Paper 2018/803

BITE: Bitcoin Lightweight Client Privacy using Trusted Execution

Sinisa Matetic, Karl Wüst, Moritz Schneider, Kari Kostiainen, Ghassan Karame, and Srdjan Capkun

Abstract

Decentralized blockchains offer attractive advantages over traditional payments such as the ability to operate without a trusted authority and increased user privacy. However, the verification of blockchain payments requires the user to download and process the entire chain which can be infeasible for resource-constrained devices, such as mobile phones. To address such concerns, most major blockchain systems support lightweight clients that outsource most of the computational and storage burden to full blockchain nodes. However, such payment verification methods leak considerable information about the underlying clients, thus defeating user privacy that is considered one of the main goals of decentralized cryptocurrencies. In this paper, we propose a new approach to protect the privacy of lightweight clients in blockchain systems like Bitcoin. Our main idea is to leverage commonly available trusted execution capabilities, such as SGX enclaves. We design and implement a system called BITEwhere enclaves on full nodes serve privacy-preserving requests from lightweight clients. As we will show, naive serving of client requests from within SGX enclaves still leaks user information. BITE therefore integrates several privacy preservation measures that address external leakage as well as SGX side-channels. We show that the resulting solution provides strong privacy protection and at the same time improves the performance of current lightweight clients.

Metadata
Available format(s)
PDF
Publication info
Preprint. MINOR revision.
Contact author(s)
sinisa matetic @ inf ethz ch
History
2018-09-06: received
Short URL
https://ia.cr/2018/803
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2018/803,
      author = {Sinisa Matetic and Karl Wüst and Moritz Schneider and Kari Kostiainen and Ghassan Karame and Srdjan Capkun},
      title = {BITE: Bitcoin Lightweight Client Privacy using Trusted Execution},
      howpublished = {Cryptology ePrint Archive, Paper 2018/803},
      year = {2018},
      note = {\url{https://eprint.iacr.org/2018/803}},
      url = {https://eprint.iacr.org/2018/803}
}
Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.