summaryrefslogtreecommitdiff
path: root/plugins/OStatus/extlib/Crypt/AES.php
blob: 4b062c4f23391fdff53295906fc10edbc7d3e1fb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
<?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:
// vim6: fdl=1: