PDF file. L. Lo Russo, E. Bianchi, Sistemi e reti, Volume 3. Cryptography in World War I and II. The Playfair cipher or Playfair square ( 1854 ), the bifid cipher ( 1901 ), the ADFGVX cipher ( 1918 ), the Vernam cipher ( 1817 ), the cipher machines: Enigma, the Lorenz Machine, Colossus, Purple and Magic.