Elizebeth Smith Friedman’s recovery of the wiring of two rotors from an enigma D machine
Department or Administrative Unit
In January 1940, the U.S. Coast Guard intercepted numerous messages that were encrypted on a commercial Enigma D machine using the same key. By solving these messages in depth and examining the resulting cipher alphabets for each position of the rotors, the Cryptanalytic Unit, headed by Elizebeth Smith Friedman, was able to recover the wiring of two of the rotors. This paper explains Friedman’s methods in detail and uses them to determine the wiring of two rotors from an Enigma M3 machine.
Boersma, S. (2022). Elizebeth Smith Friedman’s recovery of the wiring of two rotors from an enigma D machine. Cryptologia, ahead of print, 1–25. https://doi.org/10.1080/01611194.2022.2109944