Patent ID: 7707412

Claim:
A method, comprising: executing a first authentication protocol, wherein a terminal authentication protocol comprises authenticating an identity of a network entity by the terminal in a communication system; sharing a key between the terminal and the network entity for use in securing subsequent communications between the terminal and the network entity; and executing another authentication protocol comprising sharing challenge data between the network entity and the terminal; forming at the terminal test data by applying an authentication function to the challenge data; sending a message comprising terminal authentication data, from the terminal to the network entity; and determining, based on the terminal authentication data, whether to provide the terminal with access to a service, wherein the determining comprises providing the terminal with access to the service only when the terminal authentication data equals a predetermined function of at least the test data and the key; and forming at the terminal secret session keys by at least applying a predetermined function to the test data using the shared key established in the first authentication protocol, wherein the secret session keys are configured to secure the subsequent communications between the terminal and a network element.