Privacy Comparison for Bitcoin Light Client Implementations

Arad Kotzer; Ori Rottenstreich

Paper 2024/1415

Privacy Comparison for Bitcoin Light Client Implementations

Arad Kotzer

, Technion - Israel Institute of Technology

Ori Rottenstreich

, Technion - Israel Institute of Technology

Abstract

Light clients implement a simple solution for Bitcoin's scalability problem, as they do not store the entire blockchain but only the state of particular addresses of interest. To be able to keep track of the updated state of their addresses, light clients rely on full nodes to provide them with the required information. To do so, they must reveal information about the addresses they are interested in. This paper studies the two most common light client implementations, SPV and Neutrino with regards to their privacy. We define privacy metrics for comparing the privacy of the different implementations. We evaluate and compare the privacy of the implementations over time on real Bitcoin data and discuss the inherent privacy-communication tradeoff. In addition, we propose general techniques to enhance light client privacy in the existing implementations. Finally, we propose a new SPV-based light client model, the aggregation model, evaluate it, and show it can achieve enhanced privacy than in the existing light client implementations.

Metadata

Available format(s): PDF
Category: Applications
Publication info: Published elsewhere. Advances in Financial Technologies
Keywords: Blockchain Bitcoin Privacy Light Clients Bloom filter
Contact author(s): aradk @ campus technion ac il
or @ technion ac il
History: 2024-09-11: approved; 2024-09-10: received; See all versions
Short URL: https://ia.cr/2024/1415
License: CC BY

BibTeX

@misc{cryptoeprint:2024/1415,
      author = {Arad Kotzer and Ori Rottenstreich},
      title = {Privacy Comparison for Bitcoin Light Client Implementations},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1415},
      year = {2024},
      url = {https://eprint.iacr.org/2024/1415}
}