In 1930 Pietsch was appointed to the mathematical review journal,
Jahrbuch über die Fortschritte der Mathematik and held the position until the start of
World War II. This included the mathematicians
Herbert von Denffer,
Friedrich Böhm and
Hans-Peter Luzius. When he left the internment camp, Pietsch returned to work as an editor, gaining employment at the Jahrbuch über die Fortschritte der Mathematik and the
East German Academy of Sciences in
East Germany, and he maintained these positions until he died in 1967. and rested upon the discovery of a solved Enigma message that had been discovered in the Cryptanalytic Bureau
Wicher organisation in Warsaw, Poland in 1939. This was an Enigma message that had been transmitted from a German cruiser in Spanish waters during the
Spanish Civil War and had been transmitted using the officers cipher. Pietsch along with Bohm and Steinberg played an important role in conducting security studies into the Enigma that resulted from Case Wicher in the years that followed the discovery of the solved message. Two specific instances of studies leading to action were demonstrated. The first was the discovery that double encipherment of the indicator was a serious insecurity in the use of the Enigma. As a result, on 1 May 1940, nine days before the beginning of the western campaign, in army and air force, the key procedure was radically changed for the Army and Luftwaffe Enigma machines. The second in 1944 was when Pietsch recommended that the Enigma daily use should be set below 20000 letters of use a day. ==Bibliography==