SLIM: Secure and Lightweight Identity Management in VANETs with Minimum Infrastructure Reliance

Vehicular Ad-hoc Networks (VANETs) show a promising future of automobile technology as it enables vehicles to dynamically form networks for vehicle-to-vehicle (V2V) communication. For vehicles to securely and privately communicate with each other in VANETs, various privacy-preserving authentication protocols have been proposed. Most of the existing approaches assume the existence of Road-Side Units (RSUs) to serve as the trusted party during the authentication. However, building RSUs is costly and may not be able to capture the speed of the deployment of the VANETs in the near future. Aiming at minimizing the reliance on the infrastructure support, we propose a Secure and Lightweight Identity Management (SLIM) mechanism for vehicle-to-vehicle communications. Our approach is built upon self-organized groups of vehicles which take turns to serve as captain authentication unit to provide temporary local identities for member vehicles. While ensuring the vehicles' identities are verifiable to each other, we also prevent any vehicle in VANETs including the captain authentication unit from seeing the true identities of other vehicles. The proposed authentication protocols leverage the public key infrastructure in a way that the key generation workload is distributed over time and hence achieve authentication efficiency during the V2V communication. Compared to the previous related work, the proposed SLIM mechanism is more secure in that it can defend more types of attacks in VANETs, and is more efficient in that it requires much shorter response time for identity verification between vehicles.