High Level Conflict Management Strategies in Advanced Access Control Models

Specifying a security policy that includes both permissions and prohibitions, may lead to conflicts. This corresponds to a situation where a subject is both permitted and prohibited to perform a given action on a given object. We adopt a comparative approach to investigate this problem. We first investigate access control models based on rules, called Rule-BAC, and present weaknesses that arise when we try to manage conflicts in this model. In particular, Rule-BAC models fail to provide decidable solution to redundant rules and potential conflicts problems. Then, we show how a more structured model, say OR-BAC (Organization Based Access Control), gifted with inheritance mechanism make redundant rules and potential conflict problems tractable in polynomial time.