Comments on 'Dual Authentication and Key Management Techniques for Secure Data Transmission in Vehicular Ad Hoc Networks'

Recently, Vijayakumar et al. proposed a dual authentication and key management scheme for secure data transmission in vehicular ad-hoc networks. As described by Vijayakumar et al., a dual authentication scheme and the corresponding group key management mechanism are illustrated successively. The authors claimed that the proposed scheme is resistant to replay attack and masquerade attack. However, we find that the proposed scheme given by Vijayakumar et al. is still vulnerable to replay attack, which could be conducted by reusing previously acquired messages. Moreover, this scheme cannot resist masquerade attack toward the system. For the above consideration, in this paper, modifications toward the existing protocol are presented, so as to provide adequate security assurance toward the mentioned attacks.