"On This Date in Cryptologic History" Calendar
1924: Edward Hebern Received Patent
30 September 1924: Edward Hebern received a patent for an electric coding machine, the first U.S. cipher machine to use a rotor.
Unfortunately for Mr. Hebern, both William Friedman and Agnes Myer Driscoll were able to solve messages encrypted on it, so the U.S. Army and the U.S. Navy never used his rotor-based machine.