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Enigma: The End of The Nazi Mystery

Enigma was the mechanical cipher machine invented at the end of World War I by the German electrical engineer Arthur Scherbius, used for communication by the army units of Nazi Germany during World War II. Calculating and deciphering the codes encrypted by this machine was nearly impossible until the English mathematician, cryptanalyst, computer scientist, logician, philosopher, and theoretical biologist Alan Turing developed a cryptanalytic process called Banburismus at Bletchley Park. This allowed him to crack Enigma’s codes by inventing the code-breaker machine, the Bombe. This article will describe how deciphering the Enigma codes ultimately contributed to changing the course of World War II, and led to the defeat of the Nazis.

A man holds up a newspaper with the headline "Nazis Quit!" amid celebrations (1945). Bettan/Getty Images

After the National Socialist German Workers' Party took over the administration, the German army started to take up arms, first secretly and then openly. While the Germans were preparing for a new war, the remaining powerful countries of Europe, such as France and the United Kingdom, followed a peaceful path to avoid being involved, after the devastating effects of World War I. However, this peaceful approach from the European states was interpreted by Nazi Germany as their weakness. Having been left behind in the arms race, Poland, France, and the United Kingdom were powerless against Nazi Germany (Britannica, 2021). Cracking the codes of the Nazi's encrypted communication machine, Enigma, was crucial to the Allies' cause. By deciphering Enigma, they were able to learn crucial information, such as the numbers and locations of the German forces, as well as their war strategy. With this information, they were ultimately able to successfully use their limited power against the Nazis.

Portrait of Alan Turing (1912-54). Image: Science Photo Library

The British mathematics professor and cryptanalyst Alan Turing was only twenty-seven when he was accepted for the position of decrypting Enigma at Bletchley Radio Manufacturing (O'Connor & Robertson, 2003). Turing believed that the Enigma algorithm was not an encryption that the human brain could decipher. Enigma took each letter as input and applied a random replacement to output the ciphertext, just like any other encryption machine. In this case, all encryption machines are predictable and repeatable.

The feature that distinguished Enigma from other devices was the size of the key setting: the point was not to create ciphers that could never be deciphered, but to delay its decryption as much as possible by using identical machines that resulted in complex setting modifiers with a wide key setting. Enigma was working with a wheel-operated rotary mechanism: a completely new letter was defined for each letter as the wheel was rotated. The Nazis continued to expand the key settings to strengthen Enigma throughout the war. Therefore, even if the enemy had a copy of Enigma, it was almost impossible to find the appropriate key setting among thousands of them, as the key setting was expanding day by day (Ashish, 2022). According to Turing, only another machine could decode a code encrypted by Enigma. Based on this thought, he invented the code-breaking machine calle