Abstract
Most public blockchain protocols, including the popular Bitcoin and Ethereum blockchains, do not formally specify the order in which miners should select transactions from the pool of pending (or uncommitted) transactions for inclusion in the blockchain. Over the years, informal conventions or "norms"for transaction ordering have, however, emerged via the use of shared software by miners, e.g., the GetBlockTemplate (GBT) mining protocol in Bitcoin Core. Today, a widely held view is that Bitcoin miners prioritize transactions based on their offered "transaction fee-per-byte."Bitcoin users are, consequently, encouraged to increase the fees to accelerate the commitment of their transactions, particularly during periods of congestion. In this paper, we audit the Bitcoin blockchain and present statistically significant evidence of mining pools deviating from the norms to accelerate the commitment of transactions for which they have (i) a selfish or vested interest, or (ii) received dark-fee payments via opaque (non-public) side-channels. As blockchains are increasingly being used as a record-keeping substrate for a variety of decentralized (financial technology) systems, our findings call for an urgent discussion on defining neutrality norms that miners must adhere to when ordering transactions in the chains. Finally, we make our data sets and scripts publicly available.
Original language | English |
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Title of host publication | IMC 2021 |
Subtitle of host publication | Proceedings of the 2021 ACM Internet Measurement Conference |
Publisher | Association for Computing Machinery |
Pages | 320-335 |
Number of pages | 16 |
ISBN (Electronic) | 9781450391290 |
DOIs | |
Publication status | Published - Nov 2021 |
Event | 21st ACM Internet Measurement Conference, IMC 2021 - Virtual, Online, United States Duration: 2 Nov 2021 → 4 Nov 2021 |
Publication series
Name | Proceedings of the ACM SIGCOMM Internet Measurement Conference, IMC |
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Conference
Conference | 21st ACM Internet Measurement Conference, IMC 2021 |
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Country/Territory | United States |
City | Virtual, Online |
Period | 2/11/21 → 4/11/21 |
Bibliographical note
Funding Information:K. P. Gummadi acknowledges support from the European Research Council (ERC) Advanced Grant “Foundations for Fair Social Computing,” funded under the European Union’s Horizon 2020 Frame-work Programme (grant agreement no. 789373). P. Loiseau was supported by MIAI @ Grenoble Alpes (ANR-19-P3IA-0003) and by the French National Research Agency through grant ANR-20-CE23-0007. A. Mislove acknowledges support from NSF grants CNS-1900879 and CNS-1955227.
Publisher Copyright:
© 2021 Owner/Author.
Funding
K. P. Gummadi acknowledges support from the European Research Council (ERC) Advanced Grant “Foundations for Fair Social Computing,” funded under the European Union’s Horizon 2020 Frame-work Programme (grant agreement no. 789373). P. Loiseau was supported by MIAI @ Grenoble Alpes (ANR-19-P3IA-0003) and by the French National Research Agency through grant ANR-20-CE23-0007. A. Mislove acknowledges support from NSF grants CNS-1900879 and CNS-1955227.
Funders | Funder number |
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Horizon 2020 Frame-work Programme | |
MIAI @ Grenoble Alpes | ANR-19-P3IA-0003 |
National Science Foundation | CNS-1955227, CNS-1900879 |
Horizon 2020 Framework Programme | 789373 |
European Research Council | |
Agence Nationale de la Recherche | ANR-20-CE23-0007 |
Keywords
- blockchain
- transaction commit times
- transaction ordering