ABSTRACT
Historians have been more interested in the breaking than the making of codes. There is but one exception to that rule: the fascination with machines which encipher messages at one end of a communication circuit and decipher them at the other. Although this idea is centuries old and many such machines were patented between 1850 and 1920, many assume that the history of cipher machines began in 1920, with the development of the “Enigma” system. Amidst the emphasis on German experiences with “Enigma”, that of other states with such systems has been overlooked. Britain, for example, commonly is thought to have ignored cipher machines until 1926 and not to have begun to develop them until 1935.2
The British “Enigma” has a more peculiar history than this. It illustrates the problems which cryptography posed to every state during the first half of the twentieth century, and illuminates the forgotten half of the wireless war between 1939 and 1945. ULTRA was not enough for victory; Britain won not just by breaking German codes but by defending its own. Nor was that victory foredoomed. In 1939 Britain had neither the communication nor the cryptographic facilities which it needed to survive. Until 1942 its cryptography was no better than that of Germany, perhaps worse. Britain paid for these mistakes in blood. It had to rebuild its signals and its security as they faced deadly attack. Its successes in these endeavours, no less than the offensive victories of Bletchley Park, made 1942-1943 the turning point in the wireless war.
