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Diffstat (limited to 'libs/phpseclib-1.0.6/Crypt/RC4.php')
| -rw-r--r-- | libs/phpseclib-1.0.6/Crypt/RC4.php | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/libs/phpseclib-1.0.6/Crypt/RC4.php b/libs/phpseclib-1.0.6/Crypt/RC4.php new file mode 100644 index 0000000..6214554 --- /dev/null +++ b/libs/phpseclib-1.0.6/Crypt/RC4.php @@ -0,0 +1,350 @@ +<?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 + * ARCFOUR or ARC4 because RC4 is how it is referred to in the SSH1 specification. + * + * Here's a short example of how to use this library: + * <code> + * <?php + * include 'Crypt/RC4.php'; + * + * $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> + * + * 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_RC4 + * @author Jim Wigginton <terrafrost@php.net> + * @copyright 2007 Jim Wigginton + * @license http://www.opensource.org/licenses/mit-license.html MIT License + * @link http://phpseclib.sourceforge.net + */ + +/** + * Include Crypt_Base + * + * Base cipher class + */ +if (!class_exists('Crypt_Base')) { + include_once 'Base.php'; +} + +/**#@+ + * @access private + * @see self::_crypt() + */ +define('CRYPT_RC4_ENCRYPT', 0); +define('CRYPT_RC4_DECRYPT', 1); +/**#@-*/ + +/** + * Pure-PHP implementation of RC4. + * + * @package Crypt_RC4 + * @author Jim Wigginton <terrafrost@php.net> + * @access public + */ +class Crypt_RC4 extends Crypt_Base +{ + /** + * Block Length of the cipher + * + * RC4 is a stream cipher + * so we the block_size to 0 + * + * @see Crypt_Base::block_size + * @var int + * @access private + */ + var $block_size = 0; + + /** + * Key Length (in bytes) + * + * @see Crypt_RC4::setKeyLength() + * @var int + * @access private + */ + var $key_length = 128; // = 1024 bits + + /** + * The namespace used by the cipher for its constants. + * + * @see Crypt_Base::const_namespace + * @var string + * @access private + */ + var $const_namespace = 'RC4'; + + /** + * The mcrypt specific name of the cipher + * + * @see Crypt_Base::cipher_name_mcrypt + * @var string + * @access private + */ + var $cipher_name_mcrypt = 'arcfour'; + + /** + * Holds whether performance-optimized $inline_crypt() can/should be used. + * + * @see Crypt_Base::inline_crypt + * @var mixed + * @access private + */ + var $use_inline_crypt = false; // currently not available + + /** + * The Key + * + * @see self::setKey() + * @var string + * @access private + */ + var $key = "\0"; + + /** + * The Key Stream for decryption and encryption + * + * @see self::setKey() + * @var array + * @access private + */ + var $stream; + + /** + * Default Constructor. + * + * Determines whether or not the mcrypt extension should be used. + * + * @see Crypt_Base::Crypt_Base() + * @return Crypt_RC4 + * @access public + */ + function __construct() + { + parent::__construct(CRYPT_MODE_STREAM); + } + + /** + * PHP4 compatible Default Constructor. + * + * @see self::__construct() + * @access public + */ + function Crypt_RC4() + { + $this->__construct(); + } + + /** + * Test for engine validity + * + * This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine() + * + * @see Crypt_Base::Crypt_Base() + * @param int $engine + * @access public + * @return bool + */ + function isValidEngine($engine) + { + if ($engine == CRYPT_ENGINE_OPENSSL) { + $this->cipher_name_openssl = 'rc4-40'; + } + + return parent::isValidEngine($engine); + } + + /** + * 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} + * + * @param string $iv + * @see self::setKey() + * @access public + */ + function setIV($iv) + { + } + + /** + * Sets the key length + * + * Keys can be between 1 and 256 bytes long. + * + * @access public + * @param int $length + */ + function setKeyLength($length) + { + if ($length < 8) { + $this->key_length = 1; + } elseif ($length > 2048) { + $this->key_length = 256; + } else { + $this->key_length = $length >> 3; + } + + parent::setKeyLength($length); + } + + /** + * Encrypts a message. + * + * @see Crypt_Base::decrypt() + * @see self::_crypt() + * @access public + * @param string $plaintext + * @return string $ciphertext + */ + function encrypt($plaintext) + { + if ($this->engine != CRYPT_ENGINE_INTERNAL) { + return parent::encrypt($plaintext); + } + return $this->_crypt($plaintext, CRYPT_RC4_ENCRYPT); + } + + /** + * Decrypts a message. + * + * $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)). + * At least if the continuous buffer is disabled. + * + * @see Crypt_Base::encrypt() + * @see self::_crypt() + * @access public + * @param string $ciphertext + * @return string $plaintext + */ + function decrypt($ciphertext) + { + if ($this->engine != CRYPT_ENGINE_INTERNAL) { + return parent::decrypt($ciphertext); + } + return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT); + } + + + /** + * Setup the key (expansion) + * + * @see Crypt_Base::_setupKey() + * @access private + */ + function _setupKey() + { + $key = $this->key; + $keyLength = strlen($key); + $keyStream = range(0, 255); + $j = 0; + for ($i = 0; $i < 256; $i++) { + $j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255; + $temp = $keyStream[$i]; + $keyStream[$i] = $keyStream[$j]; + $keyStream[$j] = $temp; + } + + $this->stream = array(); + $this->stream[CRYPT_RC4_DECRYPT] = $this->stream[CRYPT_RC4_ENCRYPT] = array( + 0, // index $i + 0, // index $j + $keyStream + ); + } + + /** + * Encrypts or decrypts a message. + * + * @see self::encrypt() + * @see self::decrypt() + * @access private + * @param string $text + * @param int $mode + * @return string $text + */ + function _crypt($text, $mode) + { + if ($this->changed) { + $this->_setup(); + $this->changed = false; + } + + $stream = &$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]; + } + + $len = strlen($text); + for ($k = 0; $k < $len; ++$k) { + $i = ($i + 1) & 255; + $ksi = $keyStream[$i]; + $j = ($j + $ksi) & 255; + $ksj = $keyStream[$j]; + + $keyStream[$i] = $ksj; + $keyStream[$j] = $ksi; + $text[$k] = $text[$k] ^ chr($keyStream[($ksj + $ksi) & 255]); + } + + return $text; + } +} |