I went up to Bletchley Park yesterday, and felt the white heat of the technological revolution -- specifically, the heat given off by roughly 2,500 valves (vacuum tubes), some of them dating back to the war. The Colossus Mark II code-breaking machine has been rebuilt thanks to the efforts of Tony Sale, and it was working fine.
Today, the machine is officially in action. In fact, it's being used to crack German codes in the way it did during World War II. In this case, however, they are friendly messages that have been encrypted using a Lorenz SZ42 machine and transmitted by radio hams in the Heinz Nixdorf MuseumForum, Paderborn, Germany. Amusingly, Bletchley had to lend the Germans their Lorenz SZ42.
Could you do better than an old valve-based computer? This is the basis of the Cypher Challenge. If you fancy a go, here is the Planned Transmission Timetable and some Technical Details.
The Bletchley Park site has more details of The Colossus Rebuild Project. Tony Sale also helped with the code-breaking aspects of Enigma, a film based on a Robert Harris thriller.
My photo shows the back of Colossus Mark II, which you wouldn't usually see. It's not somethng you'd want to reconstruct from scratch, is it?
Update: A German amateur, Joachim Schuth, was first to read the message yesterday. Due to radio reception problems, the Colossus team "did not get a full copy of the enciphered message until after 1700 GMT," reports Mark Ward at BBC News. They did decode the message between 08.55 and 13.15 GMT today.
