--- /dev/null
+<?php\r
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */\r
+\r
+/**\r
+ * Pure-PHP implementation of RC4.\r
+ *\r
+ * Uses mcrypt, if available, and an internal implementation, otherwise.\r
+ *\r
+ * PHP versions 4 and 5\r
+ *\r
+ * Useful resources are as follows:\r
+ *\r
+ * - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}\r
+ * - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}\r
+ *\r
+ * RC4 is also known as ARCFOUR or ARC4. The reason is elaborated upon at Wikipedia. This class is named RC4 and not\r
+ * ARCFOUR or ARC4 because RC4 is how it is refered to in the SSH1 specification.\r
+ *\r
+ * Here's a short example of how to use this library:\r
+ * <code>\r
+ * <?php\r
+ * include('Crypt/RC4.php');\r
+ *\r
+ * $rc4 = new Crypt_RC4();\r
+ *\r
+ * $rc4->setKey('abcdefgh');\r
+ *\r
+ * $size = 10 * 1024;\r
+ * $plaintext = '';\r
+ * for ($i = 0; $i < $size; $i++) {\r
+ * $plaintext.= 'a';\r
+ * }\r
+ *\r
+ * echo $rc4->decrypt($rc4->encrypt($plaintext));\r
+ * ?>\r
+ * </code>\r
+ *\r
+ * LICENSE: This library is free software; you can redistribute it and/or\r
+ * modify it under the terms of the GNU Lesser General Public\r
+ * License as published by the Free Software Foundation; either\r
+ * version 2.1 of the License, or (at your option) any later version.\r
+ *\r
+ * This library is distributed in the hope that it will be useful,\r
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of\r
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU\r
+ * Lesser General Public License for more details.\r
+ *\r
+ * You should have received a copy of the GNU Lesser General Public\r
+ * License along with this library; if not, write to the Free Software\r
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,\r
+ * MA 02111-1307 USA\r
+ *\r
+ * @category Crypt\r
+ * @package Crypt_RC4\r
+ * @author Jim Wigginton <terrafrost@php.net>\r
+ * @copyright MMVII Jim Wigginton\r
+ * @license http://www.gnu.org/licenses/lgpl.txt\r
+ * @version $Id: RC4.php,v 1.8 2009/06/09 04:00:38 terrafrost Exp $\r
+ * @link http://phpseclib.sourceforge.net\r
+ */\r
+\r
+/**#@+\r
+ * @access private\r
+ * @see Crypt_RC4::Crypt_RC4()\r
+ */\r
+/**\r
+ * Toggles the internal implementation\r
+ */\r
+define('CRYPT_RC4_MODE_INTERNAL', 1);\r
+/**\r
+ * Toggles the mcrypt implementation\r
+ */\r
+define('CRYPT_RC4_MODE_MCRYPT', 2);\r
+/**#@-*/\r
+\r
+/**#@+\r
+ * @access private\r
+ * @see Crypt_RC4::_crypt()\r
+ */\r
+define('CRYPT_RC4_ENCRYPT', 0);\r
+define('CRYPT_RC4_DECRYPT', 1);\r
+/**#@-*/\r
+\r
+/**\r
+ * Pure-PHP implementation of RC4.\r
+ *\r
+ * @author Jim Wigginton <terrafrost@php.net>\r
+ * @version 0.1.0\r
+ * @access public\r
+ * @package Crypt_RC4\r
+ */\r
+class Crypt_RC4 {\r
+ /**\r
+ * The Key\r
+ *\r
+ * @see Crypt_RC4::setKey()\r
+ * @var String\r
+ * @access private\r
+ */\r
+ var $key = "\0";\r
+\r
+ /**\r
+ * The Key Stream for encryption\r
+ *\r
+ * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object\r
+ *\r
+ * @see Crypt_RC4::setKey()\r
+ * @var Array\r
+ * @access private\r
+ */\r
+ var $encryptStream = false;\r
+\r
+ /**\r
+ * The Key Stream for decryption\r
+ *\r
+ * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object\r
+ *\r
+ * @see Crypt_RC4::setKey()\r
+ * @var Array\r
+ * @access private\r
+ */\r
+ var $decryptStream = false;\r
+\r
+ /**\r
+ * The $i and $j indexes for encryption\r
