NEHCM: A Novel and Efficient Hash-chain based Certificate Management scheme for vehicular communications

In this paper, we propose a Novel and Efficient Hash-chain based Certificate Management (NEHCM) scheme for vehicular communications. In NEHCM, to protect driver privacy, each vehicle is equipped with a large set of short-time certificates, and most importantly, serial numbers of these certificates satisfy hash-chain relationship. As a result, the certificate revocation becomes an easy task by simply releasing two hash chain seeds. However, without knowing the seeds, it is infeasible to reveal the linkability among these certificates. Thus, not only vehicles can obtain enough certificates for privacy preservation, but also the size of Certificate Revocation List (CRL) remains linear to the number of revoked vehicles, irrelative to the large number of revoked certificates in NEHCM. Furthermore, NEHCM adopts Roadside Units (RSUs) aided certificate service architecture, but the service overhead for an RSU is very low and irrelated to the number of the updated certificates. Extensive simulations demonstrate that the proposed scheme outperforms previously reported works in terms of the revocation cost.