A Privacy-Preserving Authentication Scheme for VANETs with Exculpability

Message authentication and conditional privacy preservation are two critical security issues in VANETs (vehicular ad hoc networks). To achieve the corresponding security goals, many security technologies have been proposed so far. Identity-based pseudonyms and group signature-based schemes are two of the main technologies in recently published literature. However, the key escrow is difficult to achieve and pseudonym identities may reveal the physical location of the vehicle in the identity-based scheme. The global manager TA of VANETs knows the full keys given to the vehicles and can forge signatures under the vehicle’s key. Therefore, the exculpability cannot be satisfied in the group signature scheme. To address these security issues, a privacy-preserving authentication scheme for VANETs with exculpability is proposed in this paper, which applies double key approach to realize the trusted communication between vehicle and road side units and TA by combining the advantage of group-based methods and identity-based methods. Security analysis shows that the security of our scheme can resist stronger attacks than previous schemes.