Fair Multiparty Coin Tossing from Minimal Assumptions

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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