Paper 2025/485 Original: eprint.iacr.org/2025/485 ↗
Key reconstruction for QC-MDPC McEliece from imperfect distance spectrum
Abstract
McEliece cryptosystems, based on code-based cryptography, is a candidate in Round 4 of NIST's post-quantum cryptography standardization process. The QC-MDPC (quasi-cyclic moderate-density parity-check) variant is particularly noteworthy due to its small key length. The Guo-Johansson-Stankovski (GJS) attack against the QC-MDPC McEliece cryptosystem was recently proposed and has intensively been studied. This attack reconstructs the secret key using information on decoding error rate (DER). However, in practice, obtaining complete DER information is presumed to be time-consuming. This paper proposes two algorithms to reconstruct the secret key under imperfection in the DER information and evaluates the relationship between the imperfection and efficiency of key reconstruction. This will help us to increase the efficacy of the GJS attack.
Metadata
- Available format(s)
PDF- Category
- Public-key cryptography
- Publication info
- Preprint.
- History
- 2025-03-19: last updated
- 2025-03-14: published
- Short URL
- https://ia.cr/2025/485
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2025/485,
author = {Motonari Ohtsuka and Takahiro Ishimaru and Rei Iseki and Shingo Kukita and Kohtaro Watanabe},
title = {Key reconstruction for QC-MDPC McEliece from imperfect distance spectrum},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/485},
year = {2025},
url = {https://eprint.iacr.org/2025/485}
}