Patent ID: 8140845

Claim:
A method for generating a security key for a mobile node in communication with an access point of a foreign network, the method comprising: generating at the mobile node a first authenticator using a group of parameters comprising: a first random number provided to the mobile node by the access point, a second random number generated by the mobile node, a network access identifier of the mobile node, a predetermined security key shared by the mobile node and the home network of the mobile node, an identifier of the access point of the foreign network, and a randomly generated session identifier of a communications session; providing the first authenticator to a home network of the mobile node; validating at the mobile node a second authenticator received from the home network via the access point of the foreign network, wherein the second authenticator is generated by the home network upon validating the first authenticator, the first and second authenticators are generated according to a Keyed Message Authorization Code (KMAC) using each of the above listed parameters; and generating at the mobile node a security key using the predetermined security key and the second authenticator, wherein the security key generated by the mobile node is provided to the access point.