The Enigma Machine
by Laasya Aki
During World War II, both the Allies and Axis powers transmitted encrypted messages, in case they were intercepted by the enemy. Encryption methods were simple at first, easy to decipher with just a pen and paper. For example, the Caesar cipher used a shift mechanism to encode the message. Though, this method of encryption is weak. After each method of encryption proved to be unsuccessful, another method was created, designed to be more secure than the previous.
As encrypted messages evolved to be more complicated, ordinary members of the army couldn’t decrypt messages. Mathematicians and cryptologists were tasked with creating “unbreakable” ciphers and decrypting encoded messages, but most of these ciphers proved unsecure.
Then, the enigma machine was created.
The Machine
Created in 1919 by Dutchman Hugo Koch, the Enigma machine looked like a typewriter and was used for business purposes (3). Later, the Germans adapted the invention to serve a purpose in the war. The Enigma code was composed of substitutions, similar to the Caesar cipher, but more powerful. A Caesar cipher makes use of a key to determine how many letters in the alphabet each letter in the original message should be shifted by. If the message is “hello” and the key is 3, the encrypted message would be “khoor.” But, if the key is available, decrypting the message is simple. Even if the key is unknown, there are only 26 possible keys, meaning that this method of encryption is unsecure. The Enigma code mapped a letter to another based on a key, but after each letter was changed, the key was changed. Every time a letter key was pressed on the machine, the rotors turned, and the key changed (3).
The machine consisted of rotors, a keyboard, a lamp board, a plugboard (military only), and internal electronic circuits. When a letter key was pressed, the rotors would spin and encode one letter as another. Then, the output letter lit up on the lamp board. The plugboard contained slots where wires could be plugged in, altering the settings of the machine. The rotors were capable of being interchangeable and oriented in different ways, which added another level of security. Enigma machine operators received a notebook every month that contained specific plugboard and rotor settings to use each day.
This machine’s ciphers proved secure for some time, but they were cracked by the Allies using logic, math, and a large machine.
Cracking the Code
Alan Turing was a British mathematician and logician who is credited with developing the first modern computer. Turing was working at Bletchley Park, where top secret information was being processed and German codes were being deciphered (2). As one of the best mathematicians in the Park, he was tasked with breaking the Enigma codes.
Modifying the Polish Bomba machine, a device used to break Enigma code prior to the war, Turing created the British Bombe machine. This apparatus tried to determine the settings that the Enigma used to encode a message to decipher the code. The Bombe was basically 36 Enigma machines put together, with different drums to simulate the rotors on the Enigma. Different configurations were tested until the correct one was found. The Bombe could break any Enigma code in under 20 minutes, significantly less time than it took humans to complete the same task.
Conclusion
The Enigma machine is one of the most significant examples of ciphers. Without the use of encoded messages, enemies can easily intercept them, especially when they were hand-delivered. Turing’s work with the Bombe machine shortened World War II by two to four years, securing a win for the Allies. This historical example demonstrates how important strong encryption is needed to ensure security.
~ Edited by Christian Mueth
References:
- https://brilliant.org/wiki/enigma-machine/
- https://www.iwm.org.uk/history/how-alan-turing-cracked-the-enigma-code
- https://www.history.com/this-day-in-history/enigma-key-broken#:~:text=The%20Enigma%20machine%2C%20invented%20in,considered%20its%20encoding%20system%20unbreakable.
- https://www.tnmoc.org/bombe
This article was originally published at the Teach-Technology Organization, Inc. online technology blog. I volunteer as a tech blog writer at this organization, which is dedicated to bridging the gap between seniors and technology. You can read this article (and many more) at the Teach Technology site.
tags: TeachTech - math - technology