Follow up to #16223. It was mentioned in that PR that we could do some additional checking for signed ACKs, and verifying signatures:
laanwj: This could also check "signed ACKs" (and say, mark them specially, if they match the expected key for the user) if we're going there in the future.
instagibbs: laanwj I was going to suggest that as a stretch goal, so concept ACK that. Would be nice to see local pgp sigs validated.