Differential cryptanalysis using Python 3

The code implements a SPN (Substitution Permutation Network) cryptography algorithm in Python. The code defines functions for an S-Box, P-Box, and the SPN algorithm itself. The S-Box takes an integer between 0 and 15 as input and returns the output after applying a specific substitution. The P-Box takes an integer between 0 and 15 as input and returns the output after applying a specific permutation. The SPN class uses the S-Box and P-Box functions to encrypt a given input and produce the encrypted output. The class also implements intermediate calculations, such as calculating the intermediate values U, V, W, and Y, and updating the round keys. The code provides a comprehensive implementation of the SPN algorithm and can be used to study the functioning of the algorithm and its security. Code in github: https://github.com/VaggelisGkoumas1996/Differential-Cryptanalysis-using-Python-3/blob/main/diffrential%20cryptanalysis.py