A Distinct Sound...

In previous posts, I reference codebreaking efforts of the U.S. Navy and the success achieved even before the outbreak of World War II. The fascinating story of the British codebreakers at billeted at Bletchley Park shows the fruit of tenacity and painstaking effort, not unlike looking for the proverbial needle in the haystack. Add to that human effort, Providential intervention.

The secrets of the codebreaking success gained at Bletchley Park and, to a some degree, their methodology, were not revealed until about 30 years after the war. One can imagine the complexity of German engineering on anything mechanical - and it was a mechanical device used for encoding the messages sent by the elements of the German war machine. The British intelligence effort found a Polish man who actually worked on the construction of the machine, which would come to be known as Enigma. From memory he began to reconstruct the wooden box with its complex rotor system. But he could only provide insight from memory - this machine created permutations seemingly beyond the boundaries of normal human capacity to break them. The real thing was needed. So, with the help of this man and the Polish Secret Service, the Brits actually captured an entire machine and set to work on understanding how it worked.
My memory may not serve me here, but as I recall the machine would take a basic message like, "The 347th Bomber group is to fly the northern route to bomb targets of opportunity in London at 4:30 p.m. on December 29th. All crews must report for briefing at 1:oo p.m." This is not a real message - but basic details and specific details would be passed from commands to subordinates giving orders. That message would be broken into groups of letters something like this:

The34-7Bomb-ergro-upist- oflyt-henor-thern-route-tobom-btarg-etsof-oppor-tunit
yinLo-ndona-t430p-monDe-cembe-r29Al-lcrew-smust-repor-tforb-riefi-ngat1-oopmx

Kind of confusing already, eh? Numbers were probably spelled out and blank spaces were filled in by "x". The message would then be entered into the machine by keyboard. Each letter would be substituted by an equivalent in a scrambled alphabet. (Take the 26 English letters, put them in a hat and draw them out at random. Put them in a sequence. The first letter would be substituted for "A", etc.) The machine would be set mathematically to produce (if memory serves) seven permutations of the alphabet so the finished product would look nothing like the original. It required intense study - even with the machine to determine the mathematical sequencing of the machine. F.W. Winterbotham, in his book The Ultra Secret, said the following of the sequencing: "A typewriter fed the letters of the message into the machine, where they were so proliferated by the drums (rotors) that it was estimated a team of top mathematicians might take a month or more to work out all the permutations necessary to find the right answer for a single cypher setting; the setting of the drums in relation to each other was the key which the sender and receiver would no doubt keep very closely guarded."
The capture of the Enigma machine and breaking the key to it's working may be one of the great accomplishments of the war. We'll look at some interesting stories over the next day or two.