By Max Shaw
The Enigma Machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by the German engineer Arthur Scherbius at the end of World War I. The early models were used commercially from the early 1920s, and adopted by military and government services of several countries — most notably by Nazi Germany before and during World War II. Several different Enigma models were produced, but the German military models are the ones most commonly discussed.
The Polish Cipher Bureau first broke Germany's military Enigma ciphers in December 1932. Five weeks before the outbreak of World War II, on 25 July 1939, they presented their Enigma-decryption techniques and equipment to French and British military intelligence in Warsaw. From 1938 onwards, additional complexity was repeatedly added to the machines, making the initial decryption techniques increasingly unsuccessful. Nonetheless, the Polish breakthrough represented a vital basis for the later British effort