Paper 2026/493 Original: eprint.iacr.org/2026/493 ↗
The SQInstructor: a guide to SQIsign and the Deuring Correspondence with level structures
Abstract
We explore the use of level structures to generalize the SQIsign signature scheme. We give a general framework where, given the public key and the commitment, the challenge is to exhibit an isogeny between them with an additional requirement, namely to map a chosen level structure to nother. We then instantiate the framework using 1-dimensional and 2-dimensional isogenies. In doing that we provide a new explicit Deuring correspondence for supersingular elliptic curves with level structures and solve new constrained norm equations.
Metadata
- Available format(s)
PDF- Category
- Public-key cryptography
- Publication info
- Preprint.
- History
- 2026-09-22: last updated
- 2026-03-10: published
- Short URL
- https://ia.cr/2026/493
- License
- https://creativecommons.org/licenses/by-sa/4.0/
BibTeX
@misc{cryptoeprint:2026/493,
author = {Giacomo Borin and Luca De Feo and Guido Maria Lido and Sina Schaeffler},
title = {The SQInstructor: a guide to SQIsign and the Deuring Correspondence with level structures},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/493},
year = {2026},
url = {https://eprint.iacr.org/2026/493}
}