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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Class to calculate RFC 2104 compliant hashes
*
*
* PHP versions 4 and 5
*
* LICENSE: This source file is subject to version 3.0 of the PHP license
* that is available through the world-wide-web at the following URI:
* http://www.php.net/license/3_0.txt. If you did not receive a copy of
* the PHP License and are unable to obtain it through the web, please
* send a note to license@php.net so we can mail you a copy immediately.
*
* @category Encryption
* @package Crypt_HMAC
* @author Derick Rethans <derick@php.net>
* @author Matthew Fonda <mfonda@dotgeek.org>
* @copyright 1997-2005 The PHP Group
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @version CVS: $Id: HMAC.php,v 1.3 2005/02/20 19:18:29 mfonda Exp $
* @link http://pear.php.net/package/Crypt_HMAC
*/
/**
* Calculates RFC 2104 compliant HMACs
*
* @access public
* @category Encryption
* @package Crypt_HMAC
* @author Derick Rethans <derick@php.net>
* @author Matthew Fonda <mfonda@dotgeek.org>
* @copyright 1997-2005 The PHP Group
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @link http://pear.php.net/package/Crypt_HMAC
*/
class Crypt_HMAC
{
/**
* Hash function to use
* @var string
* @access private
*/
var $_func;
/**
* Inner padded key
* @var string
* @access private
*/
var $_ipad;
/**
* Outer padded key
* @var string
* @access private
*/
var $_opad;
/**
* Pack format
* @var string
* @access private
*/
var $_pack;
/**
* Constructor
* Pass method as first parameter
*
* @param string $key Key to use for hash
* @param string $func Hash function used for the calculation
* @return void
* @access public
*/
function Crypt_HMAC($key, $func = 'md5')
{
$this->setFunction($func);
$this->setKey($key);
}
/**
* Sets hash function
*
* @param string $func Hash function to use
* @return void
* @access public
*/
function setFunction($func)
{
if (!$this->_pack = $this->_getPackFormat($func)) {
die('Unsupported hash function');
}
$this->_func = $func;
}
/**
* Sets key to use with hash
*
* @param string $key
* @return void
* @access public
*/
function setKey($key)
{
/*
* Pad the key as the RFC wishes
*/
$func = $this->_func;
if (strlen($key) > 64) {
$key = pack($this->_pack, $func($key));
}
if (strlen($key) < 64) {
$key = str_pad($key, 64, chr(0));
}
/* Calculate the padded keys and save them */
$this->_ipad = (substr($key, 0, 64) ^ str_repeat(chr(0x36), 64));
$this->_opad = (substr($key, 0, 64) ^ str_repeat(chr(0x5C), 64));
}
/**
* Gets pack formats for specifed hash function
*
* @param string $func
* @return mixed false if hash function doesnt exist, pack format on success
* @access private
*/
function _getPackFormat($func)
{
$packs = array('md5' => 'H32', 'sha1' => 'H40');
return isset($packs[$func]) ? $packs[$func] : false;
}
/**
* Hashing function
*
* @param string $data string that will encrypted
* @return string
* @access public
*/
function hash($data)
{
$func = $this->_func;
return $func($this->_opad . pack($this->_pack, $func($this->_ipad . $data)));
}
}
?>
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