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

Peter Gaži; Aggelos Kiayias; Alexander Russell

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

Abstract

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.

Metadata

Available format(s): PDF
Category: Applications
Publication info: Published elsewhere. Minor revision. ACM CCS 2023
Keywords: committee selection proof of stake
Contact author(s): peter gazi @ iohk io
aggelos kiayias @ ed ac uk
acr @ uconn edu
History: 2023-11-24: revised; 2023-08-24: received; See all versions
Short URL: https://ia.cr/2023/1273
License: CC BY

BibTeX

@misc{cryptoeprint:2023/1273,
      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},
      url = {https://eprint.iacr.org/2023/1273}
}