| <?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: 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_TripleDES |
| * @author Jim Wigginton <terrafrost@php.net> |
| * @copyright MMVII Jim Wigginton |
| * @license http://www.opensource.org/licenses/mit-license.html MIT License |
| * @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', -2); |
| |
| /** |
| * 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_TripleDES::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_TripleDES::decrypt() |
| * @var String |
| * @access private |
| */ |
| var $demcrypt; |
| |
| /** |
| * Does the enmcrypt resource need to be (re)initialized? |
| * |
| * @see Crypt_TripleDES::setKey() |
| * @see Crypt_TripleDES::setIV() |
| * @var Boolean |
| * @access private |
| */ |
| var $enchanged = true; |
| |
| /** |
| * Does the demcrypt resource need to be (re)initialized? |
| * |
| * @see Crypt_TripleDES::setKey() |
| * @see Crypt_TripleDES::setIV() |
| * @var Boolean |
| * @access private |
| */ |
| var $dechanged = true; |
| |
| /** |
| * Is the mode one that is paddable? |
| * |
| * @see Crypt_TripleDES::Crypt_TripleDES() |
| * @var Boolean |
| * @access private |
| */ |
| var $paddable = false; |
| |
| /** |
| * Encryption buffer for CTR, OFB and CFB modes |
| * |
| * @see Crypt_TripleDES::encrypt() |
| * @var String |
| * @access private |
| */ |
| var $enbuffer = ''; |
| |
| /** |
| * Decryption buffer for CTR, OFB and CFB modes |
| * |
| * @see Crypt_TripleDES::decrypt() |
| * @var String |
| * @access private |
| */ |
| var $debuffer = ''; |
| |
| /** |
| * mcrypt resource for CFB mode |
| * |
| * @see Crypt_TripleDES::encrypt() |
| * @see Crypt_TripleDES::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 |
| * 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->paddable = true; |
| $this->mode = MCRYPT_MODE_ECB; |
| break; |
| case CRYPT_DES_MODE_CTR: |
| $this->mode = 'ctr'; |
| break; |
| case CRYPT_DES_MODE_CFB: |
| $this->mode = 'ncfb'; |
| break; |
| case CRYPT_DES_MODE_OFB: |
| $this->mode = MCRYPT_MODE_NOFB; |
| break; |
| case CRYPT_DES_MODE_CBC: |
| default: |
| $this->paddable = true; |
| $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->paddable = true; |
| $this->mode = $mode; |
| break; |
| case CRYPT_DES_MODE_CTR: |
| case CRYPT_DES_MODE_CFB: |
| case CRYPT_DES_MODE_OFB: |
| $this->mode = $mode; |
| break; |
| default: |
| $this->paddable = true; |
| $this->mode = CRYPT_DES_MODE_CBC; |
| } |
| } |
| } |
| |
| /** |
| * Sets the key. |
| * |
| * Keys can be of any length. Triple DES, itself, can use 128-bit (eg. strlen($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); |
| } else { |
| $key = str_pad($key, 8, chr(0)); |
| } |
| $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->enchanged = $this->dechanged = 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->enchanged = $this->dechanged = 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_TripleDES::decrypt() |
| * @see Crypt_TripleDES::encrypt() |
| * @access private |
| * @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->paddable) { |
| $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->enchanged) { |
| if (!isset($this->enmcrypt)) { |
| $this->enmcrypt = mcrypt_module_open(MCRYPT_3DES, '', $this->mode, ''); |
| } |
| mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV); |
| if ($this->mode != 'ncfb') { |
| $this->enchanged = false; |
| } |
| } |
| |
| if ($this->mode != 'ncfb') { |
| $ciphertext = mcrypt_generic($this->enmcrypt, $plaintext); |
| } else { |
| if ($this->enchanged) { |
| $this->ecb = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_ECB, ''); |
| mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0"); |
| $this->enchanged = false; |
| } |
| |
| if (strlen($this->enbuffer)) { |
| $ciphertext = $plaintext ^ substr($this->encryptIV, strlen($this->enbuffer)); |
| $this->enbuffer.= $ciphertext; |
| if (strlen($this->enbuffer) == 8) { |
| $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) & 0xFFFFFFF8; |
| $ciphertext.= $last_pos ? mcrypt_generic($this->enmcrypt, substr($plaintext, 0, $last_pos)) : ''; |
| |
| if (strlen($plaintext) & 0x7) { |
