Security against differential and linear cryptanalysis for general SPT models

Abstract

To use SP network in stream ciphers safely and efficiently,the ability against differential and linear cryptanalysis of SPT models was studied,where S and T denote different layers for substitution,in which compression could be achieved,and P denotes the layer for permutation.The upper bound of the maximum differentia lity was given when the branch number of P was optimal,and the upper bound of the maximum linear approximation probability and the maximum linear hull probability are given when the branch number of P was optimal and when S and T were balanced.As a consequence,the problem about evaluating the security against differential and linear cryptanalysis for general SPT models was resolved partially.

Keywords

• branch number;differential probability;linear probability;linear approximation probability;linear hull probability