<?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 $enabled = False;
		var $mcrypt_version = '';
		var $td = False; // Handle for mcrypt
		var $iv = '';
		var $key = '';

		function crypto($vars)
		{
			$key = $vars[0];
			$iv  = $vars[1];
			if ($GLOBALS['phpgw_info']['server']['mcrypt_enabled'] && extension_loaded('mcrypt'))
			{
				$this->enabled = True;
				$this->mcrypt_version = $GLOBALS['phpgw_info']['server']['versions']['mcrypt'];
				if ($this->mcrypt_version == '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 mcrypt isn't loaded key and iv are not needed
		}

		function cleanup()
		{
			if ($this->enabled)
			{
				if ($this->mcrypt_version != 'old')
				{
					mcrypt_generic_end ($this->td);
				}
			}
		}

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

		function encrypt($data)
		{
			// Disable all encryption if the admin didn't set it up
			if ($this->enabled)
			{
				// ONLY manipulate data if we are going to encrypt it
				// question: why do we sreialize and add slashes before encrypting?? (ed: Angles)
				$data = serialize($data);
				$data = addslashes($data);
				switch ($this->mcrypt_version)
				{
					// The old code, only works with mcrypt <= 2.2.x
					case 'old':
					{
						$encrypteddata = mcrypt_cbc(MCRYPT_TripleDES, $this->key, $data, MCRYPT_ENCRYPT);
						break;
					}
					default:
					{ // Handle 2.4 and newer API
						mcrypt_generic_init ($this->td, $this->key, $this->iv);
						$encrypteddata = mcrypt_generic($this->td, $data);
						break;
					}
				}
				$encrypteddata = bin2hex($encrypteddata);
				return $encrypteddata;
			}
			else
			{ 
				// No mcrypt == insecure !
				// Data should be returned *unmolested* if encryption is not enabled
				return $data;
			}
		}

		function decrypt($encrypteddata)
		{
			// Disable all encryption if the admin didn't set it up
			if ($this->enabled)
			{
				$data = $this->hex2bin($encrypteddata);
				switch ($this->mcrypt_version)
				{
					// The old code, only works with mcrypt <= 2.2.x
					case 'old':
						$data = mcrypt_cbc(MCRYPT_TripleDES, $this->key, $data, MCRYPT_DECRYPT);
						break;
					// Handle 2.4 and newer API
					default:
						mcrypt_generic_init ($this->td, $this->key, $this->iv);
						$data = mdecrypt_generic($this->td, $data);
						break;
				}
				// hey -- since the encrypt() function calls serialize and then addslashes,
				// we should always do the reverse -- correct? (ed: Del)
				$data = stripslashes($data);
				$data = unserialize($data);
				// question: was it necessary to serialize and addslashes *before* encryption in the first place? (ed: Angles)
			}
			else
			{
				// Data should be returned *unmolested* if encryption is not enabled
				return $data;
			}
			/*
			// this is apparently intended to allow encryption of objects
			// at this point Dec 14, 2001, we simply need to handle strings correctly
			// which was broken previously (ed: Angles)
			if(!strpos(' '.$data,'O:8:"stdClass"'))
			{
				return unserialize($data);
			}
			else
			{
				$data = stripslashes($data);
				return $data;
			}
			*/
		}
	} // class crypto
?>