Security Analysis of a Distributed Networked System Under Eavesdropping Attacks

In this brief, we consider the security problem for a network of linear time-invariant dynamical systems under eavesdropping attacks, where an eavesdropper can measure the states of some nodes in the network. We provide a necessary and sufficient condition for the eavesdropper to reveal the states of the networked system. We also present some necessary conditions for the case when the network has tail nodes or at least one node not monitored by the eavesdropper. In addition, we investigate several typical network structures and show that the networked system can be completely observed provided that the eavesdropper can monitor one node in each cycle. Further, we characterize the minimal set of necessarily monitored nodes with the upper bound set of such nodes. Finally, we verify the theoretical results by numerical simulations.