Colossus cracks German code 60 years on - but it's not the first!

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The National Museum of Computing's Cipher Challenge won by German amateur

Colossus, the Second World War computer, today successfully deciphered a coded message transmitted from Germany, recapturing the drama and excitement of Bletchley Park's code-breaking legacy.

Experts using the newly-rebuilt machine at the National Museum of Computing in Bletchley Park, Buckinghamshire, managed to beat a number of rival code breakers using modern-day computers.

But, more than 60 years on from when it helped secure the Allied victory in the war, today's Colossus team had to doff their caps to an amateur enthusiast from Germany. Joachim Schueth, a computer enthusiast from Bonn, was first to crack the message using a program he wrote specifically for The National Museum of Computing Cipher Challenge.

Andy Clark, a director of the National Museum of Computing said: "Colossus has managed to crack the Germans' code just like the old days -- although thankfully today's message was entirely peaceful in content. Mr Schueth has done fantastically well to decipher the messages first. We are delighted and most impressed by his work.”

The Cipher Challenge began yesterday when encrypted messages were transmitted from the Heinz Nixdorf Museum in Paderborn after being encrypted using the Lorenz SZ42 cipher, the same machine used by the German high command in war time.

Meanwhile at Bletchley Park Block H, the computer nerve centre used by Churchill's intelligence operations during the war, a Colossus Mark II machine, which took 14 years to rebuild, clicked and whirred into action.

Adverse atmospheric conditions produced by the sun spot cycle interfered with Bletchley Park's reception of the Paderborn transmissions on Thursday.

"While Mr Schueth was working his way to success, the Colossus team at Bletchley was struggling to get a signal – reminiscent of certain modern-day mobile phone networks," said Mr Clark.

Verifiable cipher text was eventually obtained on Thursday evening and transferred to punched paper tape for Colossus. That text was loaded on Colossus at 0855 today (Fri) and the machine started. By 1315 it had cracked the hardest of the cipher challenge messages, which had content relating to the Heinz Nixdorf Museum in Paderborn.

Andy Clark said: "The official run time for Colossus cracking the code was three hours and 35 minutes - we had 45 minutes 'injury time' when we had to replace a valve!"

The Cipher Challenge continued tonight for many amateur code breakers still battling to unravel the messages which are now available on the National Museum of Computing website www.tnmoc.org

The 10 original Colossus machines, which were located at at Bletchley Park, enabled code breakers to decrypt top-secret communications sent by German high command, leading to the war being shortened by many months and saving thousands of lives.

Owing to the secrecy surrounding Colossus at the time, the dismantling of machines at Bletchley was ordered immediately after the war. Two were sent elsewhere and dismantled in the 1960s.

Over the past 14 years Tony Sale, of the National Museum of Computing, has led a team rebuilding a Colossus computer using fragments of design plans and photographs and by gleaning information from those involved in the creation of the original.

“On the strength of today's performance, Colossus is as good as it was six decades ago,” said Tony Sale. “We are delighted to have produced a fitting tribute to the people who worked at Bletchley Park and whose brainpower devised these fantastic machines which broke these ciphers and shortened the war by many months.”

“The rebuild was extremely difficult because a lack of information, but the actual construction and its operation today was a much easier task. Everything went smoothly until a thyratron valve blew at a very inopportune moment and delayed us by just over half an hour.”

Andy Clark concluded: “We are full of admiration for Mr Schueth’s achievement and look forward to inviting him to visit Colossus to receive a very special prize. He wrote a program that was highly optimized for the challenge and he obviously designed it very well. We're really pleased and very impressed. It highlights the strength of the international community working together. I said if someone could crack the code before Colossus I would buy them a beer, so, as a man of my word, Mr Schueth, the first round's on me!"

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