+ *\r
+ * @see Crypt_RC4::_crypt()\r
+ * @var Integer\r
+ * @access private\r
+ */\r
+ var $encryptIndex = 0;\r
+\r
+ /**\r
+ * The $i and $j indexes for decryption\r
+ *\r
+ * @see Crypt_RC4::_crypt()\r
+ * @var Integer\r
+ * @access private\r
+ */\r
+ var $decryptIndex = 0;\r
+\r
+ /**\r
+ * MCrypt parameters\r
+ *\r
+ * @see Crypt_RC4::setMCrypt()\r
+ * @var Array\r
+ * @access private\r
+ */\r
+ var $mcrypt = array('', '');\r
+\r
+ /**\r
+ * The Encryption Algorithm\r
+ *\r
+ * Only used if CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT. Only possible values are MCRYPT_RC4 or MCRYPT_ARCFOUR.\r
+ *\r
+ * @see Crypt_RC4::Crypt_RC4()\r
+ * @var Integer\r
+ * @access private\r
+ */\r
+ var $mode;\r
+\r
+ /**\r
+ * Default Constructor.\r
+ *\r
+ * Determines whether or not the mcrypt extension should be used.\r
+ *\r
+ * @param optional Integer $mode\r
+ * @return Crypt_RC4\r
+ * @access public\r
+ */\r
+ function Crypt_RC4()\r
+ {\r
+ if ( !defined('CRYPT_RC4_MODE') ) {\r
+ switch (true) {\r
+ case extension_loaded('mcrypt') && (defined('MCRYPT_ARCFOUR') || defined('MCRYPT_RC4')):\r
+ // i'd check to see if rc4 was supported, by doing in_array('arcfour', mcrypt_list_algorithms('')),\r
+ // but since that can be changed after the object has been created, there doesn't seem to be\r
+ // a lot of point...\r
+ define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_MCRYPT);\r
+ break;\r
+ default:\r
+ define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL);\r
+ }\r
+ }\r
+\r
+ switch ( CRYPT_RC4_MODE ) {\r
+ case CRYPT_RC4_MODE_MCRYPT:\r
+ switch (true) {\r
+ case defined('MCRYPT_ARCFOUR'):\r
+ $this->mode = MCRYPT_ARCFOUR;\r
+ break;\r
+ case defined('MCRYPT_RC4');\r
+ $this->mode = MCRYPT_RC4;\r
+ }\r
+ }\r
+ }\r
+\r
+ /**\r
+ * Sets the key.\r
+ *\r
+ * Keys can be between 1 and 256 bytes long. If they are longer then 256 bytes, the first 256 bytes will\r
+ * be used. If no key is explicitly set, it'll be assumed to be a single null byte.\r
+ *\r
+ * @access public\r
+ * @param String $key\r
+ */\r
+ function setKey($key)\r
+ {\r
+ $this->key = $key;\r
+\r
+ if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {\r
+ return;\r
+ }\r
+\r
+ $keyLength = strlen($key);\r
+ $keyStream = array();\r
+ for ($i = 0; $i < 256; $i++) {\r
+ $keyStream[$i] = $i;\r
+ }\r
+ $j = 0;\r
+ for ($i = 0; $i < 256; $i++) {\r
+ $j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;\r
+ $temp = $keyStream[$i];\r
+ $keyStream[$i] = $keyStream[$j];\r
+ $keyStream[$j] = $temp;\r
+ }\r
+\r
+ $this->encryptIndex = $this->decryptIndex = array(0, 0);\r
+ $this->encryptStream = $this->decryptStream = $keyStream;\r
+ }\r
+\r
+ /**\r
+ * Dummy function.\r
+ *\r
+ * Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1].\r
+ * If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before\r
+ * calling setKey().\r
+ *\r
+ * [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way. Since, in that protocol,\r
+ * the IV's are relatively easy to predict, an attack described by\r
+ * {@link http://www.drizzle.com/~aboba/IEEE/rc4_ksaproc.pdf Scott Fluhrer, Itsik Mantin, and Adi Shamir}\r
+ * can be used to quickly guess at the rest of the key. The following links elaborate:\r
+ *\r
+ * {@link http://www.rsa.com/rsalabs/node.asp?id=2009 http://www.rsa.com/rsalabs/node.asp?id=2009}\r
