843 lines
35 KiB
PHP
Executable File
843 lines
35 KiB
PHP
Executable File
<?php
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/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
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/**
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* Pure-PHP implementation of Triple DES.
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*
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* Uses mcrypt, if available, and an internal implementation, otherwise. Operates in the EDE3 mode (encrypt-decrypt-encrypt).
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*
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* PHP versions 4 and 5
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*
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* Here's a short example of how to use this library:
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* <code>
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* <?php
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* include('Crypt/TripleDES.php');
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*
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* $des = new Crypt_TripleDES();
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*
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* $des->setKey('abcdefghijklmnopqrstuvwx');
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*
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* $size = 10 * 1024;
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* $plaintext = '';
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* for ($i = 0; $i < $size; $i++) {
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* $plaintext.= 'a';
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* }
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*
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* echo $des->decrypt($des->encrypt($plaintext));
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* ?>
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* </code>
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*
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* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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* @category Crypt
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* @package Crypt_TripleDES
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright MMVII Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @link http://phpseclib.sourceforge.net
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*/
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/**
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* Include Crypt_DES
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*/
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if (!class_exists('Crypt_DES')) {
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require_once('DES.php');
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}
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/**
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* Encrypt / decrypt using inner chaining
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*
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* Inner chaining is used by SSH-1 and is generally considered to be less secure then outer chaining (CRYPT_DES_MODE_CBC3).
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*/
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define('CRYPT_DES_MODE_3CBC', -2);
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/**
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* Encrypt / decrypt using outer chaining
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*
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* Outer chaining is used by SSH-2 and when the mode is set to CRYPT_DES_MODE_CBC.
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*/
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define('CRYPT_DES_MODE_CBC3', CRYPT_DES_MODE_CBC);
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/**
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* Pure-PHP implementation of Triple DES.
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*
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* @author Jim Wigginton <terrafrost@php.net>
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* @version 0.1.0
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* @access public
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* @package Crypt_TerraDES
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*/
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class Crypt_TripleDES extends Crypt_DES {
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/**
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* The Crypt_DES objects
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*
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* @var Array
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* @access private
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*/
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var $des;
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/**
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* Default Constructor.
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*
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* Determines whether or not the mcrypt extension should be used. $mode should only, at present, be
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* CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC. If not explictly set, CRYPT_DES_MODE_CBC will be used.
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*
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* @param optional Integer $mode
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* @return Crypt_TripleDES
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* @access public
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*/
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function Crypt_TripleDES($mode = CRYPT_DES_MODE_CBC)
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{
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if ( !defined('CRYPT_DES_MODE') ) {
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switch (true) {
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case extension_loaded('mcrypt') && in_array('tripledes', mcrypt_list_algorithms()):
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define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT);
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break;
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default:
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define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL);
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}
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}
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if ( $mode == CRYPT_DES_MODE_3CBC ) {
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$this->mode = CRYPT_DES_MODE_3CBC;
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$this->des = array(
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new Crypt_DES(CRYPT_DES_MODE_CBC),
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new Crypt_DES(CRYPT_DES_MODE_CBC),
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new Crypt_DES(CRYPT_DES_MODE_CBC)
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);
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$this->paddable = true;
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// we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects
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$this->des[0]->disablePadding();
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$this->des[1]->disablePadding();
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$this->des[2]->disablePadding();
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return;
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}
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switch ( CRYPT_DES_MODE ) {
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case CRYPT_DES_MODE_MCRYPT:
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switch ($mode) {
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case CRYPT_DES_MODE_ECB:
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$this->paddable = true;
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$this->mode = MCRYPT_MODE_ECB;
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break;
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case CRYPT_DES_MODE_CTR:
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$this->mode = 'ctr';
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break;
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case CRYPT_DES_MODE_CFB:
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$this->mode = 'ncfb';
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$this->ecb = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_ECB, '');
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break;
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case CRYPT_DES_MODE_OFB:
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$this->mode = MCRYPT_MODE_NOFB;
