The Fundamentals of Modern Cryptography
Aiden A. Bruen, Mario Professor Forcinito, James Professor McQuillan · 2021
This chapter presents a summary of most of the important procedures and ideas in modern cryptography. It discusses the material in such a way that mathematical prerequisites are minimized. On the question of the design of modern block ciphers, several authors will suggest that Shannon’s diffusion principle comes down just to a permutation. However, the chapter points out that there is much more to diffusion than a mere permutation. A cryptosystem consists of an encryption and decryption algorithm, together with all possible messages, cipher texts and keys. In any cryptographic system, various other related issues besides encryption need to be addressed. These issues include the following: authentication, message integrity, and digital signatures/non-repudiation. The chapter discusses some of these concerns. In some modern applications of symmetric cryptography, such as Global System for Mobile telecommunication phones, a stream cipher encryption algorithm is used. In other applications of symmetric cryptography, block cipher encryption algorithms are used.