Description
Existing peer-to-peer systems that aim to provide anonymity to its users are based on networks with unstructured or loosely-structured routing algorithms. Structured routing offers performance and robustness guarantees that these systems are unable to achieve. We therefore investigate adding anonymity support to structured peer-to-peer networks. We apply an entropy-based anonymity metric to Chord and use this metric to quantify the improvements in anonymity afforded by several possible extensions. We identify particular properties of Chord that have the strongest effect on anonymity and propose a routing extension that allows a general trade-off between anonymity and performance. Our results should be applicable to other structured peer-to-peer systems.