Feasibility and Detection of Replay Attack in Networked Constrained Cyber-Physical Systems

This paper analyzes the effect of replay attacks on constrained cyber-physical systems which are subject to linear probabilistic constraints. In order to inject an exogenous control input without being detected the attacker will hijack the sensors, observe and record their readings for a certain amount of time and repeat them afterwards while carrying out his attack. The conditions under which the attacker can induce perturbation in the control loop without being detected is studied. Then, in order to make the system resilient to the replay attack, a random signal (serving as the authentication signal) is added to the control input. Since this signal can hamper the performance of the system, finally, the optimization of the authentication signals is proposed to maximize the detection rate while keeping the process deterioration bounded. The effectiveness of the proposed scheme is demonstrated on a simulated case study.