| if (strlen($ciphertext)) { |
| $this->encryptIV = substr($ciphertext, -8); |
| } |
| $this->encryptIV = mcrypt_generic($this->ecb, $this->encryptIV); |
| $this->enbuffer = substr($plaintext, $last_pos) ^ $this->encryptIV; |
| $ciphertext.= $this->enbuffer; |
| } |
| } |
| |
| if (!$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); |
| } |
| |
| $des = $this->des; |
| |
| $buffer = &$this->enbuffer; |
| $continuousBuffer = $this->continuousBuffer; |
| $ciphertext = ''; |
| switch ($this->mode) { |
| case CRYPT_DES_MODE_ECB: |
| for ($i = 0; $i < strlen($plaintext); $i+=8) { |
| $block = substr($plaintext, $i, 8); |
| // all of these _processBlock calls could, in theory, be put in a function - say Crypt_TripleDES::_ede_encrypt() or something. |
| // only problem with that: it would slow encryption and decryption down. $this->des would have to be called every time that |
| // function is called, instead of once for the whole string of text that's being encrypted, which would, in turn, make |
| // encryption and decryption take more time, per this: |
| // |
| // http://blog.libssh2.org/index.php?/archives/21-Compiled-Variables.html |
| $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 = $this->encryptIV; |
| if (strlen($buffer)) { |
| for ($i = 0; $i < strlen($plaintext); $i+=8) { |
| $block = substr($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); |
| $buffer.= $key; |
| $key = $this->_string_shift($buffer, 8); |
| $ciphertext.= $block ^ $key; |
| } |
| } else { |
| for ($i = 0; $i < strlen($plaintext); $i+=8) { |
| $block = substr($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); |
| $ciphertext.= $block ^ $key; |
| } |
| } |
| if ($this->continuousBuffer) { |
| $this->encryptIV = $xor; |
| if ($start = strlen($plaintext) & 7) { |
| $buffer = substr($key, $start) . $buffer; |
| } |
| } |
| break; |
| case CRYPT_DES_MODE_CFB: |
| if (!empty($buffer['xor'])) { |
| $ciphertext = $plaintext ^ $buffer['xor']; |
| $iv = $buffer['encrypted'] . $ciphertext; |
| $start = strlen($ciphertext); |
| $buffer['encrypted'].= $ciphertext; |
| $buffer['xor'] = substr($buffer['xor'], strlen($ciphertext)); |
| } else { |
| $ciphertext = ''; |
| $iv = $this->encryptIV; |
| $start = 0; |
| } |
| |
| for ($i = $start; $i < strlen($plaintext); $i+=8) { |
| $block = substr($plaintext, $i, 8); |
| $iv = $des[0]->_processBlock($iv, CRYPT_DES_ENCRYPT); |
| $iv = $des[1]->_processBlock($iv, CRYPT_DES_DECRYPT); |
| $xor= $des[2]->_processBlock($iv, CRYPT_DES_ENCRYPT); |
| |
| $iv = $block ^ $xor; |
| if ($continuousBuffer && strlen($iv) != 8) { |
| $buffer = array( |
| 'encrypted' => $iv, |
| 'xor' => substr($xor, strlen($iv)) |
| ); |
| } |
| $ciphertext.= $iv; |
| } |
| |
| if ($this->continuousBuffer) { |
| $this->encryptIV = $iv; |
| } |
| break; |
| case CRYPT_DES_MODE_OFB: |
| $xor = $this->encryptIV; |
| if (strlen($buffer)) { |
| for ($i = 0; $i < strlen($plaintext); $i+=8) { |
| $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $buffer.= $xor; |
| $key = $this->_string_shift($buffer, 8); |
| $ciphertext.= substr($plaintext, $i, 8) ^ $key; |
| } |
| } else { |
| for ($i = 0; $i < strlen($plaintext); $i+=8) { |
| $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $ciphertext.= substr($plaintext, $i, 8) ^ $xor; |
| } |
| $key = $xor; |
| } |
| if ($this->continuousBuffer) { |
| $this->encryptIV = $xor; |
| if ($start = strlen($plaintext) & 7) { |
| $buffer = substr($key, $start) . $buffer; |
| } |
| } |
| } |
| |
| 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); |
| } |
| |
| 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($ciphertext) + 7) & 0xFFFFFFF8, chr(0)); |
| } |
| |
| if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) { |
| if ($this->dechanged) { |
| if (!isset($this->demcrypt)) { |
| $this->demcrypt = mcrypt_module_open(MCRYPT_3DES, '', $this->mode, ''); |
| } |
| mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV); |
| if ($this->mode != 'ncfb') { |
| $this->dechanged = false; |
| } |
| } |
| |
| if ($this->mode != 'ncfb') { |
| $plaintext = mdecrypt_generic($this->demcrypt, $ciphertext); |
| } else { |
| if ($this->dechanged) { |