+ * {@link http://en.wikipedia.org/wiki/Related_key_attack http://en.wikipedia.org/wiki/Related_key_attack}\r
+ *\r
+ * @param String $iv\r
+ * @see Crypt_RC4::setKey()\r
+ * @access public\r
+ */\r
+ function setIV($iv)\r
+ {\r
+ }\r
+\r
+ /**\r
+ * Sets MCrypt parameters. (optional)\r
+ *\r
+ * If MCrypt is being used, empty strings will be used, unless otherwise specified.\r
+ *\r
+ * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open\r
+ * @access public\r
+ * @param optional Integer $algorithm_directory\r
+ * @param optional Integer $mode_directory\r
+ */\r
+ function setMCrypt($algorithm_directory = '', $mode_directory = '')\r
+ {\r
+ if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {\r
+ $this->mcrypt = array($algorithm_directory, $mode_directory);\r
+ $this->_closeMCrypt();\r
+ }\r
+ }\r
+\r
+ /**\r
+ * Encrypts a message.\r
+ *\r
+ * @see Crypt_RC4::_crypt()\r
+ * @access public\r
+ * @param String $plaintext\r
+ */\r
+ function encrypt($plaintext)\r
+ {\r
+ return $this->_crypt($plaintext, CRYPT_RC4_ENCRYPT);\r
+ }\r
+\r
+ /**\r
+ * Decrypts a message.\r
+ *\r
+ * $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).\r
+ * Atleast if the continuous buffer is disabled.\r
+ *\r
+ * @see Crypt_RC4::_crypt()\r
+ * @access public\r
+ * @param String $ciphertext\r
+ */\r
+ function decrypt($ciphertext)\r
+ {\r
+ return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT);\r
+ }\r
+\r
+ /**\r
+ * Encrypts or decrypts a message.\r
+ *\r
+ * @see Crypt_RC4::encrypt()\r
+ * @see Crypt_RC4::decrypt()\r
+ * @access private\r
+ * @param String $text\r
+ * @param Integer $mode\r
+ */\r
+ function _crypt($text, $mode)\r
+ {\r
+ if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {\r
+ $keyStream = $mode == CRYPT_RC4_ENCRYPT ? 'encryptStream' : 'decryptStream';\r
+\r
+ if ($this->$keyStream === false) {\r
+ $this->$keyStream = mcrypt_module_open($this->mode, $this->mcrypt[0], MCRYPT_MODE_STREAM, $this->mcrypt[1]);\r
+ mcrypt_generic_init($this->$keyStream, $this->key, '');\r
+ } else if (!$this->continuousBuffer) {\r
+ mcrypt_generic_init($this->$keyStream, $this->key, '');\r
+ }\r
+ $newText = mcrypt_generic($this->$keyStream, $text);\r
+ if (!$this->continuousBuffer) {\r
+ mcrypt_generic_deinit($this->$keyStream);\r
+ }\r
+\r
+ return $newText;\r
+ }\r
+\r
+ if ($this->encryptStream === false) {\r
+ $this->setKey($this->key);\r
+ }\r
+\r
+ switch ($mode) {\r
+ case CRYPT_RC4_ENCRYPT:\r
+ $keyStream = $this->encryptStream;\r
+ list($i, $j) = $this->encryptIndex;\r
+ break;\r
+ case CRYPT_RC4_DECRYPT:\r
+ $keyStream = $this->decryptStream;\r
+ list($i, $j) = $this->decryptIndex;\r
+ }\r
+\r
+ $newText = '';\r
+ for ($k = 0; $k < strlen($text); $k++) {\r
+ $i = ($i + 1) & 255;\r
+ $j = ($j + $keyStream[$i]) & 255;\r
+ $temp = $keyStream[$i];\r
+ $keyStream[$i] = $keyStream[$j];\r
+ $keyStream[$j] = $temp;\r
+ $temp = $keyStream[($keyStream[$i] + $keyStream[$j]) & 255];\r
+ $newText.= chr(ord($text[$k]) ^ $temp);\r
+ }\r
+\r
+ if ($this->continuousBuffer) {\r
+ switch ($mode) {\r
+ case CRYPT_RC4_ENCRYPT:\r
+ $this->encryptStream = $keyStream;\r
+ $this->encryptIndex = array($i, $j);\r
+ break;\r
+ case CRYPT_RC4_DECRYPT:\r
+ $this->decryptStream = $keyStream;\r
+ $this->decryptIndex = array($i, $j);\r
+ }\r
+ }\r
+\r
+ return $newText;\r
+ }\r
+\r
+ /**\r
+ * Treat consecutive "packets" as if they are a continuous buffer.\r
+ *\r
+ * Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets\r
