942 lines
23 KiB
PHP
942 lines
23 KiB
PHP
<?php
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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
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*
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* This content is released under the MIT License (MIT)
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*
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* Copyright (c) 2014 - 2019, British Columbia Institute of Technology
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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* @package CodeIgniter
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* @author EllisLab Dev Team
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* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
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* @copyright Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
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* @license https://opensource.org/licenses/MIT MIT License
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* @link https://codeigniter.com
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* @since Version 3.0.0
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* @filesource
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*/
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defined('BASEPATH') OR exit('No direct script access allowed');
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/**
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* CodeIgniter Encryption Class
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*
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* Provides two-way keyed encryption via PHP's MCrypt and/or OpenSSL extensions.
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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 Andrey Andreev
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* @link https://codeigniter.com/user_guide/libraries/encryption.html
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*/
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class CI_Encryption {
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/**
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* Encryption cipher
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*
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* @var string
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*/
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protected $_cipher = 'aes-128';
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/**
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* Cipher mode
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*
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* @var string
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*/
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protected $_mode = 'cbc';
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/**
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* Cipher handle
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*
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* @var mixed
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*/
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protected $_handle;
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/**
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* Encryption key
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*
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* @var string
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*/
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protected $_key;
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/**
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* PHP extension to be used
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*
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* @var string
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*/
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protected $_driver;
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/**
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* List of usable drivers (PHP extensions)
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*
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* @var array
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*/
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protected $_drivers = array();
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/**
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* List of available modes
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*
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* @var array
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*/
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protected $_modes = array(
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'mcrypt' => array(
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'cbc' => 'cbc',
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'ecb' => 'ecb',
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'ofb' => 'nofb',
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'ofb8' => 'ofb',
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'cfb' => 'ncfb',
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'cfb8' => 'cfb',
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'ctr' => 'ctr',
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'stream' => 'stream'
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),
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'openssl' => array(
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'cbc' => 'cbc',
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'ecb' => 'ecb',
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'ofb' => 'ofb',
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'cfb' => 'cfb',
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'cfb8' => 'cfb8',
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'ctr' => 'ctr',
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'stream' => '',
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'xts' => 'xts'
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)
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);
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/**
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* List of supported HMAC algorithms
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*
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* name => digest size pairs
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*
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* @var array
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*/
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protected $_digests = array(
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'sha224' => 28,
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'sha256' => 32,
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'sha384' => 48,
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'sha512' => 64
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);
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/**
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* mbstring.func_overload flag
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*
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* @var bool
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*/
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protected static $func_overload;
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// --------------------------------------------------------------------
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/**
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* Class constructor
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*
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* @param array $params Configuration parameters
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* @return void
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*/
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public function __construct(array $params = array())
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{
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$this->_drivers = array(
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'mcrypt' => defined('MCRYPT_DEV_URANDOM'),
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'openssl' => extension_loaded('openssl')
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);
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if ( ! $this->_drivers['mcrypt'] && ! $this->_drivers['openssl'])
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{
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show_error('Encryption: Unable to find an available encryption driver.');
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}
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isset(self::$func_overload) OR self::$func_overload = (extension_loaded('mbstring') && ini_get('mbstring.func_overload'));
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$this->initialize($params);
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if ( ! isset($this->_key) && self::strlen($key = config_item('encryption_key')) > 0)
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{
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$this->_key = $key;
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}
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log_message('info', 'Encryption Class Initialized');
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}
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// --------------------------------------------------------------------
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/**
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* Initialize
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*
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* @param array $params Configuration parameters
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* @return CI_Encryption
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*/
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public function initialize(array $params)
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{
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if ( ! empty($params['driver']))
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{
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if (isset($this->_drivers[$params['driver']]))
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{
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if ($this->_drivers[$params['driver']])
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{
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$this->_driver = $params['driver'];
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}
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else
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{
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log_message('error', "Encryption: Driver '".$params['driver']."' is not available.");
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}
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}
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else
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{
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log_message('error', "Encryption: Unknown driver '".$params['driver']."' cannot be configured.");
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}
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}
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if (empty($this->_driver))
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{
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$this->_driver = ($this->_drivers['openssl'] === TRUE)
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? 'openssl'
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: 'mcrypt';
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log_message('debug', "Encryption: Auto-configured driver '".$this->_driver."'.");
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}
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empty($params['cipher']) && $params['cipher'] = $this->_cipher;
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empty($params['key']) OR $this->_key = $params['key'];
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$this->{'_'.$this->_driver.'_initialize'}($params);
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return $this;
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}
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// --------------------------------------------------------------------
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/**
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* Initialize MCrypt
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*
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* @param array $params Configuration parameters
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* @return void
