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Shepherd writeup

PROTO writeup for draft-ietf-dkim-rfc4871bis-12

The DKIM Working Group requests the publication of
draft-ietf-dkim-rfc4871bis-12 as a Draft Standard RFC, progressing RFC 4871
from Proposed to Draft Standard.  The implementation report to support this
request is

  (1.a) Who is the Document Shepherd for this document? Has the
        Document Shepherd personally reviewed this version of the
        document and, in particular, does he or she believe this
        version is ready for forwarding to the IESG for publication?

Barry Leiba is the document shepherd.  I have reviewed this version, and am
satisfied that it's ready.

  (1.b) Has the document had adequate review both from key WG members
        and from key non-WG members? Does the Document Shepherd have
        any concerns about the depth or breadth of the reviews that
        have been performed?

The document has adequate review, and I have no concerns about the level of

  (1.c) Does the Document Shepherd have concerns that the document
        needs more review from a particular or broader perspective,
        e.g., security, operational complexity, someone familiar with
        AAA, internationalization or XML?

I have no concerns.

  (1.d) Does the Document Shepherd have any specific concerns or
        issues with this document that the Responsible Area Director
        and/or the IESG should be aware of? For example, perhaps he
        or she is uncomfortable with certain parts of the document, or
        has concerns whether there really is a need for it. In any
        event, if the WG has discussed those issues and has indicated
        that it still wishes to advance the document, detail those
        concerns here. Has an IPR disclosure related to this document
        been filed? If so, please include a reference to the
        disclosure and summarize the WG discussion and conclusion on
        this issue.

I have no personal concerns.  See "Working Group Summary" for a discussion of
the working group's position.  I'll note here that on the surface there appear
to be many text changes between RFC 4871 and 4871bis -- perhaps an unusual
number for progression from PS to DS.  Much of that comes from the fact that
4871 was updated by RFC 5672, and 4871bis represents the merging of those
updates into the base document, along with progression to DS.  The set of
substantive changes beyond that merging is small, and the working group
believes they are appropriate for moving DKIM to Draft Standard. These changes
are listed in Appendix E.  The diffs from RFC 4871 and this draft can be found
(while the deliberations last) at

The IPR statement from Yahoo! on RFC 4871 will apply to this document as well:
Yahoo! has submitted an update to apply that IPR statement to the -09 version
of the draft, the version that was current when they made the update.  They
will update it again when the RFC is published.

  (1.e) How solid is the WG consensus behind this document? Does it
        represent the strong concurrence of a few individuals, with
        others being silent, or does the WG as a whole understand and
        agree with it?

There is rough consensus of the working group, as a whole, behind it. 
Notwithstanding that, this has been a controversial process, with strong
disagreement about a number of points.  See the "Working Group Summary", later
in this writeup, for more on this.

  (1.f) Has anyone threatened an appeal or otherwise indicated extreme
        discontent? If so, please summarise the areas of conflict in
        separate email messages to the Responsible Area Director. (It
        should be in a separate email because this questionnaire is
        entered into the ID Tracker.)

One appeal has been received and another has been threatened.  A response to
the first appeal has been returned and the primary appellant accepted the
response.  It is not clear whether the co-appellants have accepted the response.

  (1.g) Has the Document Shepherd personally verified that the
        document satisfies all ID nits? (See the Internet-Drafts Checklist
        and Boilerplate checks are
        not enough; this check needs to be thorough. Has the document
        met all formal review criteria it needs to, such as the MIB
        Doctor, media type and URI type reviews?

There are no ID nits apart from some references (see 1.h).
Note that idnits 2.12.11 incorrectly declares some nits.  Pay no attention to
the man behind that curtain.

  (1.h) Has the document split its references into normative and
        informative? Are there normative references to documents that
        are not ready for advancement or are otherwise in an unclear
        state? If such normative references exist, what is the
        strategy for their completion? Are there normative references
        that are downward references, as described in [RFC3967]? If
        so, list these downward references to support the Area
        Director in the Last Call procedure for them [RFC3967].

