Paper 2019/150
QcBits: Constant-Time Small-Key Code-Based Cryptography
Tung Chou
Abstract
This paper introduces a constant-time implementation for a quasi-cyclic moderate-density-parity-check (QC-MDPC) code based encryption scheme. At a $2^{80}$ security level, the software takes 14679937 Cortex-M4 and 1560072 Haswell cycles to decrypt a short message, while the previous records were 18416012 and 3104624 (non-constant-time) cycles. Such speed is achieved by combining two techniques: 1) performing each polynomial multiplication in $\mathbb{F}_2[x]/(x^r-1)$ and $\mathbb{Z}[x]/(x^r-1)$ using a sequence of ``constant-time rotations'' and 2) bitslicing.
Metadata
- Available format(s)
-
PDF
- Category
- Implementation
- Publication info
- Published by the IACR in CHES 2016
- DOI
- 10.1007/978-3-662-53140-2_14
- Keywords
- McElieceNiederreiterQC-MDPC codesbitslicingsoftware implementation
- Contact author(s)
- blueprint @ crypto tw
- History
- 2019-02-20: received
- Short URL
- https://ia.cr/2019/150
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2019/150,
author = {Tung Chou},
title = {{QcBits}: Constant-Time Small-Key Code-Based Cryptography},
howpublished = {Cryptology {ePrint} Archive, Paper 2019/150},
year = {2019},
doi = {10.1007/978-3-662-53140-2_14},
url = {https://eprint.iacr.org/2019/150}
}
