The Imitation Game Christopher soon dies from tuberculosis. When Britain declares war on Germany in 1939, Turing travels to Bletchley Park. Under the direction of Commander Alastair Denniston, he joins the cryptography team of Hugh Alexander, John Cairncross, Peter Hilton, Keith Furman and Charles Richards. The team are trying to decrypt the Enigma machine, which the Nazis use to send coded messages. Turing is difficult to work with, and considers his colleagues inferior; he works alone to design a machine to decipher Enigma. After Denniston refuses to fund construction of the machine, Turing writes to Prime Minister Winston Churchill, who puts Turing in
Cryptanalysis of the Enigma defined somewhat differently in that era than in modern cryptography. First, there is the "identification" of the system in use, in this case Enigma; second, "breaking" the system by establishing exactly how encryption takes place, and third, "solving", which involves finding the way that the machine was set up for an individual message, "i.e." the "message key". Today, it is often assumed that an attacker knows how the encipherment process works (see Kerckhoffs's principle) and "breaking" is often used for "solving" a key. Enigma machines, however, had so many potential internal wiring states that reconstructing the machine, independent of particular