Generalised Differential Cryptanalysis Check for Block Ciphers

Abstract

This paper is based on cryptanalysis of block ciphers. With increase Differential attack [2] on encryption algorithms, it is necessary for the new upcoming algorithms to be resistant against differential cryptanalysis. The main objective the paper is, given any block cipher, we will be able to check the minimum number of Active S-Boxes for each round using the GLPK (GNU Linear Programming Kit) solver and hence find out how many minimum rounds are required by the block cipher to be resistant to Differential Cryptanalysis [2]. We will be doing Differential Cryptanalysis using mixed-integer linear programming (MILP) (suggested by Mouha N., Wang Q., Gu D., Preneel B in [1]). After that, we will be finding out the differential probability of the S-Box from the differential characteristic using the ddt table and hence find out if the given cipher is resistant against differential cryptanalysis. We will use the GLPK solver to solve the MILP equations. This paper will also contain the class diagrams required to design the system of [1] which will help us in finding out the minimum number of active s-boxes.