In the Second World War the German military used a small coding machine called Enigma to encode and send secret messages. They believed the Enigma was invincible and its codes unbreakable. What they didn't know was that Britain's code-breaker's at top secret Bletchley Park had cracked the cypher early on in the war and were reading Enigma's coded messages for much of the conflict.
This insider information gave the Allies access to everything...