On Tue, Jun 18, 2013 at 7:59 AM, Dave Crocker <dcrocker(_at_)bbiw(_dot_)net>
On 6/18/2013 7:18 AM, Tony Hansen wrote:
I always thought it would be a nice follow-on to DKIM to provide a way
for a site to specify how that site was using i=; that is, to provide
some clarity and comprehension for that value. For example, our
implementation placed the authenticated userid into i=. I know of one
site that appears to use a hash of the authenticated userid. John L says
his site uses "how the mail was injected (submit, webmail, whatever) and
who the user was if it knows". When there is a deterministic mechanism
used to create i=, and the mechanism is known, then it is possible for
additional logic to be added to the receiving side as well.
It would also have to be something trustable. Otherwise, why should you
believe the party making such a statement? A bad guy will put any value
there that increases the likelihood of making it to the inbox, whether it's
true or not.
I'm sure Tony already knows this, but just to make sure it's part of the
Anyone can define a value-added protocol layer on top of DKIM. It
can define all sorts of additional semantics.
It needs a method of declaring its presence, such as an extra
header field or a special external query, but after that, it's free to
define anything it wants, including a public meaning for i=
ATPS did exactly this. It may be a poor example in that it has seen
approximately zero uptake due to lack of demand, but it does demonstrate
the mechanism Dave's describing here.
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