From: Bedfordshire UK
ORIGINAL: Paul McNeely
There was a show on the BBC where they spoke to the people who worked on the project, it was in 1998 or 1999 as it wasn't until then they were allowed to talk about their work.
The actual breakthrough came about because, and I think this was a Polish scientist who suggested this, they decided to try the inital cipher as A=A. The trivial solution. The British were initially skeptical but it turned out this was the combination the German's had selected. Which isn't so silly, when basically you think that the other person will never use it because it is clearly the trivial solution which no one would ever do. After that they started breaking the code on a regular basis helped along by two things.
1. Almost all messages started with "Heil Hitler", this should go on the list of things an evil overlord should never do.
2. A number of stations would come on air and say effectively the same thing every night. "This is Passow. It is 8 pm and all is well here." So if the code breakers were stimied they just waited for this message and then they could untangle the code. Another thing for the evil overlord do not do list.
Actually the show was a substantial revelation of a lot of things for me. The atlantic battle got intense in early 42 more to do with the introduction of a 4 wheel enigma then anything else. At that point they could no longer route convoys around wolfpacks (which they were routinely doing), and the sudden decay in losses a few months later normally attributed to better ASW weapons and whatnot is infact due to the capture of an enigma machine (and seeing it had 4 wheels). The CO of Crete was informed that an airborne invasion was planned but had to keep his deployment as if he expected a naval one (probably though this explains the heavy losses the Germans suffered in the attack). That attack was the end of large scale German airborne operations. Rommel went to his grave thinking there was a spy in the Italian High Command, there wasn't but every message he sent to Berlin was read by the British. I don't really see how you can win a war where the enemy knows what you are planning at about the same time you do.
I think anyone who has ever read anything about WW2 knows the British broke the code, but how extensively they could intercept German planning, and what they did with that information they were remarkably tight lipped about. The same is likely true for the Americans and the Japanese codes.
Each German Enigma message had to start with a 'Key' sequence to tell the receiving station how to set up the wheels and plugs on their Enigma machine to be able to decode the message. Captured Key Sheets helped the initial effort, but later the first action each day was to break that key sequence to get into that day's messages.
The important thing is that this was not just breaking a code, it was breaking a coding method and understanding the machine and procedures used. The British at Bletchley Park got into the minds of the operators, worked out how the machine worked and replicated with electronic machines (revolutionary at the time) that could reverse engineer the code. That is an over simplification of an intensive, complex and continuous effort by 1000's of people at Bletchley Park, every day, to keep the 'Ultra' information flowing.
The Germans had such confidence in Enigma, because they thought it impossible to go through all the possible coding combinations to break a message. Even if a messages was broken, the Enigma settings were changed regularly and that would put the code breakers back to square one, therefore Enigma was safe. What they could not conceive was that the British could build electronic machines that could do the required computations at a speed that would break the messages in a reasonable time.
There were several machines involved and the British decoding system evolved, with German developments in the use of Enigma. 'Colossus' was constructed using telephone exchange components and an unsung hero is Tommy Flowers, who developed the idea of making an electronic computing machine, using some of his own money, valves and components in general use.
When the Engima/Ultra effort started, his technical ideas joined with Alan Turing's mathematical expertise, helped create the machines used at Bletchley Park. After the war the parts went back into the General Post Office (GPO) stores and Tommy Flowers got a £1000 grant, which did not even cover his own costs, nor could he use his ideas commercially, because it was so secret.
One of the contributing factors in winning the 'Battle of the Atlantic' was that the Germans could not conceive that the British had developed centrimetric radar, operating on a short enough wavelength to detect a submarine periscope, with airborne radar. German scientist had not been able to do this, so obviously the British couldn't either.
Enigma information was useful in re-directing convoys, but what drove the U-boats out of the Atlantic, after April 1943, was that they could be detected day, or night, by aircraft, which could either attack directly, or call up hunting groups, even if the U-boats were not destroyed, continuously forced to submerge, they could no longer operate effectively.
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