+ * will yield different outputs:\r
+ *\r
+ * <code>\r
+ * echo $rc4->encrypt(substr($plaintext, 0, 8));\r
+ * echo $rc4->encrypt(substr($plaintext, 8, 8));\r
+ * </code>\r
+ * <code>\r
+ * echo $rc4->encrypt($plaintext);\r
+ * </code>\r
+ *\r
+ * The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates\r
+ * another, as demonstrated with the following:\r
+ *\r
+ * <code>\r
+ * $rc4->encrypt(substr($plaintext, 0, 8));\r
+ * echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));\r
+ * </code>\r
+ * <code>\r
+ * echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));\r
+ * </code>\r
+ *\r
+ * With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different\r
+ * outputs. The reason is due to the fact that the initialization vector's change after every encryption /\r
+ * decryption round when the continuous buffer is enabled. When it's disabled, they remain constant.\r
+ *\r
+ * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each\r
+ * encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that\r
+ * continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them),\r
+ * however, they are also less intuitive and more likely to cause you problems.\r
+ *\r
+ * @see Crypt_RC4::disableContinuousBuffer()\r
+ * @access public\r
+ */\r
+ function enableContinuousBuffer()\r
+ {\r
+ $this->continuousBuffer = true;\r
+ }\r
+\r
+ /**\r
+ * Treat consecutive packets as if they are a discontinuous buffer.\r
+ *\r
+ * The default behavior.\r
+ *\r
+ * @see Crypt_RC4::enableContinuousBuffer()\r
+ * @access public\r
+ */\r
+ function disableContinuousBuffer()\r
+ {\r
+ if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_INTERNAL ) {\r
+ $this->encryptIndex = $this->decryptIndex = array(0, 0);\r
+ $this->setKey($this->key);\r
+ }\r
+\r
+ $this->continuousBuffer = false;\r
+ }\r
+\r
+ /**\r
+ * Dummy function.\r
+ *\r
+ * Since RC4 is a stream cipher and not a block cipher, no padding is necessary. The only reason this function is\r
+ * included is so that you can switch between a block cipher and a stream cipher transparently.\r
+ *\r
+ * @see Crypt_RC4::disablePadding()\r
+ * @access public\r
+ */\r
+ function enablePadding()\r
+ {\r
+ }\r
+\r
+ /**\r
+ * Dummy function.\r
+ *\r
+ * @see Crypt_RC4::enablePadding()\r
+ * @access public\r
+ */\r
+ function disablePadding()\r
+ {\r
+ }\r
+\r
+ /**\r
+ * Class destructor.\r
+ *\r
+ * Will be called, automatically, if you're using PHP5. If you're using PHP4, call it yourself. Only really\r
+ * needs to be called if mcrypt is being used.\r
+ *\r
+ * @access public\r
+ */\r
+ function __destruct()\r
+ {\r
+ if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {\r
+ $this->_closeMCrypt();\r
+ }\r
+ }\r
+\r
+ /**\r
+ * Properly close the MCrypt objects.\r
+ *\r
+ * @access prviate\r
+ */\r
+ function _closeMCrypt()\r
+ {\r
+ if ( $this->encryptStream !== false ) {\r
+ if ( $this->continuousBuffer ) {\r
+ mcrypt_generic_deinit($this->encryptStream);\r
+ }\r
+\r
+ mcrypt_module_close($this->encryptStream);\r
+\r
+ $this->encryptStream = false;\r
+ }\r
+\r
+ if ( $this->decryptStream !== false ) {\r
+ if ( $this->continuousBuffer ) {\r
+ mcrypt_generic_deinit($this->decryptStream);\r
+ }\r
+\r
+ mcrypt_module_close($this->decryptStream);\r
+\r
+ $this->decryptStream = false;\r
+ }\r
+ }\r
+}
\ No newline at end of file
projects / friendica.git / blobdiff