VANET Authentication Protocols: Security Analysis and a Proposal

Wireless communication among vehicular ad hoc network (VANET) entities is secured through cryptography, which is used for authentication as well as to ensure the overall security of messages in this environment. Authentication protocols play a significant role and are therefore required to be free of vulnerabilities that allow entity impersonation, unauthorized entry, and general misuse of the system. A resourceful adversary can inflict serious damage to VANET systems through such vulnerabilities. We consider several VANET authentication protocols in the literature and identify vulnerabilities. In addition to the commonly considered vulnerabilities in VANETs, we observe that the often-overlooked relay attack is possible in almost all VANET authentication protocols. Relay attacks have the potential to cause damage in VANETs through misrepresentation of vehicle identity, telematic data, traffic-related warnings, and information related to overall safety in such networks. We discuss possible countermeasures to address identified vulnerabilities. We then develop an authentication protocol that uses ambient conditions to secure against relay attacks and other considered vulnerabilities. We include security proof for the proposed protocol.