Multidimensional linear distinguishing attacks and Boolean functions
Linear cryptanalysis and linear approximation methods in general are among the most important cryptanalysis methods of symmetric ciphers and their components. Recently, these methods have been extended to efficiently exploit multiple linear approximations simultaneously. It is known that high nonlinearity of Boolean functions and S-boxes is a desirable property and that the bent functions offer the strongest resistance against cryptanalysis using single linear approximations. The goal of this paper is to investigate to which extent resistance against the multidimensional extension of the linear cryptanalysis method can be achieved. For this purpose some common highly nonlinear Boolean functions as well as a basic LFSR based key stream generator using a nonlinear filter function are investigated.
distinguishing attack boolean function linear approximation multidimensional linear approximation filter generator primary 94a60 secondary 94c10 15b34