Page "Authenticator" Paragraph 3

Authenticator tokens are common when one program needs to authenticate itself to a larger server or cloud repeatedly.

For instance, you ( the human ) might sign on to a secure website with your name and password, after which you can surf around inside the secure server, visiting different web pages.

Every time you move to a new page, however, the server must believe that you are the same person who originally signed in ( otherwise it will refuse ).

Your browser keeps an authenticator token, which it sends upon every page request ( often as a browser cookie ), that does this.