contact-forms / phpseclib-crypt / AES.php

AES.php in Contact Forms by Cimatti 1.2, at phpseclib-crypt/AES.php

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1	<?php
2	/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
3
4	/**
5	* Pure-PHP implementation of AES.
6	*
7	* Uses mcrypt, if available, and an internal implementation, otherwise.
8	*
9	* PHP versions 4 and 5
10	*
11	* If {@link Crypt_AES::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
12	* {@link Crypt_AES::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's 136-bits
13	* it'll be null-padded to 160-bits and 160 bits will be the key length until {@link Crypt_Rijndael::setKey() setKey()}
14	* is called, again, at which point, it'll be recalculated.
15	*
16	* Since Crypt_AES extends Crypt_Rijndael, some functions are available to be called that, in the context of AES, don't
17	* make a whole lot of sense. {@link Crypt_AES::setBlockLength() setBlockLength()}, for instance. Calling that function,
18	* however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
19	*
20	* Here's a short example of how to use this library:
21	* <code>
22	* <?php
23	* include('Crypt/AES.php');
24	*
25	* $aes = new Crypt_AES();
26	*
27	* $aes->setKey('abcdefghijklmnop');
28	*
29	* $size = 10 * 1024;
30	* $plaintext = '';
31	* for ($i = 0; $i < $size; $i++) {
32	* $plaintext.= 'a';
33	* }
34	*
35	* echo $aes->decrypt($aes->encrypt($plaintext));
36	* ?>
37	* </code>
38	*
39	* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
40	* of this software and associated documentation files (the "Software"), to deal
41	* in the Software without restriction, including without limitation the rights
42	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
43	* copies of the Software, and to permit persons to whom the Software is
44	* furnished to do so, subject to the following conditions:
45	*
46	* The above copyright notice and this permission notice shall be included in
47	* all copies or substantial portions of the Software.
48	*
49	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
50	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
51	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
52	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
53	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
54	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
55	* THE SOFTWARE.
56	*
57	* @category Crypt
58	* @package Crypt_AES
59	* @author Jim Wigginton <terrafrost@php.net>
60	* @copyright MMVIII Jim Wigginton
61	* @license http://www.opensource.org/licenses/mit-license.html MIT License
62	* @version $Id: AES.php,v 1.7 2010/02/09 06:10:25 terrafrost Exp $
63	* @link http://phpseclib.sourceforge.net
64	*/
65
66	/**
67	* Include Crypt_Rijndael
68	*/
69	if (!class_exists('Crypt_Rijndael')) {
70	require_once 'Rijndael.php';
71	}
72
73	/**#@+
74	* @access public
75	* @see Crypt_AES::encrypt()
76	* @see Crypt_AES::decrypt()
77	*/
78	/**
79	* Encrypt / decrypt using the Counter mode.
80	*
81	* Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
82	*
83	* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
84	*/
85	define('CRYPT_AES_MODE_CTR', -1);
86	/**
87	* Encrypt / decrypt using the Electronic Code Book mode.
88	*
89	* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
90	*/
91	define('CRYPT_AES_MODE_ECB', 1);
92	/**
93	* Encrypt / decrypt using the Code Book Chaining mode.
94	*
95	* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
96	*/
97	define('CRYPT_AES_MODE_CBC', 2);
98	/**
99	* Encrypt / decrypt using the Cipher Feedback mode.
100	*
101	* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
102	*/
103	define('CRYPT_AES_MODE_CFB', 3);
104	/**
105	* Encrypt / decrypt using the Cipher Feedback mode.
106	*
107	* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
108	*/
109	define('CRYPT_AES_MODE_OFB', 4);
110	/*#@-/
111
112	/**#@+
113	* @access private
114	* @see Crypt_AES::Crypt_AES()
115	*/
116	/**
117	* Toggles the internal implementation
118	*/
119	define('CRYPT_AES_MODE_INTERNAL', 1);
120	/**
121	* Toggles the mcrypt implementation
122	*/
123	define('CRYPT_AES_MODE_MCRYPT', 2);
124	/*#@-/
125
126	/**
127	* Pure-PHP implementation of AES.
