A Unified Conflict Resolution Algorithm

While some authorization models support either positive or negative authorizations, hybrid frameworks take advantage of both authorizations. Resolving authorization conflicts is quite a challenge due to the existence of sophisticated inheritance hierarchies and the diversity of ways to combine resolution policies. Some researchers have addressed conflict resolution for tree-structured hierarchies, and others have applied a simple conflict resolution policy. The challenge is to combine several policies and to support sophisticated structures in one single framework. This paper proposes a unified framework together with a single parametric algorithm that supports all the legitimate combinations simultaneously, based on four conflict resolution policies. We validate our approach by testing the algorithm against both real data and synthetic examples to provide extensive experimental results.