Enigma Machine Anyone in the Cipher community will tell you that the Enigma Machine developed by Germany and used in WW2 was an unbreakable cipher system. Until a machine was confiscated the Germans enjoyed 100% security. The enigma machine was limited to 26 characters but the methodology of using them in a mechanical environment stumped the world. DVI does not use 26 characters. We use every keystroke available on a micro computer (upper and lower case). DVI does not code character for character. It has a more sophisticated methodology, which you can read about in the "How is DVI Different" section.