/system/libraries/Encrypt.php
PHP | 547 lines | 233 code | 80 blank | 234 comment | 33 complexity | e9df90c7f8f3af4235943f572a762124 MD5 | raw file
- <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
- /**
- * CodeIgniter
- *
- * An open source application development framework for PHP 4.3.2 or newer
- *
- * @package CodeIgniter
- * @author ExpressionEngine Dev Team
- * @copyright Copyright (c) 2008 - 2010, EllisLab, Inc.
- * @license http://codeigniter.com/user_guide/license.html
- * @link http://codeigniter.com
- * @since Version 1.0
- * @filesource
- */
- // ------------------------------------------------------------------------
- /**
- * CodeIgniter Encryption Class
- *
- * Provides two-way keyed encoding using XOR Hashing and Mcrypt
- *
- * @package CodeIgniter
- * @subpackage Libraries
- * @category Libraries
- * @author ExpressionEngine Dev Team
- * @link http://codeigniter.com/user_guide/libraries/encryption.html
- */
- class CI_Encrypt {
- var $CI;
- var $encryption_key = '';
- 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->CI =& get_instance();
- $this->_mcrypt_exists = ( ! function_exists('mcrypt_encrypt')) ? FALSE : TRUE;
- log_message('debug', "Encrypt Class Initialized");
- }
- // --------------------------------------------------------------------
- /**
- * Fetch the encryption key
- *
- * Returns it as MD5 in order to have an exact-length 128 bit key.
- * Mcrypt is sensitive to keys that are not the correct length
- *
- * @access public
- * @param string
- * @return string
- */
- function get_key($key = '')
- {
- if ($key == '')
- {
- if ($this->encryption_key != '')
- {
- return $this->encryption_key;
- }
- $CI =& get_instance();
- $key = $CI->config->item('encryption_key');
- if ($key == FALSE)
- {
- show_error('In order to use the encryption class requires that you set an encryption key in your config file.');
- }
- }
- return md5($key);
- }
- // --------------------------------------------------------------------
- /**
- * Set the encryption key
- *
- * @access public
- * @param string
- * @return void
- */
- function set_key($key = '')
- {
- $this->encryption_key = $key;
- }
- // --------------------------------------------------------------------
- /**
- * Encode
- *
- * Encodes the message string using bitwise XOR encoding.
- * The key is combined with a random hash, and then it
- * too gets converted using XOR. The whole thing is then run
- * through mcrypt (if supported) using the randomized key.
- * The end result is a double-encrypted message string
- * that is randomized with each call to this function,
- * even if the supplied message and key are the same.
- *
- * @access public
- * @param string the string to encode
- * @param string the key
- * @return string
- */
- function encode($string, $key = '')
- {
- $key = $this->get_key($key);
- if ($this->_mcrypt_exists === TRUE)
- {
- $enc = $this->mcrypt_encode($string, $key);
- }
- else
- {
- $enc = $this->_xor_encode($string, $key);
- }
- return base64_encode($enc);
- }
- // --------------------------------------------------------------------
- /**
- * Decode
- *
- * Reverses the above process
- *
- * @access public
- * @param string
- * @param string
- * @return string
- */
- function decode($string, $key = '')
- {
- $key = $this->get_key($key);
-
- if (preg_match('/[^a-zA-Z0-9\/\+=]/', $string))
- {
- return FALSE;
- }
- $dec = base64_decode($string);
- if ($this->_mcrypt_exists === TRUE)
- {
- if (($dec = $this->mcrypt_decode($dec, $key)) === FALSE)
- {
- return FALSE;
- }
- }
- else
- {
- $dec = $this->_xor_decode($dec, $key);
- }
-
- return $dec;
- }
- // --------------------------------------------------------------------
-
- /**
- * Encode from Legacy
- *
- * Takes an encoded string from the original Encryption class algorithms and
- * returns a newly encoded string using the improved method added in 2.0.0
- * This allows for backwards compatibility and a method to transition to the
- * new encryption algorithms.