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*/
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protected function _mcrypt_initialize($params)
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{
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if ( ! empty($params['cipher']))
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{
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$params['cipher'] = strtolower($params['cipher']);
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$this->_cipher_alias($params['cipher']);
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if ( ! in_array($params['cipher'], mcrypt_list_algorithms(), TRUE))
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{
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log_message('error', 'Encryption: MCrypt cipher '.strtoupper($params['cipher']).' is not available.');
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}
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else
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{
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$this->_cipher = $params['cipher'];
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}
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}
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if ( ! empty($params['mode']))
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{
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$params['mode'] = strtolower($params['mode']);
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if ( ! isset($this->_modes['mcrypt'][$params['mode']]))
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{
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log_message('error', 'Encryption: MCrypt mode '.strtoupper($params['mode']).' is not available.');
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}
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else
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{
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$this->_mode = $this->_modes['mcrypt'][$params['mode']];
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}
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}
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if (isset($this->_cipher, $this->_mode))
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{
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if (is_resource($this->_handle)
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&& (strtolower(mcrypt_enc_get_algorithms_name($this->_handle)) !== $this->_cipher
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OR strtolower(mcrypt_enc_get_modes_name($this->_handle)) !== $this->_mode)
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)
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{
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mcrypt_module_close($this->_handle);
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}
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if ($this->_handle = mcrypt_module_open($this->_cipher, '', $this->_mode, ''))
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{
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log_message('info', 'Encryption: MCrypt cipher '.strtoupper($this->_cipher).' initialized in '.strtoupper($this->_mode).' mode.');
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}
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else
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{
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log_message('error', 'Encryption: Unable to initialize MCrypt with cipher '.strtoupper($this->_cipher).' in '.strtoupper($this->_mode).' mode.');
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}
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}
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}
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// --------------------------------------------------------------------
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/**
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* Initialize OpenSSL
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*
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* @param array $params Configuration parameters
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* @return void
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*/
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protected function _openssl_initialize($params)
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{
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if ( ! empty($params['cipher']))
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{
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$params['cipher'] = strtolower($params['cipher']);
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$this->_cipher_alias($params['cipher']);
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$this->_cipher = $params['cipher'];
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}
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if ( ! empty($params['mode']))
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{
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$params['mode'] = strtolower($params['mode']);
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if ( ! isset($this->_modes['openssl'][$params['mode']]))
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{
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log_message('error', 'Encryption: OpenSSL mode '.strtoupper($params['mode']).' is not available.');
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}
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else
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{
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$this->_mode = $this->_modes['openssl'][$params['mode']];
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}
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}
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if (isset($this->_cipher, $this->_mode))
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{
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// This is mostly for the stream mode, which doesn't get suffixed in OpenSSL
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$handle = empty($this->_mode)
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? $this->_cipher
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: $this->_cipher.'-'.$this->_mode;
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if ( ! in_array($handle, openssl_get_cipher_methods(), TRUE))
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{
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$this->_handle = NULL;
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log_message('error', 'Encryption: Unable to initialize OpenSSL with method '.strtoupper($handle).'.');
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}
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else
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{
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$this->_handle = $handle;
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log_message('info', 'Encryption: OpenSSL initialized with method '.strtoupper($handle).'.');
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}
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}
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}
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// --------------------------------------------------------------------
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/**
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* Create a random key
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*
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* @param int $length Output length
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* @return string
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*/
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public function create_key($length)
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{
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if (function_exists('random_bytes'))
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{
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try
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{
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return random_bytes((int) $length);
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}
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catch (Exception $e)
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{
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log_message('error', $e->getMessage());
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return FALSE;
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}
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}
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elseif (defined('MCRYPT_DEV_URANDOM'))
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{
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return mcrypt_create_iv($length, MCRYPT_DEV_URANDOM);
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}
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$is_secure = NULL;
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$key = openssl_random_pseudo_bytes($length, $is_secure);
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return ($is_secure === TRUE)
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? $key
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: FALSE;
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}
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// --------------------------------------------------------------------
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/**
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* Encrypt
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*
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* @param string $data Input data
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* @param array $params Input parameters
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* @return string
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*/
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public function encrypt($data, array $params = NULL)
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{
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if (($params = $this->_get_params($params)) === FALSE)
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{
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return FALSE;
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}
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isset($params['key']) OR $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, self::strlen($this->_key), 'encryption');
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if (($data = $this->{'_'.$this->_driver.'_encrypt'}($data, $params)) === FALSE)
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{
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return FALSE;
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}
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$params['base64'] && $data = base64_encode($data);
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if (isset($params['hmac_digest']))
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{
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isset($params['hmac_key']) OR $params['hmac_key'] = $this->hkdf($this->_key, 'sha512', NULL, NULL, 'authentication');
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return hash_hmac($params['hmac_digest'], $data, $params['hmac_key'], ! $params['base64']).$data;
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}
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return $data;
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}
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// --------------------------------------------------------------------
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/**
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* Encrypt via MCrypt
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*
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* @param string $data Input data
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* @param array $params Input parameters
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* @return string
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*/
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protected function _mcrypt_encrypt($data, $params)
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{
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if ( ! is_resource($params['handle']))
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{
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return FALSE;
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}
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// The greater-than-1 comparison is mostly a work-around for a bug,
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// where 1 is returned for ARCFour instead of 0.
