Every so often, an authentic Enigma machine, turns up on eBay. The Enigma machine, introduced in 1923 by the Chiffriermaschinen Aktien-Gesellschaft (Cipher Machines Stock Corporation), was used by the Germans to encrypt messages during World War II. With eight days left in the auction, the current bid on this specimen is $10,100 and the reserve has not been met. According the auction listing, this Enigma is in "museum condition" and includes extra lamps. Here's a description of the Enigma that I wrote for a 1999 article in Wired:
German soldiers issued an Enigma were to make no mistake about their orders if captured: Shoot it or throw it overboard.
Based on electronic typewriters invented in the 1920s, the infamous Enigma encryption machines of World War II were controlled by wheels set with the code du jour. Each letter typed would illuminate the appropriate character to send in the coded message.
In 1940, building on work by Polish code breakers, Alan Turing and his colleagues at the famed UK cryptography center Bletchley Park devised the Bombe, a mechanical computer that deciphered Enigma-encoded messages. Even as the Nazis beefed up the Enigma architecture by adding more wheels, the codes could be cracked at the Naval Security Station in Washington, DC – giving the Allies the upper hand in the Battle of the Atlantic. The fact that the Allies had cracked the Enigma code was not officially confirmed until the 1970s.