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+<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * Code Igniter
+ *
+ * An open source application development framework for PHP 4.3.2 or newer
+ *
+ * @package CodeIgniter
+ * @author Rick Ellis
+ * @copyright Copyright (c) 2006, pMachine, Inc.
+ * @license http://www.codeignitor.com/user_guide/license.html
+ * @link http://www.codeigniter.com
+ * @since Version 1.0
+ * @filesource
+ */
+
+// ------------------------------------------------------------------------
+
+/**
+ * Code Igniter Encryption Class
+ *
+ * Provides two-way keyed encoding using XOR Hashing and Mcrypt
+ *
+ * @package CodeIgniter
+ * @subpackage Libraries
+ * @category Libraries
+ * @author Rick Ellis
+ * @link http://www.codeigniter.com/user_guide/libraries/encryption.html
+ */
+class CI_Encrypt {
+ var $_hash_type = 'sha1';
+ var $_mcrypt_exists = FALSE;
+ var $_mcrypt_cipher;
+ var $_mcrypt_mode;
+
+ /**
+ * Constructor
+ *
+ * Simply determines whether the mcrypt library exists.
+ *
+ */
+ function CI_Encrypt()
+ {
+ $this->_mcrypt_exists = ( ! function_exists('mcrypt_encrypt')) ? FALSE : TRUE;
+ log_message('debug', "Encrypt Class Initialized");
+ }
+ // END CI_Encrypt()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Fetch the encryption key
+ *
+ * Returns it as MD5 in order to have an exact-length 128 bit key.
+ * Mcrypt is sensitive to keys that are not the correct length
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function get_key($key = '')
+ {
+ if ($key == '')
+ {
+ $obj =& get_instance();
+ $key = $obj->config->item('encryption_key');
+
+ if ($key === FALSE)
+ {
+ show_error('In order to use the encryption class requires that you set an encryption key in your config file.');
+ }
+ }
+
+ return md5($key);
+ }
+ // END get_key()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Encode
+ *
+ * Encodes the message string using bitwise XOR encoding.
+ * The key is combined with a random hash, and then it
+ * too gets converted using XOR. The whole thing is then run
+ * through mcrypt (if supported) using the randomized key.
+ * The end result is a double-encrypted message string
+ * that is randomized with each call to this function,
+ * even if the supplied message and key are the same.
+ *
+ * @access public
+ * @param string the string to encode
+ * @param string the key
+ * @return string
+ */
+ function encode($string, $key = '')
+ {
+ $key = $this->get_key($key);
+ $enc = $this->_xor_encode($string, $key);
+
+ if ($this->_mcrypt_exists === TRUE)
+ {
+ $enc = $this->mcrypt_encode($enc, $key);
+ }
+ return base64_encode($enc);
+ }
+ // END encode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Decode
+ *
+ * Reverses the above process
+ *
+ * @access public
+ * @param string
+ * @param string
+ * @return string
+ */
+ function decode($string, $key = '')
+ {
+ $key = $this->get_key($key);
+ $dec = base64_decode($string);
+
+ if ($dec === FALSE)
+ {
+ return FALSE;
+ }
+
+ if ($this->_mcrypt_exists === TRUE)
+ {
+ $dec = $this->mcrypt_decode($dec, $key);
+ }
+
+ return $this->_xor_decode($dec, $key);
+ }
+ // END decode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * XOR Encode
+ *
+ * Takes a plain-text string and key as input and generates an
+ * encoded bit-string using XOR
+ *
+ * @access private
+ * @param string
+ * @param string
+ * @return string
+ */
+ function _xor_encode($string, $key)
+ {
+ $rand = '';
+ while (strlen($rand) < 32)
+ {
+ $rand .= mt_rand(0, mt_getrandmax());
+ }
+
+ $rand = $this->hash($rand);
+
+ $enc = '';
+ for ($i = 0; $i < strlen($string); $i++)
+ {
+ $enc .= substr($rand, ($i % strlen($rand)), 1).(substr($rand, ($i % strlen($rand)), 1) ^ substr($string, $i, 1));
+ }
+
+ return $this->_xor_merge($enc, $key);
+ }
+ // END _xor_encode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * XOR Decode