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break;
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case CRYPT_DES_MODE_CBC:
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default:
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$this->paddable = true;
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$this->mode = MCRYPT_MODE_CBC;
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}
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$this->enmcrypt = mcrypt_module_open(MCRYPT_3DES, '', $this->mode, '');
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$this->demcrypt = mcrypt_module_open(MCRYPT_3DES, '', $this->mode, '');
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break;
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default:
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$this->des = array(
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new Crypt_DES(CRYPT_DES_MODE_ECB),
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new Crypt_DES(CRYPT_DES_MODE_ECB),
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new Crypt_DES(CRYPT_DES_MODE_ECB)
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);
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// we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects
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$this->des[0]->disablePadding();
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$this->des[1]->disablePadding();
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$this->des[2]->disablePadding();
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switch ($mode) {
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case CRYPT_DES_MODE_ECB:
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case CRYPT_DES_MODE_CBC:
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$this->paddable = true;
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$this->mode = $mode;
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break;
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case CRYPT_DES_MODE_CTR:
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case CRYPT_DES_MODE_CFB:
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case CRYPT_DES_MODE_OFB:
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$this->mode = $mode;
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break;
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default:
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$this->paddable = true;
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$this->mode = CRYPT_DES_MODE_CBC;
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}
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if (function_exists('create_function') && is_callable('create_function')) {
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$this->inline_crypt_setup(3);
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$this->use_inline_crypt = true;
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}
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}
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}
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/**
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* Sets the key.
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*
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* Keys can be of any length. Triple DES, itself, can use 128-bit (eg. strlen($key) == 16) or
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* 192-bit (eg. strlen($key) == 24) keys. This function pads and truncates $key as appropriate.
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*
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* DES also requires that every eighth bit be a parity bit, however, we'll ignore that.
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*
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* If the key is not explicitly set, it'll be assumed to be all zero's.
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*
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* @access public
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* @param String $key
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*/
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function setKey($key)
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{
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$length = strlen($key);
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if ($length > 8) {
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$key = str_pad($key, 24, chr(0));
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// if $key is between 64 and 128-bits, use the first 64-bits as the last, per this:
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// http://php.net/function.mcrypt-encrypt#47973
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//$key = $length <= 16 ? substr_replace($key, substr($key, 0, 8), 16) : substr($key, 0, 24);
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} else {
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$key = str_pad($key, 8, chr(0));
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}
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$this->key = $key;
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switch (true) {
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case CRYPT_DES_MODE == CRYPT_DES_MODE_INTERNAL:
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case $this->mode == CRYPT_DES_MODE_3CBC:
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$this->des[0]->setKey(substr($key, 0, 8));
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$this->des[1]->setKey(substr($key, 8, 8));
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$this->des[2]->setKey(substr($key, 16, 8));
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// Merge the three DES-1-dim-key-arrays for 3DES-inline-en/decrypting
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if ($this->use_inline_crypt && $this->mode != CRYPT_DES_MODE_3CBC) {
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$this->keys = array(
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CRYPT_DES_ENCRYPT_1DIM => array_merge(
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$this->des[0]->keys[CRYPT_DES_ENCRYPT_1DIM],
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$this->des[1]->keys[CRYPT_DES_DECRYPT_1DIM],
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$this->des[2]->keys[CRYPT_DES_ENCRYPT_1DIM]
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),
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CRYPT_DES_DECRYPT_1DIM => array_merge(
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$this->des[2]->keys[CRYPT_DES_DECRYPT_1DIM],
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$this->des[1]->keys[CRYPT_DES_ENCRYPT_1DIM],
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$this->des[0]->keys[CRYPT_DES_DECRYPT_1DIM]
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),
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);
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}
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}
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$this->enchanged = $this->dechanged = true;
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}
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/**
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* Sets the password.
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*
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* Depending on what $method is set to, setPassword()'s (optional) parameters are as follows:
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* {@link http://en.wikipedia.org/wiki/PBKDF2 pbkdf2}:
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* $hash, $salt, $method
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*
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* @param String $password
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* @param optional String $method
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* @access public
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*/
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function setPassword($password, $method = 'pbkdf2')
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{
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$key = '';
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switch ($method) {
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default: // 'pbkdf2'
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list(, , $hash, $salt, $count) = func_get_args();
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if (!isset($hash)) {
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$hash = 'sha1';
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}
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// WPA and WPA2 use the SSID as the salt
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if (!isset($salt)) {
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$salt = 'phpseclib';
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}
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// RFC2898#section-4.2 uses 1,000 iterations by default
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// WPA and WPA2 use 4,096.
