Threshold ElGamal-based key management scheme for distributed RSUs in VANET

In Vehicular Ad Hoc Networks (VANETs), the vehicular scenario requires smart signaling, smart road maintenance and other services. A brand new security issue is that the semitrusted Road Side Units (RSUs) may be compromised. In this paper, we propose a Threshold ElGamal system based key management scheme for safeguarding VANET from the compromised RSUs and their collusion with the malicious vehicles. We analyze the packet loss tolerance for security performance demonstration, followed by a discussion on the threshold. After discussion of the feasibility on privacy and processing time, overhead analysis is presented from two kinds of application scenarios: Emergency Braking Notification (EBN) and Decentralized Floating Car Data (DFCD). Our method can promote security with low overhead in EBN and does not increase overhead in DFCD during security promotion.