Paper 2026/1978 Original: eprint.iacr.org/2026/1978 ↗
Succinct Two-Round Two-Party Signing from PCFs
Abstract
We introduce new two-party threshold signature schemes with strong efficiency and security. The application of our methodology to the two most popular signatures, Schnorr and ECDSA, yields two-round, two-party, stateless and deterministic signing with 4-12 ms of computation on one core of a standard laptop, extremely low communication -- 96 B for Schnorr, and 128 B for ECDSA -- and full concurrent simulatable security. At the heart of our approach is a new pseudorandom correlation function (PCF) for vector-OLE that admits an efficient key generation protocol; we design an end-to-end maliciously-secure and highly parallelizable DKG for this PCF and, using this DKG, we obtain an estimated runtime of 44 s for the (one-time) distributed setup of Schnorr and ECDSA on one core of a standard laptop.
Metadata
- Available format(s)
PDF- Category
- Cryptographic protocols
- Publication info
- Preprint.
- History
- 2026-09-11: last updated
- 2026-09-11: published
- Short URL
- https://ia.cr/2026/1978
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2026/1978,
author = {Lennart Braun and Geoffroy Couteau and Kelsey Melissaris and Mahshid Riahinia and Elahe Sadeghi},
title = {Succinct Two-Round Two-Party Signing from PCFs},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/1978},
year = {2026},
url = {https://eprint.iacr.org/2026/1978}
}