Applicability Statement: DNS Security (DNSSEC) DNSKEY Algorithm Implementation Status
draft-ietf-dnsext-dnssec-algo-imp-status-04

[Ballot comment]
I am Abstaining on this document. I have no specific objection to its
publication, but it  is so much not the document I would have written,
and I struggle to see its value as currently presented.

I was left wondering whether it is trying to do the wrong thing. Instead
of tying to mandate what must or must not be implemented it would be
more helpful to me to state the usage profile of each algorithm. This
could then be traced to "dangerous to deploy" or "must be implemented
if your implementation is to play a part in the deployment of this
function."

Anyway, here are some thoughts and comments that arose...

---

Citing conformance to this document is confusing because nearly all of
the information in the table in Section 2.2 indicates a degree of
choice. Conformance can only be interpretted with respect to the "must"
and "must not".

---

To say that the "IANA registry for these algorithms ... lacks the
implementation status of each algorithm"implies that this information
should be recorded in the registry. It should not since that is not
the purpose of the registry.                                                                             

How about...                                           

  There is currently an IANA registry for these algorithms, but there
  is no record of the recommended implementation status of each
  algorithm.                                         

---

I think Section 1 should observe that it is the intention to issue
replacements to this document when the implementation status of any
algorithm changes and when new algorithms are introduced.

---

  This implementation status indication is only to be considered for
  implementation, not deployment or operations.

I can't extract meaning from this! If something is marked "MUST NOT"
implement, how can it possibly be deployed?

---

Since this document makes no requests for IANA allocations and makes no
changes to the existing registries, I see no reason for it to be listed
in the registry. The IANA registry tracks code points, it is not a
repository for documentation references.

---

I can't square the statement in the Security Considerations section with
the MUST NOT implement status assigned to RSAMD5. Maybe a reference is
needed for the classification of RSAMD5 and that would keep Section 4
honest.

[Ballot comment]
A nit:
Section 2.1., paragraph 2:

>    Likewise, ECDSA with the two identified curves (ECDSAP256SHA256 and
>    ECDSAP384SHA384) are algorithms that may see widespread use due to
>    the precieved similar level of security offered with smaller key size
>    compared to the key sizes of algorithms such as RSA.

  s/precieved/perceived/

[Ballot comment]

I can't parse this: "It is believed that RSA/SHA-256 or
RSA/SHA-512 algorithms will replace older algorithms (e.g.
RSA/SHA-1) that have a perceived weakness or these
recommended algorithms are seen in major deployments." I
guess something's wrong but hard to know what, maybe
s/or/or as/

[Ballot discuss]
Section 1:

  This implementation status indication is only to be considered for
  implementation, not deployment or operations.  Operators are free to
  deploy any digital signature algorithm available in implementations
  or algorithms chosen by local security policies.  This status is to
  measure compliance to this document only.

I think the above paragraph is either wrong or meaningless. I don't know what it means to say that the implementation status is for implementation but not deployment. The reason that one "MUST IMPLEMENT" RSASHA1 is that an implementation will not interoperate with other DNSSEC deployments if it doesn't allow the use of RSASHA1. Similarly, the reason it is "RECOMMENDED TO IMPLEMENT" RSASHA1-NSEC3-SHA1 is that you won't interoperate in DNSSEC if you don't do it, but there are circumstances under which you might not use it. The reason you "MUST NOT IMPLEMENT" RSAMD5 is because it is a broken algorithm and use of it will cause damage. These are not about implementation; they are absolutely about interoperation. Operators *are* free to deploy anything they like, but that's because there are no protocol police and you are free to ignore the considered consensus of the IETF. But the considered consensus of the IETF is that these are protocol requirements to allow for interoperation. The IETF is *not* supposed to be writing compliance documents. Please strike the paragraph in it's entirety. See next bit on 2119 keywords for more on this.

