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The First Commercial Enigma
Germany's Arthur Scherbius created the first commercial Enigma Machine which was used to encipher secret business documents. It was soon adopted by the German military, but modified extensively- added a plugboard and reflector device, greatly increasing the possible number of encipherments. -
Polish Cryptanalytic Agency
After noticing a change in German machine encryption, Marian Rejewski joined the Polish Cryptanalytic Agency to attempt to crack the Enigma. In only a few months he had discovered the internal wiring of the machine! -
First Bomba
Using information from captured traitor Hans Thilo-Schmidt, Rejewski created the first Bomba, an electo-mechanical machine, to break into the enigma codes. However, soon, Engima increased in complexity- two rotors were added-making the Bomba useless. -
Sharing of Cryptanalytic Knowledge
With fear of war looming over them, the Polish Cryptanalytic agency shared its knowledge with France and Britain. They promised to give each country a reconstructed enigma and Zygalski sheets (instrumental in the creation of the first Bomba). -
The Creation of Bletchley Park
In early September, the Goverment Code and Cipher School (GC&CS) brought together a team of mathematicians and varied scholars to crack Enigma. This team was situated in Bletchley Park and codenamed ULTRA. -
The British Bombe
In early 1940, the British Bombe was created. Perfecting Turing's design by adding a simple stecker-board device (which reduces the amount of possible Enigma settings from thousands to a few), the new Bombe's routinely cracked into Enigma settings. Within weeks, the navy soon improved it's Enigma system by adding three more rotors- for a total of eight. The British Bombe became useless. -
Capture of U-33 and U-13
Without knowing the wiring of the three rotors, Bletchley would "remain in the dark." On February 12, the British Ship HMS Gleamer captured U-Boat U-33. They recovered two of the missing rotors, labeled VI and VII. The final rotor- VIII- was obtained from U-13 in May 1940. -
Capturing U-110
Although Bletchley knew the wiring of the missing rotors, without cribs (assumed text) the cryptanalyists could not crack the code. When the British ship Bulldog captured U-110, the boarding party, found a treasure-trove of information. From June 1941 through the summer, Bletchley could read messages as soon as it was broadcasted by the Germans. -
Doenitz Adds a Fourth Rotor
Admiral Doenitz, head of German Navy, suspected that the Allies had cracked the Enigma. Before 1941, Allied losses were at an all-time high, but soon sharply decreased. Although Nazi High-Command was not convinced, he added a thin fourth-rotor to the Enigma. The Allies were once again "in the dark." -
The United States Joins the Battle
Despite its involvement with the Allies, the United States did not take many precautions like its European counterparts. US shipping depended upon Enigma information to avoid the U-Boats. When it became apparent that Britian was not making progress on the four-rotor Bombe, the United States formed the cryptographic OP-20-G facility, headed by Joseph Desch, in Dayton, Ohio. It would serve as the center for US cryptanalytic development throughout the remainder of the war. -
Securing Valuable Information
On October 30, 1942, two men gave their lives to secure valuable information from captured U-559. Although the British knew the wirings of the fourth rotor (due to a mistake by the German navy), they required cribs (assumed text) to crack the four-rotor enigma. After boarding U-559, Colin Grazer and Anthony Fassion were able to transfer its Enigma contents to the Allies before the ship sunk. The information proved invaluable and Bletchley could read Enigma messages with only a moderate delay. -
Creation of Four-Rotor Bombes
Soon, the Code-Books expired and the Allies could no longer read U-Boat messages. On May 1, 1943 the U.S. cryptanalysists and mathematicians finished Adam and Eve (the first four-rotor Bombes). With the information gathered from the Bombes, the US was able to sink a German U-Boat refuleing tanker and three U-Boats. From then on Allied forces waged an all out assault upon the U-Boats, and Admiral Doenitz soon conceded the North Atlantic to the Allies.
