The Maximum Nonlinearity of 8-variable Balanced Boolean Functions is 116
Abstract
Does there exist an 8-variable balanced Boolean function with nonlinearity 118? This is a famous and long-standing open problem in Boolean functions. In this paper, we give a negative answer to this open problem, and prove that the maximum nonlinearity of balanced Boolean functions in 8 variables is 116, establishing the 8-variable instance of Dobbertin's conjectured recursion for the minimum Walsh peak of balanced functions. Equivalently, the covering radius of the Reed--Muller code RM(1,8) in 0-resilient Boolean functions is 116. We deduce the result by obtaining a quadratic form of polar rank 6, and reducing the problem to the existence of a 6-variable Boolean function with nonlinearity greater than 26 whose Hamming distance to a bent function is between 4 and 6.
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BibTeX
@misc{lou2026maximum,
title = {{The Maximum Nonlinearity of 8-variable Balanced Boolean Functions is 116}},
author = {Yueying Lou and Youle Xu and Qichun Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.17897},
eprint = {2610.17897},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.17897},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Maximum Nonlinearity of 8-variable Balanced Boolean Functions is 116
AU - Yueying Lou
AU - Youle Xu
AU - Qichun Wang
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.17897
UR - https://arxiv.org/abs/2610.17897
AB - Does there exist an 8-variable balanced Boolean function with nonlinearity 118? This is a famous and long-standing open problem in Boolean functions. In this paper, we give a negative answer to this open problem, and prove that the maximum nonlinearity of balanced Boolean functions in 8 variables is 116, establishing the 8-variable instance of Dobbertin's conjectured recursion for the minimum Walsh peak of balanced functions. Equivalently, the covering radius of the Reed--Muller code RM(1,8) in 0-resilient Boolean functions is 116. We deduce the result by obtaining a quadratic form of polar rank 6, and reducing the problem to the existence of a 6-variable Boolean function with nonlinearity greater than 26 whose Hamming distance to a bent function is between 4 and 6.
ER -