function encode($string)
   {
      $secString = md5("geheim");
      $length = strlen($string);
      $pos = rand(0,$length);
      $string = base64_encode($string);
	  $secured = '';
      for($i=0;$i<=$length;$i++)
      {
         if( $i == $pos )
         {
            $secured .= $secString.$string[$i];
         }
         else
         {
            $secured .= $string[$i];
         }
      }
      return $secured;
   }
function decode($string)
{
      $secString = md5("geheim");
      $string = str_replace($secString,"",$string);
      $string = base64_decode( $string );
      return $string;
}