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547 lines
11 KiB
547 lines
11 KiB
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); |
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/** |
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* CodeIgniter |
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* |
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* An open source application development framework for PHP 5.1.6 or newer |
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* |
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* @package CodeIgniter |
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* @author ExpressionEngine Dev Team |
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* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc. |
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* @license http://codeigniter.com/user_guide/license.html |
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* @link http://codeigniter.com |
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* @since Version 1.0 |
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* @filesource |
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*/ |
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// ------------------------------------------------------------------------ |
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/** |
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* CodeIgniter Encryption Class |
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* |
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* Provides two-way keyed encoding using XOR Hashing and Mcrypt |
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* |
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* @package CodeIgniter |
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* @subpackage Libraries |
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* @category Libraries |
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* @author ExpressionEngine Dev Team |
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* @link http://codeigniter.com/user_guide/libraries/encryption.html |
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*/ |
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class CI_Encrypt { |
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var $CI; |
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var $encryption_key = ''; |
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var $_hash_type = 'sha1'; |
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var $_mcrypt_exists = FALSE; |
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var $_mcrypt_cipher; |
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var $_mcrypt_mode; |
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/** |
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* Constructor |
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* |
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* Simply determines whether the mcrypt library exists. |
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* |
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*/ |
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public function __construct() |
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{ |
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$this->CI =& get_instance(); |
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$this->_mcrypt_exists = ( ! function_exists('mcrypt_encrypt')) ? FALSE : TRUE; |
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log_message('debug', "Encrypt Class Initialized"); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Fetch the encryption key |
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* |
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* Returns it as MD5 in order to have an exact-length 128 bit key. |
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* Mcrypt is sensitive to keys that are not the correct length |
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* |
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* @access public |
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* @param string |
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* @return string |
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*/ |
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function get_key($key = '') |
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{ |
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if ($key == '') |
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{ |
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if ($this->encryption_key != '') |
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{ |
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return $this->encryption_key; |
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} |
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$CI =& get_instance(); |
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$key = $CI->config->item('encryption_key'); |
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if ($key == FALSE) |
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{ |
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show_error('In order to use the encryption class requires that you set an encryption key in your config file.'); |
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} |
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} |
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return md5($key); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Set the encryption key |
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* |
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* @access public |
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* @param string |
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* @return void |
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*/ |
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function set_key($key = '') |
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{ |
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$this->encryption_key = $key; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Encode |
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* |
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* Encodes the message string using bitwise XOR encoding. |
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* The key is combined with a random hash, and then it |
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* too gets converted using XOR. The whole thing is then run |
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* through mcrypt (if supported) using the randomized key. |
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* The end result is a double-encrypted message string |
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* that is randomized with each call to this function, |
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* even if the supplied message and key are the same. |
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* |
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* @access public |
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* @param string the string to encode |
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* @param string the key |
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* @return string |
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*/ |
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function encode($string, $key = '') |
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{ |
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$key = $this->get_key($key); |
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if ($this->_mcrypt_exists === TRUE) |
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{ |
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$enc = $this->mcrypt_encode($string, $key); |
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} |
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else |
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{ |
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$enc = $this->_xor_encode($string, $key); |
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} |
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return base64_encode($enc); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Decode |
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* |
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* Reverses the above process |
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* |
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* @access public |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function decode($string, $key = '') |
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{ |
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$key = $this->get_key($key); |
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if (preg_match('/[^a-zA-Z0-9\/\+=]/', $string)) |
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{ |
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return FALSE; |
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} |
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$dec = base64_decode($string); |
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if ($this->_mcrypt_exists === TRUE) |
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{ |
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if (($dec = $this->mcrypt_decode($dec, $key)) === FALSE) |
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{ |
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return FALSE; |
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} |
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} |
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else |
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{ |
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$dec = $this->_xor_decode($dec, $key); |
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} |
