Nazi code-breaking hardware: photos

They say that it would have taken at least two more years to defeat the German military had some of the Nazis' secret codes not fallen into the hands of the Allies.

(Credit: Daniel Terdiman/CNET)

For decades, since 1918, the Germans had been using Enigma ciphers as the core of their intelligence and military communications system. The Enigma was first invented for scrambling financial communications, but while that use never took off, the military saw the promise of the system. For one thing, the Germans thought Enigma was unbreakable.

But based on techniques arrived at, and a version of Enigma built by Polish mathematicians, the master codebreakers at a secret installation about 45 minutes outside London called Bletchley Park eventually proved the Germans wrong. Still, it took years to beat Enigma, a machine with "complexity [that] was bewildering", according to information provided on the Bletchley Park Museum's website.

At the same time, the Nazi high command was sending coded messages using a device called the Lorenz. To solve that, Bletchley Park's codebreakers came up with a machine called Colossus.

This is a rebuild of the famous Colossus Mark 2 machine that finally allowed the codebreakers to quickly and efficiently break the high command's ciphers. The original Colossus was so secret that after the war was over, it was broken apart and its components destroyed. But because there were 11 surviving pictures of the machine, Bletchley Park museum personnel have been able to build a fully working reconstruction, and visitors to the National Museum of Computing here can see the new Colossus for themselves.

CNET reporter Daniel Terdiman visited Bletchley Park, which is showcased in this gallery, as well as some items from a previous trip to Fort Meade that complement what's on display at Bletchley Park.