My favourite Enigma message - as told to me by a tour guide at Bletchley Park - was thought to be a stream of indecipherable gibberish.<p>Until a WREN noticed that the message never contained the letter Z.<p>One weakness of that generation of Enigma was that it could not self-encode a letter. That is, A was never encrypted to A.<p>This had no letter Zs. A statistical improbability. Unless, so she reckoned, the <i>entire</i> message consisted of <i>only</i> the letter Z repeated.<p>Apparently, their best guess was that a bored soldier sent a stream of Zzzzzz to a friend. That was enough to crack that day's key.<p>Of course, every guide at Bletchley has a range of stories they tell credulous geeks. But it is a delightful tale of how OpSec is everything.
At this point, how long would it take to brute-force an Enigma message on a modern home computer? Is it on the order of hours, or millennia?<p>I found this:<p><a href="https://crypto.stackexchange.com/questions/33628/how-many-possible-enigma-machine-settings#:~:text=Wikipedia%20is%20your%20friend%3A%20%22Combining,159%20quintillion)%20different%20settings.%22" rel="nofollow noreferrer">https://crypto.stackexchange.com/questions/33628/how-many-po...</a><p>which says the key space is something like 10^20 or 10^23.<p>A modern supercomputer does something like 10^18 FLOPS. I assume that an enigma decryption is considerably more than a single floating point operation, but presumably just a few orders of magnitude.<p>So... if I'm reading that right, we're talking about months, perhaps?
The page doesn't make it very clear, but the analysis at the bottom says that is a message that the German recipient tried to decode in several different ways and then gave up. Apparently the message indicates the key (indicator group?) twice, but was VA in one place and VR in another, so the message was clearly received corrupted. Neither indicator worked so the recipient tried other things that also didn't work.<p>Given that the message is corrupted and the recipient with the key couldn't decode it, it's not surprising that the message remains unbroken. Even brute force isn't going to work if you start with garbage.
<a href="https://archive.is/JE6MR" rel="nofollow noreferrer">https://archive.is/JE6MR</a><p><a href="https://web.archive.org/web/20230626181049/https://enigma.hoerenberg.com/index.php?cat=Unbroken&page=P1030680" rel="nofollow noreferrer">https://web.archive.org/web/20230626181049/https://enigma.ho...</a><p>(I wasn't expecting this to hit #1)
Once in college we ran an online treasure hunt where the participant needs to decode from images, text hidden in source code.<p>Decoding using enigma was our last question. The word "That's all folks" was encoded in five different ways & configuration for enigma machine would keep changing according to the time of the day. We took reference from computerphile videos & people really loved solving this.<p>We redirected them to an online enigma decoder (Forgot the link)<p>Good old times :-)
Seeing this website here made me chuckle. Mr. Hörenberg was a teacher at my school. He once held a "guest lecture" within my CS class where he told us about his hobby of breaking engima codes and how his software worked. He once used multiple of our schools computer rooms during summer break to run his software. Luckily for him, we had CAD classes and therefore appropriate workstations.
Some of it is explained here:
<a href="https://enigma.hoerenberg.com/index.php?cat=Breaking%20the%20M4&page=How%20to%20break%20the%20ENIGMA%20M4" rel="nofollow noreferrer">https://enigma.hoerenberg.com/index.php?cat=Breaking%20the%2...</a><p>(A funny sidenote was that he wasn't and admin in our school and had now way of deactivating the screensaver then to walk from desk to desk every 14 minutes and move the mouse.)
It's unfortunate how the Wikipedia article [1] about the Enigma does not mention Alan Turing at all.<p>[1] <a href="https://en.wikipedia.org/wiki/Enigma_machine" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Enigma_machine</a>
That message could be using a new cypher that Klaus Schwab, Hilter's secret kid, is using at WEF to communicate with his buddies in a secret Nazi base in Antarctica