| $this->ecb = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_ECB, ''); |
| mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0"); |
| $this->dechanged = false; |
| } |
| |
| if (strlen($this->debuffer)) { |
| $plaintext = $ciphertext ^ substr($this->decryptIV, strlen($this->debuffer)); |
| |
| $this->debuffer.= substr($ciphertext, 0, strlen($plaintext)); |
| if (strlen($this->debuffer) == 8) { |
| $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) & 0xFFFFFFF8; |
| $plaintext.= $last_pos ? mdecrypt_generic($this->demcrypt, substr($ciphertext, 0, $last_pos)) : ''; |
| |
| if (strlen($ciphertext) & 0x7) { |
| if (strlen($plaintext)) { |
| $this->decryptIV = substr($ciphertext, $last_pos - 8, 8); |
| } |
| $this->decryptIV = mcrypt_generic($this->ecb, $this->decryptIV); |
| $this->debuffer = substr($ciphertext, $last_pos); |
| $plaintext.= $this->debuffer ^ $this->decryptIV; |
| } |
| |
| return $plaintext; |
| } |
| |
| if (!$this->continuousBuffer) { |
| mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV); |
| } |
| |
| return $this->paddable ? $this->_unpad($plaintext) : $plaintext; |
| } |
| |
| if (strlen($this->key) <= 8) { |
| $this->des[0]->mode = $this->mode; |
| $plaintext = $this->des[0]->decrypt($ciphertext); |
| return $this->paddable ? $this->_unpad($plaintext) : $plaintext; |
| } |
| |
| $des = $this->des; |
| |
| $buffer = &$this->enbuffer; |
| $continuousBuffer = $this->continuousBuffer; |
| $plaintext = ''; |
| switch ($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 = $this->decryptIV; |
| if (strlen($buffer)) { |
| for ($i = 0; $i < strlen($ciphertext); $i+=8) { |
| $block = substr($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); |
| $buffer.= $key; |
| $key = $this->_string_shift($buffer, 8); |
| $plaintext.= $block ^ $key; |
| } |
| } else { |
| for ($i = 0; $i < strlen($ciphertext); $i+=8) { |
| $block = substr($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); |
| $plaintext.= $block ^ $key; |
| } |
| } |
| if ($this->continuousBuffer) { |
| $this->decryptIV = $xor; |
| if ($start = strlen($plaintext) & 7) { |
| $buffer = substr($key, $start) . $buffer; |
| } |
| } |
| break; |
| case CRYPT_DES_MODE_CFB: |
| if (!empty($buffer['ciphertext'])) { |
| $plaintext = $ciphertext ^ substr($this->decryptIV, strlen($buffer['ciphertext'])); |
| $buffer['ciphertext'].= substr($ciphertext, 0, strlen($plaintext)); |
| if (strlen($buffer['ciphertext']) == 8) { |
| $xor = $des[0]->_processBlock($buffer['ciphertext'], CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $buffer['ciphertext'] = ''; |
| } |
| $start = strlen($plaintext); |
| $block = $this->decryptIV; |
| } else { |
| $plaintext = ''; |
| $xor = $des[0]->_processBlock($this->decryptIV, CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $start = 0; |
| } |
| |
| for ($i = $start; $i < strlen($ciphertext); $i+=8) { |
| $block = substr($ciphertext, $i, 8); |
| $plaintext.= $block ^ $xor; |
| if ($continuousBuffer && strlen($block) != 8) { |
| $buffer['ciphertext'].= $block; |
| $block = $xor; |
| } else if (strlen($block) == 8) { |
| $xor = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| } |
| } |
| if ($this->continuousBuffer) { |
| $this->decryptIV = $block; |
| } |
| break; |
| case CRYPT_DES_MODE_OFB: |
| $xor = $this->decryptIV; |
| if (strlen($buffer)) { |
| for ($i = 0; $i < strlen($ciphertext); $i+=8) { |
| $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $buffer.= $xor; |
| $key = $this->_string_shift($buffer, 8); |
| $plaintext.= substr($ciphertext, $i, 8) ^ $key; |
| } |
| } else { |
| for ($i = 0; $i < strlen($ciphertext); $i+=8) { |
| $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT); |
| $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT); |
| $plaintext.= substr($ciphertext, $i, 8) ^ $xor; |
| } |
| $key = $xor; |
| } |
| if ($this->continuousBuffer) { |
| $this->decryptIV = $xor; |
| if ($start = strlen($ciphertext) & 7) { |
| $buffer = substr($key, $start) . $buffer; |
| } |
| } |
| } |
| |
| return $this->paddable ? $this->_unpad($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); |
| } |
| |
| /** |
| * 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: |