Model-Based Encryption: Privacy of States in Networked Control Systems

In this paper, we investigate model-based encryption scheme for privacy of states against eavesdroppers with unbounded computation power in one-channel feedback networked control system (NCSs). In the one-channel feedback NCS, the states of the plant are measured by remote sensors and the controller is co-located with the actuators. To emphasize the mechanics of the proposed approach, the model-based encryption scheme is referred to as masking with system kernel (MSK). In contrast to encryption approaches based on modern cryptography, MSK does not require generation and distribution of secret keys amongst sensors and the controller. It is demonstrated that MSK guarantees privacy of states against eavesdroppers with unbounded computation power if the system parameters of the considered one-channel feedback NCS are selected in an appropriate manner.