| Security and privacy issues have long been investigated in the context of a single organization exercising control over its users' access to resources. In such a computing environment, security policies are defined and managed statically within the boundary of an organization and are typically centrally controlled. However, developing large-scale Internet-based application systems presents new challenges. This is because we do not deal with just user authentication and access control of the resources of a single organization. Rather, we deal with a network of interconnected systems and the sharing of all types of resources that belong to these organizations. There is a need for a model, a language, and a framework for modeling, specifying, and enforcing the agreement established by collaborating organizations with respect to trust and security issues. This trust agreement is needed to establish inter-organizational security policies that govern the interaction, coordination, collaboration, and resource sharing of the collaborative community.; Our study conducted basic research on and developed application-level, trust-based security technologies to support Internet-based collaborative systems. It has four specific accomplishments. First, we introduced a way to define trust agreements and develop a language for specifying the agreements. A trust agreement establishes inter-organizational security policies and constraints regarding message exchanges and resource sharing, and enables collaboration among organizations, which are originally disjointed and have their own security policies and constraints. Second, we developed a security model to capture relationships among the concepts and modeling constructs of trust and the concepts and modeling constructs of a conventional access control model. By treating trust-related concepts and constructs as "first-class" security concepts and constructs, the model allows the specification of trust policies at the inter-organizational level, which is not supported in traditional security models. Third, we established a set of criteria for evaluating nonrepudiation protocols for 13213 electronic-commerce; and developed a new protocol that meets the criteria. Fourth, we designed and implemented a prototype of a network-based trust and security management system to demonstrate the enforcement of inter-organizational security policies and constraints. |
