Erich Hüttenhain  Erich Hüttenhain (* 26. January 1905 in Siegen; † 1. December 1990 in Brühl) was a German academic mathematician and cryptographer (Cryptography) and considered a leading cryptanalyst in the Third Reich. He was Head of the cryptanalysis unit at OKW/Chi, the Cipher Department of the High Command of the Wehrmacht. Dr Hüttenhain was the son of a Conrector and studied after the high school diploma () 1924 in Siegen at the University of Marburg, the Johann Wolfgang Goethe-University Frankfurt and the University of Münster. He studied mathematics with Heinrich Behnke and astronomy at Münster. There he was assistant to Martin Lindow (1880–1967), who was director of the observatory at Münster. In 1933, at the University of Münster, he took his examination for promotion of Dr. phil. in astronomy under Lindow with the thesis titled: "Spatial infinitesimal orbits around the libration points in the straight-line case of the (3 + 1) bodies". In 1936, he was sent to the cipher bureau of the OKW OKW/Chi under Director Min.Rat. Wilhelm Fenner. Erich Hüttenhain had an interest in Mayan chronology which led him to cryptology and thus to OKW/CHi. As a recruitment test, Fenner had sent him a message which had been enciphered with a private cipher. Hüttenhain duly deciphered it and was accepted as a possible cryptanalyst. At OKW/Chi he was employed as a specialist to build a cryptanalytic research unit, and later he was most recently Executive Council Head of group IV Analytical cryptanalysis. 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. After World War II, being a high value target, he was taken by TICOM to the USA to be interrogated.