Referral networks are a kind of P2P system consisting of autonomous agents who seek, provide services, or refer other service providers. Key applications include service discovery and selection, and knowledge sharing. This use of referrals is inspired by human interactions, where referrals are a key basis for judging the trustworthiness of a given service.

The use of referrals enable an agent to control how its request is processed, it also provides an architectural basis for four kinds of interaction policies. InterPol is a language and framework supporting such policies. InterPol has been implemented using a Datalog-based policy engine for each agent. It has been applied on scenarios from a (multinational) health care project. The contribution of this paper is in a general referrals-based framework for privacy and trust management, which is shown to effectively capture a variety of privacy and trust requirements of autonomous users.