($b))
+                );
+        }
+
+        $y = $n->copy();
+        $x = $this->copy();
+        $g = new Math_BigInteger();
+        $g->value = array(1);
+
+        while ( !(($x->value[0] & 1)|| ($y->value[0] & 1)) ) {
+            $x->_rshift(1);
+            $y->_rshift(1);
+            $g->_lshift(1);
+        }
+
+        $u = $x->copy();
+        $v = $y->copy();
+
+        $a = new Math_BigInteger();
+        $b = new Math_BigInteger();
+        $c = new Math_BigInteger();
+        $d = new Math_BigInteger();
+
+        $a->value = $d->value = $g->value = array(1);
+        $b->value = $c->value = array();
+
+        while ( !empty($u->value) ) {
+            while ( !($u->value[0] & 1) ) {
+                $u->_rshift(1);
+                if ( (!empty($a->value) && ($a->value[0] & 1)) || (!empty($b->value) && ($b->value[0] & 1)) ) {
+                    $a = $a->add($y);
+                    $b = $b->subtract($x);
+                }
+                $a->_rshift(1);
+                $b->_rshift(1);
+            }
+
+            while ( !($v->value[0] & 1) ) {
+                $v->_rshift(1);
+                if ( (!empty($d->value) && ($d->value[0] & 1)) || (!empty($c->value) && ($c->value[0] & 1)) ) {
+                    $c = $c->add($y);
+                    $d = $d->subtract($x);
+                }
+                $c->_rshift(1);
+                $d->_rshift(1);
+            }
+
+            if ($u->compare($v) >= 0) {
+                $u = $u->subtract($v);
+                $a = $a->subtract($c);
+                $b = $b->subtract($d);
+            } else {
+                $v = $v->subtract($u);
+                $c = $c->subtract($a);
+                $d = $d->subtract($b);
+            }
+        }
+
+        return array(
+            'gcd' => $this->_normalize($g->multiply($v)),
+            'x'   => $this->_normalize($c),
+            'y'   => $this->_normalize($d)
+        );
+    }
+
+    /**
+     * Calculates the greatest common divisor
+     *
+     * Say you have 693 and 609.  The GCD is 21.
+     *
+     * Here's an example:
+     * <code>
+     * <?php
+     *    include('Math/BigInteger.php');
+     *
+     *    $a = new Math_BigInteger(693);
+     *    $b = new Math_BigInteger(609);
+     *
+     *    $gcd = a->extendedGCD($b);
+     *
+     *    echo $gcd->toString() . "\r\n"; // outputs 21
+     * ?>
+     * </code>
+     *
+     * @param Math_BigInteger $n
+     * @return Math_BigInteger
+     * @access public
+     */
+    function gcd($n)
+    {
+        extract($this->extendedGCD($n));
+        return $gcd;
+    }
+
+    /**
+     * Absolute value.
+     *
+     * @return Math_BigInteger
+     * @access public
+     */
+    function abs()
+    {
+        $temp = new Math_BigInteger();
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp->value = gmp_abs($this->value);
+                break;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp->value = (bccomp($this->value, '0', 0) < 0) ? substr($this->value, 1) : $this->value;
+                break;
+            default:
+                $temp->value = $this->value;
+        }
+
+        return $temp;
+    }
+
+    /**
+     * Compares two numbers.
+     *
+     * Although one might think !$x->compare($y) means $x != $y, it, in fact, means the opposite.  The reason for this is
+     * demonstrated thusly:
+     *
+     * $x  > $y: $x->compare($y)  > 0
+     * $x  < $y: $x->compare($y)  < 0
+     * $x == $y: $x->compare($y) == 0
+     *
+     * Note how the same comparison operator is used.  If you want to test for equality, use $x->equals($y).
+     *
+     * @param Math_BigInteger $x
+     * @return Integer < 0 if $this is less than $x; > 0 if $this is greater than $x, and 0 if they are equal.
+     * @access public
+     * @see equals()
+     * @internal Could return $this->subtract($x), but that's not as fast as what we do do.
+     */
+    function compare($y)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                return gmp_cmp($this->value, $y->value);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                return bccomp($this->value, $y->value, 0);
+        }
+
+        return $this->_compare($this->value, $this->is_negative, $y->value, $y->is_negative);
+    }
+
+    /**
+     * Compares two numbers.
