Sky tv in the uk generate their modem/routers with a random key 0-9 & a-z

Ive seen a few utube vids and they seem to need a dictionary file... but as its a random key surely im thinking that the key will NOT appear in the dictionary file...

so im wondering if there is a way/tut to show me a way of desyphering the key like the way of getting a WEP key?

Hi and thank you for your replies, im new so please be gentle lol

using BT 4 R2 boot cd

Lee