Introduction to ciphers and substitution. Alice and Bob and Carl and Julius: terminology and Caesar Cipher ; The key to the matter: generalizing the Caesar Cipher ; Multiplicative ciphers ; Affine ...

Kevin Sands, author of The Blackthorn Key, picks his favourite keys, codes and ciphers throughout history, from the Caesar shift to the Enigma machine If knowledge is power, then the key to power lies ...

Cryptography is nearly as old as human language. Many civilizations felt the need to conceal their messages using more or less sophisticated encryption methods, as demonstrated by some documentary ...

1. Introduction -- 2. From Julius Caesar to simple substitution -- 3. Polyalphabetic systems -- 4. Jigsaw ciphers -- 5. Two-letter ciphers -- 6. Codes -- 7. Ciphers for spies -- 8. Producing random ...