Blog reader Magnus Ekhall has created a software that simulates an Enigma breaking device. He has also published a few challenges, one of which is still unsolved.
In World War II, British codebreakers in Bletchley Park constructed a machine that could decipher Enigma messages: the Bombe (also known as the Turing Bombe or the Turing Welchman Bombe).
Source: Public Domain
The Turing Bombe
The Bombe was a development from a device that had been designed by Polish mathematician Marian Rejewski, known as the “bomba”. Using the bomba and other machines, the Polish had been breaking German Enigma messages in the 1930s. The initial Bombe design was developed by Alan Turing in 1939, with an important refinement devised by Gordon Welchman in 1940.
Over 200 copies of the Bombe were built. After the war all of them were dismantled (at least that’s the official story). From 1994 to 2007 a team of volunteers at Bletchley Park created a rebuild, which is today on display at the National Museum of Computing (a museum located next to the Bletchley Park estate).
The picture shown above is one of the few (or even the only one) known that shows an original Bombe. On the following photo, the rebuild can be seen:
Source: Public Domain
The Desch Bombe
There was also a US version of the Bombe (also known as “Desch Bombe” for its constructor Joseph Desch). The US Bombe was made to attack the four-rotor naval Enigma. An original of this machine is on display at the NSA Crypto Museum in fort Meade near Washington.
Magnus Ekhall, a Swedish software developer and reader of this blog, has created a Bombe simulator (together with Fredrik Hallenberg). This simulator is available on a website. So, if you want to break an Enigma message yourself, with the means of a WW2 codebreaker, try this software. It simulates both the British …
… and the US Bombe.
It was George Lasry who made me aware of this simulator a few days ago. George mentioned that Magnus and Fredrik provide a number of Enigma messages as challenges on their site (the following picture shows an excerpt):
When George sent me his mail, many of the challenges were still unsolved. Today, when I started writing this post and looked at the web page again, the situation had changed. This can be seen on the following chart:
Apparently, George has deciphered nine challenges over the last few days. Congratulations!
Apparently, challenge 4b is still unsolved. So, there is at least one chance left to add your name to the winners list. And then, you still have the chance to be second or third at a few other challenges. Good luck!
Further reading: My visit to Poznań, where the breaking of the Enigma began