SWAP: Secure Warning Messages Authentication and Propagation in Internet of Vehicles

The sensing and communication capabilities of the Internet of Vehicles (IoV) allow for the design of safer Intelligent Transportation Systems (ITS), with capabilities for reduced crashes and drivers' injuries. To this aim, entities in the IoV can autonomously exchange Warning Messages (WMs) on the road status to help drivers, passengers, and vehicles to take immediate actions and reduce road accidents. WMs authentication, timely propagation, and integrity is a fundamental requirement, as the injection of false WMs or their delay by a malicious user can lead to accidents or traffic congestion. The currently available WMs authentication and propagation schemes focus on the security properties, without however accounting for the scalability issues related to the large number of entities connected in the IoV. In this paper, we propose Secure Warning Message Authentication and Propagation (SWAP), an authentication protocol specifically designed for WM propagation in the Internet of Vehicles (IoV). We introduce the Warning Message Authority (WMA), a novel entity responsible for secure WMs handling. Thanks to the WMA, WMs are managed by dedicated resources that allow for the timely delivery of safety-critical information, avoiding delays due to network congestion at the Trusted Authority (TA). We prove the security of SWAP by using the Random Oracle Model (ROM) and via security analysis. Compared to state of the art authentication schemes, SWAP reduces the number of communication bits by 100 bits, and provides a ten-fold decrease of the computation time.