Distributed and Asynchronous Secure State Reconstruction for Cyber-Physical Systems

The greater availability and accessibility of IoT sensors, data acquisition systems and computer networks, led to the development of distributed control strategies aimed at monitoring and securing of Cyber-Physical Systems (CPS). In this paper, we propose a distributed asynchronous algorithm for the Secure State Reconstruction (SSR) which relies on a gossip-based procedure to let a network of agents reach a shared estimate of the process state based on measurements taken by the different agents at different time instants. In particular, the procedure aims to reduce measurement noise and provide resilience in the event of cyber attacks that modify the readings of agents or cause their disconnection, combined with the possibility of providing new virtual measurements in realtime. In addition, the gossip-based pair connection is randomly established and subsequently destroyed, making it difficult for an attacker to intercept the information exchange. In detail, we first analytically demonstrate the convergence and correctness of the proposed algorithm, and then we provide a simulation campaign to demonstrate its effectiveness.