Diamonds for security : a non-interleaving operational semantics for the applied pi-calculus

Aubert, Clément and Horne, Ross and Johansen, Christian; Klin, Bartek and Lasota, Sławomir and Muscholl, Anca, eds. (2022) Diamonds for security : a non-interleaving operational semantics for the applied pi-calculus. In: 33rd International Conference on Concurrency Theory. Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing, POL, 30:1-30:26. ISBN 9783959772464 (

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We introduce a non-interleaving structural operational semantics for the applied π-calculus and prove that it satisfies the properties expected of a labelled asynchronous transition system (LATS). LATS have well-studied relations with other standard non-interleaving models, such as Mazurkiewicz traces or event structures, and are a natural extension of labelled transition systems where the independence of transitions is made explicit. We build on a considerable body of literature on located semantics for process algebras and adopt a static view on locations to identify the parallel processes that perform a transition. By lifting, in this way, work on CCS and π-calculus to the applied π-calculus, we lay down a principled foundation for reusing verification techniques such as partial-order reduction and non-interleaving equivalences in the field of security. The key technical device we develop is the notion of located aliases to refer unambiguously to a specific output originating from a specific process. This light mechanism ensures stability, avoiding disjunctive causality problems that parallel extrusion incurs in similar non-interleaving semantics for the π-calculus.