128	*
129	* @author Jim Wigginton <terrafrost@php.net>
130	* @version 0.1.0
131	* @access public
132	* @package Crypt_AES
133	*/
134	class Crypt_AES extends Crypt_Rijndael {
135	/**
136	* mcrypt resource for encryption
137	*
138	* The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
139	* Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
140	*
141	* @see Crypt_AES::encrypt()
142	* @var String
143	* @access private
144	*/
145	var $enmcrypt;
146
147	/**
148	* mcrypt resource for decryption
149	*
150	* The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
151	* Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
152	*
153	* @see Crypt_AES::decrypt()
154	* @var String
155	* @access private
156	*/
157	var $demcrypt;
158
159	/**
160	* mcrypt resource for CFB mode
161	*
162	* @see Crypt_AES::encrypt()
163	* @see Crypt_AES::decrypt()
164	* @var String
165	* @access private
166	*/
167	var $ecb;
168
169	/**
170	* Default Constructor.
171	*
172	* Determines whether or not the mcrypt extension should be used. $mode should only, at present, be
173	* CRYPT_AES_MODE_ECB or CRYPT_AES_MODE_CBC. If not explictly set, CRYPT_AES_MODE_CBC will be used.
174	*
175	* @param optional Integer $mode
176	* @return Crypt_AES
177	* @access public
178	*/
179	function Crypt_AES($mode = CRYPT_AES_MODE_CBC)
180	{
181	if ( !defined('CRYPT_AES_MODE') ) {
182	switch (true) {
183	case extension_loaded('mcrypt') && in_array('rijndael-128', mcrypt_list_algorithms()):
184	define('CRYPT_AES_MODE', CRYPT_AES_MODE_MCRYPT);
185	break;
186	default:
187	define('CRYPT_AES_MODE', CRYPT_AES_MODE_INTERNAL);
188	}
189	}
190
191	switch ( CRYPT_AES_MODE ) {
192	case CRYPT_AES_MODE_MCRYPT:
193	switch ($mode) {
194	case CRYPT_AES_MODE_ECB:
195	$this->paddable = true;
196	$this->mode = MCRYPT_MODE_ECB;
197	break;
198	case CRYPT_AES_MODE_CTR:
199	// ctr doesn't have a constant associated with it even though it appears to be fairly widely
200	// supported. in lieu of knowing just how widely supported it is, i've, for now, opted not to
201	// include a compatibility layer. the layer has been implemented but, for now, is commented out.
202	$this->mode = 'ctr';
203	//$this->mode = in_array('ctr', mcrypt_list_modes()) ? 'ctr' : CRYPT_AES_MODE_CTR;
204	break;
205	case CRYPT_AES_MODE_CFB:
206	$this->mode = 'ncfb';
207	break;
208	case CRYPT_AES_MODE_OFB:
209	$this->mode = MCRYPT_MODE_NOFB;
210	break;
211	case CRYPT_AES_MODE_CBC:
212	default:
213	$this->paddable = true;
214	$this->mode = MCRYPT_MODE_CBC;
215	}
216
217	$this->debuffer = $this->enbuffer = '';
218
219	break;
220	default:
221	switch ($mode) {
222	case CRYPT_AES_MODE_ECB:
223	$this->paddable = true;
224	$this->mode = CRYPT_RIJNDAEL_MODE_ECB;
225	break;
226	case CRYPT_AES_MODE_CTR:
227	$this->mode = CRYPT_RIJNDAEL_MODE_CTR;
228	break;
229	case CRYPT_AES_MODE_CFB:
230	$this->mode = CRYPT_RIJNDAEL_MODE_CFB;
231	break;
232	case CRYPT_AES_MODE_OFB:
233	$this->mode = CRYPT_RIJNDAEL_MODE_OFB;
234	break;
235	case CRYPT_AES_MODE_CBC:
236	default:
237	$this->paddable = true;
238	$this->mode = CRYPT_RIJNDAEL_MODE_CBC;
239	}
240	}
241
242	if (CRYPT_AES_MODE == CRYPT_AES_MODE_INTERNAL) {
243	parent::Crypt_Rijndael($this->mode);
244	}
245	}
246
247	/**
248	* Dummy function
249	*
250	* Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.
251	*
252	* @access public
253	* @param Integer $length
254	*/
255	function setBlockLength($length)
256	{
257	return;
258	}
259
260
261	/**
262	* Sets the initialization vector. (optional)
263	*
264	* SetIV is not required when CRYPT_RIJNDAEL_MODE_ECB is being used. If not explictly set, it'll be assumed
265	* to be all zero's.
266	*
267	* @access public
268	* @param String $iv
269	*/
270	function setIV($iv)
271	{
272	parent::setIV($iv);
273	if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
274	$this->changed = true;
275	}
276	}
277
278	/**
279	* Encrypts a message.
280	*
281	* $plaintext will be padded with up to 16 additional bytes. Other AES implementations may or may not pad in the
282	* same manner. Other common approaches to padding and the reasons why it's necessary are discussed in the following
283	* URL:
284	*
285	* {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
286	*
287	* An alternative to padding is to, separately, send the length of the file. This is what SSH, in fact, does.
