Creative Commons Attribution 4.0 International license
In this work, we reexamine the vulnerability of Payment Channel Networks (PCNs) to bribing attacks, where an adversary incentivizes blockchain miners to deliberately ignore a specific transaction to undermine the punishment mechanism of PCNs. While previous studies have posited a prohibitive cost for such attacks, we show that this cost can be dramatically reduced (to approximately $125), thereby increasing the likelihood of these attacks. To this end, we introduce Bribe & Fork, a modified bribing attack that leverages the threat of a so-called feather fork which we analyze with a novel formal model for the mining game with forking. We empirically analyze historical data of some real-world blockchain implementations to evaluate the scale of this cost reduction. Our findings shed more light on the potential vulnerability of PCNs and highlight the need for robust solutions.
@InProceedings{avarikioti_et_al:LIPIcs.AFT.2024.11,
author = {Avarikioti, Zeta and K\k{e}dzior, Pawe{\l} and Lizurej, Tomasz and Michalak, Tomasz},
title = {{Bribe \& Fork: Cheap PCN Bribing Attacks via Forking Threat}},
booktitle = {6th Conference on Advances in Financial Technologies (AFT 2024)},
pages = {11:1--11:22},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-345-4},
ISSN = {1868-8969},
year = {2024},
volume = {316},
editor = {B\"{o}hme, Rainer and Kiffer, Lucianna},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.AFT.2024.11},
URN = {urn:nbn:de:0030-drops-209473},
doi = {10.4230/LIPIcs.AFT.2024.11},
annote = {Keywords: Blockchain, Payment Channels Networks, Timelock Bribing, Feather Forking}
}