Flow-based reputation: more than just ranking

TL;DR

This paper introduces a flow-based reputation metric that provides absolute trust values using all available information, improving accuracy over traditional ranking-only models in open, distributed systems.

Contribution

The paper presents a novel flow-based reputation metric that yields absolute reputation scores and analyzes its properties and robustness against attacks.

Findings

The new metric produces more accurate reputation values.

It effectively utilizes all available information.

The metric demonstrates resilience to malicious attacks.

Abstract

The last years have seen a growing interest in collaborative systems like electronic marketplaces and P2P file sharing systems where people are intended to interact with other people. Those systems, however, are subject to security and operational risks because of their open and distributed nature. Reputation systems provide a mechanism to reduce such risks by building trust relationships among entities and identifying malicious entities. A popular reputation model is the so called flow-based model. Most existing reputation systems based on such a model provide only a ranking, without absolute reputation values; this makes it difficult to determine whether entities are actually trustworthy or untrustworthy. In addition, those systems ignore a significant part of the available information; as a consequence, reputation values may not be accurate. In this paper, we present a flow-based reputation metric that gives absolute values instead of merely a ranking. Our metric makes use of all the available information. We study, both analytically and numerically, the properties of the proposed metric and the effect of attacks on reputation values.