PoF: Proof-of-Following for Vehicle Platoons

TL;DR

This paper introduces Proof-of-Following (PoF), a novel protocol that verifies vehicle proximity in platoons by leveraging environmental RF signal fading, enhancing security beyond cryptographic methods.

Contribution

It presents a new physical environment-based verification protocol for vehicle platooning that links digital identity to real-world location.

Findings

PoF effectively detects remote impersonation attacks.

The protocol performs reliably across freeway, highway, and urban conditions.

PoF withstands pre-recording and following attacks with high probability.

Abstract

Cooperative vehicle platooning significantly improves highway safety, fuel efficiency, and traffic flow. In this model, a set of vehicles move in line formation and coordinate acceleration, braking, and steering using a combination of physical sensing and vehicle-to-vehicle (V2V) messaging. The authenticity and integrity of the V2V messages are paramount to safety. For this reason, recent V2V and V2X standards support the integration of a PKI. However, a PKI cannot bind a vehicle's digital identity to the vehicle's physical state (location, velocity, etc.). As a result, a vehicle with valid cryptographic credentials can impact platoons from a remote location. In this paper, we seek to provide the missing link between the physical and the digital world in the context of vehicle platooning. We propose a new access control protocol we call Proof-of-Following (PoF) that verifies the following distance between a candidate and a verifier. The main idea is to draw security from the common, but constantly changing environment experienced by the closely traveling vehicles. We use the large-scale fading effect of ambient RF signals as a common source of randomness to construct a {\em PoF} primitive. The correlation of large-scale fading is an ideal candidate for the mobile outdoor environment because it exponentially decays with distance and time. We evaluate our PoF protocol on an experimental platoon of two vehicles in freeway, highway, and urban driving conditions. We demonstrate that the PoF withstands both the pre-recording and following attacks with overwhelming probability.