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$iv = (($iv_size = mcrypt_enc_get_iv_size($params['handle'])) > 1)
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? $this->create_key($iv_size)
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: NULL;
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if (mcrypt_generic_init($params['handle'], $params['key'], $iv) < 0)
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{
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if ($params['handle'] !== $this->_handle)
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{
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mcrypt_module_close($params['handle']);
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}
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return FALSE;
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}
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// Use PKCS#7 padding in order to ensure compatibility with OpenSSL
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// and other implementations outside of PHP.
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if (in_array(strtolower(mcrypt_enc_get_modes_name($params['handle'])), array('cbc', 'ecb'), TRUE))
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{
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$block_size = mcrypt_enc_get_block_size($params['handle']);
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$pad = $block_size - (self::strlen($data) % $block_size);
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$data .= str_repeat(chr($pad), $pad);
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}
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// Work-around for yet another strange behavior in MCrypt.
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//
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// When encrypting in ECB mode, the IV is ignored. Yet
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// mcrypt_enc_get_iv_size() returns a value larger than 0
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// even if ECB is used AND mcrypt_generic_init() complains
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// if you don't pass an IV with length equal to the said
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// return value.
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//
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// This probably would've been fine (even though still wasteful),
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// but OpenSSL isn't that dumb and we need to make the process
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// portable, so ...
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$data = (mcrypt_enc_get_modes_name($params['handle']) !== 'ECB')
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? $iv.mcrypt_generic($params['handle'], $data)
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: mcrypt_generic($params['handle'], $data);
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mcrypt_generic_deinit($params['handle']);
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if ($params['handle'] !== $this->_handle)
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{
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mcrypt_module_close($params['handle']);
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}
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return $data;
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}
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// --------------------------------------------------------------------
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/**
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* Encrypt via OpenSSL
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*
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* @param string $data Input data
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* @param array $params Input parameters
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* @return string
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*/
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protected function _openssl_encrypt($data, $params)
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{
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if (empty($params['handle']))
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{
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return FALSE;
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}
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$iv = ($iv_size = openssl_cipher_iv_length($params['handle']))
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? $this->create_key($iv_size)
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: NULL;
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$data = openssl_encrypt(
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$data,
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$params['handle'],
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$params['key'],
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1, // DO NOT TOUCH!
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$iv
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);
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if ($data === FALSE)
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{
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return FALSE;
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}
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return $iv.$data;
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}
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|
|
|
// --------------------------------------------------------------------
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|
|
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/**
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* Decrypt
|
|
*
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* @param string $data Encrypted data
|
|
* @param array $params Input parameters
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* @return string
|
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*/
|
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public function decrypt($data, array $params = NULL)
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{
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if (($params = $this->_get_params($params)) === FALSE)
|
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{
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return FALSE;
|
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}
|
|
|
|
if (isset($params['hmac_digest']))
|
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{
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// This might look illogical, but it is done during encryption as well ...
