Aperitifs -- Columnar transposition -- Monoalphabetic substitution -- Polyalphabetic substitution -- Statistical tests -- The emergence of cipher machines -- The Japanese cipher machines -- Stream ciphers -- Block-ciphers: Lucifer, DES, and AES -- The paradigm of public key cryptography -- The knapsack cryptosystem -- The RSA cryptosystem -- Prime numbers and factorization -- The discrete logarithm problem -- Elliptic curve cryptography -- Key exchange in a network -- Digital signatures and authentication -- Applications of cryptography -- Cryptographic patents