Ekhall, MagnusWaldispühl, MichelleMegyesi, Beáta2024-05-082024-05-0820241736-6305https://hdl.handle.net/10062/98468https://doi.org/10.58009/aere-perennius0093The M-209 cipher machine was used extensively by the U.S.A. during WorldWar II. It is known that German cryptanalysts under certain circumstances were able to decipher M-209 enciphered messages using pen-and-paper techniques. A German wartime document found by the allies’ Target Intelligence Committee (TICOM) in 1947 describes a electromechanical machine that supposedly could be used as an aid when breaking M-209 enciphered messages. The document, designated DF-114 by TICOM, is quite technical but does not describe how the device would work. This paper suggests a theory of how the device could have been used, and by creating a computer simulation of the device described in DF-114 explores the viability of the theory.enAttribution-NonCommercial-NoDerivatives 4.0 InternationalM-209TICOMHagelinCryptanalysisWorld War IIArticle