All references are properly separated and labelled.
There is a normative reference to RFC 5890 (IDNA), a Proposed Standard.  This
reference is necessary to specify how to encode non-ASCII domain names.

There is a normative reference to RFC 5598, an informational document.  This
document defines terms used in discussion of email architecture, and is widely
referenced in this manner.

There is an normative reference to RFC 3447 (RSA Crypto), an informational
document.  This is an IETF specification of externally defined algorithms. 
Note that this document is called out in the DOWNREF registry:

There are two normative references to non-IETF documents (FIPS-180-3-2008 (SHA)
and ITU-X660-1997 (ASN.1)).

There is an informative reference to RFC 4870 (Domain Keys), a Historical
document; this is correct.

  (1.i) Has the Document Shepherd verified that the document IANA
        consideration section exists and is consistent with the body
        of the document? If the document specifies protocol
        extensions, are reservations requested in appropriate IANA
        registries? Are the IANA registries clearly identified? If
        the document creates a new registry, does it define the
        proposed initial contents of the registry and an allocation
        procedure for future registrations? Does it suggest a
        reasonable name for the new registry? See [RFC5226]. If the
        document describes an Expert Review process has Shepherd
        conferred with the Responsible Area Director so that the IESG
        can appoint the needed Expert during the IESG Evaluation?

The IANA Considerations section is correct and adequate.  It reflects the
changes made when RFC 4871 was published, along with an update provided in this

  (1.j) Has the Document Shepherd verified that sections of the
        document that are written in a formal language, such as XML
        code, BNF rules, MIB definitions, etc., validate correctly in
        an automated checker?

The formal grammar is correct.

  (1.k) The IESG approval announcement includes a Document
        Announcement Write-Up. Please provide such a Document
        Announcement Write-Up? Recent examples can be found in the
        "Action" announcements for approved documents. The approval
        announcement contains the following sections:

     Technical Summary
        Relevant content can frequently be found in the abstract
        and/or introduction of the document. If not, this may be
        an indication that there are deficiencies in the abstract
        or introduction.

DomainKeys Identified Mail (DKIM) permits a person, role, or organization that
owns the signing domain to claim some responsibility for a message by
associating the domain with the message.  This can be an author's organization,
an operational relay or one of their agents.  DKIM separates the question of
the identity of the signer of the message from the purported author of the
message.  Assertion of responsibility is validated through a cryptographic
signature and querying the signer's domain directly to retrieve the appropriate
public key.  Message transit from author to recipient is through relays that
typically make no substantive change to the message content and thus preserve
the DKIM signature.

     Working Group Summary
        Was there anything in WG process that is worth noting? For
        example, was there controversy about particular points or
        were there decisions where the consensus was particularly

Getting this document finished has been a controversial process, with strong
disagreement about a number of points.  There is certainly broad agreement that
DKIM is a widely deployed, useful protocol, and that it's ready for
advancement.  There are major differences of opinion on several things,
including 1. The importance of giving specific advice on which email header
fields to sign. 2. What information should be considered "output" from the
signature verifier. 3. How the DKIM signature ties into, or should tie into,
domain names that appear in other parts of the email message, particularly the
RFC 5322 "from" header field. 4. How to handle potential attacks mounted by
adding extra header fields to the message after it has been signed.  This is a
particular issue with the RFC 5322 "from" header field, but affects other
header fields as well.

There have been other controversies; this list is not exhaustive.  See the
mailing list archives for more details.  In the end, though, the document as
submitted has rough and significant consensus of the working group as a whole,
even when it doesn't represent unanimity.

     Document Quality
        Are there existing implementations of the protocol? Have a
        significant number of vendors indicated their plan to
        implement the specification? Are there any reviewers that
        merit special mention as having done a thorough review,
        e.g., one that resulted in important changes or a
        conclusion that the document had no substantive issues? If
        there was a MIB Doctor, Media Type or other expert review,
        what was its course (briefly)? In the case of a Media Type
        review, on what date was the request posted?

The DKIM base protocol is widely deployed, with many implementations (see ).  This version of
the spec comes after a thorough working group review and publication of RFC
5672, which added significant clarifications to the language.