We introduce a framework of access/action control which shifts the emphasis from the participants to their relationship. The framework is based on a communication model in which participants negotiate the mutually agreed-upon boundary conditions of their relationship, and create social reference points by encapsulating them in compact "communication pacts," called "commpacts." Commpacts are designed to provide a language enabling a social mechanism of coordinated expectation. We argue that in

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... tworked environments characterized by multiple authorities and "trusted proxies," this model can deal with the complexities of general (user-and content-dependent) distributed access/action control and provides a clear userconceptual metaphor. The framework embeds naturally into the existing legal and institutional infrastructure; it generalizes work in electronic contracting. Commpacts can be seen as a third fundamental type next to access-control lists (ACLs) and capabilities. We first look briefly at the structural characteristics of the kinds of networked environments we are interested in. In particular, we identify the assumption of having certain organizations ("home providers") serve as "trusted proxies." We then place access control in context of an abstract system architecture, and review some basic properties of generic models. In particular, we identify high negotiation complexity as a constraint on usability and feasibility of general (user-and content-dependent) distributed access control, and we look in detail at one such example. Client Server Trusted Proxy