init_class('CI_Encrypt'); // ------------------------------------------------------------------------ /** * 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' AND $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 ?>