[lexman0]

This is my thinking.

>> Not a hash of the contents, just the sub/external domains' key-ids. Yes, the main page would have to change if you updated the keys. Doesn't seem too onerous to me.

Then that means each external domain has to tell all its linkers that its key will change whenever it does. Assuming it even has such a list. What if a party doesn't respond? I understand it would be said parties problem, but it sure does make re-keying difficult.