On the mixcolumns linear transformation used in AES cipher

Abstract

AES block cipher includes a linear transformation called MixColumns which transforms 32-bit input to 32-bit output. This transformation has the property that makes linear and differential attacks harder. In this study, we obtain a model of MixColumns transformation in bits. In fact, there are two reasons for obtaining this model. The first one is to show branch number of this transformation which is important cryptographic criterion from the point of linear transformations. On the other hand, the second one is to make the software performance analysis of this transformation, which is one of two important components of a block cipher, by using obtained model.