Patent ID: 7724904

Claim:
An authentication method in a communication system, comprising: acquiring a first master session key (MSK) by a first Extensible Authentication Protocol (EAP) authentication for a mobile station (MS) in an EAP-in-EAP scheme by the MS, a base station (BS), and an authorization, authentication and accounting (AAA) server; acquiring a second MSK by a second EAP authentication for the MS in the EAP-in-EAP scheme by the MS, the BS and the AAA server, after the first EAP authentication; and generating an authorization key (AK) using the first MSK and the second MSK by the MS and the BS; wherein generating the AK comprises generating a first pairwise master key (PMK) using the first MSK, generating a second PMK using the second MSK, and generating the AK using the first PMK and the second PMK.