The aim of white-box cryptography is to protect a secret key in a whitebox environment in which an adversary has full control ability over the computer’s execution process and the running environment. In order to solve the issues of lower security in static white-box algorithm and inconvenient application in traditional dynamic white-box algorithm, it is proposed that a white-box block cipher scheme based on dynamic library named WBCD. In this scheme, look-up tables and affine...

MDS Matrix has an important role in the design of Rijndael Cipher and is the most expensive component of the cipher. It is also used as a perfect diffusion primitive in some other block ciphers. In this paper, we propose a replacement of Mix Column Transformation in AES by equivalent Dynamic Mix Column Transformation. A Dynamic Mix Column Transformation comprises dynamic MDS Matrices which are based on default MDS Matrix of AES and m-bit additional key. Here m is a variable length that does...

Ciphers get their strength from the mathematical functions of confusion and diffusion, also known as substitution and permutation. These were the basics of classical cryptography and they are still the basic part of modern ciphers. In block ciphers diffusion is achieved by the use of Maximum Distance Separable (MDS) matrices. In this paper we present some methods for constructing dynamic (and random) MDS matrices.

An MDS matrix is an important building block adopted by different algorithms that provides diffusion and therefore, has been an area of active research. In this paper, we present an idea of direct exponent and direct square of a matrix. We prove that direct square of an MDS matrix results in an MDS matrix whereas direct exponent may not be an MDS matrix. We also delineate direct exponent class and scalar multiplication class of an MDS matrix and determine the number of elements in these...