A unified scheme for resource protection in automated trust negotiation

TLDR

Automated trust negotiation establishes trust between strangers by iteratively exchanging digital credentials, but access control policies—often unknown at negotiation onset—must be disclosed, risking leakage of sensitive business or privacy information. This work introduces UniPro, a unified scheme that models and protects resources—especially access control policies—within trust negotiation. UniPro treats policies as first‑class resources, protecting them with the same mechanisms as other resources, offers fine‑grained disclosure control, and separates policy disclosure from satisfaction to enable more flexible authorization. We demonstrate that UniPro works with practical negotiation strategies without compromising strategy autonomy and provide criteria guaranteeing successful trust establishment.

Abstract

Automated trust negotiation is an approach to establishing trust between strangers through iterative disclosure of digital credentials. In automated trust negotiation, access control policies play a key role in protecting resources from unauthorized access. Unlike in traditional trust management systems, the access control policy for a resource is usually unknown to the party requesting access to the resource, when trust negotiation starts. The negotiating parties can rely on policy disclosures to learn each other's access control requirements. However a policy itself may also contain sensitive information. Disclosing policies' contents unconditionally may leak valuable business information or jeopardize individuals' privacy. In this paper we propose UniPro, a unified scheme to model protection of resources, including policies, in trust negotiation. UniPro improves on previous work by modeling policies as first-class resources, protecting them in the same way as other resources, providing fine-grained control over policy disclosure, and clearly distinguishing between policy disclosure and policy satisfaction, which gives users more flexibility in expressing their authorization requirements. We also show that UniPro can be used with practical negotiation strategies without jeopardizing autonomy in the choice of strategy, and present criteria under which negotiations using UniPro are guaranteed to succeed in establishing trust.