Four-rotor encryption rarity goes under the hammer
23 Oct 2015 at 13:25, Lester Haines
A fully-functioning four-rotor M4 Enigma WW2 cipher machine has sold at auction for $365,000.
The German encryption device, as used by the U-Boat fleet and described as "one of the rarest of all the Enigma machines", went under the hammer at Bonham's in New York last night as part of the "Conflicts of the 20th Century" sale.
The M4 was adopted by the German Navy, the Kriegsmarine, in early 1942 following the capture of U-570 in August 1941*. Although the crew of U-570 had destroyed their three-rotor Enigma, the British found aboard written material which compromised the security of the machine.
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