288	* strlen($plaintext) will still need to be a multiple of 16, however, arbitrary values can be added to make it that
289	* length.
290	*
291	* @see Crypt_AES::decrypt()
292	* @access public
293	* @param String $plaintext
294	*/
295	function encrypt($plaintext)
296	{
297	if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
298	$changed = $this->changed;
299	$this->_mcryptSetup();
300	/*
301	if ($this->mode == CRYPT_AES_MODE_CTR) {
302	$iv = $this->encryptIV;
303	$xor = mcrypt_generic($this->enmcrypt, $this->_generate_xor(strlen($plaintext), $iv));
304	$ciphertext = $plaintext ^ $xor;
305	if ($this->continuousBuffer) {
306	$this->encryptIV = $iv;
307	}
308	return $ciphertext;
309	}
310	*/
311	// re: http://phpseclib.sourceforge.net/cfb-demo.phps
312	// using mcrypt's default handing of CFB the above would output two different things. using phpseclib's
313	// rewritten CFB implementation the above outputs the same thing twice.
314	if ($this->mode == 'ncfb') {
315	if ($changed) {
316	$this->ecb = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
317	mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
318	}
319
320	if (strlen($this->enbuffer)) {
321	$ciphertext = $plaintext ^ substr($this->encryptIV, strlen($this->enbuffer));
322	$this->enbuffer.= $ciphertext;
323	if (strlen($this->enbuffer) == 16) {
324	$this->encryptIV = $this->enbuffer;
325	$this->enbuffer = '';
326	mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
327	}
328	$plaintext = substr($plaintext, strlen($ciphertext));
329	} else {
330	$ciphertext = '';
331	}
332
333	$last_pos = strlen($plaintext) & 0xFFFFFFF0;
334	$ciphertext.= $last_pos ? mcrypt_generic($this->enmcrypt, substr($plaintext, 0, $last_pos)) : '';
335
336	if (strlen($plaintext) & 0xF) {
337	if (strlen($ciphertext)) {
338	$this->encryptIV = substr($ciphertext, -16);
339	}
340	$this->encryptIV = mcrypt_generic($this->ecb, $this->encryptIV);
341	$this->enbuffer = substr($plaintext, $last_pos) ^ $this->encryptIV;
342	$ciphertext.= $this->enbuffer;
343	}
344
345	return $ciphertext;
346	}
347
348	if ($this->paddable) {
349	$plaintext = $this->_pad($plaintext);
350	}
351
352	$ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
353
354	if (!$this->continuousBuffer) {
355	mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
356	}
357
358	return $ciphertext;
359	}
360
361	return parent::encrypt($plaintext);
362	}
363
364	/**
365	* Decrypts a message.
366	*
367	* If strlen($ciphertext) is not a multiple of 16, null bytes will be added to the end of the string until it is.
368	*
369	* @see Crypt_AES::encrypt()
370	* @access public
371	* @param String $ciphertext
372	*/
373	function decrypt($ciphertext)
374	{
375	if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
376	$changed = $this->changed;
377	$this->_mcryptSetup();
378	/*
379	if ($this->mode == CRYPT_AES_MODE_CTR) {
380	$iv = $this->decryptIV;
381	$xor = mcrypt_generic($this->enmcrypt, $this->_generate_xor(strlen($ciphertext), $iv));
382	$plaintext = $ciphertext ^ $xor;
383	if ($this->continuousBuffer) {
384	$this->decryptIV = $iv;
385	}
386	return $plaintext;
387	}
388	*/
389	if ($this->mode == 'ncfb') {
390	if ($changed) {
391	$this->ecb = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
392	mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
393	}
394
395	if (strlen($this->debuffer)) {
396	$plaintext = $ciphertext ^ substr($this->decryptIV, strlen($this->debuffer));
397
398	$this->debuffer.= substr($ciphertext, 0, strlen($plaintext));
399	if (strlen($this->debuffer) == 16) {
400	$this->decryptIV = $this->debuffer;
401	$this->debuffer = '';
402	mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV);
403	}
404	$ciphertext = substr($ciphertext, strlen($plaintext));
405	} else {
406	$plaintext = '';
407	}
408
409	$last_pos = strlen($ciphertext) & 0xFFFFFFF0;
410	$plaintext.= $last_pos ? mdecrypt_generic($this->demcrypt, substr($ciphertext, 0, $last_pos)) : '';
411
412	if (strlen($ciphertext) & 0xF) {
413	if (strlen($plaintext)) {
414	$this->decryptIV = substr($ciphertext, $last_pos - 16, 16);
415	}
416	$this->decryptIV = mcrypt_generic($this->ecb, $this->decryptIV);
417	$this->debuffer = substr($ciphertext, $last_pos);
418	$plaintext.= $this->debuffer ^ $this->decryptIV;
419	}
420
421	return $plaintext;
422	}
423
424	if ($this->paddable) {
425	// we pad with chr(0) since that's what mcrypt_generic does. to quote from http://php.net/function.mcrypt-generic :
426	// "The data is padded with "\0" to make sure the length of the data is n * blocksize."
