> I'm confused about the role of the petname tool in a situation where a
> site's private key changes -- for example, the key has passed its
> useful lifetime, has been compromised and changed, etc?


If that's what has happened, then the core identity
of the merchant has in some sense changed, and then
we should expect some stuff to happen.  In fact, it
is quite critical that we do surface this change of
key event as that is one of the weaknesses in the
infrastructure:  a phisher can go to any other CA
and trick them into giving out a cert in the name
of the targetted merchant.  The only serious way
to defend against this is to have the browser cache
the cert relationship, then ask the user to examine
the cert, and hope that the difference is enough
to inspire caution.  Without that defence, PKI has
a hole we could drive a ship full of trucks through.

Also, it turns out there is a much bigger case where
key changes are prevalent, and that is in the use of
hardware SSL farms.  Larger merchants use lots of
certs in hardware, and switch rapidly between them
depending on the moment.

In this case, both the trustbar and petname toolbars
have developed strategies to deal with this.  For the
former, trustbar suggests that you click-to-accept
*all* certs from that CA.  For petname, I think Tyler
outlined his approach.  Either way, there is some
experimentation to be done, we shouldn't see these
as being the ultimate word but rather steps in the
right direction of stopping the above truck-liner
being driven by phishers, as well as addressing
phishing as it is driven at the single truck level,
today.

iang
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