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ROAST: Robust Asynchronous Schnorr Threshold Signatures

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conference contribution
posted on 2023-11-29, 18:23 authored by Tim Ruffing, Viktoria Ronge, Elliott Jin, Jonas Schneider-Bensch, Dominique Schröder
Bitcoin and other cryptocurrencies have recently introduced support for Schnorr signatures whose cleaner algebraic structure, as compared to ECDSA, allows for simpler and more practical constructions of highly demanded "-of-" threshold signatures. However, existing Schnorr threshold signature schemes still fall short of the needs of real-world applications due to their assumption that the network is synchronous and due to their lack of robustness, i.e., the guarantee that honest signers are able to obtain a valid signature even in the presence of other malicious signers who try to disrupt the protocol. This hinders the adoption of threshold signatures in the cryptocurrency ecosystem, e.g., in second-layer protocols built on top of cryptocurrencies. In this work, we propose ROAST, a simple wrapper that turns a given threshold signature scheme into a scheme with a robust and asynchronous signing protocol, as long as the underlying signing protocol is semi-interactive (i.e., has one preprocessing round and one actual signing round), provides identifiable aborts, and is unforgeable under concurrent signing sessions. When applied to the state-of-the-art Schnorr threshold signature scheme FROST, which fulfills these requirements, we obtain a simple, efficient, and highly practical Schnorr threshold signature scheme.


Preferred Citation

Tim Ruffing, Viktoria Ronge, Elliott Jin, Jonas Schneider-Bensch and Dominique Schröder. ROAST: Robust Asynchronous Schnorr Threshold Signatures. In: ACM Conference on Computer and Communications Security (CCS). 2022.

Primary Research Area

  • Algorithmic Foundations and Cryptography

Name of Conference

ACM Conference on Computer and Communications Security (CCS)

Legacy Posted Date


Open Access Type

  • Unknown


@inproceedings{cispa_all_3838, title = "ROAST: Robust Asynchronous Schnorr Threshold Signatures", author = "Ruffing, Tim and Ronge, Viktoria and Jin, Elliott and Schneider-Bensch, Jonas and Schröder, Dominique", booktitle="{ACM Conference on Computer and Communications Security (CCS)}", year="2022", }

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