A trust-based architecture for managing certificates in vehicular ad hoc networks

In this paper, we propose a secure and distributed public key infrastructure for vehicular ad hoc networks VANETs based on an hybrid trust model which is used to determine the trust metric (T_m) of vehicles. The trust model consists on a monitoring system processing on two aspects: the cooperation of vehicles and the legitimacy of the broadcasted data. We propose a fuzzy-based solution in order to decide about the honesty of vehicles. Then, the vehicles which are trusted (T_m = 1) and have at least one trusted neighbor can be candidate to serve as certification authorities CAs in their clusters. In order to increase the stability of our distributed architecture, the candidate CA which has the lowest relative mobility will be elected as certification authority CA. We conducted a set of simulations in which we evaluate the efficiency and the stability of the clustering algorithm as a function of the speed, the average number of vehicles on the platoon and the percentage of confident vehicles.