Bomba (cryptography)

One theory, most likely apocryphal, originated with Polish engineer and army officer Tadeusz Lisicki (who knew Rejewski and his colleague Henryk Zygalski in wartime Britain but was never associated with the Cipher Bureau).

[2] A top-secret U.S. Army report dated 15 June 1945 stated: A machine called the "bombe" is used to expedite the solution.

[3] The U.S. Army's above description of the Polish bomba is both vague and inaccurate, as is clear from the device's description at the end of the second paragraph of the "History" section, below: "Each bomb... essentially constituted an electrically powered aggregate of six Enigmas..." Determination of a solution involved no disassembly ("a part... fall[ing] off") of the device.

Using the knowledge that the first three letters of a message were the same as the second three, Polish mathematician–cryptologist Marian Rejewski was able to determine the internal wiring of the Enigma machine and thus to reconstruct the logical structure of the device.

In order to mechanize and speed up the process, Rejewski, a civilian mathematician working at the Polish General Staff's Cipher Bureau in Warsaw, invented the "bomba kryptologiczna" (cryptologic bomb), probably in October 1938.

Each bomb (six were built in Warsaw for the Cipher Bureau before September 1939) essentially constituted an electrically powered aggregate of six Enigmas and took the place of some one hundred workers.

[5] Up to July 25, 1939, the Poles had been breaking Enigma messages for over six and a half years without telling their French and British allies.

Rejewski rejected this: "No, it was not [cryptologic] difficulties [...] that prompted us to work with the British and French, but only the deteriorating political situation.

Diagram of Rejewski's cryptologic bomb. For clarity, only one set of three rotors is shown (1); in reality, there were six such sets. An electric motor (2) turns the rotors. 3: Switches.
Enigma's plugboard, with two cables connected (ten were used during World War II ). This enhancement greatly increased the system's security.