Higher-Order Nets for Mobile Policies

Since the early 80's the combination of Petri nets and rule-based transformations has been extensively researched to obtain new concepts and results. In this paper we consider rules as tokens leading to the concept of higher-order nets for mobile policies. The rules are used on the one hand for the specification of policy rules and on the other hand for the modification of policy rules, i.e. for the definition of new rules by reusing existing rules. So the higher-order net models distribution and modification of policy rules in a systematic and structured way. We give HasCasl-specifications of rules and (local) transformations in the sense of the double-pushout approach and illustrate our concept by a small system inspired by the case study of a tax refund process [E. Bertino, E. Ferrari, E., and V. Atluri. The Specification and Enforcement of Authorization Constraints in Workflow Management Systems. ACM Transactions on Information and System Security 2 (1) (1999) 65-104].