1In 1938, the British government bought Bletchley Park, a sixty-acre estate about 90 miles north of London. 2At a safe distance from German air attacks, the estate being a secret location for decoding messages sent by the German army.
3The coding machine used by the Germans, called Enigma, was invented in 1922 by a German engineer. 4The code breakers at Bletchley Park obtained a replica of an Enigma machine in 1939. 5The keyboard was similar to a German typewriter. 6A system of parts changed the input letters many times.
7The German government assumed that the Enigma’s codes were unbreakable. 8Nonetheless, a number of things helped the cryptographers at Bletchley Park break the code. 9First, there was a flaw with the Germans’ machine. 10No letter could represent itself in a coded message. 11For example, the letter "A" could be represented by any other letter except "A." 12Messages also repeated formulaic information. 13For example, standard greetings followed by a weather report were often the first part of messages. 14The workers at Bletchley Park, knowing both the machine’s flaw and the formulaic nature of German messages, worked until the code was eventually broken.