When privacy fails, a formula describes an attack: A complete and compositional verification method for the applied-calculus

Ross Horne, Sjouke Mauw, Semen Yurkov

Abstract: Highlights•Postulates that a powerful testing equivalence (open barbed bisimilarity) is suited to modelling attacker capabilities in privacy problems.•Proves that quasi-open bisimilarity, better suited to giving proofs of privacy properties, is sound and complete with respect to such tests.•Provides a Hennessy-Milner duality showing that an intuitionistic modal logic characterises the equivalences developed.•Consequently, the logic is capable of describing all attacks on privacy properties expressed as an equivalence problem.•Equivalences proposed are congruences, hence support a compositional methodology which has been applied to private ePayment protocols.