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Mechanical & Early Computing

Enigma machine

A German rotor cipher machine sold from 1923 and used by Germany's military in World War II, broken first by Polish mathematicians.

Arthur Scherbius invented the Enigma at the end of World War I. His firm, Scherbius & Ritter, patented ideas for a cipher machine in 1918 and began selling it under the name Enigma in 1923, first to businesses.

A user typed a letter and a lamp lit above the keyboard to show a different letter. Rotors changed the electrical path with every key press, so each letter used a new code. Operators changed the starting settings every day from secret key lists.

Why it matters

Germany's armed forces used it throughout World War II. Around December 1932 Marian Rejewski of the Polish Cipher Bureau used permutation theory and flaws in German procedures to break its message keys. His work helped later Allied codebreaking.

Key facts

  • Patented ideas in 1918; sold as Enigma from 1923.
  • Invented by Arthur Scherbius.
  • Rotors scramble the 26 letters of the alphabet.
  • Settings changed daily from secret key lists.
  • Marian Rejewski broke message keys around December 1932.

Sources

  1. Wikipedia, "Enigma machine", en.wikipedia.org/wiki/Enigma_machine, accessed October 14, 2026.
  2. Wikipedia, "Marian Rejewski", en.wikipedia.org/wiki/Marian_Rejewski, accessed October 14, 2026.