Rudolf Paul Joachim Kochendörffer (21 November 1911 in Pankow – 23 August 1980 in Dortmund) was a German mathematician who was a Professor of mathematics in the University of Rostock specialising in algebra, Group theory and theory of finite groups and their representation.
During World War II, Kochendörffer worked as a mathematical cryptanalyst in the mathematical referat of Inspectorate 7/IV, that would later become part of Referat I of Group IV of the General der Nachrichtenaufklärung (abbr.
GDNA), the signals intelligence agency of the Wehrmacht and was known as a cryptographic tester of the Enigma cipher machine.
Kochendörffer was a Member of the Scientific Advisory Council for Mathematics at the State Secretariat for the Higher and Specialist Schools of the GDR, a staff member of Mathematical Reviews and collaborated with the Zentralblatt MATH