I have a Westall router and don't know my security
If you are talking about the wireless key it is normally on a sticker of some type on the router. If you are talking about the default password you are going to need the model number.
here is a website that has a list of different models and manufacturers.http://www.routerpasswords.com/
For a westell router the username is normaly admin or CSG and the passwords are password, SESAME, sysAdmin, or no password at all (as in blank).
took me less than 30 seconds to google it. =/
Keep in mind that if you or someone else changed it you are more than likely going to need to reset it to default settings to regain access.