Among the notorious inventions used by the Third Reich was the Enigma cipher machine. Still many people do not know that it was the Poles who had a significant influence on breaking its ciphers.

The origins of the Enigma date back to 1918, when the German company Scherbius & Ritter began manufacturing the cipher machine. The device was significantly improved in 1928, based on a patent by Dutch inventor Hugon Koch. Initially, the Enigma was used for the secrecy of commercial correspondence, achieving considerable success in the market. Gradually, many countries began to use it in diplomacy and the armed forces. In Germany, it was used by the Kriegsmarine from 1926, and in 1928 it was introduced into the Wehrmacht’s equipment. Then, after Adolf Hitler took power, it was sent to the Luftwaffe and also to police units. Subsequently, Enigma served the German army during the Second World War, and breaking its cipher became one of the Allies’ main objectives.

However, before 10,000 British experts at the Bletchley Park facility began working on Enigma, Poles became interested in it. As early as the late 1920s The Cipher Bureau of the Second Division of the General Staff decided to take serious steps to decipher the German machine. Having recognised the complexity of the code, which neither the English nor the French had so far managed, a mathematical approach, avant-garde at the time, was implemented instead of the linguistic analysis that had previously dominated the world of cryptologists.

Among the mathematics students admitted to the secret cryptology course were three future Enigma ‘slayers’: Marian Rejewski, Henryk Zygalski and Jerzy Różycki. By 1932, the team of cryptologists, with Rejewski in the lead, had managed to break the code of the civilian version of the device. However, the Enigma model used by the German military had a cable switch and several other improvements that complicated the matter. The work of the cryptologists was a constant race with the German ciphers, who were constantly creating more perfect versions of the machine. In the end, the Poles managed to combine several solutions, resulting in the so-called Rejewski bombs and Zygalski sheets, which allowed most of the encrypted messages to be read. In the summer of 1939, when the threat of German invasion loomed over Poland, the data was passed on to French and English intelligence, which in the future influenced the outcome of the Second World War.