Dynamic Watermarking-based Defense of Transportation Cyber-physical Systems

The transportation sector is on the threshold of a revolution as advances in real-time communication, real-time computing, and sensing technologies have brought to fruition the capability to build Transportation Cyber-Physical Systems (TCPS) such as self-driving cars, unmanned aerial vehicles, adaptive cruise control systems, truck platoons, and so on. While there are many benefits that TCPSs have to offer, a major challenge that needs to be addressed to enable their proliferation is their vulnerability to cyber attacks. In this article, we demonstrate, using laboratory prototypes of TCPSs, how the approach of Dynamic Watermarking can secure them from arbitrary sensor attacks. Specifically, we consider two TCPSs of topical interest: (i) an adaptive cruise control system and (ii) a system of self-driving vehicles tracking given trajectories. In each of these systems, we first show how cyber attacks on sensors can compromise safety and cause collisions between vehicles in spite of the presence of a collision avoidance module in the system. We then apply the approach of Dynamic Watermarking and demonstrate that it detects attacks with “low” delay. Once an attack is detected, the controller can take appropriate control actions to prevent collisions, thereby guaranteeing safety in the sense of collision freedom.