Abstract: “In traffic safety applications of Vehicular Ad-hoc Networks (VANETs), security is a very important issue. Sybil attack is a particular attack where the attacker illegitimately claims multiple identities. In the past, several approaches have been proposed to solve this problem. They are categorized into PKI-based, infrastructure-based, observer-based, and resource-testing-based schemes. In this paper, existing protocols are analyzed, and a novel scheme for detecting the Sybil nodes in VANETs is presented, reducing the effect of a Sybil attack. The proposed Sybil nodes-detection scheme, Physical Measurement-Based Sybil Nodes Detection Mechanism in VANETs (PMSD), takes advantage of physical measurements of the beacon message instead of key-based materials, which not only solves the Sybil attack problem, but also reduces the overhead of detection. The proposed scheme has no fixed infrastructure, which makes it easier to implement. The simulation results show a 95% detection rate of Sybil n”

Keywords: VANETs, Sybil Attack, Physical Measurement, Security