Paper 2026/931
Fair Multiparty Coin Tossing from Minimal Assumptions
, New York University, Columbia University, New York University, New York UniversityAbstract
Coin flipping in the presence of a dishonest majority is a fundamental cryptographic primitive whose requirements lack a clean characterization. Recent work (Bonneau et al., Eurocrypt 2025) showed a lower bound that fair dishonest-majority coin-flipping implies delay functions. However, until now known upper bounds exhibited a significant gap: All existing protocols rely on assumptions that we do not know how to instantiate in the plain model. In this work, we close this gap. Specifically, we show that fair $n$-party coin flipping in the presence of up to $n-1$ malicious corruptions follows from the minimal assumption of delay functions. This completes the equivalence between delay functions and fair dishonest-majority coin-flipping protocols.
Metadata
- Available format(s)
-
PDF
- Category
- Foundations
- Publication info
- A minor revision of an IACR publication in EUROCRYPT 2026
- Keywords
- Delay functionscoin flippingrandomness beacons
- Contact author(s)
-
marshall ball @ cs nyu edu
mchrist @ cs columbia edu
dodis @ cs nyu edu
rg5134 @ nyu edu - History
- 2026-08-03: revised
- 2026-05-11: received
- See all versions
- Short URL
- https://ia.cr/2026/931
- License
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CC BY
BibTeX
@misc{cryptoeprint:2026/931,
author = {Marshall Ball and Miranda Christ and Yevgeniy Dodis and Rachit Garg},
title = {Fair Multiparty Coin Tossing from Minimal Assumptions},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/931},
year = {2026},
url = {https://eprint.iacr.org/2026/931}
}
