Specifying distributed authorization with delegation using logic programming

Trust management is a promising approach for the authorization in distributed environment. There are two key issues for a trust management system: how to design high-level policy language and how to solve the compliance-checking problem [3, 4]. We adopt this approach to deal with distributed authorization with delegation. In this paper, we propose an authorization language AL, a human-understandable high level language to specify various authorization policies. Language AL has rich expressive power which can not only specify delegation, and threshold structures addressed in previous approaches, but also represent structured resources and privileges, positive and negative authorizations, separation of duty, incomplete information reasoning and partial authorization and delegation. We define the semantics of AL through logic programming with answer set semantics and through an authorization scenario we demonstrate the application of language AL.