Barry Leiba wrote:
Levine wrote:
By design, a broken signature is equivalent to no signature.
Yeah, that RFC 4871 anomaly "Failure Promotion to no signature" always
did baffled me.
If either one were "better", attackers would just shift to the better
one. It's simple enough to use no signature at all, if no signature
is better than a broken one. Similarly, it's easy to fake a signature
if that way be better.
Making the cases equivalent means we don't have to try to deal with
convoluted heuristics that will only be attacked anyway.
But that's really a digression; please, let's not clutter the
discussion with that issue again.
Levine brought it up. The question was if a NULL Key will help
expose an inherent NO DKIM policy (sans ADSP). He said the lack of
one will be better.
We got multiple answers to this, including thats its not possible.
So the question is still up in the air as to how a DOMAIN can protect
itself against obvious spoofed, fraud in the form of unauthorized
signed messages.
Its one thing to say or indicate, maybe as a matter of corporate
public policy, "we will always sign our mail", it is equally important
to say "we don't or never sign our mail for XYZ domains"
--
Sincerely
Hector Santos
http://www.santronics.com
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