German code breaker receives Bletchley Park honours

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Joachim Schueth – the man who beat Colossus in the National Museum of Computing’s Cipher Challenge

A German software engineer has been honoured by the National Museum of Computing at Bletchley Park for deciphering an encrypted radio message faster than Colossus, the British Second World War code-cracking computer.

Joachim Schueth, from Bonn, won the National Museum of Computing's Cipher Challenge on November 15 last year. Today (Saturday, Jan 26) he received his winner’s prize which included a valve from the working Colossus at the Museum, in Block H at Bletchley Park in Buckinghamshire, the war-time home of Colossus.

Using his laptop, Mr Schueth unravelled a code transmitted from the Heinz Nixdorf Museum in Paderborn, Germany, from a Lorenz SZ42 Cipher machine, used by the German High Command to relay secret messages during the war.

He was competing against other amateur code breakers, as well as a Colossus Mark II computer, which has been painstakingly rebuilt over the past 14 years by a team of experts led by Tony Sale, a Founder of the National Museum of Computing.

While the bus-sized Colossus whirred, clicked and clunked for 3 hours and 15 minutes before successfully unravelling the Lorenz code, Mr Schueth, using a program he wrote specifically for the Cipher Challenge, completed the task in just 46 seconds.

Joachim Schueth, speaking in front of Colossus at Bletchley Park, said: “It was unfair because I was using a modern PC, while Colossus was created more than 60 years ago. It really is astonishing and humbling that the world’s first programmable, digital computer was created in the 1940s. Without those Bletchley Park pioneers, I would be out of a job.”

On the Cipher Challenge itself, Joachim added: “I used a laptop with 1.4 GHz CPU, using NetBSD as the operating system. When fed with a usable ciphertext, my program found the settings of all 12 wheels within 46 seconds. During the Cipher Challenge, I actually spent most of the time on signal processing work, converting the noisy audio recording into the ciphertext stream of Baudot symbols rather than with the crypto tasks.

“My laptop digested ciphertext at a speed of 1.2 million characters per second – 240 times faster than Colossus. If you scale the CPU frequency by that factor, you get an equivalent clock of 5.8 MHz for Colossus. That is a remarkable speed for a computer built in 1944. Even 40 years later many computers did not reach that speed. So the Cipher Challenge would have been very much closer had it taken place 20 years ago.”

There were 10 Colossus machines built in the 1940s. They helped shorten the conflict by many months, securing Allied victory and saving many thousands of lives in the process.

Such was the secrecy surrounding the Colossus computers at the time that their very existence was kept secret and scant details about them did not begin to emerge until the 1970s.

Tony Sale said: “Joachim really showed how things have advanced from the days of Colossus. He did brilliantly on this challenge and is a deserved winner of the National Museum of Computing’s Cipher Challenge. As well as recapturing the excitement that the Bletchley Park code breakers must have felt, the Cipher Challenge has more importantly highlighted the magnitude of their achievement, their tenacity and their ingenuity. Not only did they foreshorten the war and save many thousands of lives, they paved the way for the modern computing age.”

The rebuilt Colossus is on public display at The National Museum of Computing at Bletchley Park, Buckinghamshire, following a 14-year rebuilding project led by Tony Sale, a founder of the emerging Museum.

The trustees of the Museum, which is opening in stages, plan to secure £6 million in investment to fully establish and run the facility.

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