<?php
  /**************************************************************************\
  * phpGroupWare API - Crypto                                                *
  * This file written by Joseph Engo <jengo@phpgroupware.org>                *
  * Handles encrypting strings based on various encryption schemes           *
  * Copyright (C) 2000, 2001 Dan Kuykendall                                  *
  * -------------------------------------------------------------------------*
  * This library is part of the phpGroupWare API                             *
  * http://www.phpgroupware.org/api                                          * 
  * ------------------------------------------------------------------------ *
  * This library is free software; you can redistribute it and/or modify it  *
  * under the terms of the GNU Lesser General Public License as published by *
  * the Free Software Foundation; either version 2.1 of the License,         *
  * or any later version.                                                    *
  * This library 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 Lesser General Public License for more details.              *
  * You should have received a copy of the GNU Lesser General Public License *
  * along with this library; if not, write to the Free Software Foundation,  *
  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA            *
  \**************************************************************************/

  /* $Id$ */

	class crypto
	{
		var $td = False;		// Handle for mcrypt
		var $iv = '';
		var $key = '';

		function crypto($vars)
		{
			global $phpgw, $phpgw_info;
			$key = $vars[0];
			$iv = $vars[1];
			if ($phpgw_info['server']['mcrypt_enabled'] && extension_loaded('mcrypt'))
			{
				if ($phpgw_info['server']['versions']['mcrypt'] == 'old')
				{
					$this->td = false;
					if (phpversion() > '4.0.2pl1')
					{
						$keysize = mcrypt_get_key_size(MCRYPT_TRIPLEDES);
						$ivsize  = mcrypt_get_iv_size(MCRYPT_TRIPLEDES,MCRYPT_MODE_CBC);
					}
					else
					{
						$keysize = 8;
						$ivsize = 8;
					}
				}
				else
				{
					// Start up mcrypt
					$this->td = mcrypt_module_open (MCRYPT_TRIPLEDES, '', MCRYPT_MODE_CBC, '');

					$ivsize  = mcrypt_enc_get_iv_size($this->td);
					$keysize = mcrypt_enc_get_key_size($this->td);
				}

				// Hack IV to be the correct size
				$x = strlen($iv);
				for ($i = 0; $i < $ivsize; $i++)
				{
					$this->iv .= $iv[$i % $x];
				}

				// Hack Key to be the correct size
				$x = strlen($key);

				for ($i = 0; $i < $keysize; $i++)
				{
					$this->key .= $key[$i % $x];
				}
				if ($phpgw_info['server']['versions']['mcrypt'] != 'old')
				{
					mcrypt_generic_init ($this->td, $this->key, $this->iv);
				} 
			}
			// If mcrypt isn't loaded key and iv are not needed
		}

		function cleanup()
		{
			global $phpgw_info;

			if ($phpgw_info['server']['mcrypt_enabled'] && extension_loaded('mcrypt'))
			{
				if ($phpgw_info['server']['versions']['mcrypt'] != 'old')
				{
					mcrypt_generic_end ($this->td);
				}
			}
		}

		function hex2bin($data)
		{
			$len = strlen($data);
			return pack('H' . $len, $data);
		}

		function encrypt($data)
		{
			global $phpgw_info;

			$data = serialize($data);

			// Disable all encryption if the admin didn't set it up
			if ($phpgw_info['server']['mcrypt_enabled'] && extension_loaded('mcrypt'))
			{
				switch ($phpgw_info['server']['versions']['mcrypt'])
				{
					// The old code, only works with mcrypt <= 2.2.x
					case 'old':
					{
						$encrypteddata = mcrypt_cbc(MCRYPT_TripleDES, $this->key, $data, MCRYPT_ENCRYPT);
						break;
					}
					default:
					{ // Handle 2.4 and newer API
						$encrypteddata = mcrypt_generic($this->td, $data);
					}
				}
				$encrypteddata = bin2hex($encrypteddata);
				return $encrypteddata;
			}
			else
			{  // No mcrypt == insecure !
				return $data;
			}
		}

		function decrypt($encrypteddata)
		{
			global $phpgw_info;

			// Disable all encryption if the admin didn't set it up
			if ($phpgw_info['server']['mcrypt_enabled'] && extension_loaded('mcrypt'))
			{
				$data = $this->hex2bin($encrypteddata);

				switch ($phpgw_info['server']['versions']['mcrypt'])
				{
					// The old code, only works with mcrypt <= 2.2.x
					case 'old':
					{
						$data = mcrypt_cbc(MCRYPT_TripleDES, $this->key, $data, MCRYPT_DECRYPT);
						break;
					}
					default:
					{ // Handle 2.4 and newer API
						$data = mdecrypt_generic($this->td, $data);
					}
				}
				return unserialize($data);
			}
			else
			{
				return unserialize($encrypteddata);
			}
		}
	}  // class crypto
?>