Erich Fellgiebel

Fritz Erich Fellgiebel was a German Army general of signals and a resistance fighter, participating in both the 1938 September Conspiracy to topple dictator Adolf Hitler and the Nazi Party, and the 1944 20 July plot to assassinate Hitler. In 1929, Fellgiebel became head of the cipher bureau of the Ministry of the Reichswehr, which would later become the OKW/Chi. He was a signals specialist and was instrumental in introducing a common enciphering machine, the Enigma machine. However, he was unsuccessful in promoting a single cipher agency to coordinate all operations, as was demanded by OKW/Chi and was still blocked by Joachim von Ribbentrop, Heinrich Himmler and Hermann Göring until autumn 1943. It was not achieved until General Albert Praun took over the post following Fellgiebel's arrest and execution for his role in the 20 July attempted coup.