Optimal Stealthy Deterministic Attack Strategies on Cyber-Physical Systems

In this article, we study optimal stealthy attacks on both the actuator and output communication channels of cyber-physical control systems. Using a deterministic attack framework, we ensure that the attacks are difficult for innovation-based detectors to perceive. In order to determine the maximum performance degradation that the attacks may cause, a general optimization problem that can be solved numerically is formulated for a finite attack length. For nondivergent systems over an infinite horizon, the optimal constant and alternating attacks are derived analytically for any system configuration. Characteristics of a novel low-dimensional sinusoidal class of attacks are investigated and procedures for optimization are given. Furthermore, a condition is provided for constant and alternating attacks to be superior to most or all sinusoidal attacks. Finally, numerical simulations are used to demonstrate the theoretical results.