Test your knowledge with these top questions!
How many rotors did a standard German army Enigma machine use?
The German navy added a fourth rotor in 1942, and Allied codebreakers needed months of work to break the extra layer.
Which mathematician designed the Bombe machine that broke German Enigma ciphers in World War II?
Turing took the name Bombe from the Polish cryptologic bomb, a machine built years earlier to hunt Enigma's settings.
Which country's codebreakers first broke Enigma and shared their methods with Britain and France in 1939?
Rejewski's team cracked Enigma in 1932 using permutation theory, then shared their methods with Britain and France at Pyry in July 1939.
Which effect of the Enigma's reflector helped codebreakers rule out possible settings?
The reflector also let matching Enigma settings work in both directions, so typing a coded message could decode it.
Which Enigma Machine component swapped letter pairs before and after rotor scrambling?
The plugboard swapped selected letter pairs at the machine's input and output, adding another substitution layer.
Who proposed using Navajo speakers for a U.S. military code in World War II?
Philip Johnston grew up around the Navajo reservation, learned the language, and pitched the idea to the Marines.
The Zimmermann Telegram promised Mexico help to reclaim which U.S. states?
Germany offered an alliance and financial support if Mexico fought the United States alongside Germany.
PURPLE’s cipher mechanism used which component?
Unlike rotor machines, PURPLE used telephone-style stepping switches to produce changing substitution alphabets.
PURPLE primarily encrypted what kind of Japanese messages?
PURPLE protected high-level diplomatic traffic; Japan’s military services used separate systems for military communications.
Which U.S. military branch first recruited Navajo speakers for a World War II code program?
Philip Johnston proposed the idea to the Marines in 1942, leading to the first 29 Navajo recruits.