A Logic for State-Modifying Authorization Policies

We present a logic for specifying policies where access requests can have effects on the authorization state. The logic is semantically defined by a mapping to Transaction Logic. Using this approach, updates to the state are factored out of the resource guard, thus enhancing maintainability and facilitating more expressive policies that take the history of access requests into account. We also present a sound and complete proof system for reasoning about sequences of access requests. This gives rise to a goal-oriented algorithm for finding minimal sequences that lead to a specified target authorization state.