Defending against Sybil Attacks in Vehicular Platoons

Vehicular networks are being progressively advocated for traffic and congestion management, accident prevention as well as enabling numerous location-based services. In vehicular networks, vehicles form platoons for improving operational efficiency and providing better traffic management thus resulting in optimized performance. However, platoons are vulnerable to notorious threats such as Sybil attacks wherein malicious users fabricate fictitious identities or impersonate those of legitimate nodes. In this paper, we model Sybil attacks in vehicular platoons using OMNET++, SUMO and Veins framework and evaluate their impact on performance. Further, a defense mechanism using hybrid key management in conjunction with witness based mechanisms is proposed. Evaluation shows that the proposed defense mechanism significantly limits the impact of Sybil attacks with minimal overhead. The proposed approach is lightweight in that public key based credentials are bootstrapped to set-up pairwise symmetric keys thus resulting in decreased overhead.