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if (!isset($count)) {
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$count = 1000;
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}
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if (!class_exists('Crypt_Hash')) {
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require_once('Crypt/Hash.php');
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}
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$i = 1;
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while (strlen($key) < 24) { // $dkLen == 24
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$hmac = new Crypt_Hash();
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$hmac->setHash($hash);
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$hmac->setKey($password);
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$f = $u = $hmac->hash($salt . pack('N', $i++));
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for ($j = 2; $j <= $count; $j++) {
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$u = $hmac->hash($u);
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$f^= $u;
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}
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$key.= $f;
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}
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}
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$this->setKey($key);
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}
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/**
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* Sets the initialization vector. (optional)
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*
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* SetIV is not required when CRYPT_DES_MODE_ECB is being used. If not explictly set, it'll be assumed
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* to be all zero's.
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*
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* @access public
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* @param String $iv
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*/
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function setIV($iv)
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{
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$this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));
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if ($this->mode == CRYPT_DES_MODE_3CBC) {
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$this->des[0]->setIV($iv);
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$this->des[1]->setIV($iv);
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$this->des[2]->setIV($iv);
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}
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$this->enchanged = $this->dechanged = true;
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}
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/**
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* Encrypts a message.
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*
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* @access public
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* @param String $plaintext
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*/
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function encrypt($plaintext)
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{
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if ($this->paddable) {
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$plaintext = $this->_pad($plaintext);
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}
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// if the key is smaller then 8, do what we'd normally do
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if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {
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$ciphertext = $this->des[2]->encrypt($this->des[1]->decrypt($this->des[0]->encrypt($plaintext)));
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return $ciphertext;
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}
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if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
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if ($this->enchanged) {
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mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
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if ($this->mode == 'ncfb') {
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mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0");
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}
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$this->enchanged = false;
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}
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if ($this->mode != 'ncfb' || !$this->continuousBuffer) {
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$ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
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} else {
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$iv = &$this->encryptIV;
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$pos = &$this->enbuffer['pos'];
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$len = strlen($plaintext);
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$ciphertext = '';
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$i = 0;
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if ($pos) {
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$orig_pos = $pos;
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$max = 8 - $pos;
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if ($len >= $max) {
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$i = $max;
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$len-= $max;
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$pos = 0;
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} else {
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$i = $len;
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$pos+= $len;
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$len = 0;
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}
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$ciphertext = substr($iv, $orig_pos) ^ $plaintext;
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$iv = substr_replace($iv, $ciphertext, $orig_pos, $i);
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$this->enbuffer['enmcrypt_init'] = true;
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}
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if ($len >= 8) {
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if ($this->enbuffer['enmcrypt_init'] === false || $len > 950) {
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if ($this->enbuffer['enmcrypt_init'] === true) {
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mcrypt_generic_init($this->enmcrypt, $this->key, $iv);
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$this->enbuffer['enmcrypt_init'] = false;
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}
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$ciphertext.= mcrypt_generic($this->enmcrypt, substr($plaintext, $i, $len - $len % 8));
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$iv = substr($ciphertext, -8);
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$i = strlen($ciphertext);
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$len%= 8;
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} else {
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while ($len >= 8) {
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$iv = mcrypt_generic($this->ecb, $iv) ^ substr($plaintext, $i, 8);
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$ciphertext.= $iv;
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$len-= 8;
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$i+= 8;
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}
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}
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}
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if ($len) {
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$iv = mcrypt_generic($this->ecb, $iv);
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$block = $iv ^ substr($plaintext, $i);
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$iv = substr_replace($iv, $block, 0, $len);
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$ciphertext.= $block;
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$pos = $len;
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}
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return $ciphertext;
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}
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if (!$this->continuousBuffer) {
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mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
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}
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return $ciphertext;
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}
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if (strlen($this->key) <= 8) {
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$this->des[0]->mode = $this->mode;
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return $this->des[0]->encrypt($plaintext);
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}
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if ($this->use_inline_crypt) {
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$inline = $this->inline_crypt;
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return $inline('encrypt', $this, $plaintext);
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}
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$des = $this->des;
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$buffer = &$this->enbuffer;
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$continuousBuffer = $this->continuousBuffer;
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$ciphertext = '';
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switch ($this->mode) {
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case CRYPT_DES_MODE_ECB:
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for ($i = 0; $i < strlen($plaintext); $i+=8) {
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$block = substr($plaintext, $i, 8);
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// all of these _processBlock calls could, in theory, be put in a function - say Crypt_TripleDES::_ede_encrypt() or something.
