1930s Polish cyclometer (Enigma code-breaking machine) rebuilt at Cambridge

A computing history item, rather than a retro-computing item.

Cambridge Engineering alumnus Hal Evans has built a fully-functioning replica of a 1930s Polish cyclometer—an electromechanical cryptologic device that was designed to assist in the decryption of German Enigma ciphertext. The replica currently resides in King’s College, Cambridge.
Hal said he chose to work on the cyclometer as it was the very first machine used to assist the decryption effort. To his knowledge, the replica is the first fully-functioning hardware-based electromechanical cyclometer to exist since the years preceding the Second World War. The original machines would have been destroyed in 1939 to prevent them from falling into the hands of German invaders.

“Due to the cost and the mechanical complexity of reproducing the original machine, other efforts to create a replica have been software-based to date,” said Hal. "This presented an opportunity to recreate an important fragment of history. It has been a privilege to work on such a unique project which is a fascinating combination of Engineering, History and Mathematics. The replica took just over a year to complete, with generous funding from King’s College, which saw the obvious link with the work of one of its most famous alumni, Alan Turing.

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