Jim,
I found that I got seriously bogged down on some parts of your note, as you and
everyone else will surely see. I am glad to try to set up a phone call to get
a
better channel for discussing this. Beyond the obvious timezone challenges,
this week, I've got quite a bit of flexibility in time and am glad to find a
slot where I can call you.
Also, everyone else is hereby invited to jump in and straighten me out.
That said, here's where I got in responding:
On 3/28/2011 11:27 PM, Jim Fenton wrote:
1. "authors and their organizations" could be misinterpreted to mean that the
conjunction defines a single identity.
But the current text says "...examples include the author, ..." so that
misinterpretation exists there as well. I'd be fine with just "authors'
organizations".
How is the "examples" list a misinterpretation?
The list was crafted carefully to draw some distinctions that can be
significant. Your wording loses the distinction between author and author's
organization.
I think the distinction is worth maintaining.
Just to be clear: A domain name is capable of being author-specific. I
recognize that it's not typical, but the construct of 'author' is so
fundamental
in this game, it's worth acknowledging that it is (still) permitted.
3. One form of assessment service -- of which the late Goodmail was an
example
-- can give a priori assessment and then indicate tghe assessment by
providing
the signature to the message before it is sent. That is, the authoring
organization passes the message to the assessment service and the assessment
service hands back the signature to be included in the message. (The details
can vary, of course, but this describes the basic model.) Hence the signature
is somewhat akin to a capability token. [I thought I had explained this
processing option a number of times over the years, specifically citing the
Goodmail example.]
That's a specific example of an ISP along the handling path.
Goodmail was not an ISP and it was not along the path.
................. Goodmail ..............
. .
V V
Client -> Mail -> Transfer -> Service -> Receiver -> Recipient
Goodmail interacted with the creator of the document and, separately, with the
receiving mail service, as an adjunct "back office" service. To repeat: /It
was
not in the direct handling path./
DKIM supports that mode of operation quite nicely and it is a particularly
powerful operational mode, so it is worth keeping that "configuration" in mind
explicitly. Given how persistent this confusion seems to be it might even be
worth more language, though I'm not coming up with a suggestion, offhand.
The potential for
misinterpretation of this is greater than the benefit of explaining this
potential usage scenario, especially since "assessment" has a very specific
definition in the DKIM context.
I think we've just seen a good example that indeed it is easily misunderstood.
That begs explicit reference, not potentially confusing conflation.
Section 2.9, Common ABNF tokens: Two new tokens are defined based on
field-name and dkim-quoted-printable. But where are field-name and
dkim-quoted-printable defined?
field-name is defined in Section 2.10
DKIM-Quoted-Printable is defined in Section 2.11
Would it be beneficial to rearrange the sections to avoid the forward
reference?
Sounds like moving the current 2.9 to be after the current 2.11 will solve your
concern.
6.3 paragraph 5 has changed "signing identity" to SDID. The signing identity
really corresponds to the AUID.
That has not been correct for any version of rfc4871bis. The term Signing
Identity has no normative value and is now only used in the introductory
text.
Also note that the Update removed any meaningful semantics for AUID:
The AUID comprises a domain name and an optional
<Local-part>. The domain name is the same as that used for the
SDID or is a sub-domain of it. For DKIM processing, the domain
name portion of the AUID has only basic domain name semantics; any
possible owner-specific semantics are outside the scope of DKIM.
In fact, the AUID is not part of DKIM's formal output. So the formal
specification cannot then direct it be supplied to the assessment engine.
Nevertheless, suppose a message with From address
<joe(_at_)marketing(_dot_)example(_dot_)com>
was properly signed with i=marketing.example.com and d=example.com. What the
Your example has d= using a 'parent' domain, not a sub-domain. Your following
discussion refers to aspects of the spec that concern sub-domains and I am not
understanding how the example is relevant to it. Yes, I see that i= has a
subdomain but, again, I don't see how that relates to your comments.
With obvious trepidation, I am going to raise a concern: On reviewing the
text,
I find, under the Section 3.5 text for i= includes:
"The Signer MAY choose to use the same namespace for its AUIDs as its
users' email addresses or MAY choose other means of representing its users.
However, the signer SHOULD use the same AUID for each message intended to be
evaluated as being within the same sphere of responsibility, if it wishes to
offer receivers the option of using the AUID as a stable identifier that is
finer grained than the SDID."
I suggest that the first sentence change MAY to "might" in order to make it
non-normative.
I further suggest removing the second sentence "However...". It is giving
(normative) usage guidance for something that it has already made out of scope.
text is telling us is that the mail system SHOULD take pains to ensure that
example.com is visible to the user. This is counter to all of the text in the
The closest I can come to what you describe in Section 6.3 is:
"If the SDID is not the same as the address in the From: header field,
the
mail system SHOULD take pains to ensure that the actual SDID is clear to the
reader."
As always, anything DKIM says in the space of human factors varies between
problematic and bad. "clear to the reader" nicely falls within that range. I
know something about user interface design and don't know how to satisfy this
guidance, or what it's supposed benefit is.
Offhand, it appears to reflect the original misunderstanding that DKIM
"validates" the message.
That said, I don't understand how making the SDID clear to the 'reader' is
relevant to your concern about AUID.
DKIM specification that permits keys for a subdomain to be managed in a parent
In what way is any of this counter (per your above assertion)?
domain. If these is consensus to eliminate signing for subdomains, there is a
You've jumped to a specific conclusion that implies a significant, unstated
logic sequence and I'm not yet understanding the premise, never mind the rest.
Please clarify.
lot of other stuff that needs to be removed from the spec, including the i=
tag
itself, the "s" flag in the key record, the text in section 3.9, and the
security consideration in section 8.13.
The Update removed semantics associated with the local part of the AUID, and
not
the domain-part.
Whereas I think it made changes to the semantics for the entire value.
Please point to the current version's specification of AUID "semantics".
If there is not consensus to remove subdomain signing, the wording described
here makes it meaningless. This goes to the heart of why I have been arguing
that the output of DKIM should be the AUID (or its default value, which is the
SDID), and not the SDID itself.
I am not understanding how this language affects the use of AUID at all.
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net
_______________________________________________
NOTE WELL: This list operates according to
http://mipassoc.org/dkim/ietf-list-rules.html