Mobile anonymity of dynamic groups in vehicular networks

Vehicular networks are an emerging network to improve safety, efficiency, and convenience of the existing transportation system. In order to preserve privacy in vehicular networks, it is desirable to keep users anonymous. In this paper, we argue that existing approaches, for example, ring singature and anonymous authentication, are susceptible to intersection attack in vehicular networks, resulting in reduced anonymity, even no anonymity. To quantify the achievable anonymity, we first define a graph-based model called mobile anonymity for a general dynamic environment. We show that under this model, anonymity can be achieved on the system level as long as the constructed anonymity graph is strongly connected. We then extend this model into vehicular networks by applying it to ring signature and anonymous authentication in vehicular networks. We propose two strategies, the random (RND) strategy and the latest-preferred (LPR) strategy, and evaluate them via simulation using the C3 simulator. The results show that it is promising to apply RND strategy in vehicular networks. Copyright © 2008 John Wiley & Sons, Ltd.