Paper 2023/765 Original: eprint.iacr.org/2023/765 ↗

Threshold ECDSA in Three Rounds

Jack Doerner
Yashvanth Kondi
Eysa Lee
abhi shelat
Abstract

We present a three-round protocol for threshold ECDSA signing with malicious security against a dishonest majority, which information-theoretically UC-realizes a standard threshold signing functionality, assuming only ideal commitment and two-party multiplication primitives. Our protocol combines an intermediate representation of ECDSA signatures that was recently introduced by Abram et al. (Eurocrypt'22) with an efficient statistical consistency check reminiscent of the ones used by the protocols of Doerner et al. (S&P'18, S&P'19). We show that shared keys for our signing protocol can be generated using a simple commit-release-and-complain procedure, without any proofs of knowledge, and to compute the intermediate representation of each signature, we propose a two-round vectorized multiplication protocol based on oblivious transfer that outperforms all similar constructions.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
History
2023-12-14: last updated
2023-05-26: published
Short URL
https://ia.cr/2023/765
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2023/765,
      author = {Jack Doerner and Yashvanth Kondi and Eysa Lee and abhi shelat},
      title = {Threshold ECDSA in Three Rounds},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/765},
      year = {2023},
      url = {https://eprint.iacr.org/2023/765}
}
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