Distributed Key Management with Protection Against RSU Compromise in Group Signature Based VANETs

The group signature based security scheme is a promising approach to provision privacy in vehicular ad hoc networks (VANETs). In this paper, we propose a novel distributed key management scheme for group signature based VANETs, which is expected to considerably facilitate the revocation of malicious vehicles, location privacy protection, heterogenous security policies, and maintenance of the system, compared with the centralized key management assumed by the existing group signature schemes. The distributed nature of the proposed scheme is that the road side units (RSUs) will be responsible for distributing group private keys in a localized manner. A brand- new issue induced by the distributed scheme is that the semi-trust RSUs may be compromised. So we develop security protocols for the distributed key management, which are capable of identifying the compromised RSUs and their collusion with the malicious vehicles if any. Details of possible attacks and the corresponding solutions are discussed to demonstrate the performance of the proposed security protocols.