Access Control in Virtual Communities Prohibition, Permission, Authorization and Delegation of Power in the Grid

We are interested in the design of access control policies for virtual communities of agents based on the grid infrastructure. In a virtual community agents can play both the role of resource consumers and the role of resource providers, and they remain in control of their resources. We argue that this requirement imposes a distinction between the authorization to access a resource given by the virtual community and the permission to do so issued by the resource providers. Our model is based on a logical multiagent framework that distinguishes the three roles of resource consumption, provision, and of authorization.