Paper 2023/1273

Fait Accompli Committee Selection: Improving the Size-Security Tradeoff of Stake-Based Committees

Peter Gaži, IOG
Aggelos Kiayias, University of Edinburgh, IOG
Alexander Russell, University of Connecticut, IOG

We study the problem of committee selection in the context of proof-of-stake consensus mechanisms or distributed ledgers. These settings determine a family of participating parties---each of which has been assigned a non-negative "stake"---and are subject to an adversary that may corrupt a subset of the parties. The challenge is to select a committee of participants that accurately reflects the proportion of corrupt and honest parties, as measured by stake, in the full population. The trade-off between committee size and the probability of selecting a committee that over-represents the corrupt parties is a fundamental factor in both security and efficiency of proof-of-stake consensus, as well as committee-run layer-two protocols. We propose and analyze several new committee selection schemes that improve upon existing techniques by adopting low-variance assignment of certain committee members that hold significant stake. These schemes provide notable improvements to the size--security trade-off arising from the stake distributions of many deployed ledgers.

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Publication info
Published elsewhere. Minor revision. ACM CCS 2023
committee selectionproof of stake
Contact author(s)
peter gazi @ iohk io
aggelos kiayias @ ed ac uk
acr @ uconn edu
2023-11-24: revised
2023-08-24: received
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      author = {Peter Gaži and Aggelos Kiayias and Alexander Russell},
      title = {Fait Accompli Committee Selection: Improving the Size-Security Tradeoff of Stake-Based Committees},
      howpublished = {Cryptology ePrint Archive, Paper 2023/1273},
      year = {2023},
      note = {\url{}},
      url = {}
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