Background and Objectives: Substitution-box (s-box) is one of the essential
components to create confusion and nonlinear properties in cryptography. To
strengthening a cipher against various attacks, including side channel attacks,
these boxes need to have numerous security properties. In this paper, a novel
method to generate s-boxes is introduced aimed at improving the resistance of
s-boxes against side channel attacks. Methods: In the preprocessing phase of
this approach, a suitable initial s-box which has some basic security
properties is generated by adopting a fast algorithm. Then, in the main stage,
using the initial s-box, we generate new s-boxes which not only have the
properties of the initial S-box but also have been significantly improved under
another set of security properties. To do this, new s-boxes are generated using
a genetic algorithm on a particular subset of the linear combination set of
coordinate functions of the initial s-box in the preprocessing stage. Results:
The performed experiments demonstrate that the values of all security
properties of these new s-boxes, especially the measures of transparency order,
signal-to-noise ratio, confusion coefficient, bijection property, fixed point,
and opposite fixed points, have been substantially improved. For example, our
experiments indicate that 70, 220, 2071, 43, and 406 s-boxes are found better
than the initial s-box, respectively, in the dimensions of 4×4 through 8×8
Conclusion: In this article, a new s-box construction method is introduced in
which the properties related to side channel attacks are improved, without
reducing other security properties. Besides, some results obtained from
generated s-boxes in the dimensions of 4×4 through 8×8 demonstrated that the
generated s-boxes are not only improved relative to the initial s-box, but in
some cases, considerably better than some well-known s-boxes.

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