freenetis-github/system/libraries/Encrypt.php @ 592d831c
| 8baed187 | Michal Kliment | <?php defined('SYSPATH') or die('No direct script access.');
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/**
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* The Encrypt library provides two-way encryption of text and binary strings
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* using the MCrypt extension.
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* @see http://php.net/mcrypt
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*
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* $Id: Encrypt.php 1911 2008-02-04 16:13:16Z PugFish $
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*
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* @package Core
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* @author Kohana Team
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* @copyright (c) 2007-2008 Kohana Team
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* @license http://kohanaphp.com/license.html
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*/
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class Encrypt {
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// OS-dependant RAND type to use
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protected static $rand;
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// Configuration
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protected $config;
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/**
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* Returns a singleton instance of Encrypt.
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*
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* @param array configuration options
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* @return object
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*/
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public static function instance($config = NULL)
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{
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static $instance;
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// Create the singleton
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empty($instance) and $instance = new Encrypt((array) $config);
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return $instance;
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}
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/**
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* Loads encryption configuration and validates the data.
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*
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* @throws Kohana_Exception
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*/
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public function __construct($config = array())
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{
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if ( ! defined('MCRYPT_ENCRYPT'))
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throw new Kohana_Exception('encrypt.requires_mcrypt');
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// Append the default configuration options
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$config += Config::item('encryption');
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if (empty($config['key']))
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throw new Kohana_Exception('encrypt.no_encryption_key');
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// Find the max length of the key, based on cipher and mode
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$size = mcrypt_get_key_size($config['cipher'], $config['mode']);
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if (strlen($config['key']) > $size)
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{
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// Shorten the key to the maximum size
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$config['key'] = substr($config['key'], 0, $size);
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}
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// Find the initialization vector size
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$config['iv_size'] = mcrypt_get_iv_size($config['cipher'], $config['mode']);
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// Cache the config in the object
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$this->config = $config;
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Log::add('debug', 'Encrypt Library initialized');
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}
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/**
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* Encrypts a string and returns an encrypted string that can be decoded.
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*
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* @param string data to be encrypted
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* @return string encrypted data
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*/
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public function encode($data)
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{
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// Set the rand type if it has not already been set
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if (self::$rand === NULL)
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{
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if (defined('MCRYPT_DEV_URANDOM'))
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{
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// Use /dev/urandom
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self::$rand = MCRYPT_DEV_URANDOM;
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}
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elseif (defined('MCRYPT_DEV_RANDOM'))
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{
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// Use /dev/random
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self::$rand = MCRYPT_DEV_RANDOM;
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}
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else
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{
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// Use the system random number generator
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self::$rand = MCRYPT_RAND;
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}
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}
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if (self::$rand === MCRYPT_RAND)
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{
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// The system random number generator must always be seeded each
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// time it is used, or it will not produce true random results
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mt_srand();
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}
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// Create a random initialization vector of the proper size for the current cipher
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$iv = mcrypt_create_iv($this->config['iv_size'], self::$rand);
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// Encrypt the data using the configured options and generated iv
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$data = mcrypt_encrypt($this->config['cipher'], $this->config['key'], $data, $this->config['mode'], $iv);
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// Use base64 encoding to convert to a string
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return base64_encode($iv.$data);
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}
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/**
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* Decrypts an encoded string back to it's original value.
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*
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* @param string encoded string to be decrypted
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* @return string decrypted data
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*/
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public function decode($data)
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{
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// Convert the data back to binary
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$data = base64_decode($data);
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// Extract the initialization vector from the data
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$iv = substr($data, 0, $this->config['iv_size']);
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// Remove the iv from the data
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$data = substr($data, $this->config['iv_size']);
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// Return the decrypted data, trimming the \0 padding bytes from the end of the data
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return rtrim(mcrypt_decrypt($this->config['cipher'], $this->config['key'], $data, $this->config['mode'], $iv), "\0");
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}
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} // End Encrypt
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