Traditional cryptographic approaches may not always be suitable for cyber-physical systems (CPSs). In this correspondence, we present a control theoretic approach allowing a networked controller and a smart actuator of a stochastic CPS to agree on a common secret key without resorting to classical cryptographic approaches. More precisely, by utilizing the asymmetry in the system model knowledge available to the control system defender and to the eavesdropper, we propose a key agreement scheme utilizing a simultaneous input and state estimation algorithm. The validity of the proposed solution is shown through a numerical example.

Authors: Walter Lucia, Member, Amr Youssef, "Key Agreement Scheme for Cyber-Physical Systems", IEEE Transactions on SMC: Systems, DOI: 10.1109/TSMC.2021.3121205, 2021