Comparing Rule-Based Policies

• Published in: 2008 IEEE Workshop on Policies for Distributed Systems and Networks : policy 2008, 2-4 June 2008, Palisades, New York, USA : proceedings pp. 11 - 18
• Main Authors: Bonatti, P.A., Mogavero, F.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.06.2008
• Subjects: Algebra; Arithmetic; Authorization; Automata; Conferences; Datalog query containment; Logic functions; Network servers; Policy comparison; Policy compliance; Policy verification; Policy-aware service selection; Privacy; Query processing; Rule-based policies; Security
• ISBN: 0769531334; 9780769531335
• DOI: 10.1109/POLICY.2008.16

Policy comparison is useful for a variety of applications, including policy validation and policy-aware service selection. While policy comparison is somewhat natural for policy languages based on description logics, it becomes rather difficult for rule-based policies. When policies have recursive rules, the problem is in general undecidable. Still most policies require some form of recursion to model - say - subject and object hierarchies, and certificate chains. In this paper, we show how policies with recursion can be compared by adapting query optimization techniques developed for the relational algebra. We prove soundness and completeness of our method, discuss the compatibility of the restrictive assumptions we need w.r.t. our reference application scenarios, and report the results of a preliminary set of experiments to prove the practical applicability of our approach.