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return $dec; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Encode from Legacy |
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* |
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* Takes an encoded string from the original Encryption class algorithms and |
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* returns a newly encoded string using the improved method added in 2.0.0 |
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* This allows for backwards compatibility and a method to transition to the |
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* new encryption algorithms. |
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* |
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* For more details, see http://codeigniter.com/user_guide/installation/upgrade_200.html#encryption |
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* |
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* @access public |
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* @param string |
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* @param int (mcrypt mode constant) |
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* @param string |
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* @return string |
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*/ |
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function encode_from_legacy($string, $legacy_mode = MCRYPT_MODE_ECB, $key = '') |
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{ |
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if ($this->_mcrypt_exists === FALSE) |
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{ |
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log_message('error', 'Encoding from legacy is available only when Mcrypt is in use.'); |
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return FALSE; |
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} |
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// decode it first |
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// set mode temporarily to what it was when string was encoded with the legacy |
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// algorithm - typically MCRYPT_MODE_ECB |
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$current_mode = $this->_get_mode(); |
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$this->set_mode($legacy_mode); |
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$key = $this->get_key($key); |
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if (preg_match('/[^a-zA-Z0-9\/\+=]/', $string)) |
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{ |
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return FALSE; |
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} |
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$dec = base64_decode($string); |
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if (($dec = $this->mcrypt_decode($dec, $key)) === FALSE) |
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{ |
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return FALSE; |
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} |
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$dec = $this->_xor_decode($dec, $key); |
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// set the mcrypt mode back to what it should be, typically MCRYPT_MODE_CBC |
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$this->set_mode($current_mode); |
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// and re-encode |
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return base64_encode($this->mcrypt_encode($dec, $key)); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* XOR Encode |
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* |
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* Takes a plain-text string and key as input and generates an |
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* encoded bit-string using XOR |
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* |
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* @access private |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function _xor_encode($string, $key) |
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{ |
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$rand = ''; |
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while (strlen($rand) < 32) |
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{ |
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$rand .= mt_rand(0, mt_getrandmax()); |
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} |
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$rand = $this->hash($rand); |
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$enc = ''; |
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for ($i = 0; $i < strlen($string); $i++) |
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{ |
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$enc .= substr($rand, ($i % strlen($rand)), 1).(substr($rand, ($i % strlen($rand)), 1) ^ substr($string, $i, 1)); |
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} |
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return $this->_xor_merge($enc, $key); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* XOR Decode |
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* |
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* Takes an encoded string and key as input and generates the |
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* plain-text original message |
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* |
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* @access private |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function _xor_decode($string, $key) |
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{ |
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$string = $this->_xor_merge($string, $key); |
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$dec = ''; |
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for ($i = 0; $i < strlen($string); $i++) |
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{ |
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$dec .= (substr($string, $i++, 1) ^ substr($string, $i, 1)); |
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} |
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return $dec; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* XOR key + string Combiner |
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* |
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* Takes a string and key as input and computes the difference using XOR |
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* |
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* @access private |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function _xor_merge($string, $key) |
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{ |
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$hash = $this->hash($key); |
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$str = ''; |
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for ($i = 0; $i < strlen($string); $i++) |
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{ |
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$str .= substr($string, $i, 1) ^ substr($hash, ($i % strlen($hash)), 1); |
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} |
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return $str; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Encrypt using Mcrypt |
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* |
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* @access public |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function mcrypt_encode($data, $key) |
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{ |
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$init_size = mcrypt_get_iv_size($this->_get_cipher(), $this->_get_mode()); |
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$init_vect = mcrypt_create_iv($init_size, MCRYPT_RAND); |
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return $this->_add_cipher_noise($init_vect.mcrypt_encrypt($this->_get_cipher(), $key, $data, $this->_get_mode(), $init_vect), $key); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Decrypt using Mcrypt |
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* |
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* @access public |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function mcrypt_decode($data, $key) |
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{ |
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$data = $this->_remove_cipher_noise($data, $key); |
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$init_size = mcrypt_get_iv_size($this->_get_cipher(), $this->_get_mode()); |
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if ($init_size > strlen($data)) |
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{ |
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return FALSE; |
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} |
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$init_vect = substr($data, 0, $init_size); |
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$data = substr($data, $init_size); |
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return rtrim(mcrypt_decrypt($this->_get_cipher(), $key, $data, $this->_get_mode(), $init_vect), "\0"); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Adds permuted noise to the IV + encrypted data to protect |
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* against Man-in-the-middle attacks on CBC mode ciphers |
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* http://www.ciphersbyritter.com/GLOSSARY.HTM#IV |
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* |
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* Function description |
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* |
