Region authority based collaborative scheme to detect Sybil attacks in VANET

Vehicular ad hoc networks (VANETs) are increasingly used for traffic control, accident avoidance, and management of toll stations and public areas. Security and privacy are two major concerns in VANETs. Most privacy preserving schemes are susceptible to Sybil attack in which a malicious user generates multiple identities to simulate multiple vehicles. This paper proposes an improvement for the scheme CP²DAP [1], which detects Sybil attacks by the cooperation of a central authority and a set of fixed nodes called road-side units (RSUs). The modification proposed is a region authority based collaborative scheme for detecting Sybil attacks and a revocation method using bloom filter to prevent further attacks from malicious vehicles. The detection of Sybil attack in this manner does not require any vehicle to disclose its identity; hence privacy is preserved at all times.