Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC
RFC 5702

[Ballot discuss]
This is a "discuss-discuss".  I will move to Yes on the call, but would like to consider the
following issue from Kurt Zeilenga's secdir review:

> I do note that the document appears to place an additional
> recommendation upon implementors of DNSSEC (in Section 5.1) yet does
> not "update" any DNSSEC specification.  It may be appropriate for
> this I-D to "update" (upon approval/publication) DNSSEC specifications.

For completeness, section 5.1 is included here in its entirety:

5.1.  Support for SHA-2 signatures

  DNSSEC aware implementations SHOULD be able to support RRSIG and
  DNSKEY resource records created with the RSA/SHA-2 algorithms as
  defined in this document.

[Ballot comment]
The Gen-ART Review by Gonzalo Camarillo on 15-Sep-2009 includes two
  editorial comments:

  1) Acronyms should be expanded on their first use (including the
  title of the draft and the Abstract).

  2) The paragraph referencing RFC 2119 is located at the end of the
  Introduction. Normally, it is placed in a section on its own called
  Terminology instead, which comes right after the Introduction. This is
  truly a very minor comment and I leave it up to the author to decide
  whether to leave it as is or to move the text into a new section.

IANA comments:

Upon approval of this document, IANA will make the following
assignments in the "DNS Security Algorithm Numbers" registry at
http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml

Note: * indicates that there has been no determination of
standardization of the use of this algorithm with Transaction
Security.

Zone Trans.
Value Description Mnemonic Signing Sec. References
TBA1 RSA/SHA-256 RSASHA256 y *
[RFC-dnsext-dnssec-rsasha256-14]
TBA2 RSA/SHA-512 RSASHA512 y *
[RFC-dnsext-dnssec-rsasha256-14]

Title          : Use of SHA-2 algorithms with RSA in DNSKEY and RRSIG
                  Resource Records for DNSSEC
Author(s)      : J. Jansen
Filename        : draft-ietf-dnsext-dnssec-rsasha256-14.txt
Date            : 2009-07-30
Document shepherd: Andrew Sullivan

The publication request includes a note for IANA, in section 1.d below.

(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?

Andrew Sullivan; yes; yes.

  (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? 

Yes; no.

  (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?

The document editor sent the document to the security directorate
requesting review.  A response was received from one member of the
security directorate.  It might be good if someone else also from the
security directorate reviewed the document, because the person
responding is also active in the DNSEXT working group.  In particular,
there was a question about the utility of the SHA-512 definition in
here, and particularly whether that definition is acceptable given the
limit on key size.

  (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.

There are two items to note.

First, in making a final-pass check, I note that the examples in
section 6 have (by mistake) actual algorithm numbers in them instead
of {TBD1} and {TBD2}.  Because these are just examples, I judge that
they may be fixed as an editorial matter, so I didn't want to issue
another version of the draft.  As a matter for IANA, we would in fact
like TBD1 to be 8 and TBD2 to be 10.  This is because an early
implementation used those two typecodes already.

Secondly there is the question about SHA-512 in 1.c.  Despite useful
and considered feedback received from one commentator, we decided to
go ahead leaving that section in because we believed that it does no
real harm and because it has taken a surprisingly long time to build
consensus around the document in the WG.

I found no IPR disclosure in the database.

  (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? 

I judge the consensus to be strong and broad.

A previous version of this document used algorithm aliases for NSEC
and NSEC3 application, but several participants strongly objected
to that strategy.  This version of the document uses one algorithm
identifier for both NSEC and NSEC3.  The effect of this is that
implementations that do not support NSEC3 will not be able to use
SHA-2 either.  The WG consensus is that, because of announced
deployment of NSEC3 in large zones near the root of the DNS, it
will be infeasible for a modern DNSSEC implementation not to
support NSEC3.



  (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.)

No.

  (1.g) Has the Document Shepherd personally verified that the
        document satisfies all ID nits? (See the Internet-Drafts Checklist
        and http://tools.ietf.org/tools/idnits/). 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?

The Shepherd has checked the nits.  There are no other reviews to
perform for this document as far as I understand.

  (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].

Yes; No; Not a downref, but a reference to a non-RFC standard:   

[FIPS.180-3.2008]
              National Institute of Standards and Technology, "Secure
              Hash Standard", FIPS PUB 180-3, October 2008.

As near as the Document Shepherd can tell, there is no RFC that
outlines FIPS PUB 180-3, but that's what defines SHA-2, so we need the
normative reference.

  (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 consideration does exist.  There are reservatiions in a
registry requested.  The requested algorithm identifiers are marked as
{TBD1} and {TBD 2}.  See the remarks under item (1.d) above for a
request for the actual numbers to be assigned.

  (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?

No such formal language sections are in this document.

  (1.k) The IESG approval announcement includes a Document
        Announcement Write-Up. Please provide such a Document
        Announcement Write-Up?

          Technical Summary

  This document describes how to produce RSA/SHA-256 and RSA/SHA-512
  DNSKEY and RRSIG resource records for use in the Domain Name System
  Security Extensions (DNSSEC, RFC 4033, RFC 4034, and RFC 4035).

          Working Group Summary
 
  The DNS Extensions Working Group had consensus to publish the
  document.  A strong objection to an aliasing strategy for algorithm
  identifiers was lodged at one point, and that has been addressed in
  this version.  Nobody has objected to this change.

          Document Quality

  The document received thorough review, and it is expected that
  vendors supporting DNSSEC will implement SHA-2 once the document is
  published.  The document went through a large number of revisions
  before submission, reflecting the extensive feedback and detailed
  comments received.

(1.a) Andrew Sullivan is the document shepherd. He has read this
version and believe it is ready for forwarding to the IESG.

(1.b) The document has had adequate review. The shepherd has no
concerns.

(1.c) The shepherd has no concerns that additional review is
needed, beyond the expected reviews during IETF last call.

(1.d) The shepherd has no specific concerns. It is not clear
whether the IPR claim at https://datatracker.ietf.org/ipr/1000/
applies to this draft; no specific claim has so far been made to
the shepherd's knowledge. The WG did not discuss that claim.

(1.e) The WG consensus appears to be strong enough to warrant publication.

(1.f) Nobody has threatened an appeal or indicated extrene
discontent. One participant in the WG, at a late date, has
objected to using two different algorithm identifiers, one for
NSEC and a different one for NSEC3. There appeared nevertheless
to be fairly strong consensus in favour of the current approach
during WGLC.

(1.g) The shepherd has checked all nits. The document uses the
old boilerplate from RFC 3878. Since xml2rfc >= 1.3.4 isn't out
yet, the shepherd thinks this is ok.

(1.h) References are split, and there are no downrefs.

(1.i) The IANA Considerations section exists, and is consistent.
The reservations are properly requested.

(1.j) There is no formal language segment in the document.

(1.k)
Technical Summary

This document describes how to produce RSA/SHA-256 and RSA/SHA-512
DNSKEY and RRSIG resource records for use in the Domain Name System
Security Extensions (DNSSEC, RFC 4033, RFC 4034, and RFC 4035).

Working Group Summary

The DNS Extensions Working Group had consensus to publish the document.

Document Quality

The document received thorough review, and it is expected that
vendors supporting DNSSEC will implement SHA-2 once the document is
published. During Working Group Last Call, there were objections
that an earlier approach, which tied SHA-2 to implementation of
NSEC3, would be a barrier for adoption by some vendors, so the
specification was changed to avoid the link.