Cryptanalysis and Improvement of Batch Verification Certificateless Signature Scheme for VANETs

摘要

Vehicular ad hoc networks (VANETs) has been paid more and more attention by the researchers and industry. Recently, Bayat et al. proposed a secure authentication scheme of VANETs with batch verification. Based on the computational Diffie-Hellman (CDH) assumption, they claimed that their scheme was secure. Unfortunately, we find that the scheme presented by Bayat et al. is insecure in their security model. It cannot resist the adversary attack so that a malicious vehicle can forge arbitrarily legal vehicle's signature on any message. We give a concrete attack process. Furthermore, we provide a batch verification certificateless signature scheme for VANETs. Based on the CDH assumption, we prove that the presented scheme is secure against adaptively chosen message attack in the random oracle model. The performance analysis shows that our scheme is more suitable for realistic applications.