Efficient and multi-level privacy-preserving communication protocol for VANET

In this paper, we introduce an efficient and multi-level conditional privacy preservation authentication protocol in vehicular ad hoc networks (VANETs) based on ring signature. The proposed protocol has three appealing characteristics: First, it offers conditional privacy preservation authentication: while every receiver can verify that a message issuer is an authorized participant in the system only a trusted authority can reveal the true identity of a message sender. Second, it is equipped with multi-level countermeasure: each vehicle can select the degree of privacy according to its own requirements. Third, it is efficient: our system outperforms previous proposals in message authentication and verification, cost-effective identity tracking in case of a dispute, and low storage requirements. We demonstrate the merits gained by the proposed protocol through extensive analysis.