Comment by wkat4242 | Hacker News Reader

Comment by wkat4242 | Hacker News Reader

Parent Full thread

Well the triple U (not sure why they use that) and the spelling of the letters is simple enough to check for that I guess.

From what I can gather this says something like:

To U4701 Sync message, Lubeck base, From commander 4th U-boat fleet, go with U4702 U4703 to Flender Shipyard Lubeck, more to follow

It's less gibberish than it looks like at first. They really shot themselves in the foot by not having numbers on the enigma system, this would have really made messages much shorter because they had to write them all out.

There's so much specific jargon in there that would make it really easy to detect a correct message IMO. Just make a simple list of very common words and tally up.

Indeed frequency analysis wouldn't work though but it's still pretty possible IMO.

I looked at multiple messages on that website and the pattern seems to be triple letters are for single letters and abbreviations. My theory is because if you get a letter wrong in a word and "possible" becomes "possifle" then it is still intelligible, but if "u five one four" means u-boat 514 and you get the U wrong, then it could end up as A514 and mean something airplane 514, so to be safe the letter u gets transmitted thrice.

I think your theory is correct. Back when messages where not checksummed, the French Navy used to do exactly this and sent abbreviations three times in a row. I'm quite certain that the French Navy was not the only one to do this since our communications techniques were heavily influenced by foreign nations like the US.

>Well the triple U (not sure why they use that)

The machine works a bit weirdly, in that as you find some correct settings, your results converge towards the legible result. You can get 95% of the settings correct, and produce quite legible results, at which point you stop solving. So the correct result there might actually be any other three char combo like "ABC" or "UAK", but the analyst stopped investigating, because the rest of the message was reasonably legible.

It is a bit abbreviated. However it's not hard to add such common abbreviatiosn to a dictionary for attacking (plus the tripled letters should make it even easier).

vier -> vir

sieben -> siben

nul -> null

Reply on news.ycombinator.com