Our approach to trust negotiation relies on access control policies that govern access to protected resources by specifying credential combinations that must be submitted to obtain authorization. In this project, we develop a model for trust negotiation, focusing on the central role of policies. We delineate requirements for policy languages and runtime systems for trust negotiation, and evaluate four existing policy languages for trust management with respect to those requirements. We make recommendations for extending existing policy languages or developing new policy languages to make them suitable for use in future trust negotiation systems.
K. E. Seamons, M. Winslett, T. Yu, B. Smith, E. Child, J. Jacobson, H. Mills, and L. Yu. Requirements for Policy Languages for Trust Negotiation. 3rd International Workshop on Policies for Distributed Systems and Networks (POLICY 2002), Monterey, CA, June 2002.