Government Code and Cypher School

The Government Code and Cypher School was a school at Bletchley Park during World War II. It was vital to the allied war effort. Teams of code-breakers cracked the Enigma and Lorenz cyphers used by German forces to communicate. Some historians estimated that their work shortened the war by as much as four years. (PROSE: A History of Humankind)

Behind the scenes
In the real world, the Government Code and Cypher School is today more commonly known as GCHQ.