<?php

/*

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

 * Version 1.1.6 (Caoineag beta 1)

 * Copyright (C) 2006-2008 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_gen_padding($val, $len = 32)

{

  $ret = array();

  for ( $i = 0; $i < $len; $i++ )

  {

    $ret[] = $val;

  }

  return $ret;

}

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

{

  static $block_sizes = array();

  if ( !isset($block_sizes[$hashfunc]) )

  {

    $block_sizes[$hashfunc] = strlen($hashfunc(''))/2;

  }

  $blocksize = $block_sizes[$hashfunc];

  $ipad = hmac_gen_padding(0x5c, $blocksize);

  $opad = hmac_gen_padding(0x36, $blocksize);

  if ( strlen($key) != ( $blocksize * 2 ) )

    $key = $hashfunc($key);

  $key = hmac_hexbytearray($key);

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

  {

    $ipad[$i] = $ipad[$i] ^ $key[$i];

    $opad[$i] = $opad[$i] ^ $key[$i];

  }

  return $hashfunc(hmac_bytearraytostring($opad) . $hashfunc(hmac_bytearraytostring($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');

}

?>