- *
- * For more details, see http://codeigniter.com/user_guide/installation/upgrade_200.html#encryption
- *
- * @access public
- * @param string
- * @param int (mcrypt mode constant)
- * @param string
- * @return string
- */
- function encode_from_legacy($string, $legacy_mode = MCRYPT_MODE_ECB, $key = '')
- {
- if ($this->_mcrypt_exists === FALSE)
- {
- log_message('error', 'Encoding from legacy is available only when Mcrypt is in use.');
- return FALSE;
- }
-
- // decode it first
- // set mode temporarily to what it was when string was encoded with the legacy
- // algorithm - typically MCRYPT_MODE_ECB
- $current_mode = $this->_get_mode();
- $this->set_mode($legacy_mode);
-
- $key = $this->get_key($key);
-
- if (preg_match('/[^a-zA-Z0-9\/\+=]/', $string))
- {
- return FALSE;
- }
- $dec = base64_decode($string);
-
- if (($dec = $this->mcrypt_decode($dec, $key)) === FALSE)
- {
- return FALSE;
- }
- $dec = $this->_xor_decode($dec, $key);
- // set the mcrypt mode back to what it should be, typically MCRYPT_MODE_CBC
- $this->set_mode($current_mode);
- // and re-encode
- return base64_encode($this->mcrypt_encode($dec, $key));
- }
- // --------------------------------------------------------------------
-
- /**
- * XOR Encode
- *
- * Takes a plain-text string and key as input and generates an
- * encoded bit-string using XOR
- *
- * @access private
- * @param string
- * @param string
- * @return string
- */
- function _xor_encode($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, $key);
- }
- // --------------------------------------------------------------------
- /**
- * XOR Decode
- *
- * Takes an encoded string and key as input and generates the
- * plain-text original message
- *
- * @access private
- * @param string
- * @param string
- * @return string
- */
- function _xor_decode($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 $dec;
- }
- // --------------------------------------------------------------------
- /**
- * XOR key + string Combiner
- *
- * Takes a string and key as input and computes the difference using XOR
- *
- * @access private
- * @param string
- * @param string
- * @return string
- */
- function _xor_merge($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 $str;
- }
- // --------------------------------------------------------------------
- /**
- * Encrypt using Mcrypt
- *
- * @access public
- * @param string
- * @param string
- * @return string
- */
- function mcrypt_encode($data, $key)
- {
- $init_size = mcrypt_get_iv_size($this->_get_cipher(), $this->_get_mode());
- $init_vect = mcrypt_create_iv($init_size, MCRYPT_RAND);
- return $this->_add_cipher_noise($init_vect.mcrypt_encrypt($this->_get_cipher(), $key, $data, $this->_get_mode(), $init_vect), $key);
- }
- // --------------------------------------------------------------------
- /**
- * Decrypt using Mcrypt
- *
- * @access public
- * @param string
- * @param string
- * @return string
- */
- function mcrypt_decode($data, $key)
- {
- $data = $this->_remove_cipher_noise($data, $key);
- $init_size = mcrypt_get_iv_size($this->_get_cipher(), $this->_get_mode());
- if ($init_size > strlen($data))
- {
- return FALSE;
- }
- $init_vect = substr($data, 0, $init_size);
- $data = substr($data, $init_size);
- return rtrim(mcrypt_decrypt($this->_get_cipher(), $key, $data, $this->_get_mode(), $init_vect), "\0");
- }
- // --------------------------------------------------------------------
- /**
- * Adds permuted noise to the IV + encrypted data to protect
- * against Man-in-the-middle attacks on CBC mode ciphers
- * http://www.ciphersbyritter.com/GLOSSARY.HTM#IV
- *
- * Function description
- *
- * @access private
- * @param string
- * @param string
- * @return string
- */
- function _add_cipher_noise($data, $key)
- {
- $keyhash = $this->hash($key);
- $keylen = strlen($keyhash);
- $str = '';
- for ($i = 0, $j = 0, $len = strlen($data); $i < $len; ++$i, ++$j)
- {
- if ($j >= $keylen)
- {
- $j = 0;
- }
- $str .= chr((ord($data[$i]) + ord($keyhash[$j])) % 256);
- }
- return $str;
- }
- // --------------------------------------------------------------------
- /**
- * Removes permuted noise from the IV + encrypted data, reversing
- * _add_cipher_noise()
- *
- * Function description
- *
- * @access public
- * @param type
- * @return type
- */
- function _remove_cipher_noise($data, $key)
- {
- $keyhash = $this->hash($key);
- $keylen = strlen($keyhash);
- $str = '';
- for ($i = 0, $j = 0, $len = strlen($data); $i < $len; ++$i, ++$j)
- {
- if ($j >= $keylen)
- {
- $j = 0;
- }
- $temp = ord($data[$i]) - ord($keyhash[$j]);
- if ($temp < 0)
- {
- $temp = $temp + 256;
- }
-
- $str .= chr($temp);
- }
- return $str;
- }
- // --------------------------------------------------------------------
-
- /**
- * Set the Mcrypt Cipher
- *
- * @access public
- * @param constant
- * @return string
- */
- function set_cipher($cipher)
- {
- $this->_mcrypt_cipher = $cipher;
- }
- // --------------------------------------------------------------------
- /**
- * Set the Mcrypt Mode
- *
- * @access public
- * @param constant
- * @return string
- */
- function set_mode($mode)
- {
- $this->_mcrypt_mode = $mode;
- }
- // --------------------------------------------------------------------
- /**
- * Get Mcrypt cipher Value
- *
- * @access private
- * @return string
- */
- function _get_cipher()
- {
- if ($this->_mcrypt_cipher == '')
- {
- $this->_mcrypt_cipher = MCRYPT_RIJNDAEL_256;
- }
- return $this->_mcrypt_cipher;
- }
- // --------------------------------------------------------------------
- /**
- * Get Mcrypt Mode Value
- *
- * @access private
- * @return string
- */
- function _get_mode()
- {
- if ($this->_mcrypt_mode == '')
- {
- $this->_mcrypt_mode = MCRYPT_MODE_CBC;
- }
-
- return $this->_mcrypt_mode;
- }
- // --------------------------------------------------------------------
- /**
- * Set the Hash type
- *
- * @access public
- * @param string
- * @return string
- */
- function set_hash($type = 'sha1')
- {
- $this->_hash_type = ($type != 'sha1' AND $type != 'md5') ? 'sha1' : $type;
- }
- // --------------------------------------------------------------------
- /**
- * Hash encode a string
- *
- * @access public
- * @param string
- * @return string
- */
- function hash($str)
- {
- return ($this->_hash_type == 'sha1') ? $this->sha1($str) : md5($str);
- }
- // --------------------------------------------------------------------
- /**
- * Generate an SHA1 Hash
- *
- * @access public
- * @param string
- * @return string
- */
- function sha1($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 CI_Encrypt class
- /* End of file Encrypt.php */
- /* Location: ./system/libraries/Encrypt.php */