Desirable World War II–era American M-209-B mechanical pin-and-lug cipher machine, measuring 7.25˝ x 5.25˝ x 3.5˝, identified on the plate on the top of the case: "Signal Corps, Converter M-209-B, 79306:CACH, 19449-PHILA-44-24." Held inside the top of the case are the oiler, screwdriver, paper tape, and tweezers. Also includes the original olive drab canvas carrying bag, marked "M-209-B" on the front, with the front pocket containing a spare reel of paper tape, TM11-380 War Department Technical Manual, and Signal Corps Message Book M-210.
The M-209 is a portable hand-operated mechanical cipher machine initially developed in the late 1930s by the entrepreneur and inventor, Boris Hagelin. Hagelin fled Sweden for the United States at the outbreak of WWII and worked with the US Military to refine his cipher machine design. The M-209 was the result of this collaboration and the machine would be used by the US during WWII, as well as many other countries for decades after the end of the war. The relationship between Hagelin and the US goes much deeper than the collaborations during WWII: a February 2020 article in the Washington Post detailed the secret relationship Hagelin had with the CIA and German Intelligence services. The development of the M-209 led to one of the biggest intelligence operations in CIA history, known as 'Operation Rubicon.' In this operation the CIA used their secret technique to allow them to read all of the M-209 and other Hagelin cipher machine-enciphered messages until 2018.
This rotor-based cipher machine does not require electricity and is lightweight and durable, making it perfectly suited for tactical front line use. While the code generated by the M-209 was not as strong as the Enigma code, and could sometimes be read within 4 to 24 hours by the Germans, it was considered secure enough for tactical messages that were of no value after that length of time. The key is set by using the six adjustable cipher wheels with moveable lugs. Text is entered letter-by-letter using the selector wheel on the left side, and the encoded output letter is printed on the narrow paper strip.
