Patent attributes
Systems and methods for user authentication within federated computing systems are provided. In a session, a user can be authenticated multiple times by different authentication methods for different servers of the federated system, however, once the user has been authenticated by any given authentication method, the user need not repeat that method. Systems of the present invention comprise a plurality of servers including an authentication server. The authentication server maintains authentication records for users, where each record includes which authentication methods apply to which servers. When a user first seeks access to a particular server, the server identifies the user and the server to the authentication server. If the user has already been authenticated elsewhere according to the authentication method required by the new server, the authentication server indicates to the new server that the user is authenticated, else the authentication server invokes the necessary authentication method.