DATA CONVERTER, AND STORAGE MEDIUM WITH RECORDED PROGRAM FOR EXECUTION DATA CONVERSION

摘要

PROBLEM TO BE SOLVED: To increase resistance against a differential decording method and a linear decording method. SOLUTION: A 4×4 matrix expressing processing of a linear transforming part 344A provided between the first nonlinear transforming part 343 and the second nonlinear transforming part 345 constituting a nonlinear function part is composed of four vectors of which a hamming weight is T-1 or more with respect to a safety threshold value T. In a data converter suitable for an encipherment device to make data secret, safety is secured and high speed encipherment processing is conducted without increasing remarkably a step number by constituting the converter to satisfy the safety and high speed processability simultaneously.