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Enigma Machine

Breaking The Code

Learning enemy secrets was vital as Britain battled for survival in 1939. British intelligence gathered an eclectic array of mathematicians, linguists, artists, and thinkers at Bletchley Park. Their assignment was simple: break Germany's codes. But with the Nazi's Enigma machine capable of 150,000,000,000,000,000,000 combinations, this task was dauntingly complex. 

Originally designed to encode business communications, the Germans adapted the Enigma cipher machine for use in World War II. The machine linked a keyboard to a series of rotors using electric current. The rotors transposed each keystroke multiple times. The message was then sent in Morse code. 

Enigma generated millions of combinations. The rotor order, starting positions and plug board connections were reset daily. To decipher a message, Enigma’s daily settings key—sometimes encoded in the message itself—was needed. Even more, the machine was easily portable. Thousands were used in army divisions, theater headquarters, SS divisions, Luftwaffe wings, U-boats and other field environments. Given the quality of this fascinating machine, and quantity at their disposal, the Germans believed Enigma provided an unbreakable code.

Deciphering Enigma’s trillions of combinations could not be done by hand. A fast, efficient number-crunching machine would be required—and the bombe was that machine. The bombe was a high-speed electro-mechanical device named by its Polist inventors either for its ticking sound or a popular ice cream dessert called a bomba

With five hundred electrical relays, eleven miles of wiring, and a million soldered joints, the bombe tested guessed plain texts against intercepted cryptograms to see whether any Enigma setting would produce that result. If one were found, it would be the key for all messages sent on that cryptonet for that day.

Led by Alan Turing, a British team was gathered at Bletchley Park to decipher German communications using the bombe, as well as the Colossus, which solved German high command encrypted teletypewriter messages used electronic processing. Like many early attempts at automation, these machines could be programmed to do only one thing; however, they were quite sophisticated for their time. Devices like the original bombe and the Colossus used at Bletchley Park were important milestones in the history of computing.

The first team at Bletchley Park consisted of only 100 code-breakers. Soon, that number mushroomed to 10,000, mostly women. Fifty miles north of London, on the grounds of a peaceful Victorian estate, the Allies quietly won the "brain battle" of World War II behind the secretive walls of Bletchley Park, successfully cracking the Nazi Enigma code. Working day and night, they repeatedly defied the odds. Equally remarkable, they successfully kept Bletchley's secret throughout the war…and for 30 years after.

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