Secure Spatial Authentication for Mobile Stations In Hybrid 3G-WLAN Serving Networks

The coexistence of cellular and wireless local area networks (WLAN) is enabling very interesting scenarios from both business and technical point of view. Various integration scenarios between third generation cellular (3G) and WLAN technologies have the potential to create seamless communication environments and increase the efficiency in using wireless spectrum. One of the major challenges to the integration of3G and WLAN are related to security. More specifically, providing secure access to 3G through WLAN is a concern and object of research. Due to their centralized management nature, 3G technologies enable the implementation of stronger security solutions, compared to the highly distributed WLAN environments. One very interesting aspect of security in hybrid 3G-WLAN scenarios is location authentication. A potential risk is presented to 3G operators since no prior relationship or trust may exist with specific WLAN-s´ owners. The mobile stations may collude with the WLAN operator to falsify its location. In this paper, we propose to use hybrid 3G-WLAN devices to help for the location authentication of WLAN devices, when they try to access 3G services though WLANs. In order to avoid security problems created by the potential collusion among hybrid and WLAN devices we propose threshold cryptographic tools. We analyze the tradeoff between number of hybrid devices, their trust level, overhead and risk factors.