+     *
+     * @param Array $x_value
+     * @param Boolean $x_negative
+     * @param Array $y_value
+     * @param Boolean $y_negative
+     * @return Integer
+     * @see compare()
+     * @access private
+     */
+    function _compare($x_value, $x_negative, $y_value, $y_negative)
+    {
+        if ( $x_negative != $y_negative ) {
+            return ( !$x_negative && $y_negative ) ? 1 : -1;
+        }
+
+        $result = $x_negative ? -1 : 1;
+
+        if ( count($x_value) != count($y_value) ) {
+            return ( count($x_value) > count($y_value) ) ? $result : -$result;
+        }
+        $size = max(count($x_value), count($y_value));
+
+        $x_value = array_pad($x_value, $size, 0);
+        $y_value = array_pad($y_value, $size, 0);
+
+        for ($i = count($x_value) - 1; $i >= 0; --$i) {
+            if ($x_value[$i] != $y_value[$i]) {
+                return ( $x_value[$i] > $y_value[$i] ) ? $result : -$result;
+            }
+        }
+
+        return 0;
+    }
+
+    /**
+     * Tests the equality of two numbers.
+     *
+     * If you need to see if one number is greater than or less than another number, use Math_BigInteger::compare()
+     *
+     * @param Math_BigInteger $x
+     * @return Boolean
+     * @access public
+     * @see compare()
+     */
+    function equals($x)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                return gmp_cmp($this->value, $x->value) == 0;
+            default:
+                return $this->value === $x->value && $this->is_negative == $x->is_negative;
+        }
+    }
+
+    /**
+     * Set Precision
+     *
+     * Some bitwise operations give different results depending on the precision being used.  Examples include left
+     * shift, not, and rotates.
+     *
+     * @param Math_BigInteger $x
+     * @access public
+     * @return Math_BigInteger
+     */
+    function setPrecision($bits)
+    {
+        $this->precision = $bits;
+        if ( MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_BCMATH ) {
+            $this->bitmask = new Math_BigInteger(chr((1 << ($bits & 0x7)) - 1) . str_repeat(chr(0xFF), $bits >> 3), 256);
+        } else {
+            $this->bitmask = new Math_BigInteger(bcpow('2', $bits, 0));
+        }
+
+        $temp = $this->_normalize($this);
+        $this->value = $temp->value;
+    }
+
+    /**
+     * Logical And
+     *
+     * @param Math_BigInteger $x
+     * @access public
+     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>
+     * @return Math_BigInteger
+     */
+    function bitwise_and($x)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_and($this->value, $x->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $left = $this->toBytes();
+                $right = $x->toBytes();
+
+                $length = max(strlen($left), strlen($right));
+
+                $left = str_pad($left, $length, chr(0), STR_PAD_LEFT);
+                $right = str_pad($right, $length, chr(0), STR_PAD_LEFT);
+
+                return $this->_normalize(new Math_BigInteger($left & $right, 256));
+        }
+
+        $result = $this->copy();
+
+        $length = min(count($x->value), count($this->value));
+
+        $result->value = array_slice($result->value, 0, $length);
+
+        for ($i = 0; $i < $length; ++$i) {
+            $result->value[$i] = $result->value[$i] & $x->value[$i];
+        }
+
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Logical Or
+     *
+     * @param Math_BigInteger $x
+     * @access public
+     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>
+     * @return Math_BigInteger
+     */
+    function bitwise_or($x)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_or($this->value, $x->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $left = $this->toBytes();
+                $right = $x->toBytes();
+
+                $length = max(strlen($left), strlen($right));
+
+                $left = str_pad($left, $length, chr(0), STR_PAD_LEFT);
+                $right = str_pad($right, $length, chr(0), STR_PAD_LEFT);
+
+                return $this->_normalize(new Math_BigInteger($left | $right, 256));
+        }
+
+        $length = max(count($this->value), count($x->value));
+        $result = $this->copy();
+        $result->value = array_pad($result->value, 0, $length);
+        $x->value = array_pad($x->value, 0, $length);
+
+        for ($i = 0; $i < $length; ++$i) {
+            $result->value[$i] = $this->value[$i] | $x->value[$i];
+        }
+
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Logical Exclusive-Or
+     *
+     * @param Math_BigInteger $x
+     * @access public
