Page "World War II" Paragraph 59

Most major belligerents attempted to solve the problems of complexity and security presented by using large codebooks for cryptography with the use of ciphering machines, the most well known being the German Enigma machine.

SIGINT ( signals intelligence ) was the countering process of decryption, with the notable examples being the Allied breaking of Japanese naval codes and British Ultra, which was derived from methodology given to Britain by the Polish Cipher Bureau, which had been decoding Enigma for seven years before the war.

Another aspect of military intelligence was the use of deception, which the Allies used to great effect, such as in operations Mincemeat and Bodyguard.

Other technological and engineering feats achieved during, or as a result of, the war include the world's first programmable computers ( Z3, Colossus, and ENIAC ), guided missiles and modern rockets, the Manhattan Project's development of nuclear weapons, operations research and the development of artificial harbours and oil pipelines under the English Channel.