|
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// The 'base64' value is effectively an inverted "raw data" parameter
|
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$digest_size = ($params['base64'])
|
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? $this->_digests[$params['hmac_digest']] * 2
|
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: $this->_digests[$params['hmac_digest']];
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|
|
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if (self::strlen($data) <= $digest_size)
|
|
{
|
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return FALSE;
|
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}
|
|
|
|
$hmac_input = self::substr($data, 0, $digest_size);
|
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$data = self::substr($data, $digest_size);
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|
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isset($params['hmac_key']) OR $params['hmac_key'] = $this->hkdf($this->_key, 'sha512', NULL, NULL, 'authentication');
|
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$hmac_check = hash_hmac($params['hmac_digest'], $data, $params['hmac_key'], ! $params['base64']);
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|
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// Time-attack-safe comparison
|
|
$diff = 0;
|
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for ($i = 0; $i < $digest_size; $i++)
|
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{
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$diff |= ord($hmac_input[$i]) ^ ord($hmac_check[$i]);
|
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}
|
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|
|
if ($diff !== 0)
|
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{
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return FALSE;
|
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}
|
|
}
|
|
|
|
if ($params['base64'])
|
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{
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$data = base64_decode($data);
|
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}
|
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isset($params['key']) OR $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, self::strlen($this->_key), 'encryption');
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return $this->{'_'.$this->_driver.'_decrypt'}($data, $params);
|
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}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Decrypt via MCrypt
|
|
*
|
|
* @param string $data Encrypted data
|
|
* @param array $params Input parameters
|
|
* @return string
|
|
*/
|
|
protected function _mcrypt_decrypt($data, $params)
|
|
{
|
|
if ( ! is_resource($params['handle']))
|
|
{
|
|
return FALSE;
|
|
}
|
|
|
|
// The greater-than-1 comparison is mostly a work-around for a bug,
|
|
// where 1 is returned for ARCFour instead of 0.
|
|
if (($iv_size = mcrypt_enc_get_iv_size($params['handle'])) > 1)
|
|
{
|
|
if (mcrypt_enc_get_modes_name($params['handle']) !== 'ECB')
|
|
{
|
|
$iv = self::substr($data, 0, $iv_size);
|
|
$data = self::substr($data, $iv_size);
|
|
}
|
|
else
|
|
{
|
|
// MCrypt is dumb and this is ignored, only size matters
|
|
$iv = str_repeat("\x0", $iv_size);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
$iv = NULL;
|
|
}
|
|
|
|
if (mcrypt_generic_init($params['handle'], $params['key'], $iv) < 0)
|
|
{
|
|
if ($params['handle'] !== $this->_handle)
|
|
{
|
|
mcrypt_module_close($params['handle']);
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
$data = mdecrypt_generic($params['handle'], $data);
|
|
// Remove PKCS#7 padding, if necessary
|
|
if (in_array(strtolower(mcrypt_enc_get_modes_name($params['handle'])), array('cbc', 'ecb'), TRUE))
|
|
{
|
|
$data = self::substr($data, 0, -ord($data[self::strlen($data)-1]));
|
|
}
|
|
|
|
mcrypt_generic_deinit($params['handle']);
|
|
if ($params['handle'] !== $this->_handle)
|
|
{
|
|
mcrypt_module_close($params['handle']);
|
|
}
|
|
|
|
return $data;
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Decrypt via OpenSSL
|
|
*
|
|
* @param string $data Encrypted data
|
|
* @param array $params Input parameters
|
|
* @return string
|
|
*/
|
|
protected function _openssl_decrypt($data, $params)
|
|
{
|
|
if ($iv_size = openssl_cipher_iv_length($params['handle']))
|
|
{
|
|
$iv = self::substr($data, 0, $iv_size);
|
|
$data = self::substr($data, $iv_size);
|
|
}
|
|
else
|
|
{
|
|
$iv = NULL;
|
|
}
|
|
|
|
return empty($params['handle'])
|
|
? FALSE
|
|
: openssl_decrypt(
|
|
$data,
|
|
$params['handle'],
|
|
$params['key'],
|
|
1, // DO NOT TOUCH!