+ *
+ * Takes an encoded string and key as input and generates the
+ * plain-text original message
+ *
+ * @access private
+ * @param string
+ * @param string
+ * @return string
+ */
+ function _xor_decode($string, $key)
+ {
+ $string = $this->_xor_merge($string, $key);
+
+ $dec = '';
+ for ($i = 0; $i < strlen($string); $i++)
+ {
+ $dec .= (substr($string, $i++, 1) ^ substr($string, $i, 1));
+ }
+
+ return $dec;
+ }
+ // END _xor_decode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * XOR key + string Combiner
+ *
+ * Takes a string and key as input and computes the difference using XOR
+ *
+ * @access private
+ * @param string
+ * @param string
+ * @return string
+ */
+ function _xor_merge($string, $key)
+ {
+ $hash = $this->hash($key);
+ $str = '';
+ for ($i = 0; $i < strlen($string); $i++)
+ {
+ $str .= substr($string, $i, 1) ^ substr($hash, ($i % strlen($hash)), 1);
+ }
+
+ return $str;
+ }
+ // END _xor_merge()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Encrypt using Mcrypt
+ *
+ * @access public
+ * @param string
+ * @param string
+ * @return string
+ */
+ function mcrypt_encode($data, $key)
+ {
+ $this->_get_mcrypt();
+ $init_size = mcrypt_get_iv_size($this->_mcrypt_cipher, $this->_mcrypt_mode);
+ $init_vect = mcrypt_create_iv($init_size, MCRYPT_RAND);
+ return mcrypt_encrypt($this->_mcrypt_cipher, $key, $data, $this->_mcrypt_mode, $init_vect);
+ }
+ // END mcrypt_encode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Decrypt using Mcrypt
+ *
+ * @access public
+ * @param string
+ * @param string
+ * @return string
+ */
+ function mcrypt_decode($data, $key)
+ {
+ $this->_get_mcrypt();
+ $init_size = mcrypt_get_iv_size($this->_mcrypt_cipher, $this->_mcrypt_mode);
+ $init_vect = mcrypt_create_iv($init_size, MCRYPT_RAND);
+ return rtrim(mcrypt_decrypt($this->_mcrypt_cipher, $key, $data, $this->_mcrypt_mode, $init_vect), "\0");
+ }
+ // END mcrypt_decode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set the Mcrypt Cypher
+ *
+ * @access public
+ * @param constant
+ * @return string
+ */
+ function set_cypher($cypher)
+ {
+ $this->_mcrypt_cipher = $cypher;
+ }
+ // END set_cypher()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set the Mcrypt Mode
+ *
+ * @access public
+ * @param constant
+ * @return string
+ */
+ function set_mode($mode)
+ {
+ $this->_mcrypt_mode = $mode;
+ }
+ // END set_mode()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Get Mcrypt value
+ *
+ * @access private
+ * @param string
+ * @return string
+ */
+ function _get_mcrypt()
+ {
+ if ($this->_mcrypt_cipher == '')
+ {
+ $this->_mcrypt_cipher = MCRYPT_RIJNDAEL_256;
+ }
+ if ($this->_mcrypt_mode == '')
+ {
+ $this->_mcrypt_mode = MCRYPT_MODE_ECB;
+ }
+ }
+ // END _get_mcrypt()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set the Hash type
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function set_hash($type = 'sha1')
+ {
+ $this->_hash_type = ($type != 'sha1' OR $type != 'md5') ? 'sha1' : $type;
+ }
+ // END set_hash()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Hash encode a string
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function hash($str)
+ {
+ return ($this->_hash_type == 'sha1') ? $this->sha1($str) : md5($str);
+ }
+ // END hash()
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Generate an SHA1 Hash
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function sha1($str)
+ {
+ if ( ! function_exists('sha1'))
+ {
+ if ( ! function_exists('mhash'))
+ {
+ require_once(BASEPATH.'libraries/Sha1'.EXT);
+ $SH = new CI_SHA;
+ return $SH->generate($str);
+ }
+ else
+ {
+ return bin2hex(mhash(MHASH_SHA1, $str));
+ }
+ }
+ else
+ {
+ return sha1($str);
+ }
+ }
+ // END sha1()
+
+}
+
+// END CI_Encrypt class
+?> \ No newline at end of file
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