Web Encryption.

Ini adalah snippet source code dari soal MeePwnCTF Encryption.

<?php


function tsu_super_encrypt0($c)
{
  return gzcompress($c,-1);
}

function tsu_super_encrypt1($c,$key)
{
    $l=strlen($key);
    $string="";
    for($i=0;$i<strlen($c);$i++)
    {
        $string[$i]=chr((ord($c[$i]) | ord($key[$i%$l])) & (256+~(ord($c[$i]) & ord($key[$i%$l])))%256);
    }
    return implode("",$string);
}

function tsu_super_encrypt2($c)
{
    $l=strlen($c);
    $string="";
    for($i=0;$i<$l;$i++)
    {
        $string[$i]=chr((ord($c[$i])+$i)%256);
    }
    return implode("",$string);
}

function tsu_super_encrypt3($c)
{
  $l=strlen($c);
  $k=$l%8;
  $string="";
  for($i=0;$i<$l;$i++)
  {

  $string[$i]=chr(((ord($c[$i])<<$k)|ord($c[$i])>>(8-$k))&0xff);
  }
  return implode("",$string);
}




  $key = 'jasfjkahfjk';
  $gen_token=md5(uniqid(rand(), true));
  $enc="ini hasilnya";
  $flag="ini fflagnya";
  $query="secret=".$flag."string=".$enc;
  $encrypted0=tsu_super_encrypt0($query);
  $encrypted1=tsu_super_encrypt1($encrypted0,$key);
  $encrypted2=tsu_super_encrypt2($encrypted1);
  $encrypted3=tsu_super_encrypt3($encrypted2); //I'm too sleepy, i think i should stop here..., oyasuminasai...mm..mm..zz..
  $final=base64_encode($encrypted3);
  echo '<pre><font color="red">Hey onii-chan...Here is your crypt...</font><font color="blue">'.$final.'</font></pre>'; 
  
  
?>