|
|
$iv
|
|
);
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Get params
|
|
*
|
|
* @param array $params Input parameters
|
|
* @return array
|
|
*/
|
|
protected function _get_params($params)
|
|
{
|
|
if (empty($params))
|
|
{
|
|
return isset($this->_cipher, $this->_mode, $this->_key, $this->_handle)
|
|
? array(
|
|
'handle' => $this->_handle,
|
|
'cipher' => $this->_cipher,
|
|
'mode' => $this->_mode,
|
|
'key' => NULL,
|
|
'base64' => TRUE,
|
|
'hmac_digest' => 'sha512',
|
|
'hmac_key' => NULL
|
|
)
|
|
: FALSE;
|
|
}
|
|
elseif ( ! isset($params['cipher'], $params['mode'], $params['key']))
|
|
{
|
|
return FALSE;
|
|
}
|
|
|
|
if (isset($params['mode']))
|
|
{
|
|
$params['mode'] = strtolower($params['mode']);
|
|
if ( ! isset($this->_modes[$this->_driver][$params['mode']]))
|
|
{
|
|
return FALSE;
|
|
}
|
|
|
|
$params['mode'] = $this->_modes[$this->_driver][$params['mode']];
|
|
}
|
|
|
|
if (isset($params['hmac']) && $params['hmac'] === FALSE)
|
|
{
|
|
$params['hmac_digest'] = $params['hmac_key'] = NULL;
|
|
}
|
|
else
|
|
{
|
|
if ( ! isset($params['hmac_key']))
|
|
{
|
|
return FALSE;
|
|
}
|
|
elseif (isset($params['hmac_digest']))
|
|
{
|
|
$params['hmac_digest'] = strtolower($params['hmac_digest']);
|
|
if ( ! isset($this->_digests[$params['hmac_digest']]))
|
|
{
|
|
return FALSE;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
$params['hmac_digest'] = 'sha512';
|
|
}
|
|
}
|
|
|
|
$params = array(
|
|
'handle' => NULL,
|
|
'cipher' => $params['cipher'],
|
|
'mode' => $params['mode'],
|
|
'key' => $params['key'],
|
|
'base64' => isset($params['raw_data']) ? ! $params['raw_data'] : FALSE,
|
|
'hmac_digest' => $params['hmac_digest'],
|
|
'hmac_key' => $params['hmac_key']
|
|
);
|
|
|
|
$this->_cipher_alias($params['cipher']);
|
|
$params['handle'] = ($params['cipher'] !== $this->_cipher OR $params['mode'] !== $this->_mode)
|
|
? $this->{'_'.$this->_driver.'_get_handle'}($params['cipher'], $params['mode'])
|
|
: $this->_handle;
|
|
|
|
return $params;
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Get MCrypt handle
|
|
*
|
|
* @param string $cipher Cipher name
|
|
* @param string $mode Encryption mode
|
|
* @return resource
|
|
*/
|
|
protected function _mcrypt_get_handle($cipher, $mode)
|
|
{
|
|
return mcrypt_module_open($cipher, '', $mode, '');
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Get OpenSSL handle
|
|
*
|
|
* @param string $cipher Cipher name
|
|
* @param string $mode Encryption mode
|
|
* @return string
|
|
*/
|
|
protected function _openssl_get_handle($cipher, $mode)
|
|
{
|
|
// OpenSSL methods aren't suffixed with '-stream' for this mode
|
|
return ($mode === 'stream')
|
|
? $cipher
|
|
: $cipher.'-'.$mode;
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Cipher alias
|
|
*
|
|
* Tries to translate cipher names between MCrypt and OpenSSL's "dialects".
|
|
*
|
|
* @param string $cipher Cipher name
|
|
* @return void
|
|
*/
|
|
protected function _cipher_alias(&$cipher)
|
|
{
|
|
static $dictionary;
|
|
|
|
if (empty($dictionary))
|
|
{
|
|
$dictionary = array(
|
|
'mcrypt' => array(
|
|
'aes-128' => 'rijndael-128',
|
|
'aes-192' => 'rijndael-128',
|
|
'aes-256' => 'rijndael-128',
|
|
'des3-ede3' => 'tripledes',
|
|
'bf' => 'blowfish',
|
|
'cast5' => 'cast-128',
|
|
'rc4' => 'arcfour',
|
|
'rc4-40' => 'arcfour'
|
|
),
|
|
'openssl' => array(
|
|
'rijndael-128' => 'aes-128',
|
|
'tripledes' => 'des-ede3',
|
|
'blowfish' => 'bf',
|
|
'cast-128' => 'cast5',
|
|
'arcfour' => 'rc4-40',
|
|
'rc4' => 'rc4-40'
|
|
)
|
|
);
|
|
|
|
// Notes:
|
|
//
|
|
// - Rijndael-128 is, at the same time all three of AES-128,
|
|
// AES-192 and AES-256. The only difference between them is
|
|
// the key size. Rijndael-192, Rijndael-256 on the other hand
|
|
// also have different block sizes and are NOT AES-compatible.
|
|
//
|
|
// - Blowfish is said to be supporting key sizes between
|
|
// 4 and 56 bytes, but it appears that between MCrypt and
|
|
// OpenSSL, only those of 16 and more bytes are compatible.
