### Analysis and Probing of Parallel Channels in the Lightning Network

##### Abstract

Bitcoin can process only a few transactions per second, which is insufficient for a global payment network. The Lightning Network (LN) aims to address this challenge. The LN allows for low-latency bitcoin transfers through a network of payment channels. In contrast to regular Bitcoin transactions, payments in the LN are not globally broadcast. Thus it may improve not only Bitcoin’s scalability but also privacy. However, the probing attack allows an adversary to discover channel balances, threatening users’ privacy. Prior work on probing did not account for the possibility of multiple (parallel) channels between two nodes. Naive probing algorithms yield false results for parallel channels. In this work, we develop a new probing model that accurately accounts for parallel channels. We describe jamming-enhanced probing that allows for full balance information extraction in multi-channel hops, which was impossible with earlier probing methods. We quantify the attacker’s information gain and propose an optimized algorithm for choosing probe amounts for multi-channel hops. We demonstrate its efficiency based on real-world data using our own probing-focused LN simulator. Finally, we discuss countermeasures such as new forwarding strategies, intra-hop payment split, rebalancing, and unannounced channels.

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Publication info
Published elsewhere. Financial Cryptography 2022
Keywords
privacy Bitcoin Lightning Network payment channels payment channel network
Contact author(s)
sergey s tikhomirov @ gmail com
History
2022-07-08: last of 5 revisions
See all versions
Short URL
https://ia.cr/2021/384

CC BY

BibTeX

@misc{cryptoeprint:2021/384,
author = {Alex Biryukov and Gleb Naumenko and Sergei Tikhomirov},
title = {Analysis and Probing of Parallel Channels in the Lightning Network},
howpublished = {Cryptology ePrint Archive, Paper 2021/384},
year = {2021},
note = {\url{https://eprint.iacr.org/2021/384}},
url = {https://eprint.iacr.org/2021/384}
}

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