An Enhanced Authentication Solution for Infrastructureless Vehicle Environments

Robust vehicle authentication is essential in order to ensure an effective audit of vehicle-to-vehicle (V2V) communications. However, most existing approaches rely on a centralized infrastructure to access both authorities' certificates andrevocation lists, thus making them ineffective in dynamic and infrastructureless environments. In this paper, we highlight this critical limitation, and propose a method which enables the vehicles to update their local authentication databases independently from infrastructure availability. Our approach aim to allow vehicles to perform V2V authentication using locally stored data, in order to ensure continuity of secure communications even when disconnected from the Infrastructure. We further analyze the probability of successful authentication under two scenarios, which are the first with up-to-date databases, and the second with outdated ones. The analytical results show that the authentication probability decreases to below <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{7 5 \%}$</tex> after <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3 0}$</tex> hours of disconnection with long-lived certificates, while updates keep it above 90% in highway scenarios, even with short-lived certificates. These findings demonstrate the feasibility of maintaining reliable V2V authentication outside the infrastructure coverage, and point out the necessary improvements for evolving towards secure and auditable V2V communications.