+     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>
+     * @return Math_BigInteger
+     */
+    function bitwise_xor($x)
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $temp = new Math_BigInteger();
+                $temp->value = gmp_xor($this->value, $x->value);
+
+                return $this->_normalize($temp);
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $left = $this->toBytes();
+                $right = $x->toBytes();
+
+                $length = max(strlen($left), strlen($right));
+
+                $left = str_pad($left, $length, chr(0), STR_PAD_LEFT);
+                $right = str_pad($right, $length, chr(0), STR_PAD_LEFT);
+
+                return $this->_normalize(new Math_BigInteger($left ^ $right, 256));
+        }
+
+        $length = max(count($this->value), count($x->value));
+        $result = $this->copy();
+        $result->value = array_pad($result->value, 0, $length);
+        $x->value = array_pad($x->value, 0, $length);
+
+        for ($i = 0; $i < $length; ++$i) {
+            $result->value[$i] = $this->value[$i] ^ $x->value[$i];
+        }
+
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Logical Not
+     *
+     * @access public
+     * @internal Implemented per a request by Lluis Pamies i Juarez <lluis _a_ pamies.cat>
+     * @return Math_BigInteger
+     */
+    function bitwise_not()
+    {
+        // calculuate "not" without regard to $this->precision
+        // (will always result in a smaller number.  ie. ~1 isn't 1111 1110 - it's 0)
+        $temp = $this->toBytes();
+        $pre_msb = decbin(ord($temp[0]));
+        $temp = ~$temp;
+        $msb = decbin(ord($temp[0]));
+        if (strlen($msb) == 8) {
+            $msb = substr($msb, strpos($msb, '0'));
+        }
+        $temp[0] = chr(bindec($msb));
+
+        // see if we need to add extra leading 1's
+        $current_bits = strlen($pre_msb) + 8 * strlen($temp) - 8;
+        $new_bits = $this->precision - $current_bits;
+        if ($new_bits <= 0) {
+            return $this->_normalize(new Math_BigInteger($temp, 256));
+        }
+
+        // generate as many leading 1's as we need to.
+        $leading_ones = chr((1 << ($new_bits & 0x7)) - 1) . str_repeat(chr(0xFF), $new_bits >> 3);
+        $this->_base256_lshift($leading_ones, $current_bits);
+
+        $temp = str_pad($temp, ceil($this->bits / 8), chr(0), STR_PAD_LEFT);
+
+        return $this->_normalize(new Math_BigInteger($leading_ones | $temp, 256));
+    }
+
+    /**
+     * Logical Right Shift
+     *
+     * Shifts BigInteger's by $shift bits, effectively dividing by 2**$shift.
+     *
+     * @param Integer $shift
+     * @return Math_BigInteger
+     * @access public
+     * @internal The only version that yields any speed increases is the internal version.
+     */
+    function bitwise_rightShift($shift)
+    {
+        $temp = new Math_BigInteger();
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                static $two;
+
+                if (!isset($two)) {
+                    $two = gmp_init('2');
+                }
+
+                $temp->value = gmp_div_q($this->value, gmp_pow($two, $shift));
+
+                break;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp->value = bcdiv($this->value, bcpow('2', $shift, 0), 0);
+
+                break;
+            default: // could just replace _lshift with this, but then all _lshift() calls would need to be rewritten
+                     // and I don't want to do that...
+                $temp->value = $this->value;
+                $temp->_rshift($shift);
+        }
+
+        return $this->_normalize($temp);
+    }
+
+    /**
+     * Logical Left Shift
+     *
+     * Shifts BigInteger's by $shift bits, effectively multiplying by 2**$shift.
+     *
+     * @param Integer $shift
+     * @return Math_BigInteger
+     * @access public
+     * @internal The only version that yields any speed increases is the internal version.
+     */
+    function bitwise_leftShift($shift)
+    {
+        $temp = new Math_BigInteger();
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                static $two;
+
+                if (!isset($two)) {
+                    $two = gmp_init('2');
+                }
+
+                $temp->value = gmp_mul($this->value, gmp_pow($two, $shift));
+
+                break;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $temp->value = bcmul($this->value, bcpow('2', $shift, 0), 0);
+
+                break;
+            default: // could just replace _rshift with this, but then all _lshift() calls would need to be rewritten
+                     // and I don't want to do that...
