LDAPAccountManager/lam/lib/3rdParty/phpseclib/Crypt/RC4.php

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<?php
/**
* Pure-PHP implementation of RC4.
*
* Uses mcrypt, if available, and an internal implementation, otherwise.
*
* PHP versions 4 and 5
*
* Useful resources are as follows:
*
* - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}
* - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}
*
* RC4 is also known as ARCFOUR or ARC4. The reason is elaborated upon at Wikipedia. This class is named RC4 and not
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* ARCFOUR or ARC4 because RC4 is how it is referred to in the SSH1 specification.
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*
* Here's a short example of how to use this library:
* <code>
* <?php
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* include 'Crypt/RC4.php';
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*
* $rc4 = new Crypt_RC4();
*
* $rc4->setKey('abcdefgh');
*
* $size = 10 * 1024;
* $plaintext = '';
* for ($i = 0; $i < $size; $i++) {
* $plaintext.= 'a';
* }
*
* echo $rc4->decrypt($rc4->encrypt($plaintext));
* ?>
* </code>
*
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* 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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*
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* @category Crypt
* @package Crypt_RC4
* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2007 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
/**
* Include Crypt_Base
*
* Base cipher class
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*/
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if (!class_exists('Crypt_Base')) {
include_once 'Base.php';
}
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/**#@+
* @access private
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* @see self::_crypt()
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*/
define('CRYPT_RC4_ENCRYPT', 0);
define('CRYPT_RC4_DECRYPT', 1);
/**#@-*/
/**
* Pure-PHP implementation of RC4.
*
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* @package Crypt_RC4
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* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
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class Crypt_RC4 extends Crypt_Base
{
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/**
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* Block Length of the cipher
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*
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* RC4 is a stream cipher
* so we the block_size to 0
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*
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* @see Crypt_Base::block_size
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* @var int
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* @access private
*/
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var $block_size = 0;
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/**
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* Key Length (in bytes)
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*
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* @see Crypt_RC4::setKeyLength()
* @var int
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* @access private
*/
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var $key_length = 128; // = 1024 bits
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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
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* @access private
*/
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var $const_namespace = 'RC4';
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/**
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* The mcrypt specific name of the cipher
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*
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* @see Crypt_Base::cipher_name_mcrypt
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* @var string
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* @access private
*/
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var $cipher_name_mcrypt = 'arcfour';
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/**
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* Holds whether performance-optimized $inline_crypt() can/should be used.
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*
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* @see Crypt_Base::inline_crypt
* @var mixed
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* @access private
*/
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var $use_inline_crypt = false; // currently not available
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/**
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* The Key
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*
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* @see self::setKey()
* @var string
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* @access private
*/
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var $key = "\0";
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/**
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* The Key Stream for decryption and encryption
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*
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* @see self::setKey()
* @var array
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* @access private
*/
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var $stream;
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/**
* Default Constructor.
*
* Determines whether or not the mcrypt extension should be used.
*
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* @see Crypt_Base::Crypt_Base()
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* @return Crypt_RC4
* @access public
*/
function Crypt_RC4()
{
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parent::Crypt_Base(CRYPT_MODE_STREAM);
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}
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/**
* Test for engine validity
*
* This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine()
*
* @see Crypt_Base::Crypt_Base()
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* @param int $engine
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* @access public
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* @return bool
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*/
function isValidEngine($engine)
{
switch ($engine) {
case CRYPT_ENGINE_OPENSSL:
switch (strlen($this->key)) {
case 5:
$this->cipher_name_openssl = 'rc4-40';
break;
case 8:
$this->cipher_name_openssl = 'rc4-64';
break;
case 16:
$this->cipher_name_openssl = 'rc4';
break;
default:
return false;
}
}
return parent::isValidEngine($engine);
}
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/**
* Dummy function.
*
* Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1].
* If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before
* calling setKey().
*
* [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way. Since, in that protocol,
* the IV's are relatively easy to predict, an attack described by
* {@link http://www.drizzle.com/~aboba/IEEE/rc4_ksaproc.pdf Scott Fluhrer, Itsik Mantin, and Adi Shamir}
* can be used to quickly guess at the rest of the key. The following links elaborate:
*
* {@link http://www.rsa.com/rsalabs/node.asp?id=2009 http://www.rsa.com/rsalabs/node.asp?id=2009}
* {@link http://en.wikipedia.org/wiki/Related_key_attack http://en.wikipedia.org/wiki/Related_key_attack}
*
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* @param string $iv
* @see self::setKey()
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* @access public
*/
function setIV($iv)
{
}
/**
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* Sets the key length
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*
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* Keys can be between 1 and 256 bytes long.
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*
* @access public
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* @param int $length
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*/
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function setKeyLength($length)
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{
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if ($length < 8) {
$this->key_length = 1;
} elseif ($length > 2048) {
$this->key_length = 248;
} else {
$this->key_length = $length >> 3;
}
parent::setKeyLength($length);
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}
/**
* Encrypts a message.
*
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* @see Crypt_Base::decrypt()
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* @see self::_crypt()
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* @access public
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* @param string $plaintext
* @return string $ciphertext
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*/
function encrypt($plaintext)
{
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if ($this->engine != CRYPT_ENGINE_INTERNAL) {
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return parent::encrypt($plaintext);
}
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return $this->_crypt($plaintext, CRYPT_RC4_ENCRYPT);
}
/**
* Decrypts a message.
*
* $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).
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* At least if the continuous buffer is disabled.
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*
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* @see Crypt_Base::encrypt()
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* @see self::_crypt()
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* @access public
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* @param string $ciphertext
* @return string $plaintext
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*/
function decrypt($ciphertext)
{
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if ($this->engine != CRYPT_ENGINE_INTERNAL) {
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return parent::decrypt($ciphertext);
}
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return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT);
}
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/**
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* Setup the key (expansion)
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*
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* @see Crypt_Base::_setupKey()
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* @access private
*/
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function _setupKey()
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{
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$key = $this->key;
$keyLength = strlen($key);
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$keyStream = range(0, 255);
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$j = 0;
for ($i = 0; $i < 256; $i++) {
$j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;
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$temp = $keyStream[$i];
$keyStream[$i] = $keyStream[$j];
$keyStream[$j] = $temp;
}
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$this->stream = array();
$this->stream[CRYPT_RC4_DECRYPT] = $this->stream[CRYPT_RC4_ENCRYPT] = array(
0, // index $i
0, // index $j
$keyStream
);
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}
/**
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* Encrypts or decrypts a message.
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*
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* @see self::encrypt()
* @see self::decrypt()
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* @access private
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* @param string $text
* @param int $mode
* @return string $text
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*/
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function _crypt($text, $mode)
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{
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if ($this->changed) {
$this->_setup();
$this->changed = false;
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}
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$stream = &$this->stream[$mode];
if ($this->continuousBuffer) {
$i = &$stream[0];
$j = &$stream[1];
$keyStream = &$stream[2];
} else {
$i = $stream[0];
$j = $stream[1];
$keyStream = $stream[2];
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}
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$len = strlen($text);
for ($k = 0; $k < $len; ++$k) {
$i = ($i + 1) & 255;
$ksi = $keyStream[$i];
$j = ($j + $ksi) & 255;
$ksj = $keyStream[$j];
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$keyStream[$i] = $ksj;
$keyStream[$j] = $ksi;
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$text[$k] = $text[$k] ^ chr($keyStream[($ksj + $ksi) & 255]);
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}
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return $text;
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}
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}