Battle Against the Machines: World War II 1939–1945

While the 1930s saw the first efforts to cryptanalyze the new cipher machines, the advent of World War II made this work much more imperative. The EnigmaEnigma, the Typex and the M-134C/SIGABA were the epitome of these machines and the efforts to create and cryptanalyze them led us into the computer age. This chapter examines the race to break the ever more sophisticated cipher machines of the 1940s and looks in some detail at the cryptographic construction of the Enigma and the M-134C/SIGABA.