Paper 2026/1566 Original: eprint.iacr.org/2026/1566 ↗
On the Security of Rotational (Non-)linearity in Sbox
Abstract
Recently, zero-knowledge proof protocols have gained much popularity due to the adoption in blockchain applications, e.g., zero-knowledge virtual machines. However, using the current standardized hash functions inside the generation of zero-knowledge proofs would incur much overhead in proof size, as well as prover and verifier’s runtime. In the past few years, various circuit-friendly hash functions has been proposed. Skyscraper-v2 is one example of such hash functions applying the split-and-lookup approach for better performance. In this paper, we expand the linear approximation definitions by extending it with circular shifts embedded in the approximation. Specifically, we consider the rotation of bits at both the input and output sides. We demonstrate it with Skyscraper-v2 Sbox. It allows us to better capture the recurring sequence in nonlinear Skyscraper-v2 SBox.
Metadata
- Available format(s)
PDF- Category
- Applications
- Publication info
- Preprint.
- History
- 2026-07-30: last updated
- 2026-07-30: published
- Short URL
- https://ia.cr/2026/1566
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2026/1566,
author = {Yadi Zhong},
title = {On the Security of Rotational (Non-)linearity in Sbox},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/1566},
year = {2026},
url = {https://eprint.iacr.org/2026/1566}
}