Poles\' Role in Breaking Enigma

On 25 July 1939 in Pyry near Warsaw, Polish cryptologists turned over a copy of the German Enigma, the world’s most famous cipher machine, to the French and UK secret services.

What seemed an impossible task was achieved by a team of mathematicians led by Lieutenant Maksymilian Ciężki. For many years, Poland’s crucial role in breaking Enigma has been overlooked.

 In the early 1930s, when the first Enigma-coded signals were communicated on the radio, Lt Ciężki was the head of a German section at the Cypher Bureau in Poznan and it was him who figured out that mathematics should be the key to reveal the machine’s secrets. He invited 26 students of Poznan University’s Department of Mathematics to a course in cryptology. The brightest eight of them later worked in a branch of the Cypher Bureau in Poznan. After three years, three stayed on: Jerzy Różycki, Henryk Zygalski and Marian Rejewski, and it was they who were to crack the Enigma code, later on in Warsaw.

 Enigma’s German designers realised that in case of war the machine would have been seized by the enemy sooner or later. Therefore, messages were secured by changing code keys, which happened every day.  However, one of Berlin’s Chiffierstelle employees was selling the keys to Frenchmen, who shared them with Britons. The Allies judged this intelligence worthless and fed it as such to Poles.

Lt Rejewski focused on the mathematics side of Enigma code right away. He first discovered the cyclical pattern of the code, invented a mathematical model of the machine, and ultimately reconstructed an Enigma clone with its code keys and reconstituted the first encrypted message, just before Adolf Hitler took power in Germany.

Young Polish mathematicians made a few decoding devices, including the so-called cryptologic bomb. Just before the outbreak of the Second World War, the Poles without any preconditions turned their expertise and a copy of Enigma over to the UK and French secret services, at a meeting in a radio intelligence facility in Pyry. That helped the Allies in instantly working out the movements and intentions of German forces.

When the war broke out, most of the Polish cryptologist team went to France. The facility in Pyry was discontinued and the authors of the groundbreaking invention were sidelined, with the British code and cypher facility in Bletchley Park playing an increasingly prominent role in breaking Enigma codes. The Polish cryptologists learnt about the existence of the British facility 30 years after the war. 

The significance of Polish mathematicians’ theoretical input into cracking Enigma codes was most nicely summed up by their British colleague, Professor John Irving Good, who worked at Bletchley Park during the war. Years later, he referred to one of Rejewski’s formulas devised in his pioneering attempt at breaking the Enigma code as “the formula that had won the Second World War.” 

Today in Poland, Enigma can be viewed on display at, among others, the Museum of Science in the Palace of Culture and Science in Warsaw and at the Museum of the Polish Army.

MFA Press Office