+                $temp->value = $this->value;
+                $temp->_lshift($shift);
+        }
+
+        return $this->_normalize($temp);
+    }
+
+    /**
+     * Logical Left Rotate
+     *
+     * Instead of the top x bits being dropped they're appended to the shifted bit string.
+     *
+     * @param Integer $shift
+     * @return Math_BigInteger
+     * @access public
+     */
+    function bitwise_leftRotate($shift)
+    {
+        $bits = $this->toBytes();
+
+        if ($this->precision > 0) {
+            $precision = $this->precision;
+            if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_BCMATH ) {
+                $mask = $this->bitmask->subtract(new Math_BigInteger(1));
+                $mask = $mask->toBytes();
+            } else {
+                $mask = $this->bitmask->toBytes();
+            }
+        } else {
+            $temp = ord($bits[0]);
+            for ($i = 0; $temp >> $i; ++$i);
+            $precision = 8 * strlen($bits) - 8 + $i;
+            $mask = chr((1 << ($precision & 0x7)) - 1) . str_repeat(chr(0xFF), $precision >> 3);
+        }
+
+        if ($shift < 0) {
+            $shift+= $precision;
+        }
+        $shift%= $precision;
+
+        if (!$shift) {
+            return $this->copy();
+        }
+
+        $left = $this->bitwise_leftShift($shift);
+        $left = $left->bitwise_and(new Math_BigInteger($mask, 256));
+        $right = $this->bitwise_rightShift($precision - $shift);
+        $result = MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_BCMATH ? $left->bitwise_or($right) : $left->add($right);
+        return $this->_normalize($result);
+    }
+
+    /**
+     * Logical Right Rotate
+     *
+     * Instead of the bottom x bits being dropped they're prepended to the shifted bit string.
+     *
+     * @param Integer $shift
+     * @return Math_BigInteger
+     * @access public
+     */
+    function bitwise_rightRotate($shift)
+    {
+        return $this->bitwise_leftRotate(-$shift);
+    }
+
+    /**
+     * Set random number generator function
+     *
+     * $generator should be the name of a random generating function whose first parameter is the minimum
+     * value and whose second parameter is the maximum value.  If this function needs to be seeded, it should
+     * be seeded prior to calling Math_BigInteger::random() or Math_BigInteger::randomPrime()
+     *
+     * If the random generating function is not explicitly set, it'll be assumed to be mt_rand().
+     *
+     * @see random()
+     * @see randomPrime()
+     * @param optional String $generator
+     * @access public
+     */
+    function setRandomGenerator($generator)
+    {
+        $this->generator = $generator;
+    }
+
+    /**
+     * Generate a random number
+     *
+     * @param optional Integer $min
+     * @param optional Integer $max
+     * @return Math_BigInteger
+     * @access public
+     */
+    function random($min = false, $max = false)
+    {
+        if ($min === false) {
+            $min = new Math_BigInteger(0);
+        }
+
+        if ($max === false) {
+            $max = new Math_BigInteger(0x7FFFFFFF);
+        }
+
+        $compare = $max->compare($min);
+
+        if (!$compare) {
+            return $this->_normalize($min);
+        } else if ($compare < 0) {
+            // if $min is bigger then $max, swap $min and $max
+            $temp = $max;
+            $max = $min;
+            $min = $temp;
+        }
+
+        $generator = $this->generator;
+
+        $max = $max->subtract($min);
+        $max = ltrim($max->toBytes(), chr(0));
+        $size = strlen($max) - 1;
+        $random = '';
+
+        $bytes = $size & 1;
+        for ($i = 0; $i < $bytes; ++$i) {
+            $random.= chr($generator(0, 255));
+        }
+
+        $blocks = $size >> 1;
+        for ($i = 0; $i < $blocks; ++$i) {
+            // mt_rand(-2147483648, 0x7FFFFFFF) always produces -2147483648 on some systems
+            $random.= pack('n', $generator(0, 0xFFFF));
+        }
+
+        $temp = new Math_BigInteger($random, 256);
+        if ($temp->compare(new Math_BigInteger(substr($max, 1), 256)) > 0) {
+            $random = chr($generator(0, ord($max[0]) - 1)) . $random;
+        } else {
+            $random = chr($generator(0, ord($max[0])    )) . $random;
+        }
+
+        $random = new Math_BigInteger($random, 256);
+
+        return $this->_normalize($random->add($min));
+    }
+
+    /**
+     * Generate a random prime number.
