A Cambridge post-graduate student has recreated the “cyclometer”, the decryption device devised by Polish mathematicians that informed Alan Turing’s later code-breaking efforts.

Turing famously devised the “Bombe”, a machine that was capable of decrypting messages encoded by Nazi Germany’s fiendish Enigma machines. Breaking the Enigma code produced intelligence credited with shortening the Second World War and saving innumerable lives. Turing’s work on the Bombe grew into the digital computers on which you are reading this story.

While Turing has rightly been celebrated, Polish mathematician Marian Rejewski intuited the workings of Enigma and devised machines capable of decrypting Enigma-coded messages. The cyclometer was their first effort and a later project, “bomba kryptologiczna”, was an even better code-breaker.

Rejewski and his colleagues were known to allied intelligence, which recognised the value of their work and kept the team out of Nazi hands. Alan Turing met the team in France to talk crypto in the early months of 1940. The team moved to Vichy, France, and later escaped to the UK where they worked at Boxmoor in Hemel Hempstead, and Turing again took up their work to produce his own devices at Bletchley Park.

Masters student Hal Evans is the proto-boffin behind the box, and said that it interested him because it’s previously been reconstructed only as software.

In the video below, Evans shows off the machine and explains its workings.

Youtube Video

Evans believes his replica is the first working or complete Cyclometer in existence since the war.

“The successes at Bletchley Park are well known in the UK and, while the Polish contribution is certainly acknowledged, I think its exact extent and significance are not widely recognised,” Evans said. “Researching into Rejewski and his colleagues, I wanted to discover more about their efforts, and the more I looked, the more interesting the story became – quite how advanced the Poles were in their understanding of Enigma compared to the British in 1939 is remarkable.” ®

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