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542 lines
18 KiB
PHP
542 lines
18 KiB
PHP
<?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 AES.
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*
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* Uses mcrypt, if available, and an internal implementation, otherwise.
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*
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* PHP versions 4 and 5
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*
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* If {@link Crypt_AES::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
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* {@link Crypt_AES::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's 136-bits
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* it'll be null-padded to 160-bits and 160 bits will be the key length until {@link Crypt_Rijndael::setKey() setKey()}
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* is called, again, at which point, it'll be recalculated.
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*
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* Since Crypt_AES extends Crypt_Rijndael, some functions are available to be called that, in the context of AES, don't
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* make a whole lot of sense. {@link Crypt_AES::setBlockLength() setBlockLength()}, for instance. Calling that function,
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* however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
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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/AES.php');
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*
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* $aes = new Crypt_AES();
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*
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* $aes->setKey('abcdefghijklmnop');
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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 $aes->decrypt($aes->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_AES
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright MMVIII Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @version $Id: AES.php,v 1.7 2010/02/09 06:10:25 terrafrost Exp $
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* @link http://phpseclib.sourceforge.net
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*/
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/**
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* Include Crypt_Rijndael
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*/
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if (!class_exists('Crypt_Rijndael')) {
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require_once 'Rijndael.php';
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}
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/**#@+
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* @access public
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* @see Crypt_AES::encrypt()
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* @see Crypt_AES::decrypt()
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*/
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/**
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* Encrypt / decrypt using the Counter mode.
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*
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* Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
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*
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* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
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*/
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define('CRYPT_AES_MODE_CTR', -1);
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/**
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* Encrypt / decrypt using the Electronic Code Book mode.
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*
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* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
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*/
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define('CRYPT_AES_MODE_ECB', 1);
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/**
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* Encrypt / decrypt using the Code Book Chaining mode.
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*
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* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
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*/
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define('CRYPT_AES_MODE_CBC', 2);
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/**
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* Encrypt / decrypt using the Cipher Feedback mode.
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*
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* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
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*/
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define('CRYPT_AES_MODE_CFB', 3);
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/**
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* Encrypt / decrypt using the Cipher Feedback mode.
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*
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* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
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*/
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define('CRYPT_AES_MODE_OFB', 4);
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/**#@-*/
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/**#@+
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* @access private
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* @see Crypt_AES::Crypt_AES()
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*/
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/**
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* Toggles the internal implementation
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*/
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define('CRYPT_AES_MODE_INTERNAL', 1);
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/**
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* Toggles the mcrypt implementation
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*/
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define('CRYPT_AES_MODE_MCRYPT', 2);
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/**#@-*/
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/**
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* Pure-PHP implementation of AES.
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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_AES
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*/
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class Crypt_AES extends Crypt_Rijndael {
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/**
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* mcrypt resource for encryption
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*
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* The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
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* Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
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*
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* @see Crypt_AES::encrypt()
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* @var String
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* @access private
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*/
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var $enmcrypt;
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/**
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* mcrypt resource for decryption
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*
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* The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
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* Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
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*
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* @see Crypt_AES::decrypt()
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* @var String
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* @access private
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*/
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var $demcrypt;
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/**
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* mcrypt resource for CFB mode
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*
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* @see Crypt_AES::encrypt()
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* @see Crypt_AES::decrypt()
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* @var String
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* @access private
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*/
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var $ecb;
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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_AES_MODE_ECB or CRYPT_AES_MODE_CBC. If not explictly set, CRYPT_AES_MODE_CBC will be used.
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*
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* @param optional Integer $mode
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* @return Crypt_AES
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* @access public
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*/
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function Crypt_AES($mode = CRYPT_AES_MODE_CBC)
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{
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if ( !defined('CRYPT_AES_MODE') ) {
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switch (true) {
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case extension_loaded('mcrypt') && in_array('rijndael-128', mcrypt_list_algorithms()):
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define('CRYPT_AES_MODE', CRYPT_AES_MODE_MCRYPT);
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break;
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default:
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define('CRYPT_AES_MODE', CRYPT_AES_MODE_INTERNAL);
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}
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}
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switch ( CRYPT_AES_MODE ) {
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case CRYPT_AES_MODE_MCRYPT:
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switch ($mode) {
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case CRYPT_AES_MODE_ECB:
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$this->paddable = true;
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$this->mode = MCRYPT_MODE_ECB;
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break;
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case CRYPT_AES_MODE_CTR:
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// ctr doesn't have a constant associated with it even though it appears to be fairly widely
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// supported. in lieu of knowing just how widely supported it is, i've, for now, opted not to
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// include a compatibility layer. the layer has been implemented but, for now, is commented out.