+     *
+     * If there's not a prime within the given range, false will be returned.  If more than $timeout seconds have elapsed,
+     * give up and return false.
+     *
+     * @param optional Integer $min
+     * @param optional Integer $max
+     * @param optional Integer $timeout
+     * @return Math_BigInteger
+     * @access public
+     * @internal See {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap4.pdf#page=15 HAC 4.44}.
+     */
+    function randomPrime($min = false, $max = false, $timeout = false)
+    {
+        $compare = $max->compare($min);
+
+        if (!$compare) {
+            return $min;
+        } else if ($compare < 0) {
+            // if $min is bigger then $max, swap $min and $max
+            $temp = $max;
+            $max = $min;
+            $min = $temp;
+        }
+
+        // gmp_nextprime() requires PHP 5 >= 5.2.0 per <http://php.net/gmp-nextprime>.
+        if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_GMP && function_exists('gmp_nextprime') ) {
+            // we don't rely on Math_BigInteger::random()'s min / max when gmp_nextprime() is being used since this function
+            // does its own checks on $max / $min when gmp_nextprime() is used.  When gmp_nextprime() is not used, however,
+            // the same $max / $min checks are not performed.
+            if ($min === false) {
+                $min = new Math_BigInteger(0);
+            }
+
+            if ($max === false) {
+                $max = new Math_BigInteger(0x7FFFFFFF);
+            }
+
+            $x = $this->random($min, $max);
+
+            $x->value = gmp_nextprime($x->value);
+
+            if ($x->compare($max) <= 0) {
+                return $x;
+            }
+
+            $x->value = gmp_nextprime($min->value);
+
+            if ($x->compare($max) <= 0) {
+                return $x;
+            }
+
+            return false;
+        }
+
+        static $one, $two;
+        if (!isset($one)) {
+            $one = new Math_BigInteger(1);
+            $two = new Math_BigInteger(2);
+        }
+
+        $start = time();
+
+        $x = $this->random($min, $max);
+        if ($x->equals($two)) {
+            return $x;
+        }
+
+        $x->_make_odd();
+        if ($x->compare($max) > 0) {
+            // if $x > $max then $max is even and if $min == $max then no prime number exists between the specified range
+            if ($min->equals($max)) {
+                return false;
+            }
+            $x = $min->copy();
+            $x->_make_odd();
+        }
+
+        $initial_x = $x->copy();
+
+        while (true) {
+            if ($timeout !== false && time() - $start > $timeout) {
+                return false;
+            }
+
+            if ($x->isPrime()) {
+                return $x;
+            }
+
+            $x = $x->add($two);
+
+            if ($x->compare($max) > 0) {
+                $x = $min->copy();
+                if ($x->equals($two)) {
+                    return $x;
+                }
+                $x->_make_odd();
+            }
+
+            if ($x->equals($initial_x)) {
+                return false;
+            }
+        }
+    }
+
+    /**
+     * Make the current number odd
+     *
+     * If the current number is odd it'll be unchanged.  If it's even, one will be added to it.
+     *
+     * @see randomPrime()
+     * @access private
+     */
+    function _make_odd()
+    {
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                gmp_setbit($this->value, 0);
+                break;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                if ($this->value[strlen($this->value) - 1] % 2 == 0) {
+                    $this->value = bcadd($this->value, '1');
+                }
+                break;
+            default:
+                $this->value[0] |= 1;
+        }
+    }
+
+    /**
+     * Checks a numer to see if it's prime
+     *
+     * Assuming the $t parameter is not set, this function has an error rate of 2**-80.  The main motivation for the
+     * $t parameter is distributability.  Math_BigInteger::randomPrime() can be distributed accross multiple pageloads
+     * on a website instead of just one.
