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Diffstat (limited to 'system/libraries/Encrypt.php')
| -rw-r--r-- | system/libraries/Encrypt.php | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/system/libraries/Encrypt.php b/system/libraries/Encrypt.php new file mode 100644 index 0000000..15d4087 --- /dev/null +++ b/system/libraries/Encrypt.php @@ -0,0 +1,176 @@ +<?php defined('SYSPATH') OR die('No direct access allowed.'); +/** + * The Encrypt library provides two-way encryption of text and binary strings + * using the MCrypt extension. + * @see http://php.net/mcrypt + * + * $Id: Encrypt.php 4729 2009-12-29 20:35:19Z isaiah $ + * + * @package Kohana + * @author Kohana Team + * @copyright (c) 2007-2009 Kohana Team + * @license http://kohanaphp.com/license + */ +class Encrypt_Core { + + // OS-dependant RAND type to use + protected static $rand; + + // Configuration + protected $config; + + /** + * Returns a singleton instance of Encrypt. + * + * @param array configuration options + * @return Encrypt_Core + */ + public static function instance($config = NULL) + { + static $instance; + + // Create the singleton + empty($instance) and $instance = new Encrypt((array) $config); + + return $instance; + } + + /** + * Loads encryption configuration and validates the data. + * + * @param array|string custom configuration or config group name + * @throws Kohana_Exception + */ + public function __construct($config = FALSE) + { + if ( ! defined('MCRYPT_ENCRYPT')) + throw new Kohana_Exception('To use the Encrypt library, mcrypt must be enabled in your PHP installation'); + + if (is_string($config)) + { + $name = $config; + + // Test the config group name + if (($config = Kohana::config('encryption.'.$config)) === NULL) + throw new Kohana_Exception('The :name: group is not defined in your configuration.', array(':name:' => $name)); + } + + if (is_array($config)) + { + // Append the default configuration options + $config += Kohana::config('encryption.default'); + } + else + { + // Load the default group + $config = Kohana::config('encryption.default'); + } + + if (empty($config['key'])) + throw new Kohana_Exception('To use the Encrypt library, you must set an encryption key in your config file'); + + // Find the max length of the key, based on cipher and mode + $size = mcrypt_get_key_size($config['cipher'], $config['mode']); + + if (strlen($config['key']) > $size) + { + // Shorten the key to the maximum size + $config['key'] = substr($config['key'], 0, $size); + } + + // Find the initialization vector size + $config['iv_size'] = mcrypt_get_iv_size($config['cipher'], $config['mode']); + + // Cache the config in the object + $this->config = $config; + + Kohana_Log::add('debug', 'Encrypt Library initialized'); + } + + /** + * Encrypts a string and returns an encrypted string that can be decoded. + * + * @param string data to be encrypted + * @return string encrypted data + */ + public function encode($data) + { + // Set the rand type if it has not already been set + if (Encrypt::$rand === NULL) + { + if (KOHANA_IS_WIN) + { + // Windows only supports the system random number generator + Encrypt::$rand = MCRYPT_RAND; + } + else + { + if (defined('MCRYPT_DEV_URANDOM')) + { + // Use /dev/urandom + Encrypt::$rand = MCRYPT_DEV_URANDOM; + } + elseif (defined('MCRYPT_DEV_RANDOM')) + { + // Use /dev/random + Encrypt::$rand = MCRYPT_DEV_RANDOM; + } + else + { + // Use the system random number generator + Encrypt::$rand = MCRYPT_RAND; + } + } + } + + if (Encrypt::$rand === MCRYPT_RAND) + { + // The system random number generator must always be seeded each + // time it is used, or it will not produce true random results + mt_srand(); + } + + // Create a random initialization vector of the proper size for the current cipher + $iv = mcrypt_create_iv($this->config['iv_size'], Encrypt::$rand); + + // Encrypt the data using the configured options and generated iv + $data = mcrypt_encrypt($this->config['cipher'], $this->config['key'], $data, $this->config['mode'], $iv); + + // Use base64 encoding to convert to a string + return base64_encode($iv.$data); + } + + /** + * Decrypts an encoded string back to its original value. + * + * @param string encoded string to be decrypted + * @return string decrypted data or FALSE if decryption fails + */ + public function decode($data) + { + // Convert the data back to binary + $data = base64_decode($data, TRUE); + + if ( ! $data) + { + // Invalid base64 data + return FALSE; + } + + // Extract the initialization vector from the data + $iv = substr($data, 0, $this->config['iv_size']); + + if ($this->config['iv_size'] !== strlen($iv)) + { + // The iv is not the correct size + return FALSE; + } + + // Remove the iv from the data + $data = substr($data, $this->config['iv_size']); + + // Return the decrypted data, trimming the \0 padding bytes from the end of the data + return rtrim(mcrypt_decrypt($this->config['cipher'], $this->config['key'], $data, $this->config['mode'], $iv), "\0"); + } + +} // End Encrypt |