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// only problem with that: it would slow encryption and decryption down. $this->des would have to be called every time that
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// function is called, instead of once for the whole string of text that's being encrypted, which would, in turn, make
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// encryption and decryption take more time, per this:
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//
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// http://blog.libssh2.org/index.php?/archives/21-Compiled-Variables.html
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$block = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);
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$block = $des[1]->_processBlock($block, CRYPT_DES_DECRYPT);
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$block = $des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);
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$ciphertext.= $block;
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}
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break;
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case CRYPT_DES_MODE_CBC:
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$xor = $this->encryptIV;
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for ($i = 0; $i < strlen($plaintext); $i+=8) {
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$block = substr($plaintext, $i, 8) ^ $xor;
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$block = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);
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$block = $des[1]->_processBlock($block, CRYPT_DES_DECRYPT);
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$block = $des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);
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$xor = $block;
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$ciphertext.= $block;
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}
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if ($this->continuousBuffer) {
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$this->encryptIV = $xor;
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}
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break;
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case CRYPT_DES_MODE_CTR:
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$xor = $this->encryptIV;
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if (strlen($buffer['encrypted'])) {
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for ($i = 0; $i < strlen($plaintext); $i+=8) {
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$block = substr($plaintext, $i, 8);
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if (strlen($block) > strlen($buffer['encrypted'])) {
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$key = $this->_generate_xor($xor);
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$key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
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$key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
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$key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
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$buffer['encrypted'].= $key;
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}
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$key = $this->_string_shift($buffer['encrypted']);
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$ciphertext.= $block ^ $key;
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}
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} else {
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for ($i = 0; $i < strlen($plaintext); $i+=8) {
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$block = substr($plaintext, $i, 8);
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$key = $this->_generate_xor($xor);
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$key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
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$key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
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$key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
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$ciphertext.= $block ^ $key;
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}
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}
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if ($this->continuousBuffer) {
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$this->encryptIV = $xor;
