"Our main cargo is a one-time cryptographic pad. The source is Commercial Security at Sjandra Kei; the destination is the certificants' High colony. It was the usual arrangement: We're carrying a one-third xor of the pad. Independent shippers are carrying the others. At the destination, the three parts would be xor'd together. The result could supply a dozen worlds' crypto needs on the Net for --"
Because the book was written 2 years before it was discovered quantum computers had applications to cryptanalysis of RSA.
> But that's a miss, it's like one of those Neal Stephenson moments where the creator is using the right language […snip…] but they don't understand what's actually going on.
And to support the commenter who expressed surprise about that given Vernor Vinge is a mathematician. Clearly he does know what’s going on. And I think the fact you just posted supports this even more.
Anyways I have no horse in this race, haven’t read the book, just another internet pedant who saw something on HN that could be corrected.
Maybe since our universe doesn't have FTL any author trying to make this work will almost inevitably screw it up? Like how the only novel I've read with the "Protagonist is much, much smarter than everybody else" that works does it by cheating - it's "Tatja Grimm's World" and [spoiler] Tatja isn't actually smarter than us everybody else on her world is stupid by our standards for reasons the plot justifies eventually.
Greg Egan, like some of the newer Stross novels, mostly says no FTL, you can go a long way but it takes a long time, for everybody else if not for you - suck it up. Which isn't a bad excuse, but also isn't FTL at all.
btw one of my favourite "the protagonist is much smarter than everyone else" novels is kress's badly underrated "an alien light", where sort of like tatja grimm she's a genius in a primitive society, but that comes to light when aliens try to teach the natives some basic science and she figures out a lot more than they bargained for.
https://arxiv.org/pdf/2110.02836
So there is a risk that there are even more improved attacks that people aren't looking for due to the conventional wisdom that grover's is the best you can do for symmetric crypto. Hopefully this risk doesn't end up materializing.
It's the difference between stealing Bearer Bonds which you can notionally insist are arbitrarily valuable despite the modest amount in Die Hard†, and stealing literal Gold Bars in Die Hard with a Vengeance which is silly because we know how valuable each bar is and they're much too heavy for the heist to actually work as depicted.
† Die Hard is set after bearer bonds don't make sense for non-crooks and thus didn't exist for crooks to steal because their tax treatment changed, however the novel Die Hard is based on was set before these tax changes so it did make sense when it was written.
That feels a bit harsh when reading a book written in 1992. Shor's algorithm was only invented in 1994. There was no indication about our quantum future at the time that novel was written
A Fire upon the deep is set in the far future. Its easy to imagine all non information-theoretic secure cryptosystems failing thousands of years from now. I think that prediction is more reasonable than most far-future scifi predictions.
If i remember right, i think that is the novel that predicts we'd still be using usenet when talking between planets (i read a long time ago), so i think the crypto prediction aged a lot better than that.
It's true that we have no apriori justification for the existence of symmetric cryptography and so in principle somebody might have a constructive proof that you can't do this at all and we're boned. There was no evidence for this when the book was written and there's no evidence for it now, but it's nowhere close to as crazy as the Zones of Thought physics so, sure.
OTP is in theory the correct choice if you don't have working symmetric cryptography but in fact the "Quantum computer" approach barely dents our symmetric cryptography.
I've written about this before, DES was standardized in 1977, almost 50 years ago and you might think "Well but DES is broken". Yes, DES broke exactly the way it was designed to. Literally nothing went wrong, when it was standardized we knew the keys are too small (yup, you can break it by trying all the keys) and the blocks are too small (yup, you can "just" make duplicate blocks) and it was broken by leaning on these weaknesses with huge fast modern computers.
AES is an entirely different cryptosystem, but the two most important choices were that the keys are big enough (128-bit or 256-bit commonly) and the blocks are too (128 bits). And those may seem like a small upgrade, only 2-4x as big, who cares? Well those are bit lengths so that's an exponential increase, and your quantum computer barely helps (assuming it magically is the same price rather than incredibly expensive). It is not physically practical for the necessary computation to be done, AES is broken only if there's some mathematical backdoor we didn't know about.
"We'll crack AES with a quantum computer" is a Hollywood movie plot, it's not a thing that makes any actual sense.
[Edited: I wrote "Bruce Sterling" but I meant "William Gibson", I apologise to both people for muddling them, though not for my opinion]