PHP Token(令牌)设计应用

转自：http://my.oschina.net/u/912810/blog/358973

<?php  
class GEncrypt {  
    protected static function keyED($txt,$encrypt_key){     
        $encrypt_key = md5($encrypt_key);     
        $ctr=0;     
        $tmp = "";     
        for ($i=0;$i<strlen($txt);$i++){     
            if ($ctr==strlen($encrypt_key)) $ctr=0;     
            $tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1);     
            $ctr++;     
        }     
        return $tmp;     
    } 

    public static function encrypt($txt,$key){     
        //$encrypt_key = md5(rand(0,32000));  
        $encrypt_key = md5(((float) date("YmdHis") + rand(10000000000000000,99999999999999999)).rand(100000,999999));  
        $ctr=0;     
        $tmp = "";     
        for ($i=0;$i<strlen($txt);$i++){  
            if ($ctr==strlen($encrypt_key)) $ctr=0;     
            $tmp.= substr($encrypt_key,$ctr,1) . (substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1));     
            $ctr++;     
        }     
        return base64_encode(self::keyED($tmp,$key));  
    } 

    public static function decrypt($txt,$key){  
        $txt = self::keyED( base64_decode($txt),$key);     
        $tmp = "";  
        for ($i=0;$i<strlen($txt);$i++){     
            $md5 = substr($txt,$i,1);     
            $i++;     
            $tmp.= (substr($txt,$i,1) ^ $md5);     
        }  
        return $tmp;  
    }      
}  
?> 

完毕。