Enigma

A German electromechanical rotor cipher machine, used by the Wehrmacht among others. Its cipher was first broken by Polish cryptologists in 1932.

Enigma was based on Hugo Koch's rotor machine, the patent for which Arthur Scherbius bought in 1928.¹

According to the Foreign Intelligence Agency, the machine quickly became a commercial success, and in a modified version it was adopted by the German armed forces and intelligence. Thanks to material brought from France on 8 December 1932 by Captain Gustave Bertrand, the Cipher Bureau cryptologists Marian Rejewski, Jerzy Różycki and Henryk Zygalski – graduates of a secret cryptology course in Poznań – first read Enigma ciphertexts on 31 December 1932 in the Saxon Palace in Warsaw. The Warsaw firm AVA built a dozen or so Polish replicas of the machine for the Cipher Bureau, which were already in use in 1934.¹

The Germans repeatedly made Enigma procedures more difficult, and the Poles responded with successive tools: the cyclometer and the card catalogue, the clock method, Zygalski sheets and the cryptologic bomb. On 25–26 July 1939 at Pyry they handed over their achievements to the French and the British; at Bletchley Park the work was continued on a large scale (see Ultra). The date the cyclometer was built (1934 or 1936) is disputed in the sources – see the entry Breaking Enigma.^1,2,3

More in the operation card: Breaking Enigma.