Polish Enigma doubles

Enigma "doubles" were machines produced by the Polish Cipher Bureau, based on Marian Rejewski's reconstruction of the German Enigma machine's wirings.

Doubles built in Poland before World War II

In February 1933, the Polish Cipher Bureau ordered "doubles" of the military Enigma machine from the AVA Radio Manufacturing Company, in Warsaw. By 1934, fifteen "made-in-Poland" Enigmas with plugboard had been delivered. Ultimately about seventy such units would be produced.

Precious gift

In 1939, two Enigma doubles were sent to Paris and London. Until then, German military Enigma traffic had utterly defeated the British and French, and they had faced the disturbing prospect that German communications would remain "black" to them for the duration of the coming war.

Doubles built in France

After Germany invaded Poland in September 1939 and key Polish Cipher Bureau personnel evacuated to France, the Cipher Bureau resumed its interrupted work at PC Bruno, outside Paris. The Poles had only three Enigma doubles to work with, and these were wearing out from round-the-clock use. French Army intelligence officer Gustave Bertrand ordered parts for forty doubles from a French precision-mechanics firm. Manufacture proceeded sluggishly, however; it was only after the fall of France and the opening of underground work in the Free Zone of the south in October 1940 that "four" machines were finally assembled.

ee also

* Cipher Bureau.
* Saxon Palace, in Warsaw, where German Enigma ciphers were first broken (December 1932).
* Cryptologic methods and technology
**"ANX method."
**Enigma "doubles" (1932).
**Grill.
**Clock.
**Cyclometer (1934).
**Card catalog (1935).
**Cryptologic bomb (1938): a machine designed by Marian Rejewski to facilitate the retrieval of Enigma keys.
**Zygalski sheets (1938): invented by Henryk Zygalski, and called "perforated sheets" by the Poles, the device made possible the reconstitution of the Enigma's entire cipher key.

References

* Władysław Kozaczuk, "Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two", edited and translated by Christopher Kasparek, Frederick, MD, University Publications of America, 1984.

* Władysław Kozaczuk, Jerzy Straszak, "Enigma: How the Poles Broke the Nazi Code", Hippocrene Books, 2004, ISBN 0-7818-0941-X.

* Zbigniew Brzezinski, "The Unknown Victors," pp.15–18 in Jan Stanisław Ciechanowski, ed., "Marian Rejewski, 1905–1980: Living with the Enigma Secret", Bydgoszcz, Bydgoszcz City Council, 2005, ISBN 83-7208-117-4.