Git-Center/Crypt/AES.php

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<?php
/**
* Pure-PHP implementation of AES.
*
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* Uses mcrypt, if available/possible, and an internal implementation, otherwise.
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*
* PHP versions 4 and 5
*
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* NOTE: Since AES.php is (for compatibility and phpseclib-historical reasons) virtually
* just a wrapper to Rijndael.php you may consider using Rijndael.php instead of
* to save one include_once().
*
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* If {@link Crypt_AES::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
* {@link Crypt_AES::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's 136-bits
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* it'll be null-padded to 192-bits and 192 bits will be the key length until {@link Crypt_AES::setKey() setKey()}
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* is called, again, at which point, it'll be recalculated.
*
* Since Crypt_AES extends Crypt_Rijndael, some functions are available to be called that, in the context of AES, don't
* make a whole lot of sense. {@link Crypt_AES::setBlockLength() setBlockLength()}, for instance. Calling that function,
* however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
*
* Here's a short example of how to use this library:
* <code>
* <?php
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* include 'Crypt/AES.php';
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*
* $aes = new Crypt_AES();
*
* $aes->setKey('abcdefghijklmnop');
*
* $size = 10 * 1024;
* $plaintext = '';
* for ($i = 0; $i < $size; $i++) {
* $plaintext.= 'a';
* }
*
* echo $aes->decrypt($aes->encrypt($plaintext));
* ?>
* </code>
*
* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
* 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
* 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.
*
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* @category Crypt
* @package Crypt_AES
* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2008 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
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*/
/**
* Include Crypt_Rijndael
*/
if (!class_exists('Crypt_Rijndael')) {
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include_once 'Rijndael.php';
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}
/**#@+
* @access public
* @see Crypt_AES::encrypt()
* @see Crypt_AES::decrypt()
*/
/**
* Encrypt / decrypt using the Counter mode.
*
* Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
*/
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define('CRYPT_AES_MODE_CTR', CRYPT_MODE_CTR);
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/**
* Encrypt / decrypt using the Electronic Code Book mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
*/
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define('CRYPT_AES_MODE_ECB', CRYPT_MODE_ECB);
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/**
* Encrypt / decrypt using the Code Book Chaining mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
*/
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define('CRYPT_AES_MODE_CBC', CRYPT_MODE_CBC);
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/**
* Encrypt / decrypt using the Cipher Feedback mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
*/
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define('CRYPT_AES_MODE_CFB', CRYPT_MODE_CFB);
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/**
* Encrypt / decrypt using the Cipher Feedback mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
*/
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define('CRYPT_AES_MODE_OFB', CRYPT_MODE_OFB);
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/**#@-*/
/**
* Pure-PHP implementation of AES.
*
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* @package Crypt_AES
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* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
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class Crypt_AES extends Crypt_Rijndael
{
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/**
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* The namespace used by the cipher for its constants.
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*
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* @see Crypt_Base::const_namespace
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* @var String
* @access private
*/
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var $const_namespace = 'AES';
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/**
* Dummy function
*
* Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.
*
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* @see Crypt_Rijndael::setBlockLength()
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* @access public
* @param Integer $length
*/
function setBlockLength($length)
{
return;
}
/**
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* Sets the key length
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*
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* Valid key lengths are 128, 192, and 256. If the length is less than 128, it will be rounded up to
* 128. If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
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*
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* @see Crypt_Rijndael:setKeyLength()
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* @access public
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* @param Integer $length
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*/
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function setKeyLength($length)
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{
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switch ($length) {
case 160:
$length = 192;
break;
case 224:
$length = 256;
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}
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parent::setKeyLength($length);
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}
/**
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* Sets the key.
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*
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* Rijndael supports five different key lengths, AES only supports three.
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*
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* @see Crypt_Rijndael:setKey()
* @see setKeyLength()
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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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parent::setKey($key);
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if (!$this->explicit_key_length) {
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$length = strlen($key);
switch (true) {
case $length <= 16:
$this->key_size = 16;
break;
case $length <= 24:
$this->key_size = 24;
break;
default:
$this->key_size = 32;
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}
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$this->_setEngine();
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}
}
}