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US Navy bombe at the National Cryptologic Museum. Partial schematics of the US Navy bombe.. 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.
The top drum corresponds to the left-hand Enigma rotor, the middle drum to the middle rotor and the bottom drum to the right-hand rotor. Wire brushes on the back of a drum from the rebuilt Bombe The bombe was an electro-mechanical device that replicated the action of several Enigma machines wired together.
The German Enigma used a combination key to control the operation of the machine: rotor order, which rotors to install, which ring setting for each rotor, which initial setting for each rotor, and the settings of the stecker plugboard. The rotor settings were trigrams (for example, "NJR") to indicate the way the operator was to set the machine.
Despite the introduction of the 4-rotor Enigma for Atlantic U-boats, the analysis of traffic enciphered with the 3-rotor Enigma proved of immense value to the Allied navies. Banburismus was used until July 1943, when it became more efficient to use the many more bombes that had become available.
The previous 3-rotor Enigma model had been modified with the old reflector replaced by a thin rotor and a new thin reflector. Breaking Shark on 3-rotor bombes would have taken 50 to 100 times as long as an average Air Force or Army message. It seemed, therefore, that effective, fast, 4-rotor bombes were the only way forward.
NEMA was declassified on 9 July 1992, and machines were offered for sale to the public on 4 May 1994. The NEMA machine was a Swiss rotor machine , designed to replace commercial Enigma machines . NEMA uses 10 wheels, of which one is a reflector, four are normal rotors, and the remaining five are "Drive wheels", which control the stepping of the ...
On 1 February 1942, Enigma U-boat traffic became unreadable because of the introduction of a different 4-rotor Enigma machine. This situation persisted until December 1942, although other German naval Enigma messages were still being deciphered, such as those of the U-boat training command at Kiel. [ 62 ]
List of Enigma machine simulators lists software implementations of the Enigma machine, a rotor cypher device that was invented by German engineer Arthur Scherbius at the end of World War I. [ 1 ] and used in the early- to mid-20th century to protect commercial, [ 2 ] diplomatic, and military communication.