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 review.

  (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 document.

  (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.