Codebreakers at Bletchley Park, c 1942.

UNITED KINGDOM - OCTOBER 22: This shows codebreakers using modified British Typex cipher machines in Hut 6 at Bletchley Park, Milton Keynes, Buckinghamshire. Bletchley Park was the British forces' intelligence centre during WWII, where cryptographers deciphered top-secret military communiques between Hitler and his armed forces. These communiques were encrypted in the Lorenz code which the Germans considered unbreakable, but the codebreakers at Bletchley cracked the code with the help of 'Colossus', the world's first electronic programmable computer, and so aided the Allies victory. (Photo by SSPL/Getty Images)