On Constructing of a 32 ×32 Binary Matrix as a Diffusion Layer for a 256-Bit Block Cipher

Abstract

In this paper, we describe how to construct a 32 ×32 binary matrix of branch number 10, and use some mathematical techniques to find a form in product of matrices for increasing efficiency in software implementations of the binary matrix. We estimate a security against cryptanlysis when the binary matrix is used as a diffusion layer of a 256-bit SPN block cipher with an 8-bit s-box as a substitution layer in a round function. Also we describe the cryptanalytic properties such as the resistances to differential, linear, impossible differential, and truncated differential cryptanalysis. The number of operations to be required for implementing the binary matrix as a diffusion layer of a 256-bit SPN block cipher are given in this paper. We have a result that the binary matrix A is more efficient than the diffusion layer used Rijndael-256 on low bit platforms, such as 8-bit processors.