/phpseclib/Crypt/AES.php
PHP | 606 lines | 280 code | 60 blank | 266 comment | 45 complexity | 94d7ca70cea3f2a7fb6595e497a01e90 MD5 | raw file
- <?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: Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- *
- * @category Crypt
- * @package Crypt_AES
- * @author Jim Wigginton <terrafrost@php.net>
- * @copyright MMVIII Jim Wigginton
- * @license http://www.opensource.org/licenses/mit-license.html MIT License
- * @version $Id: AES.php,v 1.7 2010/02/09 06:10:25 terrafrost Exp $
- * @link http://phpseclib.sourceforge.net
- */
- namespace phpseclib;
- /**
- * 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 {
- /**#@+
- * @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
- */
- const 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
- */
- const 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
- */
- const MODE_CBC = 2;
- /**
- * Encrypt / decrypt using the Cipher Feedback mode.
- *
- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
- */
- const MODE_CFB = 3;
- /**
- * Encrypt / decrypt using the Cipher Feedback mode.
- *
- * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
- */
- const MODE_OFB = 4;
- /**#@-*/
- /**#@+
- * @access private
- * @see Crypt_AES::Crypt_AES()
- */
- /**
- * Toggles the internal implementation
- */
- const MODE_INTERNAL = 1;
- /**
- * Toggles the mcrypt implementation
- */
- const MODE_MCRYPT = 2;
- /**#@-*/
- /**
- * 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;
- /**
- * mcrypt resource for CFB mode
- *
- * @see Crypt_AES::encrypt()
- * @see Crypt_AES::decrypt()
- * @var String
- * @access private
- */
- var $ecb;
- /**
- * Default Constructor.
- *
- * Determines whether or not the mcrypt extension should be used. $mode should only, at present, be
- * self::MODE_ECB or self::MODE_CBC. If not explictly set, self::MODE_CBC will be used.
- *
- * @param optional Integer $mode
- * @return Crypt_AES
- * @access public
- */
- function __construct($mode = self::MODE_CBC)
- {
- if ( !defined('CRYPT_AES_MODE') ) {
- switch (true) {
- case extension_loaded('mcrypt') && in_array('rijndael-128', mcrypt_list_algorithms()):
- define('CRYPT_AES_MODE', self::MODE_MCRYPT);
- break;
- default:
- define('CRYPT_AES_MODE', self::MODE_INTERNAL);
- }
- }
- switch ( CRYPT_AES_MODE ) {
- case self::MODE_MCRYPT:
- switch ($mode) {
- case self::MODE_ECB:
- $this->paddable = true;
- $this->mode = MCRYPT_MODE_ECB;
- break;
- case self::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' : self::MODE_CTR;
- break;
- case self::MODE_CFB:
- $this->mode = 'ncfb';
- break;
- case self::MODE_OFB:
- $this->mode = MCRYPT_MODE_NOFB;
- break;
- case self::MODE_CBC:
- default:
- $this->paddable = true;
- $this->mode = MCRYPT_MODE_CBC;
- }
- $this->debuffer = $this->enbuffer = '';
- break;
- default:
- switch ($mode) {
- case self::MODE_ECB:
- $this->paddable = true;
- $this->mode = CRYPT_RIJNDAEL_MODE_ECB;
- break;
- case self::MODE_CTR:
- $this->mode = CRYPT_RIJNDAEL_MODE_CTR;
- break;
- case self::MODE_CFB:
- $this->mode = CRYPT_RIJNDAEL_MODE_CFB;
- break;
- case self::MODE_OFB:
- $this->mode = CRYPT_RIJNDAEL_MODE_OFB;
- break;
- case self::MODE_CBC:
- default:
- $this->paddable = true;
- $this->mode = CRYPT_RIJNDAEL_MODE_CBC;
- }
- }
- if (CRYPT_AES_MODE == self::MODE_INTERNAL) {
- parent::__construct($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;
- }
- /**
- * 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)
- {
- parent::setIV($iv);
- if ( CRYPT_AES_MODE == self::MODE_MCRYPT ) {
- $this->changed = true;
- }
- }
- /**
- * 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 == self::MODE_MCRYPT ) {
- $changed = $this->changed;
- $this->_mcryptSetup();
- /*
- if ($this->mode == self::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 $ciphertext;
- }
- */
- // re: http://phpseclib.sourceforge.net/cfb-demo.phps
- // using mcrypt's default handing of CFB the above would output two different things. using phpseclib's
- // rewritten CFB implementation the above outputs the same thing twice.
- if ($this->mode == 'ncfb') {
- if ($changed) {
- $this->ecb = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
- mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
- }
- if (strlen($this->enbuffer)) {
- $ciphertext = $plaintext ^ substr($this->encryptIV, strlen($this->enbuffer));
- $this->enbuffer.= $ciphertext;
- if (strlen($this->enbuffer) == 16) {
- $this->encryptIV = $this->enbuffer;
- $this->enbuffer = '';
- mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
- }
- $plaintext = substr($plaintext, strlen($ciphertext));
- } else {
- $ciphertext = '';
- }
- $last_pos = strlen($plaintext) & 0xFFFFFFF0;
- $ciphertext.= $last_pos ? mcrypt_generic($this->enmcrypt, substr($plaintext, 0, $last_pos)) : '';
- if (strlen($plaintext) & 0xF) {
- if (strlen($ciphertext)) {
- $this->encryptIV = substr($ciphertext, -16);
- }
- $this->encryptIV = mcrypt_generic($this->ecb, $this->encryptIV);
- $this->enbuffer = substr($plaintext, $last_pos) ^ $this->encryptIV;
- $ciphertext.= $this->enbuffer;
- }
- return $ciphertext;
- }
- if ($this->paddable) {
- $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 == self::MODE_MCRYPT ) {
- $changed = $this->changed;
- $this->_mcryptSetup();
- /*
- if ($this->mode == self::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 == 'ncfb') {
- if ($changed) {
- $this->ecb = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
- mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
- }
- if (strlen($this->debuffer)) {
- $plaintext = $ciphertext ^ substr($this->decryptIV, strlen($this->debuffer));
- $this->debuffer.= substr($ciphertext, 0, strlen($plaintext));
- if (strlen($this->debuffer) == 16) {
- $this->decryptIV = $this->debuffer;
- $this->debuffer = '';
- mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV);
- }
- $ciphertext = substr($ciphertext, strlen($plaintext));
- } else {
- $plaintext = '';
- }
- $last_pos = strlen($ciphertext) & 0xFFFFFFF0;
- $plaintext.= $last_pos ? mdecrypt_generic($this->demcrypt, substr($ciphertext, 0, $last_pos)) : '';
- if (strlen($ciphertext) & 0xF) {
- if (strlen($plaintext)) {
- $this->decryptIV = substr($ciphertext, $last_pos - 16, 16);
- }
- $this->decryptIV = mcrypt_generic($this->ecb, $this->decryptIV);
- $this->debuffer = substr($ciphertext, $last_pos);
- $plaintext.= $this->debuffer ^ $this->decryptIV;
- }
- return $plaintext;
- }
- if ($this->paddable) {
- // 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->paddable ? $this->_unpad($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;
- }
- $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, chr(0));
- $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, 16), 16, chr(0));
- if (!isset($this->enmcrypt)) {
- $mode = $this->mode;
- //$mode = $this->mode == self::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: