The history books give credit for breaking the Enigma cipher to the brilliant mathematicians at Bletchley Park, particularly Alan Turing. What those books often omit is that by the time the British got seriously involved, Polish cryptanalysts had already broken Enigma — and had been reading German military communications for years.
Marian Rejewski was born in Bydgoszcz in 1905. In 1932, while working for the Polish Cipher Bureau at just 27 years old, he was given a near-impossible task: break the German Enigma machine using only mathematical analysis. The Poles had obtained a commercial Enigma machine and some documents through a French intelligence source, but the military version was different and should have been unbreakable.
Rejewski attacked the problem using group theory and abstract algebra — mathematical tools not normally associated with cryptanalysis. German operators habitually followed a protocol of transmitting the message key twice at the start of each message. Rejewski realized that this repetition created a mathematical structure that could be exploited. He worked through the winter of 1932-33 and emerged with the solution: a mathematical description of how to reconstruct the Enigma's settings for any given day.
The Polish Cipher Bureau built replica Enigma machines and electromechanical devices called "bomby" to speed up the decryption process. For years, they read German military communications. Then, in 1938, the Germans increased Enigma's complexity: instead of three rotors, operators could choose from five. The number of possible settings increased exponentially. The Poles could no longer keep up.
In July 1939, facing an inevitable German invasion, the Polish Cipher Bureau made the fateful decision to share everything they had learned with the British and French. At a meeting in Warsaw, Rejewski and his colleagues handed over their replica Enigma machines, their mathematical methods, their bomby blueprints — everything.
The British were stunned. They had not cracked Enigma at all and had not known the Poles had. With this foundation, Alan Turing and Gordon Welchman built the more advanced British bombes at Bletchley Park. It was not Turing who first broke Enigma — it was Rejewski. Turing extended and industrialized the work.
Rejewski survived the war, eventually reaching Britain, but could not reveal his wartime work. He returned to Poland after the war where he lived quietly working as an accountant, his cryptographic achievements classified. Only in the 1970s did the full story begin to emerge. He died in 1980, having seen the beginning of his recognition but not its full extent. The statue of him in Poznan, unveiled in 2007, stands in quiet tribute to perhaps the most underacknowledged genius of the Second World War.