AntiSybil: Standing against Sybil Attacks in Privacy-Preserved VANET

In this paper, we aim at two conflicting goals, privacy and Sybil attacks in Vehicular Ad Hoc NETworks (VANETs). Sybil attack refers to impersonation of one physical entity for many, namely Sybil nodes. Such attacks may cause dire consequences such as traffic jams or even deadly accidents. We leverage pseudonymless beaconing in order to preserve privacy. To cope with the Sybil attack, we put forth a two fold strategy. For scheduled beacons, we mploy TRM (Tamper Resistant Module) to perform a lightweight pre-assembly data analysis on beacons whereas for ERMs (Event Reporting Messages), RSUs distribute authorized tokens among benign vehicular nodes which in turn are consumed to report ERM. Our proposed scheme preserves privacy in both beacons and ERMs, and offers conditional anonymity.