  In distributed environments, access control decisions depend on statements of
multiple agents rather than only one central trusted party. However, existing
policy languages put few emphasis on authorization provenances. The capability
of managing these provenances is important and useful in various security areas
such as computer auditing and authorization recycling. Based on our previously
proposed logic, we present several case studies of this logic. By doing this,
we show its expressiveness and usefulness in security arena.
