A Robust Authentication Protocol with Non-Repudiation Service for Integrating WLAN and 3G Network

Abstract

The third-generation cellular systems provide great coverage, complete subscriber management and nearly universal roaming. Nevertheless, 3G systems suffer the high installation cost and low bandwidth. Though WLAN provides hot spot coverage with high data rates, it lacks roaming and mobility support. From users' points of views, the integration of WLAN and 3G systems is an attractive way that will provide them a convenient access to network. When integrating WLAN and 3G, there are still some problems should be concerned in terms of authentication and security, such as authentication efficiency and repudiation problem. In this paper, we review the authentication scheme for WLAN and 3G/UMTS interworking which is specified by 3GPP and propose a robust localized fast authentication protocol with non-repudiation service for integrating WLAN and 3G network. The localized re-authentication protocol can shorten the authentication time delay. On the other hand, with the non-repudiation service, the assumption, that subscriber has to fully trust 3G home operator, can be deleted and the trust management between the independent WLAN operator, 3G visited operator and 3G home operator can be eliminated. In other words, our proposed protocol provides legal evidences to prevent the 3G home operator from overcharge toward the subscriber and also prevent the WLAN operator and 3G visited operator from overcharge toward the 3G home operator. The authentication protocol employs HMAC, hash-chaining techniques, and public-key digital signature to achieve localized fast re-authentication and non-repudiation service.