427	$ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 15) & 0xFFFFFFF0, chr(0));
428	}
429
430	$plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
431
432	if (!$this->continuousBuffer) {
433	mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
434	}
435
436	return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
437	}
438
439	return parent::decrypt($ciphertext);
440	}
441
442	/**
443	* Setup mcrypt
444	*
445	* Validates all the variables.
446	*
447	* @access private
448	*/
449	function _mcryptSetup()
450	{
451	if (!$this->changed) {
452	return;
453	}
454
455	if (!$this->explicit_key_length) {
456	// this just copied from Crypt_Rijndael::_setup()
457	$length = strlen($this->key) >> 2;
458	if ($length > 8) {
459	$length = 8;
460	} else if ($length < 4) {
461	$length = 4;
462	}
463	$this->Nk = $length;
464	$this->key_size = $length << 2;
465	}
466
467	switch ($this->Nk) {
468	case 4: // 128
469	$this->key_size = 16;
470	break;
471	case 5: // 160
472	case 6: // 192
473	$this->key_size = 24;
474	break;
475	case 7: // 224
476	case 8: // 256
477	$this->key_size = 32;
478	}
479
480	$this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, chr(0));
481	$this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, 16), 16, chr(0));
482
483	if (!isset($this->enmcrypt)) {
484	$mode = $this->mode;
485	//$mode = $this->mode == CRYPT_AES_MODE_CTR ? MCRYPT_MODE_ECB : $this->mode;
486
487	$this->demcrypt = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', $mode, '');
488	$this->enmcrypt = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', $mode, '');
489	} // else should mcrypt_generic_deinit be called?
490
491	mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
492	mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
493
494	$this->changed = false;
495	}
496
497	/**
498	* Encrypts a block
499	*
500	* Optimized over Crypt_Rijndael's implementation by means of loop unrolling.
501	*
502	* @see Crypt_Rijndael::_encryptBlock()
503	* @access private
504	* @param String $in
505	* @return String
506	*/
507	function _encryptBlock($in)
508	{
509	$state = unpack('N*word', $in);
510
511	$Nr = $this->Nr;
512	$w = $this->w;
513	$t0 = $this->t0;
514	$t1 = $this->t1;
515	$t2 = $this->t2;
516	$t3 = $this->t3;
517
518	// addRoundKey and reindex $state
519	$state = array(
520	$state['word1'] ^ $w[0][0],
521	$state['word2'] ^ $w[0][1],
522	$state['word3'] ^ $w[0][2],
523	$state['word4'] ^ $w[0][3]
524	);
525
526	// shiftRows + subWord + mixColumns + addRoundKey
527	// we could loop unroll this and use if statements to do more rounds as necessary, but, in my tests, that yields
528	// only a marginal improvement. since that also, imho, hinders the readability of the code, i've opted not to do it.
