[Jedd]

Concur that PK is probably inappropriate, but not necessarily that this means PCQ would be (irrelevant).

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.

[bawolff]

> Concur that PK is probably inappropriate, but not necessarily that this means PCQ would be (irrelevant).

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)