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Post by alank2 on Mar 28, 2017 15:36:32 GMT
We all know where the plugboard is, between the keyboard/lampboard and the entry wheel. The plugboard can also be thought of as a non-rotating rotor. The question is, would the placement of the plugboard make the Enigma stronger or weaker? For example, if it were between the 2nd and 3rd rotors instead of near the keyboard/lampboard, would it have been harder to break? Or the same?
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Post by lpaseen on Mar 28, 2017 16:37:57 GMT
Have to think about it a bit but I think mathematically the combinations ends up being the same.
Have to think about that a bit but I think you're right in that you can see the plugboard as another rotor that never turns so in one way they did that with M4, the leftmost rotor never rotates. In that case BP just got 26*2 more combinations to test but if that rotor could be rewired each day it would be way more combinations.
Another thing is that the way the bombe works it bypass the plugboard completely, it only figure out the rotor setting. Would have to read up a bit more on how that bypass is archived before I can guess on having it at a rotor position would make a difference.
Practically speaking it would also be a problem to actually put the plugboard between some rotors but I guess it could be used instead of the reflector (UKW) without to much problem. Not sure how much it does to security since practically speaking it is already at the entry wheel position.
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Post by alank2 on Mar 28, 2017 17:05:26 GMT
That is what I wonder, my instinct tells me it would be the same, but I wonder if that depends on how they defeated the plugboard. If it was a human factor where someone was eyeing over the text and looking for letter patterns that could be words, then perhaps a plugboard in the middle would scramble things more. For example if the word little were looked at only through the plugboard it might be aiqqab where someone could recognize the q and a pattern might be relevant, but if the plugboard were in the middle of the rotors, could it be seperated from them for this type of analysis?
If the bombe didn't do anything with the plugboard, how did it know it had a match? I suppose I need to go back and read the details of the bombe and how it worked. My understanding was they plugged a crib into it, but wouldn't the plugboard have to have been dealt with?
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Post by Arduino Enigma on Mar 31, 2017 3:18:13 GMT
interesting point. Mathematically it seems to make no difference. It would however, seem to affect the way Bletchley Park broke into Enigma.
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