obfuscation-class

<?php
/**
  * s=(rot13)%{if num}[SALT](rot5){else}(rot13)[EXPLODER](rot13)%{if num}[SALT](rot5){else}(rot13) ...
  **/

class obfuscation
{
    private $request;
    private $equal;
    private $int_salt;
    private $exploder;
    private $debugging;

    public function __construct()
    {
        if(isset($_GET['s']))
            $this->request = $_GET['s'];
        else
            $this->request = "";

        $this->equal = md5("hahaha");
        $this->int_salt = "999999";
        $this->exploder = "gghztfjafdsg";
        $this->debugging = array();
    }

    public function getDebuginfo(){
        $ret = "";
        foreach($this->debugging as $x){
            $ret .= $x;
        }
        return $ret;
    }

    // buggy
    private function rot5($str, $n=5){
        $replace = [];
        for($i=0;$i<26;$i++){
            $replace[chr(65+$i)] = chr(65+(($i+$n)%26));
            $replace[chr(97+$i)] = chr(97+(($i+$n)%26));
        }
        return strtr($str, $replace);
    }

    public function encode($link)
    {
        $e = explode('?', $link);
        $f = $e[0];
        $p = explode('&', $e[1]);
        unset($e);
        $arr = array();
        foreach($p as $part){
            $e = explode('=', $part);
            $param = $e[0];
            $value = $e[1];
            unset($e);
            if(is_numeric($value))
                $nval = "" . $this->int_salt . "" . self::rot5($value) . "";
            else
                $nval = str_rot13($value);

            $arr[] = "" . str_rot13($param) . "" . $this->equal . "" . $nval . "";
        }
        $crypted = implode($this->exploder, $arr);
        $out = $f . "?s=" . $crypted . "";
        return $out;
    }

    public function decode($debug = false)
    {
        $e = explode($this->exploder, $this->request);
        foreach($e as $p){
            $c = explode($this->equal, $p);
            $pa = str_rot13($c[0]);
            if(is_numeric($c[1])){
                $re = "";
                $va = str_replace($this->int_salt, $re, $c[1]);
                $va = self::rot5($va);
            }else{
                $va = str_rot13($c[1]);
            }
            $_GET[$pa] = $va;
            if($debug)
                $this->debugging[] = " " . $pa . " => " . $va . ",<br>";
            //array_push($_GET,array($pa => $va));
        }
        return $_GET;
    }

}
?>