Updating policy base: an application of knowledge base in authorizations

Knowledge bases have long been applied to the areas such as quality control, financial analysis, manufacturing, medicine etc. But their application in authorization is quite new and challenging. We propose a logic based approach using a knowledge base to specify authorization policies and to update them. Our approach has more powerful expressiveness than the traditional matrix representation for authorization policies, and is able to represent both implicit and incomplete authorization requirements and to reason about nonmonotonic properties