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if ($start = strlen($plaintext) & 7) {
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$buffer['encrypted'] = substr($key, $start) . $buffer['encrypted'];
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}
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}
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break;
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case CRYPT_DES_MODE_CFB:
|
|
if (strlen($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['xor'])) {
|
|
for ($i = 0; $i < strlen($plaintext); $i+=8) {
|
|
$block = substr($plaintext, $i, 8);
|
|
if (strlen($block) > strlen($buffer['xor'])) {
|
|
$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'].= $xor;
|
|
}
|
|
$key = $this->_string_shift($buffer['xor']);
|
|
$ciphertext.= $block ^ $key;
|
|
}
|
|
} else {
|
|
for ($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) {
|
|
$buffer['xor'] = substr($key, $start) . $buffer['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);
|
|
}
|
|
|
|
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) {
|
|
mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV);
|
|
if ($this->mode == 'ncfb') {
|
|
mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0");
|
|
}
|
|
$this->dechanged = false;
|
|
}
|
|
|
|
if ($this->mode != 'ncfb' || !$this->continuousBuffer) {
|
|
$plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
|
|
} else {
|
|
$iv = &$this->decryptIV;
|
|
$pos = &$this->debuffer['pos'];
|
|
$len = strlen($ciphertext);
|
|
$plaintext = '';
|
|
$i = 0;
|
|
if ($pos) {
|
|
$orig_pos = $pos;
|
|
$max = 8 - $pos;
|
|
if ($len >= $max) {
|
|
$i = $max;
|
|
$len-= $max;
|
|
$pos = 0;
|
|
} else {
|
|
$i = $len;
|
|
$pos+= $len;
|
|
$len = 0;
|
|
}
|
|
$plaintext = substr($iv, $orig_pos) ^ $ciphertext;
|
|
$iv = substr_replace($iv, substr($ciphertext, 0, $i), $orig_pos, $i);
|
|
}
|
|
if ($len >= 8) {
|
|
$cb = substr($ciphertext, $i, $len - $len % 8);
|
|
$plaintext.= mcrypt_generic($this->ecb, $iv . $cb) ^ $cb;
|
|
$iv = substr($cb, -8);
|
|
$len%= 8;
|
|
}
|
|
if ($len) {
|
|
$iv = mcrypt_generic($this->ecb, $iv);
|
|
$cb = substr($ciphertext, -$len);
|
|
$plaintext.= $iv ^ $cb;
|
|
$iv = substr_replace($iv, $cb, 0, $len);
|
|
$pos = $len;
|
|
}
|
|
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) : $plaintext;
|
|
}
|
|
|
|
if ($this->use_inline_crypt) {
|
|
$inline = $this->inline_crypt;
|
|
return $inline('decrypt', $this, $ciphertext);
|
|
}
|
|
|
|
$des = $this->des;
|
|
|
|
$buffer = &$this->debuffer;
|
|
$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['ciphertext'])) {
|
|
for ($i = 0; $i < strlen($ciphertext); $i+=8) {
|
|
$block = substr($ciphertext, $i, 8);
|
|
if (strlen($block) > strlen($buffer['ciphertext'])) {
|
|
$key = $this->_generate_xor($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['ciphertext'].= $key;
|
|
}
|
|
$key = $this->_string_shift($buffer['ciphertext']);
|
|
$plaintext.= $block ^ $key;
|
|
}
|
|
} else {
|
|
for ($i = 0; $i < strlen($ciphertext); $i+=8) {
|
|
$block = substr($ciphertext, $i, 8);
|
|
$key = $this->_generate_xor($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) {
|
|
$buffer['ciphertext'] = substr($key, $start) . $buffer['ciphertext'];
|
|
}
|
|
}
|
|
break;
|
|
case CRYPT_DES_MODE_CFB:
|
|
if (strlen($buffer['ciphertext'])) {
|
|
$plaintext = $ciphertext ^ substr($this->decryptIV, strlen($buffer['ciphertext']));
|
|
$buffer['ciphertext'].= substr($ciphertext, 0, strlen($plaintext));
|
|
if (strlen($buffer['ciphertext']) != 8) {
|
|
$block = $this->decryptIV;
|
|
} else {
|
|
$block = $buffer['ciphertext'];
|
|
$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);
|
|
} 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['xor'])) {
|
|
for ($i = 0; $i < strlen($ciphertext); $i+=8) {
|
|
$block = substr($ciphertext, $i, 8);
|
|
if (strlen($block) > strlen($buffer['xor'])) {
|
|
$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'].= $xor;
|
|
}
|
|
$key = $this->_string_shift($buffer['xor']);
|
|
$plaintext.= $block ^ $key;
|
|
}
|
|
} else {
|
|
for ($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) {
|
|
$buffer['xor'] = substr($key, $start) . $buffer['xor'];
|
|
}
|
|
}
|
|
}
|
|
|
|
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;
|
|
$this->enchanged = true;
|
|
$this->dechanged = true;
|
|
$this->enbuffer = array('encrypted' => '', 'xor' => '', 'pos' => 0, 'enmcrypt_init' => true);
|
|
$this->debuffer = array('ciphertext' => '', 'xor' => '', 'pos' => 0, 'demcrypt_init' => true);
|
|
|
|
if ($this->mode == CRYPT_DES_MODE_3CBC) {
|
|
$this->des[0]->disableContinuousBuffer();
|
|
$this->des[1]->disableContinuousBuffer();
|
|
$this->des[2]->disableContinuousBuffer();
|
|
}
|
|
}
|
|
}
|
|
|
|
// vim: ts=4:sw=4:et:
|
|
// vim6: fdl=1:
|