Virtual fingerprinting as a foundation for reputation in open systems

The lack of available identity information in attribute-based trust management systems complicates the design of the audit and incident response systems, anomaly detection algorithms, collusion detection/prevention mechanisms, and reputation systems taken for granted in traditional distributed systems. In this paper, we show that as two entities in an attribute-based trust management system interact, each learns one of a limited number of virtual fingerprints describing their communication partner. We show that these virtual fingerprints can be disclosed to other entities in the open system without divulging any attribute or absolute-identity information, thereby forming an opaque pseudo-identity that can be used as the basis for the above-mentioned types of services. We explore the use of virtual fingerprints as the basis of Xiphos, a system that allows reputation establishment without requiring explicit knowledge of entities' civil identities. We discuss the trade-off between privacy and trust, examine the impacts of several attacks on the Xiphos system, and discuss the performance of Xiphos in a simulated grid computing system.