Virtual Code Machine for Messages Between Hitler and Generals Appears Online

The British National Museum of Computing has put online a virtual version of the Lorenz SZ42 machine, which, among other things, encrypted messages between Hitler and his generals during World War II.

The museum says it has unveiled the virtual variant in honor of Bill Tutte, who was born about a hundred years ago. He was instrumental in cracking the Lorenz code. According to the museum, this was one of the “greatest intellectual achievements of the war.” The Germans used the Lorenz cipher machine to encrypt messages at the highest level. The device uses twelve rotors and applies a Gilbert Vernam coding method.

The cracking of the communication was eventually made possible by intercepting two almost identical, encrypted texts that differed from each other in certain respects due to the use of abbreviations. Crucially, the same setting of the machine was used twice. This eventually made it possible to decrypt messages sent with the Lorenz machine. This was done, among other things, with the help of the Colossus computers.

Martin Gillow, who developed the virtual machine, says he did this because he was inspired by recreating the Colossus, both physically and virtually. When he finished the virtual version of the Colossus, he decided to create a Lorenz virtual machine with it, which took him several months. It can now be used by anyone online. The online machine is even equipped with sound, which starts to get on the nerves after a few minutes, but can of course be switched off.