Completely Stealthy and Energy-Stealthy Sensor Attacks With Constrained Channels: Existence and Design

In this article, the security of state estimation is studied under stealthy false-data injection attacks launched in the sensor-to-estimator channels. It is proved that there is no strictly stealthy sensor attack such that the state estimation is insecure. Thus, we focus on the existence of the attacks with complete and energy stealthiness to gradually remove the attack impact on detectors. Since the existence of stealthy attacks is significantly affected by accessing attack channels, the necessary and sufficient conditions of such two types of attacks with constrained channels are proposed by matrix decomposition techniques and the reachability analysis of system dynamics. In general, deeper stealthiness for attacks will require harsher constraints on the system dynamics, while it turns out that the completely-stealthy attacks are achievable under the same existence conditions as the generally stealthy attacks. Meanwhile, we indicate that though launching energy-stealthy attacks needs more demanding system dynamics, they can deceive detectors more deeply. The simulation examples demonstrate the effectiveness of the presented theoretical results.