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$this->mode = 'ctr';
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//$this->mode = in_array('ctr', mcrypt_list_modes()) ? 'ctr' : CRYPT_AES_MODE_CTR;
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break;
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case CRYPT_AES_MODE_CFB:
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$this->mode = 'ncfb';
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break;
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case CRYPT_AES_MODE_OFB:
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$this->mode = MCRYPT_MODE_NOFB;
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break;
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case CRYPT_AES_MODE_CBC:
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default:
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$this->paddable = true;
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$this->mode = MCRYPT_MODE_CBC;
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}
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break;
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default:
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switch ($mode) {
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case CRYPT_AES_MODE_ECB:
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$this->paddable = true;
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$this->mode = CRYPT_RIJNDAEL_MODE_ECB;
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break;
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case CRYPT_AES_MODE_CTR:
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$this->mode = CRYPT_RIJNDAEL_MODE_CTR;
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break;
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case CRYPT_AES_MODE_CFB:
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$this->mode = CRYPT_RIJNDAEL_MODE_CFB;
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break;
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case CRYPT_AES_MODE_OFB:
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$this->mode = CRYPT_RIJNDAEL_MODE_OFB;
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break;
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case CRYPT_AES_MODE_CBC:
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default:
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$this->paddable = true;
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$this->mode = CRYPT_RIJNDAEL_MODE_CBC;
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}
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}
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if (CRYPT_AES_MODE == CRYPT_AES_MODE_INTERNAL) {
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parent::Crypt_Rijndael($this->mode);
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}
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}
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/**
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* Dummy function
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*
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* Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.
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*
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* @access public
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* @param Integer $length
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*/
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function setBlockLength($length)
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{
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return;
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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_RIJNDAEL_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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parent::setIV($iv);
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if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
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$this->changed = true;
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}
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}
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/**
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* Encrypts a message.
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*
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* $plaintext will be padded with up to 16 additional bytes. Other AES implementations may or may not pad in the
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* same manner. Other common approaches to padding and the reasons why it's necessary are discussed in the following
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* URL:
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*
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* {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
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*
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* An alternative to padding is to, separately, send the length of the file. This is what SSH, in fact, does.
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* strlen($plaintext) will still need to be a multiple of 16, however, arbitrary values can be added to make it that
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* length.
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*
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* @see Crypt_AES::decrypt()
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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 ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
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$this->_mcryptSetup();
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// re: http://phpseclib.sourceforge.net/cfb-demo.phps
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// using mcrypt's default handing of CFB the above would output two different things. using phpseclib's
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// rewritten CFB implementation the above outputs the same thing twice.
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if ($this->mode == 'ncfb' && $this->continuousBuffer) {
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$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 = 16 - $pos;
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if ($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 ($len >= 16) {
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if ($this->enbuffer['enmcrypt_init'] === false || $len > 280) {
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if ($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 - $len % 16));
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$iv = substr($ciphertext, -16);
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$len%= 16;
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} else {
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while ($len >= 16) {
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$iv = mcrypt_generic($this->ecb, $iv) ^ substr($plaintext, $i, 16);
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$ciphertext.= $iv;
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$len-= 16;
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$i+= 16;
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}
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}
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}
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if ($len) {
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$iv = mcrypt_generic($this->ecb, $iv);
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$block = $iv ^ substr($plaintext, -$len);
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$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->paddable) {
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$plaintext = $this->_pad($plaintext);
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}
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$ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
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if (!$this->continuousBuffer) {
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mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
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}
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return $ciphertext;
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}
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return parent::encrypt($plaintext);
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}
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/**
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* Decrypts a message.
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*
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* If strlen($ciphertext) is not a multiple of 16, null bytes will be added to the end of the string until it is.
