# Detecting Integrity Attacks on Control Systems using a Moving Target Approach

## TL;DR

This paper proposes a moving target approach with unknown time-varying dynamics and external states to detect and prevent integrity attacks on control systems, even when adversaries have extensive access.

## Contribution

It introduces a novel moving target method using unknown linear time-varying dynamics and external states to enhance attack detection in control systems.

## Key findings

- The approach can detect stealthy attacks with bounded performance.
- External states improve detection of adversaries attempting system identification.
- The method is robust against adversaries with full access to sensors and actuators.

## Abstract

Maintaining the security of control systems in the presence of integrity attacks is a significant challenge. In literature, several possible attacks against control systems have been formulated including replay, false data injection, and zero dynamics attacks. The detection and prevention of these attacks may require the defender to possess a particular subset of trusted communication channels. Alternatively, these attacks can be prevented by keeping the system model secret from the adversary. In this paper, we consider an adversary who has the ability to modify and read all sensor and actuator channels. To thwart this adversary, we introduce external states dependent on the state of the control system, with linear time-varying dynamics unknown to the adversary. We also include sensors to measure these states. The presence of unknown time-varying dynamics is leveraged to detect an adversary who simultaneously aims to identify the system and inject stealthy outputs. Potential attack strategies and bounds on the attacker's performance are provided.