Stream Ciphers and Block Ciphers
Shannon W. Bray · 2020
This chapter introduces the development of stream ciphers, block ciphers, and cryptographically secure pseudorandom number generators (CSPRNGs). It explains how to convert between hexdigest and plaintext. The chapter explores private-key cryptography by looking at what stream ciphers are and examines them as a combination of the one-time pad and CSPRNGs. Block ciphers take in a fixed-length message, a private key, and produce a ciphertext that is the same length as the fixed-length plaintext message. The chapter examines the construction of block ciphers. Advanced Encryption Standard and Triple Data Encryption Standard are the most common block ciphers in use today. The block ciphers are considered a cryptographic primitive, or a basic building block to a more useful cryptographic message system. In the cryptography world, a block cipher mode of operation is an algorithm that uses a block cipher to provide encryption.