Rating Agencies Interoperation for Peer-to-Peer Online Transactions

In current peer-to-peer systems users interact with unknown services and users for the purpose of online transactions such as file sharing and trading of commodities. Peer-to-Peer reputation systems allow users to assess the trustworthiness of unknown entities based on subjective feedback from the other peers. However, this cannot constitute sufficient proof for many transactions like service composition, negotiations and coalition formation in which users require more solid proof of the quality of unknown services. Ratings certified by trusted third parties in the form of a security token are objective and reliable and, hence, allow building trust between peers. Because of the decentralized and distributed nature of peer-to-peer networks, a central authority (or hierarchy of them) issuing such certificates would not scale up. We propose a framework for peer-to-peer agencies interoperation based on rating certificates and metacertificates describing bilateral agencies relations.