Preface Foundational aspects of security

• Joshua Guttman in “Establishing and preserving protocol security goals” proposes a model-theoretic approach to the verification of security properties, where the models are executions, and the security goals are implications over the geometric fragment of predicate logic. This methodology also leads to a new reading of protocol refinement and transformation, and offers the possibility of reasoning about these concepts in semantic terms. • “Effective verification of confidentiality for multi-threaded programs”, by Tri Ngo, Mariëlle Stoelinga and Marieke Huisman, focuses on the verification of confidentiality properties in concurrent systems via model checking. More specifically, it studies observational determinism (a property that ensures secure information flow) in multi-threaded programs, under a given scheduler. The latter guarantees robustness with respect to refinement attacks. Moreover, it proposes a counter-example generation technique which allows to extract an actual attack when the verification of a program fails. • Finally, in “Union, intersection and refinement types and reasoning about type disjointness for secure protocol implementations”, Michael Backes, Cătălin Hriţcu and Matteo Maffei present a new type system for verifying the security of cryptographic protocol implementations, where the main novelty is the capability to check statically the disjointness of types. The increased expressivity enables the analysis of protocol classes that were previously out of reach for the type-based approach, such as signatures of private data and encryptions of authenticated data. The proposed system and parts of the soundness proof are formalized in Coq.