Encryption-decryption-based distributed state estimation against eavesdropping attacks over sensor networks with communication protocol

Abstract

The secure distributed state estimation problem is investigated for a class of discrete time-varying systems over sensor networks regulated by encryption–decryption mechanism and round-robin protocol. To save energy and alleviate network congestion, the round-robin protocol is introduced to schedule the transmission order of the measurement data. To mitigate privacy leakage, an encryptor is designed to encrypt the measurement information of each sensor node, and then the encrypted measurements can be decrypted by the user. The primary objective of this paper is to present a distributed state estimation algorithm with recursive format for such time-varying systems, in which an upper bound on the estimation error covariance is derived, and appropriate estimator gains are determined to minimize this upper bound. In addition, a sufficient condition is provided to ensure that the estimation error of the user is exponentially bounded in the mean-square sense. Particularly, the properly designed encryption–decryption parameters guarantee that the state estimation error of the eavesdropper is unbounded. Finally, two simulation experiments are conducted to demonstrate the feasibility of the developed encryption–decryption-based distributed state estimation algorithm.