Towards an algebraic approach to solve policy conflicts

Policy-based security is one of the most innovative area in the security arena. A policy represents the high level targets and is applied by using sets of rules. A rule consists in a set of conditions expressing the domain of application and a set of actions that must be performed when conditions are met. One of the major problems is the conflict management, that is the decision of the action to be executed when more than one rule applies. In this paper we present a formal definition of policy, policy rules (in if-conditions-then-actions format) and policy conflicts and we use semi-lattices to solve inconsistencies. These algebraic structures are helpful to convey information about the actions to enforce when conflicts occur as well as the importance or the severity of the actions. We also extend the semi-lattice based approach to AND-ed and OR-ed sets of actions.