D-algebra for composing access control policy decisions

This paper proposes a D-algebra to compose decisions from multiple access control policies. Compared to other algebra-based approaches aimed at policy composition, D-algebra is the only one that satisfies both functional completeness (any possible decision matrix can be expressed by a D-algebra formula) and computational effectiveness (a formula can be computed efficiently given any decision matrix). The D-algebra has several relevant applications in the context of access control policies, namely the analysis of policy languages decision mechanisms, and the development of tools for policy authoring and enforcement. Copyright 2009 ACM.