True, I can only know that the owner of the private key signed but not how the document was created. But I suppose there is some trust involved that a person I know who signs doesn't sign some AI generated stuff. To establish the initial link, I suppose we need something more mainstream/scalable than the old key signing parties I remember from CCC etc.

But at least for friends and family it should be possible to create some flow where every member has a key-combo and you trust them to only sign stuff they wrote etc. and have local mini-keysign parties.

>and you trust them to only sign stuff they wrote

You have far too much faith in humanity. The majority of my extended family members are not smart enough to resist continuous attacks and would eventually not only sign, but give away the key in question.

Simply put I think we are stretching humanity farther than intellectual ability allows in a lot of people.

Do we need new key signing for friends/family? I can trust that all messages coming from a friend/family’s account originated from them, or else their account was compromised. I don’t see how a ‘non-ai’ key adds enough more trust to be worth it.