Your article says GCHQ has often highlighted the success British cryptanalysts had in cracking the German Enigma machines during the second world war (Get cracking: work as a team to solve our festive puzzle, says GCHQ, 14 December). But let’s not forget where Enigma codebreaking had its beginnings – Poland.
This year marks 90 years since Marian Rejewski broke the Enigma code. Thanks to the achievements of cryptologists and possession of the commercial machine and documents provided by French intelligence, Poles started work on building a copy of the Enigma soon after. To put that into perspective, on 30 January 1933, one month after the code was broken, Hitler became chancellor of Germany. With the second world war looming, Poles had to share their knowledge about the Enigma with British and French colleagues. During a meeting in Pyry, near Warsaw, in July 1939, Rejewski and his colleagues demonstrated how to crack the machine and gave each allied side a replica. This allowed Alan Turing to continue their work at Bletchley Park.
Having returned from the UK to a communist-ruled Poland after the war, for many decades Rejewski could not speak about his achievements. In 1973, when the French intelligence chief Gustave Bertrand released his memoirs, Polish newspapers started looking for codebreakers. It was only then that Rejewski came forward as the cracker of the Enigma code.
Robert Gawłowski
London