Encrypt?

[eluser]suba[/eluser]
Hi,

URL:
-------
http://example.com/sims/index.php/exam/r...4Xb9U9R+uw==
This is my url.

Code:

function results()
{
$this->load->library('encrypt');
$this->data['title']='display students\' results';
$this->load->view('header/menu_link',$this->data);
$this->data['show']=1;
$this->load->view('students_index',$this->data);
$str=$this->encrypt->decode($this->uri->segment(3)); // get uri value.
}

I want get data from URL.
So I used uri helper
Without encryption , I can get uri value through

Code:

$this->uri->segement(3)

But encoded value, I cannot get through

Code:

$this->uri->segement(3)

error comes out
The URI you submitted has disallowed characters.

can you suggest me , how do i get encoded string/value from uri?

Thanks for your advice