On February 18, 1918, Arthur Scherbius filed a patent for an electro-mechanical cipher machine using rotating wired disks to scramble letters into code. Commercialized in the 1920s and later adopted by the German military, the device evolved into the Enigma machine, whose codes British codebreakers at Bletchley Park — including Alan Turing — famously cracked during World War II.
Scherbius, a German electrical engineer, was not thinking of warfare when he filed his patent; he envisioned Enigma as a commercial product for banks and businesses wanting to protect sensitive telegraph communications from industrial espionage. His company struggled to sell the machines throughout the 1920s, and Scherbius died in 1929 after a horse-drawn carriage accident, never seeing his invention become one of the most consequential objects of the twentieth century.
The German military adopted modified versions of the machine in the late 1920s and 1930s, believing its billions of possible rotor and plugboard settings made it mathematically unbreakable. Polish cryptanalysts made the first crucial breaks in the 1930s, and their work was passed to British intelligence just before the outbreak of war.
At Bletchley Park, Alan Turing and colleagues built the Bombe, an electromechanical device that could test cipher possibilities at speed, ultimately cracking German naval Enigma traffic. Winston Churchill later said the intelligence gained shortened the war by an estimated two years — a legacy improbably traced back to a patent filed for peacetime commerce in 1918.