2.3.0.1 Discussion

Koch follows exactly the paradigm of authorisation policies of the Imperial College. The restrictions in this area, as described before, are consequently present here. Again, success or failure of a policy enforcement is not specified in the policy. Adding a postcondition as a counterpart to the precondition in the constraint statement would be a solution. Otherwise, the policy is dependent on the results of an action it invokes. This is a restriction when using policies in heterogeneous environments. Applying them in homogeneous ones, as Koch is doing, will not cause these kinds of problems. Negative obligation policies are not used. The policy notation is therefore more consistent as the one described in the previous subsection.