+     *
+     * @param optional Integer $t
+     * @return Boolean
+     * @access public
+     * @internal Uses the
+     *     {@link http://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test Miller-Rabin primality test}.  See 
+     *     {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap4.pdf#page=8 HAC 4.24}.
+     */
+    function isPrime($t = false)
+    {
+        $length = strlen($this->toBytes());
+
+        if (!$t) {
+            // see HAC 4.49 "Note (controlling the error probability)"
+                 if ($length >= 163) { $t =  2; } // floor(1300 / 8)
+            else if ($length >= 106) { $t =  3; } // floor( 850 / 8)
+            else if ($length >= 81 ) { $t =  4; } // floor( 650 / 8)
+            else if ($length >= 68 ) { $t =  5; } // floor( 550 / 8)
+            else if ($length >= 56 ) { $t =  6; } // floor( 450 / 8)
+            else if ($length >= 50 ) { $t =  7; } // floor( 400 / 8)
+            else if ($length >= 43 ) { $t =  8; } // floor( 350 / 8)
+            else if ($length >= 37 ) { $t =  9; } // floor( 300 / 8)
+            else if ($length >= 31 ) { $t = 12; } // floor( 250 / 8)
+            else if ($length >= 25 ) { $t = 15; } // floor( 200 / 8)
+            else if ($length >= 18 ) { $t = 18; } // floor( 150 / 8)
+            else                     { $t = 27; }
+        }
+
+        // ie. gmp_testbit($this, 0)
+        // ie. isEven() or !isOdd()
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                return gmp_prob_prime($this->value, $t) != 0;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                if ($this->value === '2') {
+                    return true;
+                }
+                if ($this->value[strlen($this->value) - 1] % 2 == 0) {
+                    return false;
+                }
+                break;
+            default:
+                if ($this->value == array(2)) {
+                    return true;
+                }
+                if (~$this->value[0] & 1) {
+                    return false;
+                }
+        }
+
+        static $primes, $zero, $one, $two;
+
+        if (!isset($primes)) {
+            $primes = array(
+                3,    5,    7,    11,   13,   17,   19,   23,   29,   31,   37,   41,   43,   47,   53,   59,   
+                61,   67,   71,   73,   79,   83,   89,   97,   101,  103,  107,  109,  113,  127,  131,  137,  
+                139,  149,  151,  157,  163,  167,  173,  179,  181,  191,  193,  197,  199,  211,  223,  227,  
+                229,  233,  239,  241,  251,  257,  263,  269,  271,  277,  281,  283,  293,  307,  311,  313,  
+                317,  331,  337,  347,  349,  353,  359,  367,  373,  379,  383,  389,  397,  401,  409,  419,  
+                421,  431,  433,  439,  443,  449,  457,  461,  463,  467,  479,  487,  491,  499,  503,  509,  
+                521,  523,  541,  547,  557,  563,  569,  571,  577,  587,  593,  599,  601,  607,  613,  617,  
+                619,  631,  641,  643,  647,  653,  659,  661,  673,  677,  683,  691,  701,  709,  719,  727,  
+                733,  739,  743,  751,  757,  761,  769,  773,  787,  797,  809,  811,  821,  823,  827,  829,  
+                839,  853,  857,  859,  863,  877,  881,  883,  887,  907,  911,  919,  929,  937,  941,  947,  
+                953,  967,  971,  977,  983,  991,  997
+            );
+
+            if ( MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_INTERNAL ) {
+                for ($i = 0; $i < count($primes); ++$i) {
+                    $primes[$i] = new Math_BigInteger($primes[$i]);
+                }
+            }
+
+            $zero = new Math_BigInteger();
+            $one = new Math_BigInteger(1);
+            $two = new Math_BigInteger(2);
+        }
+
+        if ($this->equals($one)) {
+            return false;
+        }
+
+        // see HAC 4.4.1 "Random search for probable primes"
+        if ( MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_INTERNAL ) {
+            foreach ($primes as $prime) {
+                list(, $r) = $this->divide($prime);
+                if ($r->equals($zero)) {
