Anonymity in Structured Peer-to-Peer Networks

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 [SMK01] 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.

[1]  Roger Dingledine,et al.  Reliable MIX Cascade Networks through Reputation , 2002, Financial Cryptography.

[2]  George Danezis.  Mix-Networks with Restricted Routes , 2003, Privacy Enhancing Technologies.

[3]  Micah Adler,et al.  An Analysis of the Degradation of Anonymous Protocols , 2002, NDSS.

[4]  Ian Clarke,et al.  Freenet: A Distributed Anonymous Information Storage and Retrieval System , 2000, Workshop on Design Issues in Anonymity and Unobservability.

[5]  David R. Karger,et al.  Chord: A scalable peer-to-peer lookup service for internet applications , 2001, SIGCOMM '01.

[6]  George Danezis,et al.  Towards an Information Theoretic Metric for Anonymity , 2002, Privacy Enhancing Technologies.

[7]  Bart Preneel,et al.  Towards Measuring Anonymity , 2002, Privacy Enhancing Technologies.

[8]  Bernhard Plattner,et al.  Introducing MorphMix: peer-to-peer based anonymous Internet usage with collusion detection , 2002, WPES '02.

[9]  Robert Tappan Morris,et al.  Tarzan: a peer-to-peer anonymizing network layer , 2002, CCS '02.

[10]  David Chaum,et al.  Untraceable electronic mail, return addresses, and digital pseudonyms , 1981, CACM.

[11]  Krishna P. Gummadi,et al.  The impact of DHT routing geometry on resilience and proximity , 2003, SIGCOMM '03.

[12]  Steven Hazel,et al.  Achord: A Variant of the Chord Lookup Service for Use in Censorship Resistant Peer-to-Peer Publishing Systems , 2002 .

[13]  Gene Tsudik,et al.  Towards an Analysis of Onion Routing Security , 2000, Workshop on Design Issues in Anonymity and Unobservability.

[14]  Robert Morris,et al.  Chord: A scalable peer-to-peer lookup service for internet applications , 2001, SIGCOMM 2001.

[15]  Micah Adler,et al.  Defending anonymous communications against passive logging attacks , 2003, 2003 Symposium on Security and Privacy, 2003..

[16]  Christian Grothoff,et al.  gap - Practical Anonymous Networking , 2003, Privacy Enhancing Technologies.

[17]  Robert Tappan Morris,et al.  Security Considerations for Peer-to-Peer Distributed Hash Tables , 2002, IPTPS.

[18]  Michael K. Reiter,et al.  Crowds: anonymity for Web transactions , 1998, TSEC.