As part of the Stanford Digital Libraries Project, we have prototyped a novel architecture for security and access control in heterogeneous, networked environments. Conceptually, this architecture recasts security issues from an “information access” metaphor into a “relationship management” framewo rk and uniformly applies a contracting model. Architecturally, it introduces a “network-centric” design that generalizes previous models of client- or server-centered control into a third, relationship-based form.

We introduce a framework for access/action control which shifts the emphasis from the participants to their relationships. The framework is based on a communication model in which participants negotiate the mutually agreed-upon boundary conditions of their relationships, 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 networked 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 user-conceptual 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.

People keep pieces of information in diverse collections such as folders, hotlists, e-mail inboxes, newsgroups, and mailing lists. These collections mediate various types of collaborations including communicating, structuring, sharing information, and organizing people. Grassroots is a system that provides a uniform framework to support people's collaborative activities mediated by collections of information. The system seamlessly integrates functionalities currently found in such disparate systems as e-mail, newsgroups, shared hotlists, hierarchical indexes, hypermail, etc. Grassroots co-exists with these systems in that its users benefit from the uniform image provided by Grassroots, but other people can continue using other mechanisms, and Grassroots leverages from them. The current Grassroots prototype is based on an http-proxy implementation, and can be used with any Web browser. In the context of the design of a next-generation version of the Web, Grassroots demonstrates the utility of a uniform notification infrastructure.

This paper describes a system we have implemented that enables people to share structured in-place annotations attached to material in arbitrary documents on the WWW. The basic conceptual decisions are laid out, and a prototypical example of the client-server interaction is given. We then explain the usage perspective, describe our experience with using the system, and discuss other experimental usages of our prototype implementation, such as collaborative filtering, seals of approval, and value-added trails. We show how this is a specific instantiation of a more general “virtual document” architecture in which, with the help of light-weight distributed meta information, viewed documents can incorporate material that is dynamically integrated from multiple distributed sources. Development of that architecture is part of a larger project on Digital Libraries that we are engaged in.