A New Cyber-Secure Countermeasure for LTI systems under DoS attacks
For control systems engineers, this work addresses the vulnerability of LTI systems to prioritized DoS attacks by introducing a rerouting strategy, though it is incremental as it builds on existing LQR and H2 control methods.
This paper proposes a countermeasure for denial-of-service (DoS) attacks in LTI systems by rerouting high-priority state transmissions through lower-priority links and recomputing optimal feedback gains via structured H2 control. Simulations demonstrate the effectiveness of the approach.
This paper presents a new counter-measure to mitigate denial-of-service cyber-attacks in linear time-invariant (LTI) systems. We first design a sparse linear quadratic regulator (LQR) optimal controller for a given LTI plant and evaluate the priority of the feedback communication links in terms of the loss of closed-loop performance when the corresponding block of the feedback gain matrix is removed. An attacker may know about this priority ordering, and thereby attack the links with the highest priority. To prevent this, we present a message rerouting strategy by which the states that are scheduled to be transmitted through the high priority links can be rerouted through lower priority ones in case the former get attacked. Since the attacked link is not available for service, and the states of the low priority links can no longer be accommodated either, we run a structured $\mathcal{H}_2$ control algorithm to determine the post-attack optimal feedback gains. We illustrate various aspects of the proposed algorithms by simulations.