Increasing the Robustness of DES and TDEA Against the Differential Cryptoattack

The study of DES (Data Encryption Standard) algorithm reveals some vulnerabilities caused by the permutation and substitution functions used by it. These vulnerabilities decreases the robustness of DES against differential cryptoattack and TDEA (Triple Data Encryption Algorithm) inherits them. We analyze the permutation vectors and the S-boxes of DES over algebraic finite fields, using polynomials, and propose using more performant functions and vectors such as Costas arrays which can be almost perfect non-linear permutations, increasing the nonlinearity and the strength of these encryption algorithms.