Section 1.1:

2119 keywords are used as part of the implementation status. This is awfully confusing because you lose the meaning of the 2119. Please (a) title case the implementations status throughout Section 2 by changing, e.g., MUST IMPLEMENT to "Must Implement", etc. and then (b) define the terms in section 1.1:

  The implementation statuses used in this document are defined as follows:
 
  - "Must Implement" means that the algorithm MUST be used in order
    to interoperate with other implementations on the Internet.

  - "Must Not Implement" means that the algorithm MUST NOT be used so
    as to prevent the compromise of the DNS data; the algorithm has
    known weaknesses and is not considered safe to use anymore.

  - "Recommended To Implement" means that the algorithm SHOULD be
    used in order to interoperate with other implementations on the
    Internet, though there may be exist valid reasons in particular
    circumstances not to do so. An implementer must understand and
    weigh the full implications of choosing not to implement this
    particular algorithm.

  - "Optional" means that the algorithm MAY be implemented, but that
    all implementations MUST be prepared to interoperate with
    implementations that do or do not implement this algorithm.

Section 2.2:

  Their implementation (or lack thereof) therefore cannot be included
  when judging compliance to this document.

Strike this sentence. Again, it is meaningless in the context of an IETF document. This document should only talk about interoperability requirements.

With regard to the status and title of this document:

I believe in the normal course of events, each time a new document with a list of statuses is published, we will get implementation experience with the statuses to determine if they are correct. When we do, we can advance the document to indicate that, yes, we are sure that implementations have now taken up this new document and it is considered the standard way to implement. I therefore think that this document should be standards track instead of BCP. Indeed, the title of "Applicability Statement" I think is exactly right, and it's using the term as 2026 envisioned, which puts this on the standards track.

If there is for some reason not consensus to move this to the standards track, I think a change of title and abstract are in order. "Applicability Statement" gets used in an odd way in the IETF (and in 2026 in particular), and I think using it for a BCP will add to our overall confusion. But I still believe that this is appropriate to the standards track.

[Ballot comment]
Section 1:

Please also add a paragraph to indicate what's coming in 2.3:

  Since one of the motivations of this document is to keep a single
  up-to-date list of implementations statuses, this document also
  establishes a procedure for updates to this document in the future.

Section 2.2:

Please add the sentence, "Any registered algorithm not listed in the table above has the status "Optional"."

Section 2.3:

  Algorithms entered into the registry using that procedure are to be
  considered OPTIONAL for implementation purposes.  Specifications that
  follow this path do not need to obsolete or update this document.

I think the above got things around backwards. That is, we don't need this document (and obsoleting it) to be tied so directly to registration. We want to say that any registered algorithm that does not appear in this document is, by definition, "Optional". In fact, you can remove the specific algorithms in the "Optional" column in 2.2 and simply say, "Any IANA registered DNS Algorithm not otherwise listed." If you do that, this entire section can be:

2.3 Statuses For New Algorithms and Updating Existing Statuses

  This document establishes a procedure for additions and changes to
  the list of algorithm implementation statuses. In particular, it has
  turned out to be desirable for implementations to be able to point to
  a single document that describes the implementation statuses of all
  algorithms that they might use. Therefore, when a new algorithm is
  registered that has an implementation status other than "Optional",
  this document shall be obsoleted by a new similar document, adding
  the new algorithm to the table in section 2.2. Similarly, if any
  algorithm currently listed in the table in 2.2 changes status, this
  document shall be obsoleted by a new similar document and the table
  in 2.2 shall be fully replaced. In this way, there is always one
  authoritative document with the list of implementation statuses.

I understand that you might want the "shall"s in the above to be "SHALL"s. I don't think it is necessary, and I think it's not a proper use of 2119 keywords, other IETF practice notwithstanding.

[Ballot comment]
Former DISCUSS, leaving it here for the record.

In principle, I like the idea of preventing fragmentation of the documentation by keeping the Section 2.2 table in one place, and by always replacing the document that has it with another, in its entirety.

Only... isn't that what the IANA registry is supposed to be for?  Why isn't that table just added to the IANA registry, and then maintained there?  Doesn't this document now require us to OBSOLETE this document and replace it every time we want to change the registry?

