Pasarella Sánchez, Ana EdelmiraLobo, Jorge2019-05-132019-05-132015Pasarella E, Lobo J. Reasoning about policy behavior in logic-based trust management systems: some complexity results and an operational framework. In: IEEE 28th Computer Security Foundations Symposium; 2015 Jul 13-17: Verona, Italy. New Jersey: Institute of Electrical and Electronics Engineers, 2015. p. 232-42. DOI: 10.1109/CSF.2015.232377-5459http://hdl.handle.net/10230/37213Comunicació presentada a: IEEE 28th Computer Security Foundations Symposium celebrat del 13 al 17 de juliol de 2015 a Verona, Itàlia.In this paper we show that the logical framework proposed by Becker et al. [1] to reason about security policy behavior in a trust management context can be captured by an operational framework that is based on the language proposed by Miller in 1989 to deal with scoping and/or modules in logic programming. The framework of Becker et al. uses propositional Horn clauses to represent both policies and credentials, implications in clauses are interpreted in counterfactual logic, a Hilbert-style proof system is defined and a system based on SAT is used to prove whether properties about credentials, permissions and policies are valid, i.e. true under all possible policies. Our contributions in this paper are three. First, we show that this kind of validation can rely on an operational semantics (derivability relation) of a language very similar to Miller's language, which is very close to derivability in logic programs. Second, we are able to establish that, as in propositional logic, validity of formulas is a co-NP-complete problem. And third, we present a provably correct implementation of a goal-oriented algorithm for validity.application/pdfeng© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The final published article can be found at http://dx.doi.org/10.1109/CSF.2015.23info:eu-repo/semantics/conferenceObjecthttp://dx.doi.org/10.1109/CSF.2015.23Trust Management SystemsSemanticsAnswer Set ProgrammingLogic Programsinfo:eu-repo/semantics/openAccess