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<?php
/**
* Pure-PHP implementation of AES.
*
* Uses mcrypt, if available/possible, and an internal implementation, otherwise.
*
* PHP versions 4 and 5
*
* If {@link Crypt_AES::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
* {@link Crypt_AES::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's 136-bits
* it'll be null-padded to 192-bits and 192 bits will be the key length until {@link Crypt_AES::setKey() setKey()}
* is called, again, at which point, it'll be recalculated.
*
* Since Crypt_AES extends Crypt_Rijndael, some functions are available to be called that, in the context of AES, don't
* make a whole lot of sense. {@link Crypt_AES::setBlockLength() setBlockLength()}, for instance. Calling that function,
* however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
*
* Here's a short example of how to use this library:
* <code>
* <?php
* include 'Crypt/AES.php';
*
* $aes = new Crypt_AES();
*
* $aes->setKey('abcdefghijklmnop');
*
* $size = 10 * 1024;
* $plaintext = '';
* for ($i = 0; $i < $size; $i++) {
* $plaintext.= 'a';
* }
*
* echo $aes->decrypt($aes->encrypt($plaintext));
* ?>
* </code>
*
* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @category Crypt
* @package Crypt_AES
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2008 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
/**
* Include Crypt_Rijndael
*/
if (!class_exists('Crypt_Rijndael')) {
include_once 'Rijndael.php';
}
/**#@+
* @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
*/
define('CRYPT_AES_MODE_CTR', CRYPT_MODE_CTR);
/**
* Encrypt / decrypt using the Electronic Code Book mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
*/
define('CRYPT_AES_MODE_ECB', CRYPT_MODE_ECB);
/**
* Encrypt / decrypt using the Code Book Chaining mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
*/
define('CRYPT_AES_MODE_CBC', CRYPT_MODE_CBC);
/**
* Encrypt / decrypt using the Cipher Feedback mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
*/
define('CRYPT_AES_MODE_CFB', CRYPT_MODE_CFB);
/**
* Encrypt / decrypt using the Cipher Feedback mode.
*
* @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
*/
define('CRYPT_AES_MODE_OFB', CRYPT_MODE_OFB);
/**#@-*/
/**#@+
* @access private
* @see Crypt_Base::Crypt_Base()
*/
/**
* Toggles the internal implementation
*/
define('CRYPT_AES_MODE_INTERNAL', CRYPT_MODE_INTERNAL);
/**
* Toggles the mcrypt implementation
*/
define('CRYPT_AES_MODE_MCRYPT', CRYPT_MODE_MCRYPT);
/**#@-*/
/**
* Pure-PHP implementation of AES.
*
* @package Crypt_AES
* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
class Crypt_AES extends Crypt_Rijndael
{
/**
* The namespace used by the cipher for its constants.
*
* @see Crypt_Base::const_namespace
* @var String
* @access private
*/
var $const_namespace = 'AES';
/**
* Dummy function
*
* Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.
*
* @see Crypt_Rijndael::setBlockLength()
* @access public
* @param Integer $length
*/
function setBlockLength($length)
{
return;
}
/**
* Sets the key length
*
* 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.
*
* @see Crypt_Rijndael:setKeyLength()
* @access public
* @param Integer $length
*/
function setKeyLength($length)
{
switch ($length) {
case 160:
$length = 192;
break;
case 224:
$length = 256;
}
parent::setKeyLength($length);
}
/**
* Sets the key.
*
* Rijndael supports five different key lengths, AES only supports three.
*
* @see Crypt_Rijndael:setKey()
* @see setKeyLength()
* @access public
* @param String $key
*/
function setKey($key)
{
parent::setKey($key);
if (!$this->explicit_key_length) {
$length = strlen($key);
switch (true) {
case $length <= 16:
$this->key_size = 16;
break;
case $length <= 24:
$this->key_size = 24;
break;
default:
$this->key_size = 32;
}
$this->_setupEngine();
}
}
}
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