During his time in OKW/Chi he succeeded, among other things, in the deciphering of the Japanese Purple cipher machine (William Frederick Friedman) He and his staff also temporarily succeeded in deciphering American rotary machines, such as the M 138 A and the M-209 in North Africa. Later in the war, when the allies invaded Italy, the allies learned in turn by deciphering Italian ciphers that their later systems, e.g. among others the SIGABA designed by Friedman, had not been broken and around that time, Hüttenhain had no more major successes.