Cryptographic Techniques
Yi Qian, Feng Ye, Hsiao‐Hwa Chen · 2021
This chapter presents several symmetric key cryptographic techniques. Symmetric encryption was the only type of encryption in use before the development of public-key encryption in the 1970s. The chapter introduces a group of traditional cryptographic schemes. It provides a few classical cryptographic algorithms in details, such as Caesar cipher, monoalphabetic cipher, the Playfair cipher, polyalphabetic cipher, Vigenère cipher. The two basic building blocks of all encryption technique are substitution and transposition. The chapter also presents modern stream cipher and block cipher, and demonstrates the design of modern block ciphers based on Feistel cipher structure. Modern block ciphers are some of the most widely used types of cryptographic algorithms. The chapter also introduces the basics of modern block cipher design and data encryption standards (DES). The analysis of DES security can be done in several aspects: avalanche effect, key size, and analytic attacks.