[ietf-dkim] A few SSP axioms

[John Levine]

>As I read the later case, the only signature present (C's) is not one that is 
>included in A's SSP.  In this case we have a message with a signature that is 
>outside the scope what A has said is authorized (or not included in A's 
>authoritative list).  If A is a high profile phishing target and signs all of 
>it's mail, then it would be useful (I think) for receivers to recognize that 
>the message has been signed by someone other than who A said it would.

Why do you want to prevent people from forwarding genuine, unmodified
messages?  That's a feature, not a bug.  

If ebay sends a message with a valid ebay signature, how can any chain
of forwarding and added signatures change the fact that it's a real
ebay message?  Let's assume that ebay has enough sense to sign its
MIME headers and not to use l=, so the message that's delivered is the
same one that was sent.

R's,
John