International Association for Cryptologic Research

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Asymptotically Optimal Adaptive Asynchronous Common Coin and DKG with Silent Setup

Authors:
Hanwen Feng , University of Sydney
Qiang Tang , University of Sydney
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Conference: CRYPTO 2025
Abstract: We present the first optimal-resilient, adaptively secure asynchronous common coin protocol with $O(\secpar n^2)$ communication complexity and $O(1)$ rounds, requiring only a public silent setup. Our protocol immediately implies a sequence of quadratic-communication, constant-round asynchronous Byzantine agreement protocols, and also asynchronous distributed key generation with a silent setup. Along the way, we formulate a new primitive called {\em asynchronous subset alignment}, and introduce a simple framework to reason about specific composition security suitable for asynchronous common coin, enhancing security and functionality of silent-setup threshold encryption, which may be of independent interests.
BibTeX
@inproceedings{crypto-2025-35645,
  title={Asymptotically Optimal Adaptive Asynchronous Common Coin and DKG with Silent Setup},
  publisher={Springer-Verlag},
  author={Hanwen Feng and Qiang Tang},
  year=2025
}