Secure vehicle location-sharing for trajectory-based message delivery on VANETs

Trajectory-based message delivery is a message forwarding scheme that utilizes the message destination vehicle's trajectory to deliver messages to moving vehicles from infrastructure nodes such as roadside units in vehicular ad hoc networks. To support trajectory-based message delivery to moving vehicles, the driving locations of a vehicle need to be shared with message senders. However, from a security perspective, users want their driving locations not to be exposed to others except their desired senders for location privacy preservation. Therefore, in this paper, we propose a secure location-sharing system to allow a vehicle to share its driving trajectory with roadside units authorized by the vehicle. To design the proposed system, we put a central manager which maintains vehicles trajectory data and acts as a broker between vehicles and roadside units to share the trajectory data. Nevertheless, we make the trajectory data are hidden from not only unauthorized entities but also the central manager by making use of proxy re-encryption schemes. Hence, a vehicle can control that only the sender roadside unit designated by the vehicle can access the trajectory data of the vehicle.