Patent ID: 7512796
Filing Date: 2009-03-31
Classification: H04L,H04W

Abstract:
1. A method in a system comprising a mobile node, a packet data network and a telecommunication network, the mobile node being configured for communicating directly over two different communication links, a telecommunication network link with the telecommunication network and a packet data network link with the packet data network, the method comprising: storing in the mobile node and in the telecommunication network a mobile node identity and a shared secret specific to the mobile node identity corresponding to the mobile node, which mobile node identity and shared secret are capable of authenticating the mobile node to the telecommunication network for communications over the telecommunication network link; providing the mobile node with a protection code; sending the mobile node identity and the protection code from the mobile node to the packet data network over the packet data network link; the telecommunication network providing the packet data network with authentication information corresponding to said mobile node identity, the authentication information comprising a challenge and a session secret, wherein said session secret corresponds to the mobile node identity and the session secret is derivable from the challenge together with the shared secret; forming cryptographic information using at least the protection code and the session secret; the packet data network sending the challenge and the cryptographic information to the mobile node over the packet data network link; the mobile node checking the validity of the cryptographic information using the challenge and the shared secret; the mobile node deriving based on the shared secret, the session secret and a first response corresponding to the challenge; the mobile node sending the first response to the packet data network over the packet data network link; and the packet data network checking the first response for authenticating the mobile node.