+                    return $this->equals($prime);
+                }
+            }
+        } else {
+            $value = $this->value;
+            foreach ($primes as $prime) {
+                list(, $r) = $this->_divide_digit($value, $prime);
+                if (!$r) {
+                    return count($value) == 1 && $value[0] == $prime;
+                }
+            }
+        }
+
+        $n   = $this->copy();
+        $n_1 = $n->subtract($one);
+        $n_2 = $n->subtract($two);
+
+        $r = $n_1->copy();
+        $r_value = $r->value;
+        // ie. $s = gmp_scan1($n, 0) and $r = gmp_div_q($n, gmp_pow(gmp_init('2'), $s));
+        if ( MATH_BIGINTEGER_MODE == MATH_BIGINTEGER_MODE_BCMATH ) {
+            $s = 0;
+            // if $n was 1, $r would be 0 and this would be an infinite loop, hence our $this->equals($one) check earlier
+            while ($r->value[strlen($r->value) - 1] % 2 == 0) {
+                $r->value = bcdiv($r->value, '2', 0);
+                ++$s;
+            }
+        } else {
+            for ($i = 0, $r_length = count($r_value); $i < $r_length; ++$i) {
+                $temp = ~$r_value[$i] & 0xFFFFFF;
+                for ($j = 1; ($temp >> $j) & 1; ++$j);
+                if ($j != 25) {
+                    break;
+                }
+            }
+            $s = 26 * $i + $j - 1;
+            $r->_rshift($s);
+        }
+
+        for ($i = 0; $i < $t; ++$i) {
+            $a = $this->random($two, $n_2);
+            $y = $a->modPow($r, $n);
+
+            if (!$y->equals($one) && !$y->equals($n_1)) {
+                for ($j = 1; $j < $s && !$y->equals($n_1); ++$j) {
+                    $y = $y->modPow($two, $n);
+                    if ($y->equals($one)) {
+                        return false;
+                    }
+                }
+
+                if (!$y->equals($n_1)) {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Logical Left Shift
+     *
+     * Shifts BigInteger's by $shift bits.
+     *
+     * @param Integer $shift
+     * @access private
+     */
+    function _lshift($shift)
+    {
+        if ( $shift == 0 ) {
+            return;
+        }
+
+        $num_digits = (int) ($shift / 26);
+        $shift %= 26;
+        $shift = 1 << $shift;
+
+        $carry = 0;
+
+        for ($i = 0; $i < count($this->value); ++$i) {
+            $temp = $this->value[$i] * $shift + $carry;
+            $carry = (int) ($temp / 0x4000000);
+            $this->value[$i] = (int) ($temp - $carry * 0x4000000);
+        }
+
+        if ( $carry ) {
+            $this->value[] = $carry;
+        }
+
+        while ($num_digits--) {
+            array_unshift($this->value, 0);
+        }
+    }
+
+    /**
+     * Logical Right Shift
+     *
+     * Shifts BigInteger's by $shift bits.
+     *
+     * @param Integer $shift
+     * @access private
+     */
+    function _rshift($shift)
+    {
+        if ($shift == 0) {
+            return;
+        }
+
+        $num_digits = (int) ($shift / 26);
+        $shift %= 26;
+        $carry_shift = 26 - $shift;
+        $carry_mask = (1 << $shift) - 1;
+
+        if ( $num_digits ) {
+            $this->value = array_slice($this->value, $num_digits);
+        }
+
+        $carry = 0;
+
+        for ($i = count($this->value) - 1; $i >= 0; --$i) {
+            $temp = $this->value[$i] >> $shift | $carry;
+            $carry = ($this->value[$i] & $carry_mask) << $carry_shift;
+            $this->value[$i] = $temp;
+        }
+
+        $this->value = $this->_trim($this->value);
+    }
+
+    /**
+     * Normalize
+     *
+     * Removes leading zeros and truncates (if necessary) to maintain the appropriate precision
+     *
+     * @param Math_BigInteger
+     * @return Math_BigInteger
+     * @see _trim()
+     * @access private
+     */
+    function _normalize($result)
+    {
+        $result->precision = $this->precision;
+        $result->bitmask = $this->bitmask;
+
+        switch ( MATH_BIGINTEGER_MODE ) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                if (!empty($result->bitmask->value)) {
+                    $result->value = gmp_and($result->value, $result->bitmask->value);
