--- /dev/null
+<?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 Crypt_RC4::Crypt_RC4()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_RC4_MODE_INTERNAL', CRYPT_MODE_INTERNAL);
+/**
+ * Toggles the mcrypt implementation
+ */
+define('CRYPT_RC4_MODE_MCRYPT', CRYPT_MODE_MCRYPT);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see Crypt_RC4::_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 Integer
+ * @access private
+ */
+ var $block_size = 0;
+
+ /**
+ * The default password key_size used by setPassword()
+ *
+ * @see Crypt_Base::password_key_size
+ * @see Crypt_Base::setPassword()
+ * @var Integer
+ * @access private
+ */
+ var $password_key_size = 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 Crypt_RC4::setKey()
+ * @var String
+ * @access private
+ */
+ var $key = "\0";
+
+ /**
+ * The Key Stream for decryption and encryption
+ *
+ * @see Crypt_RC4::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 Crypt_RC4()
+ {
+ parent::Crypt_Base(CRYPT_MODE_STREAM);
+ }
+
+ /**
+ * 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 $iv
+ * @see Crypt_RC4::setKey()
+ * @access public
+ */
+ function setIV($iv)
+ {
+ }
+
+ /**
+ * Sets the key.
+ *
+ * Keys can be between 1 and 256 bytes long. If they are longer then 256 bytes, the first 256 bytes will
+ * be used. If no key is explicitly set, it'll be assumed to be a single null byte.
+ *
+ * @access public
+ * @see Crypt_Base::setKey()
+ * @param String $key
+ */
+ function setKey($key)
+ {
+ parent::setKey(substr($key, 0, 256));
+ }
+
+ /**
+ * Encrypts a message.
+ *
+ * @see Crypt_Base::decrypt()
+ * @see Crypt_RC4::_crypt()
+ * @access public
+ * @param String $plaintext
+ * @return String $ciphertext
+ */
+ function encrypt($plaintext)
+ {
+ if ($this->engine == CRYPT_MODE_MCRYPT) {
+ return parent::encrypt($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 Crypt_RC4::_crypt()
+ * @access public
+ * @param String $ciphertext
+ * @return String $plaintext
+ */
+ function decrypt($ciphertext)
+ {
+ if ($this->engine == CRYPT_MODE_MCRYPT) {
+ return parent::decrypt($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 Crypt_RC4::encrypt()
+ * @see Crypt_RC4::decrypt()
+ * @access private
+ * @param String $text
+ * @param Integer $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;
+ }
+}
projects / friendica-addons.git / blobdiff