The Policy Machine for Security Policy Management

Many different access control policies and models have been developed to suit a variety of goals; these include Role-Based Access Control, One-directional Information Flow, Chinese Wall, Clark-Wilson, N-person Control, and DAC, in addition to more informal ad hoc policies. While each of these policies has a particular area of strength, the notational differences between these policies are substantial. As a result it is difficult to combine them, both in making formal statements about systems which are based on differing models and in using more than one access control policy model within a given system. Thus, there is a need for a unifying formalism which is general enough to encompass a range of these policies and models. In this paper, we propose an open security architecture called the Policy Machine (PM) that would meet this need. We also provide examples showing how the PM specifies and enforces access control polices.