When radio communication was first deployed on the battlefield in the late-19th and early 20th century, military commanders faced a challenge: how to ensure these wireless messages did not fall into the hands of the enemy? One of Nazi Germany’s answers to this was Enigma, an encoding machine that had unprecedented capabilities to encrypt communications, with only the intended recipient with their own Enigma able to decrypt and read the message.
During the Second World War, breaking the Enigma encryption took painstaking effort by Allied forces, including the Polish intelligence services and the work of Alan Turing and his team at Bletchley Park. Cracking the code provided essential intelligence to Allied commanders, particularly in the Battle of the Atlantic. Here, historian and author Dermot Turing, and naval historian Larry Paterson, tell us what could have changed if the Allies had failed to achieve such an extraordinary codebreaking feat.
Dermot Turing
What was the Enigma code and why was it such a formidable challenge for codebreakers?
At the beginning of the Great War, the introduction of radio communications made armed forces aware that they needed to think about encryption. Broadcast media was accessible to anybody who happened to be listening. The military devised primitive encryption techniques whereby common words or phrases could be disguised by having code sequences held in a code book.
However, these code books were easy to reconstruct through linguistic analysis. During the interwar period, the Germans invented the Enigma machine, which enciphered a message, so every letter was converted. Instead of a classic Caesar Cipher, where a letter is changed in the same way each time, the encryption happens a different
