Cooperative Sybil Attack Detection for Position Based Applications in Privacy Preserved VANETs

In this paper, we propose a security protocol to detect sybil attacks for position based applications in privacy preserved vehicular ad hoc networks (VANETs). Vehicles in our protocol identify sybil attacks locally in a cooperative way by examining the rationality of vehicles´ positions to their own neighbors. The attack detection utilizes the characteristics of communication and vehicles´ GPS positions which are included in the periodically broadcasted safety related messages. No extra hardware and little communication and computation overhead will be introduced to vehicles. Therefore, our protocol is very light weighted and suitable for real applications. Moreover, a smart attacker scenario in which a malicious vehicle may adjust its communication range to avoid detection and the malicious vehicles´ collusion scenario are also considered. Simulation results based on NS2 are presented to demonstrate the performance of the proposed protocol.