Use encrypt helper,how to

[eluser]chmod[/eluser]
I use CI's encrypt helper.

Code:

$datetime = date('Y-m-d H:i:s',time());
$keycode = $game_id.'|'.$area_id.'|'.$datetime;
$sid = $this->encrypt->encode($keycode);         $this->session->set_userdata('sid',$sid);

and the result of $sid maybe include following character :
space
+
=

when I use get pass $sid,the space character will be translate:
hexadecimal ,so the encrypt result will not equal.

If i want use enctypt helper ,but wipe out the space or + or =，how can I do?