Original URL: http://www.theregister.co.uk/2013/03/05/enigma_challenge/

Wannabe infosec kiddies put Enigma Bombe machine to the test

Shove off, Simon Cowell. This is the X Plus Why? Factor

By John Leyden

Posted in Security, 5th March 2013 09:34 GMT

GCHQ historians will this month put the team that rebuilt the British code-cracking Bombe machine to the test in a third Enigma Challenge.

The Bombe squad will race against time to break Enigma-encoded messages sent by members of the public and GCHQ’s Historical Section. The exercise is due to take place at The Big Bang Fair, a four-day event for young scientists and engineers at London’s ExCel centre between 14 and 17 March.

Visitors to the X Plus Why? Factor stand will be able to encrypt a message on a real German Enigma machine and send it Bletchley Park, the home of British wartime code breakers.

Once at Bletchley, the message will be decrypted using the original procedures and reconstructed code-cracking Bombe machine technology, mimicking the task face by Bletchley's boffins during the Second World War. The decoded message will then be tweeted back to The Big Bang Fair, the whole process displayed live on large TV screens at both sites.

The modern-day code-breakers at Bletchley Park will use the Bombe Rebuild, which is a faithful copy of the original, built as a tribute to those who invented, built and maintained the machines that were crucial to the Allies' success. The electromechanical Bombe machine was developed at Bletchley Park to speed up the process of deducing the encryption configuration of Enigma machines. The three-rotor German contraption had approximately 158 million million million possible settings for scrambling military memos.

The previous Enigma Challenge, held in October 2012, involved the Bombe team beating its own record time for deducing the Enigma settings. The GCHQ historians were at the Museum of Science and Industry in Manchester, where visitors were able to send their own enciphered messages. The fastest time in which the Bombe squad breaking the German device's encryption was two hours and fifteen minutes. They were then able to decipher messages quickly and tweet the plain text so those taking part could get a better idea of how the process worked.

Veteran wrens who operated the machines during the Second World War recall it took an average of four hours each night to work out the day’s settings on each German military network, most of which were changed at midnight every day. ®