The Enigma VS Alan Turing
After the Vignere cipher was cracked, cipher technology stagnated for a long period of time. New ciphers were invented, but all these ciphers were easily cracked, and private transmissions, especially in the military, were being cracked left and right. That was until Arthur Scherbius invented a device called the Enigma.
The Enigma took advantage of electronic engineering to create a cipher that was almost unbreakable, while still being easy for the intended receiver to decipher. The Enigma machine consisted of multiple rings, each with a maze of wires on them like so:
The operator would type a letter, and the letter would correspond to a wire on the first wheel, which would correspond to a wire on the second wheel, and so on, depending on how many wheels the machine had(the number varied from model to model). Finally, each wire of the last wheel corresponded to a lamp with a letter on it, which would be lit up. revealing the letter in the ciphertext. This may seem like a simple substitution cipher, but that is only the beginning. Every time a letter was typed, the first wheel would move, creating a new path for the wires, and in effect, a new key. Every time the first wheel made a full rotation, the second wheel would move. Every time the second wheel made a full rotation, the third wheel would move, and so on. This created a ridiculous number of keys, 105,456, in fact, and that’s for just the 3-rotor model. Rotors could also be swapped out with other rotors, providing even more keys.
The Enigma models were invented in the 1930s and famously sold to the German government, which used them to send military transmissions. Adolf Hitler was chancellor at the time, and his blitzkrieg military strategy relied heavily upon fast, secret communications. Therefore, the Enigma played a huge role in the German military, and by extent, WW2. It became such a major player that the UK started a brand new cryptoanalysis department for the purposes of trying to crack the Enigma code. Eventually, the mathematician Alan Turing figured out an exploit which is a bit too complex to explain here, but regardless, the Enigma was cracked.
