Anonymity Properties of the Bitcoin P2P Network

Bitcoin is a popular alternative to fiat money, widely used for its perceived anonymity properties. However, recent attacks on Bitcoin's peer-to-peer (P2P) network demonstrated that its gossip-based flooding protocols, which are used to ensure global network consistency, may enable user deanonymization---the linkage of a user's IP address with her pseudonym in the Bitcoin network. In 2015, the Bitcoin community responded to these attacks by changing the network's flooding mechanism to a different protocol, known as diffusion. However, no systematic justification was provided for the change, and it is unclear if diffusion actually improves the system's anonymity. In this paper, we model the Bitcoin networking stack and analyze its anonymity properties, both pre- and post-2015. In doing so, we consider new adversarial models and spreading mechanisms that have not been previously studied in the source-finding literature. We theoretically prove that Bitcoin's networking protocols (both pre- and post-2015) offer poor anonymity properties on networks with a regular-tree topology. We validate this claim in simulation on a 2015 snapshot of the real Bitcoin P2P network topology.

[1]  Andrew Miller,et al.  Discovering Bitcoin ’ s Public Topology and Influential Nodes , 2015 .

[2]  Martin Vetterli,et al.  Locating the Source of Diffusion in Large-Scale Networks , 2012, Physical review letters.

[3]  Shie Mannor,et al.  Network forensics: random infection vs spreading epidemic , 2012, SIGMETRICS '12.

[4]  Stefan Katzenbeisser,et al.  Structure and Anonymity of the Bitcoin Transaction Graph , 2013, Future Internet.

[5]  Svante Janson,et al.  Functional limit theorems for multitype branching processes and generalized Pólya urns , 2004 .

[6]  Alex Biryukov,et al.  Deanonymisation of Clients in Bitcoin P2P Network , 2014, CCS.

[7]  Devavrat Shah,et al.  Rumors in a Network: Who's the Culprit? , 2009, IEEE Transactions on Information Theory.

[8]  Devavrat Shah,et al.  Rumor centrality: a universal source detector , 2012, SIGMETRICS '12.

[9]  Mikko Alava,et al.  Branching Processes , 2009, Encyclopedia of Complexity and Systems Science.

[10]  Devavrat Shah,et al.  Finding Rumor Sources on Random Trees , 2011, Oper. Res..

[11]  Fergal Reid,et al.  An Analysis of Anonymity in the Bitcoin System , 2011, PASSAT 2011.

[12]  Krishna P. Gummadi,et al.  Proceedings of the 2013 conference on Internet measurement conference , 2013, IMC 2013.

[13]  Lei Ying,et al.  Information source detection in the SIR model: A sample path based approach , 2012, 2013 Information Theory and Applications Workshop (ITA).

[14]  Patrick D. McDaniel,et al.  An Analysis of Anonymity in Bitcoin Using P2P Network Traffic , 2014, Financial Cryptography.

[15]  G. Pólya,et al.  Über die Statistik verketteter Vorgänge , 1923 .

[16]  Hosam M. Mahmoud,et al.  Polya Urn Models , 2008 .

[17]  S A R A H M E I K L E J O H N,et al.  A Fistful of Bitcoins Characterizing Payments Among Men with No Names , 2013 .

[18]  Alex Biryukov,et al.  Bitcoin over Tor isn't a Good Idea , 2014, 2015 IEEE Symposium on Security and Privacy.

[19]  J. Mačys.  On the Euler-Mascheroni constant , 2013 .

[20]  Lenka Zdeborová,et al.  Inferring the origin of an epidemy with dynamic message-passing algorithm , 2013, Physical review. E, Statistical, nonlinear, and soft matter physics.

[21]  Vincenzo Fioriti,et al.  Predicting the sources of an outbreak with a spectral technique , 2012, ArXiv.

[22]  Devavrat Shah,et al.  Detecting sources of computer viruses in networks: theory and experiment , 2010, SIGMETRICS '10.

[23]  Ghassan O. Karame,et al.  Evaluating User Privacy in Bitcoin , 2013, Financial Cryptography.

[24]  Christos Faloutsos,et al.  Spotting Culprits in Epidemics: How Many and Which Ones? , 2012, 2012 IEEE 12th International Conference on Data Mining.

[25]  Ethan Heilman,et al.  TumbleBit: An Untrusted Tumbler for Bitcoin-Compatible Anonymous Payments , 2016, IACR Cryptol. ePrint Arch..

[26]  Adi Shamir,et al.  Quantitative Analysis of the Full Bitcoin Transaction Graph , 2013, Financial Cryptography.

[27]  S. Orszag,et al.  Advanced Mathematical Methods For Scientists And Engineers , 1979 .

[28]  Eli Ben-Sasson,et al.  Zerocash: Decentralized Anonymous Payments from Bitcoin , 2014, 2014 IEEE Symposium on Security and Privacy.

[29]  Yasuhiro Takeuchi,et al.  Global stability of an SIR epidemic model with time delays , 1995, Journal of mathematical biology.

[30]  D. Shah,et al.  Finding Rumor Sources on Random Graphs , 2012 .

[31]  Chee Wei Tan,et al.  Rumor source detection with multiple observations: fundamental limits and algorithms , 2014, SIGMETRICS '14.

[32]  Po-Ling Loh,et al.  Confidence Sets for the Source of a Diffusion in Regular Trees , 2015, IEEE Transactions on Network Science and Engineering.