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Enigma Machine Stolen
bullgod writes "The BBC is reporting this story about the theft of one of the remaining three Enigma machines. Bummer! Presumably stolen to order -- I doubt you could fence one of these. Lets hope it's found & returned soon." You might also want to check out the Enigma displayed at the National Cryptologic Museum, run by the same folks who deny bringing you Echelon.
The Enigma was only used for short-term tactical communications. The Army and Air Force version used 3 wheels, while the later naval versions used 4 wheels. All of the Enigma cryptosystems shared certain traits that made them especially amenable to a type of cryptanalysis known as the Index of Coincidence method (a letter could never be encrypted to its plaintext equivalent). There was never any real need to capture a naval Enigma, although if this occured, it would certainly have been a great help. Later German innovations, such as the plugboard and better keying techniques, made it more difficult for British cryptanalysts to break Enigma messages in useful durations of time. While there are indeed more than 3 extant Enigma machines, I believe that the article refers to 3 of a specific type and manufacture.
The details of the high-level encryption systems (such as the Lorentz cipher machines between German operational command and the leadership) have not ever been declassified yet, although it is known that they too were broken by the Allies. To this day, the details of how the Japanese PURPLE machine was broken are not known either. Rotor machines were used by the Allies as well during WWII, and by most nations until probably the late 1950s. It has additionally been rumored that codebreaking agencies had discovered astonishingly general techniques for breaking messages encrypted with rotor machines.