Marian Rejewski
Marian Rejewski (pronounced "MAH-ree-ahn re-YEV-skee") (August 26 1905-February 131980) was a Polish mathematician and cryptographer.Born in Bydgoszcz, Rejewski was a fellow of Poznan University and a member of Polish military intelligence. He studied statistics as an advanced student at Gottingen in Germany, and on his return joined the Biuro Szyfrow (Cypher Bureau of Polish Military Intelligence). Shortly thereafter, he was asked to examine the German Army's new crypto system, Enigma, not long after it first came into use.
In doing so, he fundamentally advanced cryptanalysis. Previously, cryptanalytic methods exploited patterns and statistics in natural language writing; for example, letter frequency analysis. Rejewski, however, applied techniques from pure mathematics for the first time in his attack on the Enigma cypher. He was able to deduce not only the wirings of the Enigma rotors used by the Wehrmacht (which differed from those in the closest commercial Enigma variant, model D), but also practical ways to break the cypher as it was then being used. Working with Jerzy Rozycki and Henryk Zygalski, fellow mathematics students form Poznan also working at the Biuro, as well as the Biuro staff, he designed and built a working replica of the German Army machine early in the 1930's.
The group also designed machinery to help with the cryptanalytic work. The cyclometer was the first, followed by the Bomba (more or less, a multiple Enigma). The Bomba could find Enigma keyss (ie, machine settings used for a message) by brute force search if the number of possibilities could be sufficiently reduced beforehand. Similar machines, designed and built later by the British were called bombes, and some built by the Americans, 'bombs'.
Details about the Polish breakthroughs were passed to the Allies (ie, British and French intelligence) in a meeting in Warsaw on 25 July 1939. The German Army had made Enigma changes (in September 1938) which substantially increased the difficulty of breaking messages, and as it became clear that war was imminent, and Polish resources would not be sufficient, the decision was made to look for help. With this assistance, the British (at Bletchley Park, and later the Americans) were able to break not only German Army Enigma traffic, but also German Air Force Enigma traffic, Nazi Party SD traffic, and (though with substantially greater difficulty) German Naval Enigma traffic. It would not be unreasonable to characterize Rejewski's early 1930's conceptual breakthrough as the single most valuable contribution by an individual to the winning of WWII by the Allies.
Rejewski and many others of the Biuro staff were evacuated, with considerable difficulty, from Poland after the Germans attacked. Many of them, including Rejewski, ended up in France at Station PC Bruno, where they carried on their work with the Enigma traffic. When PC Bruno was finally shut down, some, including Rejewski, made it to Britain. Ironically, he was not used for cryptographic work for the rest of the War and was quite surprised to learn (when information about Bletchley Park and its crytanalysts finally became public in the 1970s) of the importance of the work he had begun in the early 30's.
After the WWII he returned to Poland in 1946 to re-unite with his wife and two children. He worked in a factory in Poland until retirement, and was silent about his work during and before the War.
He wrote a book and two articles about his work during the breaking of Enigma, although the book was not published during his lifetime. Rejewski died in 1980 in Warsaw and is buried there in the Powazki Cemetery.
The Polish Mathematical Society has honoured him with a special medal.
An odd footnote to the story of his cryptographic contributions is that his role and importance in WWII cryptanalysis was so obscure that at least one best selling book (A Man Called Intrepid, by William Stevenson, 1976) not only didn't credit him with the work he did (it repeats the 'machine stolen from a transport truck' story, with variations) but identified him as Mademoiselle Marian Rewjeski.
Further reading