What data has to stay secret for 100 years?
To extrapolate backwards, was there anything in 1925 that would be still sensitive today? Its hard to imagine.
The fact you don't know about these might in fact simply indicate the efficacy of the secret keepers.
This feels like a bad argument for religion.
The point though is not that i don't know any but that i can't concieve of any. I can't even imagine such a scenario, even hypothetically.
I'm confident there's fairly mundane multi-generational secrets, without having to summon the illuminati or knights templar. Either way it doesn't negate the interest in having a technology that could provide that.
I feel we're coming full circle towards the original discussion about pqc.
(Also, I feel cryptography is very much a tech that can assist you in keeping secrets at rest.)
If you want your secret to last more than one human lifetime, you have to enroll new people into the system somehow.
My main argument would be that cryptography is mostly useless in such a scenario. It makes much more sense to put the secret in a filing cabinet, put a lock on the filing cabinet, and if you are really paranoid, maybe hire some people with guns to guard it. Cryptography for such a scenario is the sort of thing that happens in movies not real life.
And even if cryptography was used, it doesn't seem like public-key would be very applicable at all, so pcq is extra irrelavent.
The Voynich manuscript is likely a despairingly poor example of any argument, but it's the most famous long-lived / unresolved encoded text I could think of. (I think a year or two there was a claim it was properly decrypted but I'm not convinced it ever will be, mostly because I suspect it wasn't ever meant to make sense.)
Back to the key rotation question - I think we agree that's not a necessary requirement.
PCQ is almost exclusively about public key crypto since traditional symmetric crypto is already quantum safe (with a caveat that you might need to double key lengths to reduce risk from grover's algorithm)
There is plenty of reason to want to keep diplomatic and military communications secret for a long time.
>There is plenty of reason to want to keep diplomatic and military communications secret for a long time.
I don't think that makes sense. Why would you want to keep implicating communications around for 100 years? Wouldn't you just destroy them?
Cryptography isn't useful for secrets you want nobody to know. Its useful for secrets you want some people to know but not others.
That said it also seems questionable how much people care about atrocities hundred years after the fact. For example, nobody is boycotting IBM today for their role in the holocaust.
Because that was the number the person i was responding to gave.
In any case north korea has the bomb. I think the secret is out. The most difficult thing at this point is the engineering challenge not the book knowledge.
You are never keeping that secret against an interested adversary.