The Germans had cipher devices even more sophisticated than the Enigma. The Lorenz SZ40/42, given the code name Tunny (British slang for "tuna"), was one such high-grade cryptomachine. It used the international telegraphic "Baudot" cipher and an additive placed on the cipher by the rotors to stream high-level teleprinter messages, according to the NSA. Bletchley Park researchers focused on the Tunny, which was in full use by the Germans for high-level communications by 1941.
Credit: National Security Agency
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