A Formal Framework for Adaptive Access Control Models

For several reasons enterprises are frequently subject to organizational change. Respective adaptations may concern business processes, but also other components of an enterprise architecture. In particular, changes of organizational structures often become necessary. The information about organizational entities and their relationships is maintained in organizational models. Therefore the quick and correct adaptation of these models is fundamental to adequately cope with organizational changes. However, model changes alone are not sufficient to guarantee consistency. Since organizational models also provide the basis for defining access rules (e.g., actor assignments in workflow management systems or access rules in document-centered applications) this information has to be adapted accordingly (e.g., to avoid dangling references or non-resolvable actor assignments). Current approaches do not adequately address this problem, which often leads to security gaps and delayed change implementation. In this paper we introduce a formal framework for the controlled evolution of organizational models and related access rules. Firstly, we introduce a set of operators with well-defined semantics for defining and changing organizational models. Secondly, we show how to define access rules based on such models. In this context we also define a notion of correctness for access rules. Thirdly, we present a formal framework for the (semi-automated) adaptation of access rules when the underlying organizational model is changed by exploiting the semantics of the applied changes. Altogether the presented approach provides an important contribution for realizing adaptive access control frameworks.