<?php
# MetInfo Enterprise Content Management System 
# Copyright (C) MetInfo Co.,Ltd (http://www.metinfo.cn). All rights reserved. 

defined('IN_MET') or exit('No permission');

class auth {
	
	public $auth_key;
	
	public function __construct() {
		global $_M;
		$this->auth_key = $_M['config']['met_webkeys'];
	}
	
	public function decode($str, $key = ''){
		return $this->authcode($str, 'DECODE', $this->auth_key.$key);
	}
	
	public function encode($str, $key = '', $time = 0){
		return $this->authcode($str, 'ENCODE', $this->auth_key.$key, $time);
	}
		
	public function creatkey($length = '10'){
		$str="A2B3C4zD5yE6xF7wG8vH9uitJsKrLnMmNlPkQjRiShTgUfVeWdXcYbZa";
		$result="";
		for($i=0;$i<$length;$i++){
			$num[$i]=rand(0,25);
			$result.=$str[$num[$i]];
		}
		return $result;
	}
	
	public function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0){
		$ckey_length = 4;  
		$key = md5($key ? $key : UC_KEY);
		$keya = md5(substr($key, 0, 16));
		$keyb = md5(substr($key, 16, 16));
		$keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : '';
		$cryptkey = $keya.md5($keya.$keyc);
		$key_length = strlen($cryptkey);
		$string = $operation == 'DECODE' ? base64_decode(substr($string, $ckey_length)) : sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;
		$string_length = strlen($string);
		$result = '';
		$box = range(0, 255);
		$rndkey = array();
		for($i = 0; $i <= 255; $i++) {
			$rndkey[$i] = ord($cryptkey[$i % $key_length]);
		}
		for($j = $i = 0; $i < 256; $i++) {
			$j = ($j + $box[$i] + $rndkey[$i]) % 256;
			$tmp = $box[$i];
			$box[$i] = $box[$j];
			$box[$j] = $tmp;
		}

		for($a = $j = $i = 0; $i < $string_length; $i++) {
			$a = ($a + 1) % 256;
			$j = ($j + $box[$a]) % 256;
			$tmp = $box[$a];
			$box[$a] = $box[$j];
			$box[$j] = $tmp;
			$result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
		}

		if($operation == 'DECODE') {
			if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {
			   return substr($result, 26);
			} else {
			   return '';
			}
		}else{
			return $keyc.str_replace('=', '', base64_encode($result));
		}
	}

}

# This program is an open source system, commercial use, please consciously to purchase commercial license.
# Copyright (C) MetInfo Co., Ltd. (http://www.metinfo.cn). All rights reserved.
?>