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* @access private |
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* @param string |
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* @param string |
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* @return string |
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*/ |
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function _add_cipher_noise($data, $key) |
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{ |
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$keyhash = $this->hash($key); |
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$keylen = strlen($keyhash); |
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$str = ''; |
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for ($i = 0, $j = 0, $len = strlen($data); $i < $len; ++$i, ++$j) |
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{ |
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if ($j >= $keylen) |
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{ |
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$j = 0; |
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} |
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$str .= chr((ord($data[$i]) + ord($keyhash[$j])) % 256); |
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} |
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return $str; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Removes permuted noise from the IV + encrypted data, reversing |
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* _add_cipher_noise() |
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* |
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* Function description |
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* |
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* @access public |
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* @param type |
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* @return type |
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*/ |
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function _remove_cipher_noise($data, $key) |
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{ |
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$keyhash = $this->hash($key); |
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$keylen = strlen($keyhash); |
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$str = ''; |
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for ($i = 0, $j = 0, $len = strlen($data); $i < $len; ++$i, ++$j) |
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{ |
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if ($j >= $keylen) |
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{ |
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$j = 0; |
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} |
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$temp = ord($data[$i]) - ord($keyhash[$j]); |
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if ($temp < 0) |
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{ |
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$temp = $temp + 256; |
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} |
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$str .= chr($temp); |
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} |
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return $str; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Set the Mcrypt Cipher |
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* |
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* @access public |
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* @param constant |
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* @return string |
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*/ |
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function set_cipher($cipher) |
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{ |
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$this->_mcrypt_cipher = $cipher; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Set the Mcrypt Mode |
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* |
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* @access public |
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* @param constant |
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* @return string |
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*/ |
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function set_mode($mode) |
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{ |
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$this->_mcrypt_mode = $mode; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Get Mcrypt cipher Value |
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* |
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* @access private |
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* @return string |
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*/ |
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function _get_cipher() |
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{ |
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if ($this->_mcrypt_cipher == '') |
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{ |
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$this->_mcrypt_cipher = MCRYPT_RIJNDAEL_256; |
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} |
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return $this->_mcrypt_cipher; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Get Mcrypt Mode Value |
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* |
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* @access private |
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* @return string |
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*/ |
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function _get_mode() |
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{ |
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if ($this->_mcrypt_mode == '') |
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{ |
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$this->_mcrypt_mode = MCRYPT_MODE_CBC; |
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} |
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return $this->_mcrypt_mode; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Set the Hash type |
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* |
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* @access public |
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* @param string |
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* @return string |
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*/ |
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function set_hash($type = 'sha1') |
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{ |
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$this->_hash_type = ($type != 'sha1' AND $type != 'md5') ? 'sha1' : $type; |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Hash encode a string |
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* |
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* @access public |
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* @param string |
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* @return string |
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*/ |
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function hash($str) |
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{ |
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return ($this->_hash_type == 'sha1') ? $this->sha1($str) : md5($str); |
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} |
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// -------------------------------------------------------------------- |
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/** |
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* Generate an SHA1 Hash |
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* |
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* @access public |
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* @param string |
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* @return string |
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*/ |
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function sha1($str) |
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{ |
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if ( ! function_exists('sha1')) |
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{ |
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if ( ! function_exists('mhash')) |
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{ |
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require_once(BASEPATH.'libraries/Sha1.php'); |
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$SH = new CI_SHA; |
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return $SH->generate($str); |
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} |
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else |
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{ |
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return bin2hex(mhash(MHASH_SHA1, $str)); |
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} |
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} |
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else |
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{ |
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return sha1($str); |
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} |
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} |
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} |
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// END CI_Encrypt class |
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/* End of file Encrypt.php */ |
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/* Location: ./system/libraries/Encrypt.php */ |