HEURISTIC ANALYSIS OF SUBSTITUTION BOX

Abstract

This report represents an investigation about Substitution Box (S-Box) used in cryptography system. S-Box is one of prime part of cryptographic algorithm. Various properties of Substitution Box makes cryptographic algorithm susceptible to attacks. Will first study attacker strategy with possible attacks on cryptographic system and then about S-Box design principles. The goal of any assaulter is to find the key by an effective technique (finds properties which distinguished cipher text from random text). Then we will study about the methods by which the cryptographic algorithm is supposed to be compromised. S-Box should produce output which is comparable to any random generator. Here in order to measure the deviation of Substitution box from a randomly generated permutation, I have generated large number of random permutations and then measured it with the distribution of used terms in every vectors, analysis them with respect to actual figures fetched from AES Substitution box.