Cryptographic Algorithm and Key Usage Update to DomainKeys Identified Mail (DKIM)
draft-ietf-dcrup-dkim-usage-06

[Ballot comment]
-4: "Verifiers MUST verify using rsa-sha256."

Should this say "...MUST be able to..."? That is, am I correct in assuming that a verifier will use the scheme specified by the signer if it is capable of doing so, and that it doesn't make sense to try to verify with rsa-sha256 if the signer used something else?

[Ballot comment]
I would have expected section 4 to be explicit in the interaction between the requirement that "rsa-sha1 MUST NOT be used for signing or verifying" and the Authentication-Results header defined in RFC 7001. In particular, I would have expected to see guidance here whether receipt of a message using sha1 should be coded as "neutral" or "policy": as an implementor, I would be unsure which one to use.

[Ballot comment]
I would have expected section 4 to be more explicit in the interaction between the requirement that "rsa-sha1 MUST NOT be used for signing or verifying" and the Authentication-Results header defined in RFC 7001. In particular, I would have expected to see guidance here whether receipt of a message using sha1 should be coded as "neutral" or "policy": as an implementor, I would be unsure which one to use.

[Ballot comment]
Please check and address the feedback provided by the gen-art review (Thanks Jari!). My understanding is that the normative language was discussed in detail for this draft but Jari brought up a point on forward-comparability with future algorithms regarding verification. I would also be interested to at least see a reply to that!

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Services Operator has completed its review of draft-ietf-dcrup-dkim-usage-04. If any part of this review is inaccurate, please let us know.

The IANA Services Operator understands that, upon approval of this document, there is a single action which we must complete.

In the DKIM Hash Algorithms registry on the DomainKeys Identified Mail (DKIM) Parameters registry page located at

https://www.iana.org/assignments/dkim-parameters/

the existing registration for sha1 will be changed from the current registration to

TYPE: sha1
REFERENCE: [ RFC6376 ]
STATUS: historic

The IANA Services Operator understands that this is the only action required to be completed upon approval of this document.

Note:  The action requested in this document will not be completed until the document has been approved for publication as an RFC. This message is only to confirm the actions to be performed.

Thank you,

Amanda Baber
Lead IANA Services Specialist

The following Last Call announcement was sent out (ends 2017-09-13):

From: The IESG
To: IETF-Announce
CC: dcrup@ietf.org, seth@sethblank.com, dcrup-chairs@ietf.org, alexey.melnikov@isode.com, draft-ietf-dcrup-dkim-usage@ietf.org, Seth Blank
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Cryptographic Algorithm and Key Usage Update to DKIM) to Proposed Standard


The IESG has received a request from the DKIM Crypto Update WG (dcrup) to
consider the following document: - 'Cryptographic Algorithm and Key Usage
Update to DKIM'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2017-09-13. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  The cryptographic algorithm and key size requirements included when
  DKIM was designed in the last decade are functionally obsolete and in
  need of immediate revision.  This document updates DKIM requirements
  to those minimaly suitable for operation with currently specified
  algorithms.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-dcrup-dkim-usage/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-dcrup-dkim-usage/ballot/


No IPR declarations have been submitted directly on this I-D.


The document contains these normative downward references.
See RFC 3967 for additional information:
    rfc8017: PKCS #1: RSA Cryptography Specifications Version 2.2 (Informational - IETF stream)

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

Proposed Standard. This is appropriate because it is updating a standards track document.

(2) 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

The cryptographic algorithm and key size requirements included when DKIM was designed in the last decade are functionally obsolete and in need of immediate revision.  This document updates DKIM requirements to those minimally suitable for operation with currently specified algorithms.

Working Group Summary

There were two points which were discussed at length, but consensus was reached and is appropriately reflected in the document. Additional concerns have been moved to other documents.

Document Quality

This has received security and DKIM community participation. No further expert reviews are warranted. This document removes obsolete protocol elements from a widely deployed and understood standard.

Personnel

Seth Blank is the Document Shepherd, and Alexey Melnikov is the responsible Area Director.

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

I believe this document is ready for publication. Since this is my first time as document shepherd, I was assisted by DCRUP chair Murray Kucherawy.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

No.

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

No additional expert reviews are warranted.

(6) Describe any specific concerns or issues that the Document Shepherd
has 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.

No.

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

Yes.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

No.

(9) 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 was only one contentious issue (MUST NOT vs SHOULD NOT verify for validating rsa-sha1), and the working group reached consensus on MUST NOT after the objectors backed down. The current text survived a WGLC and appears therefore to have consensus. There are roughly 20 active participants of the working group, of which slightly more than half have been active on this document.

(10) 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 publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

New downreference to 8017.

RFC 3447 is an existing downref in RFC 6376 that this draft merely updates to use the newer RFC since 3447 is obsolete.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

No additional formal reviews are necessary.

(13) Have all references within this document been identified as
either normative or informative?

Yes.

(14) 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 plan for their completion?

No.

(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

Yes. There is a downward reference to 8017.

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

No.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

I have confirmed compliance with all the above or that they do not apply.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

There are none.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

No such review is necessary.