Reducing the User Authentication Cost in Next Generation Networks

Next Generation Networks (NGN) provide multimedia services to mobile users through different access networks including WLAN. The security architecture of NGN specifies that a WLAN user must follow a multi-pass Authentication and Key Agreement (AKA) procedure, in order to get access to the IP multimedia subsystem (IMS) services. This includes a repetition of authentication steps and protocols which introduce an unnecessary overhead. This paper presents a one-pass AKA procedure that eliminates the repeated steps without compromising the provided level of security. The presented procedure has minimal impact on the network infrastructure and functionality and does not require any changes to the existing authentication protocols. We investigate the induced performance improvement regarding the user authentication cost of the one-pass over the multi-pass AKA. To this end we consider a simple analytic model that quantifies the performance of one-pass and multi-pass AKA. This study identifies the cases in which the one-pass AKA presents substantial benefits, e.g., when the mobile user has lengthy session time with short residence time in the service area of an access point.