529	for ($round = 1; $round < $this->Nr; $round++) {
530	$state = array(
531	$t0[$state[0] & 0xFF000000] ^ $t1[$state[1] & 0x00FF0000] ^ $t2[$state[2] & 0x0000FF00] ^ $t3[$state[3] & 0x000000FF] ^ $w[$round][0],
532	$t0[$state[1] & 0xFF000000] ^ $t1[$state[2] & 0x00FF0000] ^ $t2[$state[3] & 0x0000FF00] ^ $t3[$state[0] & 0x000000FF] ^ $w[$round][1],
533	$t0[$state[2] & 0xFF000000] ^ $t1[$state[3] & 0x00FF0000] ^ $t2[$state[0] & 0x0000FF00] ^ $t3[$state[1] & 0x000000FF] ^ $w[$round][2],
534	$t0[$state[3] & 0xFF000000] ^ $t1[$state[0] & 0x00FF0000] ^ $t2[$state[1] & 0x0000FF00] ^ $t3[$state[2] & 0x000000FF] ^ $w[$round][3]
535	);
536
537	}
538
539	// subWord
540	$state = array(
541	$this->_subWord($state[0]),
542	$this->_subWord($state[1]),
543	$this->_subWord($state[2]),
544	$this->_subWord($state[3])
545	);
546
547	// shiftRows + addRoundKey
548	$state = array(
549	($state[0] & 0xFF000000) ^ ($state[1] & 0x00FF0000) ^ ($state[2] & 0x0000FF00) ^ ($state[3] & 0x000000FF) ^ $this->w[$this->Nr][0],
550	($state[1] & 0xFF000000) ^ ($state[2] & 0x00FF0000) ^ ($state[3] & 0x0000FF00) ^ ($state[0] & 0x000000FF) ^ $this->w[$this->Nr][1],
551	($state[2] & 0xFF000000) ^ ($state[3] & 0x00FF0000) ^ ($state[0] & 0x0000FF00) ^ ($state[1] & 0x000000FF) ^ $this->w[$this->Nr][2],
552	($state[3] & 0xFF000000) ^ ($state[0] & 0x00FF0000) ^ ($state[1] & 0x0000FF00) ^ ($state[2] & 0x000000FF) ^ $this->w[$this->Nr][3]
553	);
554
555	return pack('N*', $state[0], $state[1], $state[2], $state[3]);
556	}
557
558	/**
559	* Decrypts a block
560	*
561	* Optimized over Crypt_Rijndael's implementation by means of loop unrolling.
562	*
563	* @see Crypt_Rijndael::_decryptBlock()
564	* @access private
565	* @param String $in
566	* @return String
567	*/
568	function _decryptBlock($in)
569	{
570	$state = unpack('N*word', $in);
571
572	$Nr = $this->Nr;
573	$dw = $this->dw;
574	$dt0 = $this->dt0;
575	$dt1 = $this->dt1;
576	$dt2 = $this->dt2;
577	$dt3 = $this->dt3;
578
579	// addRoundKey and reindex $state
580	$state = array(
581	$state['word1'] ^ $dw[$this->Nr][0],
582	$state['word2'] ^ $dw[$this->Nr][1],
583	$state['word3'] ^ $dw[$this->Nr][2],
584	$state['word4'] ^ $dw[$this->Nr][3]
585	);
586
587
588	// invShiftRows + invSubBytes + invMixColumns + addRoundKey
589	for ($round = $this->Nr - 1; $round > 0; $round--) {
590	$state = array(
591	$dt0[$state[0] & 0xFF000000] ^ $dt1[$state[3] & 0x00FF0000] ^ $dt2[$state[2] & 0x0000FF00] ^ $dt3[$state[1] & 0x000000FF] ^ $dw[$round][0],
592	$dt0[$state[1] & 0xFF000000] ^ $dt1[$state[0] & 0x00FF0000] ^ $dt2[$state[3] & 0x0000FF00] ^ $dt3[$state[2] & 0x000000FF] ^ $dw[$round][1],
593	$dt0[$state[2] & 0xFF000000] ^ $dt1[$state[1] & 0x00FF0000] ^ $dt2[$state[0] & 0x0000FF00] ^ $dt3[$state[3] & 0x000000FF] ^ $dw[$round][2],
594	$dt0[$state[3] & 0xFF000000] ^ $dt1[$state[2] & 0x00FF0000] ^ $dt2[$state[1] & 0x0000FF00] ^ $dt3[$state[0] & 0x000000FF] ^ $dw[$round][3]
595	);
596	}
597
598	// invShiftRows + invSubWord + addRoundKey
599	$state = array(
600	$this->_invSubWord(($state[0] & 0xFF000000) ^ ($state[3] & 0x00FF0000) ^ ($state[2] & 0x0000FF00) ^ ($state[1] & 0x000000FF)) ^ $dw[0][0],
601	$this->_invSubWord(($state[1] & 0xFF000000) ^ ($state[0] & 0x00FF0000) ^ ($state[3] & 0x0000FF00) ^ ($state[2] & 0x000000FF)) ^ $dw[0][1],
602	$this->_invSubWord(($state[2] & 0xFF000000) ^ ($state[1] & 0x00FF0000) ^ ($state[0] & 0x0000FF00) ^ ($state[3] & 0x000000FF)) ^ $dw[0][2],
603	$this->_invSubWord(($state[3] & 0xFF000000) ^ ($state[2] & 0x00FF0000) ^ ($state[1] & 0x0000FF00) ^ ($state[0] & 0x000000FF)) ^ $dw[0][3]
604	);
605
606	return pack('N*', $state[0], $state[1], $state[2], $state[3]);
607	}
608	}
609
610	// vim: ts=4:sw=4:et:
611	// vim6: fdl=1:
612