A virtual version of the machine that was used to encrypt Hitler’s messages sent during the Second World War has been created in honour of the British code breaker who cracked the original.

The online Lorenz SZ42 has been made available 100 years after the birth of Bill Tutte, the Bletchley Park mathematician who worked out how the device scrambled messages sent by Hitler to his generals despite never seeing it in action.

The SZ42 was used by the Nazis in the war and was composed of 12 wheels and a number of switches that muddled up text into secret code, producing more than 16 billion billion combinations.

But a duplicate message sent in error by the Germans gave the British a key insight into how it worked and Tutte’s data analysis finally figured it out.

[Read more: Cracking the Enigma code: How Turing's Bombe turned the tide of WWII]

His continued analysis led to the development of the first set of computers, the Colossus, which helped crack many more codes for the remainder of the war.

bletchley park
Bletchley Park, the home of the British code breakers (Chris Radburn/PA)


The virtual Lorenz allows anyone to encrypt their own messages, see the machine’s inner workings and hear its authentic sounds. Users can also connect to others on the site at the same time and communicate via an encrypted channel.

Professional programmer Martin Gillow, who spent months working on the virtual device, told the BBC: “Creating this made me realise what Bill Tutte was up against.”

He added that he would like people to know as much about Tutte as they do about fellow Bletchley code breaker Alan Turing.

Turing is known for cracking the code of Enigma, another machine used by the Germans in the war prior to the more complex and advanced Lorenz.

Read more: Tommy Flower Institute for ICT launched at BT's Adastral Park