Paper 2020/1158 Original: eprint.iacr.org/2020/1158 ↗
Don't throw your nonces out with the bathwater: Speeding up Dilithium by reusing the tail of y
Abstract
We suggest a small change to the Dilithium signature scheme, that allows one to reuse computations between rejected nonces, for a speed-up in signing time. The modification is based on the idea that, after rejecting on a too large $\|\mathbf{r}_0\|_\infty$, not all elements of the nonce $\mathbf{y}$ are spent. We swap the order of the checks; and if this $\mathbf{r}_0$-check fails, we only need to resample $y_1$. We provide a proof that shows that the modification does not affect the security of the scheme. We present measurements of the performance of the modified scheme on AVX2, Cortex M4, and Cortex M3, which show a speed-up ranging from 11% for Dilithium2 on M3 to 22% for Dilithium3 on AVX2.
Metadata
- Available format(s)
PDF- Category
- Public-key cryptography
- Publication info
- Preprint.
- History
- 2023-05-24: last updated
- 2020-09-25: published
- Short URL
- https://ia.cr/2020/1158
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2020/1158,
author = {Amber Sprenkels and Bas Westerbaan},
title = {Don't throw your nonces out with the bathwater: Speeding up Dilithium by reusing the tail of y},
howpublished = {Cryptology {ePrint} Archive, Paper 2020/1158},
year = {2020},
url = {https://eprint.iacr.org/2020/1158}
}