United States Naval Computing Machine Laboratory

The United States Naval Computing Machine Laboratory (NCML) was a highly secret design and manufacturing site for code-breaking machinery located in Building 26 of the National Cash Register (NCR) company in Dayton, Ohio and operated by the United States Navy during World War II. It is now on the List of IEEE Milestones, and one of its machines is on display at the National Cryptologic Museum.

History

The laboratory was established in 1942 by the Navy and National Cash Register Company to design and manufacture a series of code-breaking machines ("bombes") targeting German Enigma machines, based on earlier work by the British at Bletchley Park (which in turn owed something to pre-war Polish cryptanalytical work). Joseph Desch led the effort. Preliminary designs, approved in September 1942, called for a fully electronic machine to be delivered by year's end. However, these plans were soon judged infeasible, and revised plans were approved in January 1943 for an electromechanical machine, which became the US Navy bombe.

These designs were proceeding in parallel with, and influenced by, British attempts to build a high-speed bombe for the German 4-rotor Enigma. Indeed, Alan Turing visited Dayton in December 1942. His reaction was far from enthusiastic:

It seems a pity for them to go out of their way to build a machine to do all this stopping if it is not necessary. I am now converted to the extent of thinking that starting from scratch on the design of a Bombe, this method is about as good as our own. The American Bombe program was to produce 336 Bombes, one for each wheel order.