Who was Claude Shannon, and how did he contribute to cryptography?
Preliminaries In Session 2, we looked at the historical context of encryption, learned some important terms and basic concepts, and looked at various encryption techniques such as transposition, substitution and steganography. In this week’s session we will drill down a little deeper by taking a look at more sophisticated ciphers that achieve added security by combining substitution and transposition, one-time pads, and ciphers implemented with machines, e.g., cipher wheels, Hagelin machines, and Enigma and Purple machines. Also, we will look at the concept of multiliteral substitution ciphers. Having gained an appreciation for how encryption works, we’ll look at the other side of the coin: how ciphers are cracked, i.e., the study of cryptanalysis. We’ll start by cracking a simple substitution code, and then attempt to categorize cryptanalysis approaches. Then, we’ll look at some classic cryptanalysis attacks. A couple of side notes before we start this week’s session: • This week’s se
