Moving Target Defense based on Switched Supervisory Control: A New Technique for Mitigating Sensor Deception Attacks

In this paper, we introduce a new notion of switched supervisory control in the context of discrete event systems. We assume a single event-driven system (plant) controlled by a set of supervisors, where each pair plant/supervisor generates a different event-driven system. A switching mechanism coordinates which plant/supervisor is active at a given time. We investigate the problem of synthesizing a set of supervisors and a switching mechanism such that safety, liveness and maximal permissiveness specifications are satisfied. Sufficient and necessary conditions to solve this problem are presented. Second, a direct application of this new switched supervisory control theory is provided in the context of cyber-security. Namely, this new framework is used as basis for a Moving Target Defense paradigm. Again, sufficient and necessary conditions to solve this problem are presented.