@inproceedings{8e92102a2ece4b169da59f6543e70e3a,
title = "Practical Settlement Bounds for Proof-of-Work Blockchains",
abstract = "Nakamoto proof-of-work ledger consensus currently underlies the majority of deployed cryptocurrencies and smart-contract blockchains. While a long and fruitful line of work has succeeded to identify its exact security region-that is, the set of parametrizations under which it possesses asymptotic security-the existing theory does not provide concrete settlement time guarantees that are tight enough to inform practice. In this work we provide a new approach for obtaining concrete and practical settlement time guarantees suitable for reasoning about deployed systems. We give an efficient method for computing explicit upper bounds on settlement time as a function of primary system parameters: honest and adversarial computational power and a bound on network delays. We implement this computational method and provide a comprehensive sample of concrete bounds for several settings of interest. We also analyze a well-known attack strategy to provide lower bounds on the settlement times. For Bitcoin, for example, our upper and lower bounds are within 90 seconds of each other for 1-hour settlement assuming 10 second network delays and a 10% adversary. In comparison, the best prior result has a gap of 2 hours in the upper and lower bounds with the same parameters.",
keywords = "bitcoin, blockchains, proof of work",
author = "Peter Gazi and Ling Ren and Alexander Russell",
note = "Publisher Copyright: {\textcopyright} 2022 Owner/Author.; 28th ACM SIGSAC Conference on Computer and Communications Security, CCS 2022 ; Conference date: 07-11-2022 Through 11-11-2022",
year = "2022",
month = nov,
day = "7",
doi = "10.1145/3548606.3559368",
language = "English (US)",
series = "Proceedings of the ACM Conference on Computer and Communications Security",
publisher = "Association for Computing Machinery",
pages = "1217--1230",
booktitle = "CCS 2022 - Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security",
address = "United States",
}