|
|
// Also, don't know what MCrypt's 'blowfish-compat' is.
|
|
//
|
|
// - CAST-128/CAST5 produces a longer cipher when encrypted via
|
|
// OpenSSL, but (strangely enough) can be decrypted by either
|
|
// extension anyway.
|
|
// Also, it appears that OpenSSL uses 16 rounds regardless of
|
|
// the key size, while RFC2144 says that for key sizes lower
|
|
// than 11 bytes, only 12 rounds should be used. This makes
|
|
// it portable only with keys of between 11 and 16 bytes.
|
|
//
|
|
// - RC4 (ARCFour) has a strange implementation under OpenSSL.
|
|
// Its 'rc4-40' cipher method seems to work flawlessly, yet
|
|
// there's another one, 'rc4' that only works with a 16-byte key.
|
|
//
|
|
// - DES is compatible, but doesn't need an alias.
|
|
//
|
|
// Other seemingly matching ciphers between MCrypt, OpenSSL:
|
|
//
|
|
// - RC2 is NOT compatible and only an obscure forum post
|
|
// confirms that it is MCrypt's fault.
|
|
}
|
|
|
|
if (isset($dictionary[$this->_driver][$cipher]))
|
|
{
|
|
$cipher = $dictionary[$this->_driver][$cipher];
|
|
}
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* HKDF
|
|
*
|
|
* @link https://tools.ietf.org/rfc/rfc5869.txt
|
|
* @param $key Input key
|
|
* @param $digest A SHA-2 hashing algorithm
|
|
* @param $salt Optional salt
|
|
* @param $length Output length (defaults to the selected digest size)
|
|
* @param $info Optional context/application-specific info
|
|
* @return string A pseudo-random key
|
|
*/
|
|
public function hkdf($key, $digest = 'sha512', $salt = NULL, $length = NULL, $info = '')
|
|
{
|
|
if ( ! isset($this->_digests[$digest]))
|
|
{
|
|
return FALSE;
|
|
}
|
|
|
|
if (empty($length) OR ! is_int($length))
|
|
{
|
|
$length = $this->_digests[$digest];
|
|
}
|
|
elseif ($length > (255 * $this->_digests[$digest]))
|
|
{
|
|
return FALSE;
|
|
}
|
|
|
|
self::strlen($salt) OR $salt = str_repeat("\0", $this->_digests[$digest]);
|
|
|
|
$prk = hash_hmac($digest, $key, $salt, TRUE);
|
|
$key = '';
|
|
for ($key_block = '', $block_index = 1; self::strlen($key) < $length; $block_index++)
|
|
{
|
|
$key_block = hash_hmac($digest, $key_block.$info.chr($block_index), $prk, TRUE);
|
|
$key .= $key_block;
|
|
}
|
|
|
|
return self::substr($key, 0, $length);
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* __get() magic
|
|
*
|
|
* @param string $key Property name
|
|
* @return mixed
|
|
*/
|
|
public function __get($key)
|
|
{
|
|
// Because aliases
|
|
if ($key === 'mode')
|
|
{
|
|
return array_search($this->_mode, $this->_modes[$this->_driver], TRUE);
|
|
}
|
|
elseif (in_array($key, array('cipher', 'driver', 'drivers', 'digests'), TRUE))
|
|
{
|
|
return $this->{'_'.$key};
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Byte-safe strlen()
|
|
*
|
|
* @param string $str
|
|
* @return int
|
|
*/
|
|
protected static function strlen($str)
|
|
{
|
|
return (self::$func_overload)
|
|
? mb_strlen($str, '8bit')
|
|
: strlen($str);
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
|
|
/**
|
|
* Byte-safe substr()
|
|
*
|
|
* @param string $str
|
|
* @param int $start
|
|
* @param int $length
|
|
* @return string
|
|
*/
|
|
protected static function substr($str, $start, $length = NULL)
|
|
{
|
|
if (self::$func_overload)
|
|
{
|
|
// mb_substr($str, $start, null, '8bit') returns an empty
|
|
// string on PHP 5.3
|
|
isset($length) OR $length = ($start >= 0 ? self::strlen($str) - $start : -$start);
|
|
return mb_substr($str, $start, $length, '8bit');
|
|
}
|
|
|
|
return isset($length)
|
|
? substr($str, $start, $length)
|
|
: substr($str, $start);
|
|
}
|
|
}
|