A Survey on Non-interference with Petri Nets

Several notions of non-interference have been proposed in the literature to study the problem of confidentiality in nondeterministic and concurrent systems. Here we rephrase some of them – notably SNNI and BNDC – over the model of safe Place/Transition Petri Nets. The common feature of these non-interference properties is that they are all defined as extensional properties based on some notion of behavioural equivalence on systems. Here we also address the problem of defining non-interference by looking at the structure of the net systems under investigation. We define structural non-interference properties based on the absence of particular places in the net. We characterize structural properties that are slight refinement of well-known properties such as SNNI and SBNDC. We then argue that, in order to capture all the intuitive interferences at the structural level, it is necessary to consider the net originated by the region construction, yielding the property RBNI we advocate.