How to Improve the Nonlinearity of Bijective S-boxes

摘要

A method for the systematic improvement of the nonlinearity of bijective substitution boxes is presented. It is shown how to select two outputs so that swapping them increases the nonlinearity. Experimental results show that highly nonlinear bijective substitutions can be obtained by this method that are difficult to obtain by random generation. A survey of results in the design of S-boxes is included.