Verification of Current-state Opacity for Discrete Event Systems Modeled With Unbounded Petri Nets

Abstract

This research analyzes current-state-based opacity in discrete event systems, which is a type of state-based opacity verification. We consider an unbounded Petri net to model this system, in which we assume that each transition is unobservable and partial places are observable (the number of tokens can be measured). A novel coverability graph based on partial markings is proposed, which is used to construct an estimator for current-state estimation. Current-state opacity is verified in this work employing the proposed new coverability graph. This paper proposes a sufficient and necessary condition for the verification of current-state opacity, as well as a concrete example to explain the approach.