Abstract: The present invention generally relates to the field of secure centralized single sign-on and session maintenance for web servers on the Internet. In a preferred implementation, a single sign-on protocol for use by web servers is independent of the actual authentication mechanism used by any of the individual web servers accessed by the user. Users authenticate themselves with any one of a group of federated servers so that a user does not need to be re-authenticated by other servers in the federation. In a preferred implementation there is also a centralized server that provides for the transparent sign-on, session management, and session termination within each server in the federation of servers, and each federated server communicates with the central sign-on server.