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*
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* @see Crypt_AES::encrypt()
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* @access public
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* @param String $ciphertext
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*/
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function decrypt($ciphertext)
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{
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if ( CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT ) {
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$this->_mcryptSetup();
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if ($this->mode == 'ncfb' && $this->continuousBuffer) {
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$iv = &$this->decryptIV;
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$pos = &$this->debuffer['pos'];
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$len = strlen($ciphertext);
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$plaintext = '';
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$i = 0;
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if ($pos) {
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$orig_pos = $pos;
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$max = 16 - $pos;
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if ($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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// ie. $i = min($max, $len), $len-= $i, $pos+= $i, $pos%= $blocksize
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$plaintext = substr($iv, $orig_pos) ^ $ciphertext;
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$iv = substr_replace($iv, substr($ciphertext, 0, $i), $orig_pos, $i);
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}
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if ($len >= 16) {
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$cb = substr($ciphertext, $i, $len - $len % 16);
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$plaintext.= mcrypt_generic($this->ecb, $iv . $cb) ^ $cb;
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$iv = substr($cb, -16);
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$len%= 16;
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}
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if ($len) {
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$iv = mcrypt_generic($this->ecb, $iv);
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$plaintext.= $iv ^ substr($ciphertext, -$len);
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$iv = substr_replace($iv, substr($ciphertext, -$len), 0, $len);
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$pos = $len;
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}
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return $plaintext;
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}
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if ($this->paddable) {
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// we pad with chr(0) since that's what mcrypt_generic does. to quote from http://php.net/function.mcrypt-generic :
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// "The data is padded with "\0" to make sure the length of the data is n * blocksize."
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$ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 15) & 0xFFFFFFF0, chr(0));
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}
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$plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
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if (!$this->continuousBuffer) {
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mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
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}
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return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
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}
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return parent::decrypt($ciphertext);
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}
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/**
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* Setup mcrypt
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*
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* Validates all the variables.
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*
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* @access private
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*/
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function _mcryptSetup()
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{
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if (!$this->changed) {
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return;
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}
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if (!$this->explicit_key_length) {
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// this just copied from Crypt_Rijndael::_setup()
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$length = strlen($this->key) >> 2;
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if ($length > 8) {
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$length = 8;
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} else if ($length < 4) {
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$length = 4;
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}
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$this->Nk = $length;
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$this->key_size = $length << 2;
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}
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switch ($this->Nk) {
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case 4: // 128
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$this->key_size = 16;
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break;
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case 5: // 160
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case 6: // 192
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$this->key_size = 24;
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break;
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case 7: // 224
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case 8: // 256
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$this->key_size = 32;
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}
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$this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, chr(0));
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$this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, 16), 16, chr(0));
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if (!isset($this->enmcrypt)) {
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$mode = $this->mode;
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//$mode = $this->mode == CRYPT_AES_MODE_CTR ? MCRYPT_MODE_ECB : $this->mode;
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$this->demcrypt = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', $mode, '');
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$this->enmcrypt = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', $mode, '');
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if ($mode == 'ncfb') {
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$this->ecb = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
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}
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} // else should mcrypt_generic_deinit be called?
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mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
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mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
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if ($this->mode == 'ncfb') {
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mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
|
|
}
|
|
|
|
$this->changed = false;
|
|
}
|
|
|
|
/**
|
|
* Treat consecutive "packets" as if they are a continuous buffer.
|
|
*
|
|
* The default behavior.
|
|
*
|
|
* @see Crypt_Rijndael::disableContinuousBuffer()
|
|
* @access public
|
|
*/
|
|
function enableContinuousBuffer()
|
|
{
|
|
parent::enableContinuousBuffer();
|
|
|
|
if (CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT) {
|
|
$this->enbuffer['enmcrypt_init'] = true;
|
|
$this->debuffer['demcrypt_init'] = true;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Treat consecutive packets as if they are a discontinuous buffer.
|
|
*
|
|
* The default behavior.
|
|
*
|
|
* @see Crypt_Rijndael::enableContinuousBuffer()
|
|
* @access public
|
|
*/
|
|
function disableContinuousBuffer()
|
|
{
|
|
parent::disableContinuousBuffer();
|
|
|
|
if (CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT) {
|
|
mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
|
|
mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
|
|
}
|
|
}
|
|
}
|
|
|
|
// vim: ts=4:sw=4:et:
|
|
// vim6: fdl=1:
|