Hitler’s most secret code machine comes to Bletchley Park

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Hitler’s most secret cipher machine has arrived at The National Museum of Computing at Bletchley Park.

The 1940s Lorenz SZ42 was cutting edge technology in its time and is extremely rare today.

It will join the other code-breaking machines, including the famous Enigma, at the museum.

Much more complex than the enigma, the Lorenz cipher could only be broken by clever deduction from Bill Tutte who worked out the machine’s architecture without ever having set eyes on it.

As a result, the Allies were routinely able to read German High Command’s top secret messages.

From 1944, with the creation of the colossus computer by Tommy Flowers, they were able to reduce the decrypt time from weeks to just hours.

The Lorenz was handed over to the museum on long-term loan this week at a ceremony in London.

The audience included two Wrens who had worked on Colossus, along with relatives of those involved in the breaking of Lorenz.

It is estimated that about 200 Lorenz machines were in existence during World War II, but only four are known to have survived.

The machine to be displayed at TNMOC has the serial number 1137 and was used at the German HQ in Norway at Lillehammer, north of Oslo.

Since Norway was occupied by the Germans until the end of the war, it is believed it will have received the final surrender instruction message at 24:00 hrs on 8 May 1945, marking the end of the war.

The loan to the museum completes the set of artefacts that tell the remarkable Lorenz story in its entirety from encrypt to decrypt.

Nowhere else in the world is it possible to see the full range of innovative technologies used by both the British and the Germans to send and receive the most complex and important encrypted messages of World War II.

Irene Dixon, one of the first operators of Colossus in 1944, said: “I am thrilled that TNMOC is able to tell the Lorenz story even better than before by displaying the amazingly complex Lorenz machine. For years, I had to keep silent about the incredible work of Tommy Flowers and his team, but the growing publicity today about their achievements is very exciting. I would love every schoolchild to know the names of Tommy Flowers and Bill Tutte.”

Receiving the Lorenz machine, Andy Clark, chairman of TNMOC, said: “We are enormously grateful to the Norwegian Armed Forces Museum for its generous loan. It completes a truly unique set at TNMOC and helps bring further life to the story that we have always wanted to tell as clearly and dynamically as possible. The technologies at the core of the Lorenz story – encryption, communications and computing – are at the very heart of our modern world, so the narrative is as relevant today as it was then and an inspiration to the next generation of computer scientists and engineers.

“In leading the team to rebuild Colossus and co-founding TNMOC, the late Tony Sale had the dual aims of honouring all those who worked in wartime Bletchley Park and ensuring that the once-secret story of the breaking of Lorenz could inspire future generations. I’m sure that he would be thrilled that his vision is being advanced by the arrival of the Lorenz. It brings into even sharper focus the astonishing achievements of those wartime code-breakers.”

Margaret Sale, a trustee of TNMOC and wife of the late Tony Sale, said: “When Tony and I became founder members of the Save Bletchley Park Campaign in 1992 to honour all the wartime codebreakers, we never dreamed that we would be able to tell the story of the most important wartime code-breaking at Bletchley Park so well. TNMOC volunteers have worked with great determination and resourcefulness to source original equipment where possible and reconstruct where necessary. We even have an original Spruchtafel, the Lorenz wheel-setting aid, kindly loaned by fellow trustee, Tim Reynolds. It is only one of two known to be in existence!”