Paper 2026/433
Round-Optimal Threshold Blind Signatures without Random Oracles
Abstract
This paper presents the first round-optimal threshold blind signature without random oracles. Our construction achieves security in the algebraic group model (AGM) for asymmetric pairing groups, and tolerates adaptive corruption of up to $t-1$ signers, where $t$ is the threshold. We improve upon the recent threshold blind signatures of Lehmann, Nazarian and Özbay (EUROCRYPT 2025) and Jarecki and Nazarian (ASIACRYPT 2025) in two ways: we eliminate both the reliance on random oracles and the need for $q$-type assumptions in the AGM. As a core building block, we introduce a new pairing-based round-optimal blind signature without random oracles, based on the $2$-DL assumption in the AGM. Both blind signature schemes achieve communication and computation costs only twice that of the celebrated blind BLS signature.
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- Preprint.
- Keywords
- blind signaturesthreshold signaturesanonymous credentials
- Contact author(s)
-
georg fuchsbauer @ tuwien ac at
fabian regen @ tuwien ac at
wee @ di ens fr - History
- 2026-03-05: approved
- 2026-03-03: received
- See all versions
- Short URL
- https://ia.cr/2026/433
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2026/433,
author = {Georg Fuchsbauer and Fabian Regen and Hoeteck Wee},
title = {Round-Optimal Threshold Blind Signatures without Random Oracles},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/433},
year = {2026},
url = {https://eprint.iacr.org/2026/433}
}