+                }
+
+                return $result;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                if (!empty($result->bitmask->value)) {
+                    $result->value = bcmod($result->value, $result->bitmask->value);
+                }
+
+                return $result;
+        }
+
+        $value = &$result->value;
+
+        if ( !count($value) ) {
+            return $result;
+        }
+
+        $value = $this->_trim($value);
+
+        if (!empty($result->bitmask->value)) {
+            $length = min(count($value), count($this->bitmask->value));
+            $value = array_slice($value, 0, $length);
+
+            for ($i = 0; $i < $length; ++$i) {
+                $value[$i] = $value[$i] & $this->bitmask->value[$i];
+            }
+        }
+
+        return $result;
+    }
+
+    /**
+     * Trim
+     *
+     * Removes leading zeros
+     *
+     * @return Math_BigInteger
+     * @access private
+     */
+    function _trim($value)
+    {
+        for ($i = count($value) - 1; $i >= 0; --$i) {
+            if ( $value[$i] ) {
+                break;
+            }
+            unset($value[$i]);
+        }
+
+        return $value;
+    }
+
+    /**
+     * Array Repeat
+     *
+     * @param $input Array
+     * @param $multiplier mixed
+     * @return Array
+     * @access private
+     */
+    function _array_repeat($input, $multiplier)
+    {
+        return ($multiplier) ? array_fill(0, $multiplier, $input) : array();
+    }
+
+    /**
+     * Logical Left Shift
+     *
+     * Shifts binary strings $shift bits, essentially multiplying by 2**$shift.
+     *
+     * @param $x String
+     * @param $shift Integer
+     * @return String
+     * @access private
+     */
+    function _base256_lshift(&$x, $shift)
+    {
+        if ($shift == 0) {
+            return;
+        }
+
+        $num_bytes = $shift >> 3; // eg. floor($shift/8)
+        $shift &= 7; // eg. $shift % 8
+
+        $carry = 0;
+        for ($i = strlen($x) - 1; $i >= 0; --$i) {
+            $temp = ord($x[$i]) << $shift | $carry;
+            $x[$i] = chr($temp);
+            $carry = $temp >> 8;
+        }
+        $carry = ($carry != 0) ? chr($carry) : '';
+        $x = $carry . $x . str_repeat(chr(0), $num_bytes);
+    }
+
+    /**
+     * Logical Right Shift
+     *
+     * Shifts binary strings $shift bits, essentially dividing by 2**$shift and returning the remainder.
+     *
+     * @param $x String
+     * @param $shift Integer
+     * @return String
+     * @access private
+     */
+    function _base256_rshift(&$x, $shift)
+    {
+        if ($shift == 0) {
+            $x = ltrim($x, chr(0));
+            return '';
+        }
+
+        $num_bytes = $shift >> 3; // eg. floor($shift/8)
+        $shift &= 7; // eg. $shift % 8
+
+        $remainder = '';
+        if ($num_bytes) {
+            $start = $num_bytes > strlen($x) ? -strlen($x) : -$num_bytes;
+            $remainder = substr($x, $start);
+            $x = substr($x, 0, -$num_bytes);
+        }
+
+        $carry = 0;
+        $carry_shift = 8 - $shift;
+        for ($i = 0; $i < strlen($x); ++$i) {
+            $temp = (ord($x[$i]) >> $shift) | $carry;
+            $carry = (ord($x[$i]) << $carry_shift) & 0xFF;
+            $x[$i] = chr($temp);
+        }
+        $x = ltrim($x, chr(0));
+
+        $remainder = chr($carry >> $carry_shift) . $remainder;
+
+        return ltrim($remainder, chr(0));
+    }
+
+    // one quirk about how the following functions are implemented is that PHP defines N to be an unsigned long
+    // at 32-bits, while java's longs are 64-bits.
+
+    /**
+     * Converts 32-bit integers to bytes.
+     *
+     * @param Integer $x
+     * @return String
+     * @access private
+     */
+    function _int2bytes($x)
+    {
+        return ltrim(pack('N', $x), chr(0));
+    }
+
+    /**
+     * Converts bytes to 32-bit integers
+     *
+     * @param String $x
+     * @return Integer
+     * @access private
+     */
+    function _bytes2int($x)
+    {
+        $temp = unpack('Nint', str_pad($x, 4, chr(0), STR_PAD_LEFT));
+        return $temp['int'];
+    }
 }
\ No newline at end of file