Abstract:
It is shown that the linearity and differential uniformity of the substitution multiplied by transposition may be calculated with time complexities $O\left(2^{2n}\right)$ and $O\left(2^{n}\right)$ respectively. Some heuristic algorithms of constructing s-boxes are optimized in this paper.
Key words:s-box, substitution, heuristic optimization, linearity, linear spectrum, linear approximation table, differential uniformity, differential spectrum, difference distribution table.