An electromechanical device for recovering Enigma keys automatically, designed by Marian Rejewski after yet another change in the German enciphering procedure (sources give 1938 or 1936).
GCHQ calls it the first electromechanical device to support cryptanalysis. Conversations with Rejewski in 1940 were the basis of the concept of the first British bombe at Bletchley Park.1
Sources differ on the year it was built: 1938 according to the Internal Security Agency (ABW) publication and the AW text on decryption, 1936 according to Rejewski’s biographical note on the AW website.2,3,4
More in the operation card: Breaking Enigma.
Sources
- GCHQ, The Pyry Forest meeting
- Internal Security Agency, Marian Rejewski: in the service of Polish cryptology (ABW Publishing House, Wiązowna 2022, ISBN 978-83-964225-4-5) (in Polish)
- Foreign Intelligence Agency, Enigma decryption
- Foreign Intelligence Agency, They broke Enigma (in Polish, with English versions of the biographies)
Checked: 4 November 2026