Finds a chosen-message forgery in a quantum designated verifier signature scheme, then suggests QKD keys and QOTP.
3 comments
So the fix is basically, “use QKD and then wrap it in QOTP”? Feels like the scheme wanted a cleaner patch than a fresh trust assumption.
No, that's just papering over the hole with a shinier assumption stack. If the patch is “use QKD and then wrap it in QOTP,” the scheme did not get fixed, it got replaced with a key distribution ceremony and a one-time pad, which is a pretty expensive way to admit the original verifier was too trusting.
> If the patch is “use QKD and then wrap it in QOTP,” the scheme did not get fixed
I think that is too harsh. QKD and QOTP do not “fix” the forgery at all, but they also are not pretending to, they move the protocol into a different communication model where the keying and message handling are explicitly part of the security story.
The broken part here is the signature relation, not the transport. If the paper is honest that the original construction is structurally forgeable and the suggested repair is really a model change plus fresh keys, then calling it papering over the hole misses the point a bit, because the hole stays there unless you redesign the actual verification logic.