Resolving Policy Conflicts - Integrating Policies from Multiple Authors

In this paper we show that the static conflict resolution strategy of XACML is not always sufficient to satisfy the policy needs of an organisation where multiple parties provide their own individual policies. Different conflict resolution strategies are often required for different situations. Thus combining one or more sets of policies into a single XACML ‘super policy’ that is evaluated by a single policy decision point (PDP), cannot always provide the correct authorisation decision, due to the static conflict resolution algorithms that have to be built in. We therefore propose a dynamic conflict resolution strategy that chooses different conflict resolution algorithms based on the authorisation request context. The proposed system receives individual and independent policies, as well as conflict resolution rules, from different policy authors, but instead of combining these into one super policy with static conflict resolution rules, each policy is evaluated separately and the conflicts among their authorisation decisions is dynamically resolved using the conflict resolution algorithm that best matches the authorisation decision request. It further combines the obligations of independent policies returning similar decisions which XACML can’t do while keeping each author’s policy intact.