Christopher is the name given in The Imitation Game to the codebreaking machine built by Alan Turing’s team.
The 2014 film uses “Christopher” as Turing’s personal name for the machine, recalling his childhood friend Christopher Morcom. In the story, the machine is designed at Bletchley Park to help break German Enigma messages during World War II.
Historically, the British machine was known as the Bombe. Turing was a major contributor to its design, working with Gordon Welchman and other cryptanalysts. The film’s personal naming choice makes the machine an emotional symbol as well as a technical device.
A frequent mix-up is answering “Colossus.” Colossus was a separate British machine used primarily against the Lorenz cipher, not the Bombe used against Enigma.