<?php

/*

 * Enano - an open-source CMS capable of wiki functions, Drupal-like sidebar blocks, and everything in between

 * Copyright (C) 2006-2009 Dan Fuhry

 * hmac.php - HMAC cryptographic functions

 *

 * This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied

 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.

 */

function hmac_core($message, $key, $hashfunc)

{

	if ( strlen($key) % 2 == 1 )

		$key .= '0';

	if ( strlen($key) > 128 )

		$key = $hashfunc($key);

	while ( strlen($key) < 128 )

	{

		$key .= '00';

	}

	$opad = hmac_hexbytearray($key);

	$ipad = $opad;

	for ( $i = 0; $i < count($ipad); $i++ )

	{

		$opad[$i] = $opad[$i] ^ 0x5c;

		$ipad[$i] = $ipad[$i] ^ 0x36;

	}

	$opad = hmac_bytearraytostring($opad);

	$ipad = hmac_bytearraytostring($ipad);

	return $hashfunc($opad . hexdecode($hashfunc($ipad . $message)));

}

function hmac_hexbytearray($val)

{

	$val = hexdecode($val);

	return hmac_bytearray($val);

}

function hmac_bytearray($val)

{

	$val = str_split($val, 1);

	foreach ( $val as &$char )

	{

		$char = ord($char);

	}

	return $val;

}

function hmac_bytearraytostring($val)

{

	foreach ( $val as &$char )

	{

		$char = chr($char);

	}

	return implode('', $val);

}

function hmac_md5($message, $key)

{

	return hmac_core($message, $key, 'md5');

}

function hmac_sha1($message, $key)

{

	return hmac_core($message, $key, 'sha1');

}

function hmac_sha256($message, $key)

{

	require_once(ENANO_ROOT . '/includes/math.php');

	require_once(ENANO_ROOT . '/includes/diffiehellman.php');

	return hmac_core($message, $key, 'sha256');

}

?>