Proposals and Implementations of MDS Diffusion Layer Dynamic Algorithms for AES Block Cipher

Abstract

Block ciphers are an interesting cryptographictopic that is widely used today. Therefore, the issue of improving the security of block ciphers is increasingly concerned today. There have been many research directions to animate block ciphers to improve their security against well-known strong attacks. In [1], we proposed two diffusion layer dynamic algorithms for SPN block ciphers. In this paper, we will execute these two algorithms with recursive MDS matrices of size 4, 8, and 16, then evaluate the cryptographic properties of the obtained dynamic MDS matrices including branch number, number of fixed points, coefficient of fixed points, number of XOR and Xtime operations. Then, we apply these two dynamic algorithms to dynamically modify the AES block cipher and evaluate the execution speed of thedynamic AES block ciphers. We propose two new diffusionlayer dynamic algorithms, implement these two algorithmsand modify dynamically AES block cipher according to thesetwo algorithms, and evaluate the speed of dynamic AES blockciphers. We also evaluate the security and implementationresources for dynamically modified AES block ciphers. Theproposed diffusion layer dynamic algorithms contribute toimproving the security of the AES block cipher against manycurrent strong attacks.