Non-interference notions based on reveals and excludes relations for petri nets

In distributed systems, it is often important that a user is not able to infer if a given action has been performed by another component, while still being able to interact with that component. This kind of problems has been studied with the help of a notion of "interference" in formal models of concurrent systems (e.g. CCS, Petri nets). Here, we propose several new notions of interference for ordinary Petri nets, study some of their properties, and compare them with notions already proposed in the literature. Our new notions rely on the unfolding of Petri nets, and on an adaptation of the "reveals" relation for ordinary Petri nets, previously defined on occurrence nets, and on a new relation, called "excludes", here introduced for detecting negative information flow.