Whose code was broken at Bletchley Park?

During the Second World War, the British codebreaking centre at Bletchley Park worked to break the encrypted communications of Nazi Germany. Their most famous target was the Enigma machine, a device the Germans used to scramble military messages in ways they believed were unbreakable. A team of brilliant minds, most notably the mathematician Alan Turing, developed machines called bombes to help crack the daily Enigma settings. They also broke the even more complex Lorenz cipher used for high-level German commands, which spurred the creation of Colossus, one of the first programmable electronic computers. The intelligence gained, code-named Ultra, is widely credited with shortening the war by an estimated two years and saving countless lives. The work remained secret for decades after the war ended.