Bombe

The Bombe was a machine created by Alan Turing to crack the Enigma machine it was an electromechanical machine that basically bruteforced all the possible settings for a crib(known text), to match up to a enciphered string, by using logical deductions until you got a few possible settings. Then Alan Turing and his group would test them.

It would stop turning on the settings when it got a possible answer and you would get the settings.