International Association for Cryptologic Research

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Stateless Deterministic Multi-Party EdDSA Signatures with Low Communication

Authors:
Qi Feng , Wuhan University
Kang Yang , State Key Laboratory of Cryptology
Kaiyi Zhang , Shanghai Jiao Tong University
Xiao Wang , Northwestern University
Yu Yu , Shanghai Jiao Tong University, Shanghai Qi Zhi Institute
Xiang Xie , Primus, Shanghai Qi Zhi Institute
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Conference: PKC 2025
Abstract: EdDSA is a standardized signing algorithm, by both the IRTF and NIST, that is widely used in blockchain, e.g., Hyperledger, Cardano, Zcash, etc. It is a variant of the well-known Schnorr signature scheme that leverages Edwards curves. It features stateless and deterministic nonce generation, meaning it does not rely on a reliable source of randomness or state continuity. Recently, NIST issued a call for multi-party threshold EdDSA signatures, with one approach verifying nonce generation through zero-knowledge (ZK) proofs. In this paper, we propose a new stateless and deterministic multi-party EdDSA protocol in the full-threshold setting, capable of tolerating all-but-one malicious corruption. Compared to the state-of-the-art multi-party EdDSA protocol by Garillot et al. (Crypto’21), our protocol reduces communication cost by a factor of 56x while maintaining the same three-round structure, albeit with a roughly 2.25x increase in computational cost. We utilize information-theoretic message authentication codes (IT-MACs) in a multi-verifier setting to authenticate values and transform them from the Boolean domain to the arithmetic domain by refining multi-verifier extended doubly-authenticated bits (mv-edabits). Additionally, we employ pseudorandom correlation functions (PCF) to generate IT-MACs in a stateless and deterministic manner. Combining these elements, we design a multi-verifier zero-knowledge (MVZK) protocol for stateless and deterministic nonce generation. Our protocol can be used to build secure blockchain wallets and custody solutions, enhancing key protection.
BibTeX
@inproceedings{pkc-2025-35043,
  title={Stateless Deterministic Multi-Party EdDSA Signatures with Low Communication},
  publisher={Springer-Verlag},
  author={Qi Feng and Kang Yang and Kaiyi Zhang and Xiao Wang and Yu Yu and Xiang Xie},
  year=2025
}