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IPTC: Caption
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United States Navy "Woman Accepted for Volunteer Emergency Service" (WAVES) handles a National Cash Register Company (NCR) N-530 Bombe decryption machine for decoding German Kriegsmarine (Navy) naval cyphers encoded with their 4-rotor "Enigma" machine. She is adjusting the fourth commutator wheel. The British, using advanced codebreaking machines developed by the Poles before that country succumbed to the Nazis in September 1939, developed 3-rotor "Enigma" machines that could read U-Boat messages until Grossadmiral (Grand Admiral) Karl Doenitz changed the U-Boats to a 4-rotor system in February 1942. The British were unable to build a Bombe to break the 4-rotor "Enigma" code, even though they had enough intelligence to build it. The United States Navy contracted NCR to build 4-rotor bombes at their factory in Dayton, Ohio, in March 1942. At the time, American losses in the Atlantic were reaching critical levels. The British had promised to supply the United States with 4-rotor Enigma traffic by August 1942, but it was apparent that Bletchley Park, the British Cryptology center, would not be able to meet that deadline. American Naval officers had drawings of the British bombe; working with NCR technician Joseph Desch, realized they could improve the British design. British theorist Alan Turing, who designed the British Bombe, was skeptical. Yet Desch's design worked, and the NCR N-530 was ordered into production. The American Navy Bombes stood seven feet high, two feet wide and ten feet long. Each weighed 5,000 pounds. The front and back of the Bombes each had eight columns of four rotors. The top wheel mimicked the Enigma's new fourth rotor while the bottom commutator represented the rightmost, or fastest, rotor of the Enigma. The bottom rotor spun at a speed of 1,725 revolutions per minute, which allowed the machine to complete its run in only twenty minutes. Much of the work was done in secret, with WAVEs soldering and wiring the Bombes without knowing what they
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IPTC: Copyright Notice
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Caption ©2007 MFA Productions LLC
Image in the Public Domain
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