Paper 2026/294 Original: eprint.iacr.org/2026/294 ↗
Post-Quantum Adaptor Signatures with Strong Security from Cryptographic Group Actions
Abstract
We present One Round "Cheating" Adaptor Signatures (OR- CAS): a novel and efficient construction of adaptor signature schemes from CSI-FiSh. Our protocol improves substantially on existing group action-based schemes: Unlike IAS (Tairi et al., FC 2021), our scheme does not require expensive non-interactive zero-knowledge proofs, and unlike adaptor MCSI-FiSh (Jana et al., CANS 2024) our construction does not require any modification to the underlying digital signature scheme. We prove the protocol’s security under the strong security no- tions of Dai et al. (Indocrypt 2022) and Gerhart et al. (Eurocrypt 2024).
Metadata
- Available format(s)
PDF- Category
- Cryptographic protocols
- Publication info
- Preprint.
- History
- 2026-02-24: last updated
- 2026-02-17: published
- Short URL
- https://ia.cr/2026/294
- License
- https://creativecommons.org/licenses/by-sa/4.0/
BibTeX
@misc{cryptoeprint:2026/294,
author = {Ryann Cartor and Nathan Daly and Giulia Gaggero and Jason T. LeGrow and Andrea Sanguineti and Silvia Sconza},
title = {Post-Quantum Adaptor Signatures with Strong Security from Cryptographic Group Actions},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/294},
year = {2026},
url = {https://eprint.iacr.org/2026/294}
}