Hebern rotor machine

The Hebern Rotor Machine was an electro-mechanical encryption machine built by combining the mechanical parts of a standard typewriter with the electrical parts of an electric typewriter, connecting the two through a scrambler. It is the first example (though just barely) of a class of machines known as rotor machines that would become the primary form of encryption during World War II and for some time after, and which included such famous examples as the German Enigma. Edward Hugh Hebern was a building contractor who was jailed in 1908 for stealing a horse. It is claimed that, with time on his hands, he started thinking about the problem of encryption, and eventually devised a means of mechanizing the process with a typewriter. He filed his first patent application for a cryptographic machine (not a rotor machine) in 1912. At the time he had no funds to be able to spend time working on such a device, but he continued to produce designs. Hebern made his first drawings of a rotor-based machine in 1917, and in 1918 he built a model of it. In 1921 he applied for a patent for it, which was issued in 1924. He continued to make improvements, adding more rotors. Agnes Driscoll, the chief civilian employee of the US Navy's cryptography operation (later to become OP-20-G) between WWI and WWII, spent some time working with Hebern before returning to Washington and OP-20-G in the mid-'20s. Hebern was so convinced of the future success of the system that he formed the Hebern Electric Code company with money from several investors. Over the next few years he repeatedly tried to sell the machines both to the US Navy and Army, as well as to commercial interests such as banks. None was terribly interested, as at the time cryptography was not widely considered important outside governments. It was probably because of William F. Friedman's confidential analysis of the Hebern machine's weaknesses (substantial, though repairable) that its sales to the US government were so limited; Hebern was never told of them.