On the day The Imitation Game hits cinemas, a look at how Allied codebreakers untangled the Enigma
Like all the best cryptography, the Enigma machine is simple to describe, but infuriating to break.
Straddling the border between mechanical and electrical, Enigma looked from the outside like an oversize typewriter. Enter the first letter of your message on the keyboard and a letter lights up showing what it has replaced within the encrypted message. At the other end, the process is the same: type in the ciphertext and the letters which light are the decoded missive.
Continue reading...