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Created: Sun, Sep 28, 12:49 AM

cookie_hasher.php
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	<?php
	/**
	* @version $Id: cookie_hasher.php 14572 2012-12-07 15:25:49Z erik $
	* @package In-Portal
	* @copyright Copyright (C) 1997 - 2012 Intechnic. All rights reserved.
	* @license GNU/GPL
	* In-Portal is Open Source software.
	* This means that this software may have been modified pursuant
	* the GNU General Public License, and as distributed it includes
	* or is derivative of works licensed under the GNU General Public License
	* or other free or open source software licenses.
	* See http://www.in-portal.org/license for copyright notices and details.
	*/

	defined('FULL_PATH') or die('restricted access!');

	/**
	* Class to encrypt/decrypt cookies.
	*
	*/
	class kCookieHasher extends kBase {

	protected static $_vector = null;

	/**
	* Holds list of cookie names, that should not be processed
	*
	* @var Array
	* @access protected
	*/
	protected $_plainTextCookies = Array ();

	public function __construct($secret = '')
	{
	parent::__construct();

	if ( !$secret ) {
	$secret = $this->Application->ConfigValue('RandomString');
	}

	$this->_config = Array (
	'secret' => substr($secret, 0, 32), // used cipher only allows 256bit (or less) key length
	'cipher' => MCRYPT_RIJNDAEL_256,
	'mode' => MCRYPT_MODE_CBC,
	'vector' => static::_vector(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC)
	);

	$plain_text_cookies = (string)$this->Application->ConfigValue('PlainTextCookies');

	if ( $plain_text_cookies ) {
	$plain_text_cookies = array_filter(array_map('trim', explode(',', $plain_text_cookies)));
	$this->_plainTextCookies = array_unique(array_merge($this->_plainTextCookies, $plain_text_cookies));
	}
	}

	/**
	* Determines if cookie should be processed or passed through as is
	*
	* @param string $cookie_name
	* @return bool
	* @access protected
	*/
	protected function _isPassThrough($cookie_name)
	{
	return in_array($cookie_name, $this->_plainTextCookies);
	}

	/**
	* Generates encryption vector and returns it
	*
	* @param string $cipher
	* @param string $mode
	* @return string
	* @access protected
	*/
	protected static function _vector($cipher, $mode)
	{
	if ( static::$_vector ) {
	return static::$_vector;
	}

	$size = static::_vectorSize($cipher, $mode);

	return static::$_vector = mcrypt_create_iv($size, MCRYPT_DEV_URANDOM);
	}

	/**
	* Returns vector size for given cipher and encryption mode
	*
	* @param string $cipher
	* @param string $mode
	* @return int
	* @access protected
	*/
	protected static function _vectorSize($cipher, $mode)
	{
	return mcrypt_get_iv_size($cipher, $mode);
	}

	/**
	* Encrypts a cookie
	*
	* @param string $cookie_name
	* @param mixed $plain_value
	* @return string
	* @access public
	*/
	public function encrypt($cookie_name, $plain_value)
	{
	if ( $this->_isPassThrough($cookie_name) ) {
	return $plain_value;
	}

	$cipher = $this->_config['cipher'];
	$secret = $this->_config['secret'];
	$mode = $this->_config['mode'];
	$vector = $this->_config['vector'];

	$data = Array ($cookie_name => $plain_value);
	$encrypted = mcrypt_encrypt($cipher, $secret, serialize($data), $mode, $vector);

	return base64_encode($encrypted) . base64_encode($vector);
	}

	/**
	* Decrypts a cookie
	*
	* @param string $cookie_name
	* @param string $encrypted_value
	* @return mixed
	* @access public
	*/
	public function decrypt($cookie_name, $encrypted_value)
	{
	if ( $this->_isPassThrough($cookie_name) ) {
	return $encrypted_value;
	}

	$cipher = $this->_config['cipher'];
	$secret = $this->_config['secret'];
	$mode = $this->_config['mode'];

	$vector_size = static::_vectorSize($cipher, $mode);
	$base64_vector_size = strlen(base64_encode(str_repeat(' ', $vector_size)));
	$vector = $this->_safeBase64Decode(substr($encrypted_value, -$base64_vector_size));
	$data = $this->_safeBase64Decode(substr($encrypted_value, 0, -$base64_vector_size));

	if ( $vector === false \|\| $data === false \|\| strlen($vector) != $vector_size ) {
	// non-encrypted or malformed cookie value given
	return '';
	}

	// non-serialized array is decrypted in case of decrypting old cookies after a secret change
	$decrypted = trim(mcrypt_decrypt($cipher, $secret, $data, $mode, $vector));
	$data = kUtil::IsSerialized($decrypted) ? unserialize($decrypted) : Array ();

	// check if cookie value was actually copied from other cookie
	return isset($data[$cookie_name]) ? $data[$cookie_name] : '';
	}

	/**
	* Safely decodes base64-encoded string
	*
	* @param string $encoded_string
	* @return string\|bool
	* @access protected
	*/
	protected function _safeBase64Decode($encoded_string)
	{
	$decoded_string = base64_decode($encoded_string);

	if ( (string)base64_encode($decoded_string) !== (string)$encoded_string ) {
	return false;
	}

	return $decoded_string;
	}
	}

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