------------
Update 1
------------
I had no idea of the history of this, until Andrew pointed me at this:

  https://datatracker.ietf.org/doc/draft-ietf-dnsext-dnssec-registry-fixes/ballot/

I need to talk this over with Pete, Robert, and Russ, at least, on the telechat, and understand why we think we can't use the IANA registry the way registries are meant to be used.

------------
Update 2
------------
After more discussion with the chairs, here's what I understand...

1. The conformance table needs to be normative, stable, and with maintained history.  It needs to be clear, when you say you conform as of [date X], what it is that you claimed to conform to.  You can conform to an RFC, because once it's published, you have a stable, immutable reference, and you can give the RFC number.  But if I asked you whether something conformed to the RRTYPEs registry, you'd have to ask "at what date?"  And IANA doesn't maintain a history.

2. The conformance table is necessary in the first place because as things stand, you can say you "implement DNSSEC" when (for instance) you don't do NSEC3.  That's not going to be very useful, given that .com, .net, and .org are all using NSEC3.  We need a single document to which people can point and say, "We do it the way that says to."

3. If it takes an RFC to update the registry, then any change to the table needs an RFC anyway.  Thus, I suppose there's no *harm* in just publishing the table in the RFC and not in the registry.  I do like that the basic table is still in the registry, and that this just extracts the conformance criteria into an RFC-maintained table.

There's no point now, but it would have helped if, especially given the history of the earlier document, some of this information had been in the shepherd writeup.  But now that I understand the issues, I'm OK with this method of handling it.

[Ballot comment]
Former DISCUSS, leaving it here for the record.

In principle, I like the idea of preventing fragmentation of the documentation by keeping the Section 2.2 table in one place, and by always replacing the document that has it with another, in its entirety.

Only... isn't that what the IANA registry is supposed to be for?  Why isn't that table just added to the IANA registry, and then maintained there?  Doesn't this document now require us to OBSOLETE this document and replace it every time we want to change the registry?

Update: I had no idea of the history of this, until Andrew pointed me at this:
  https://datatracker.ietf.org/doc/draft-ietf-dnsext-dnssec-registry-fixes/ballot/
I need to talk this over with Pete, Robert, and Russ, at least, on the telechat, and understand why we think we can't use the IANA registry the way registries are meant to be used.

[Ballot discuss]
This is a DISCUSS-DISCUSS; no action is required by the document editor or working group.

In principle, I like the idea of preventing fragmentation of the documentation by keeping the Section 2.2 table in one place, and by always replacing the document that has it with another, in its entirety.

Only... isn't that what the IANA registry is supposed to be for?  Why isn't that table just added to the IANA registry, and then maintained there?  Doesn't this document now require us to OBSOLETE this document and replace it every time we want to change the registry?

Update: I had no idea of the history of this, until Andrew pointed me at this:
  https://datatracker.ietf.org/doc/draft-ietf-dnsext-dnssec-registry-fixes/ballot/
I need to talk this over with Pete, Robert, and Russ, at least, on the telechat, and understand why we think we can't use the IANA registry the way registries are meant to be used.

My extreme apologies for getting the dnsext working group caught in the middle of a "daddy wants this and mommy wants that" argument.

[Ballot discuss]
In principle, I like the idea of preventing fragmentation of the documentation by keeping the Section 2.2 table in one place, and by always replacing the document that has it with another, in its entirety.

Only... isn't that what the IANA registry is supposed to be for?  Why isn't that table just added to the IANA registry, and then maintained there?  Doesn't this document now require us to OBSOLETE this document and replace it every time we want to change the registry?

IANA has reviewed draft-ietf-dnsext-dnssec-algo-imp-status-03 and has
the following comments:

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

In the IANA Matrix located at:

http://www.iana.org/protocols/

the reference for the Domain Name System Security (DNSSEC) Algorithm
Numbers located at:

http://www.iana.org/assignments/dns-sec-alg-numbers

should be updated to reference [ RFC-to-be ]. In addition, the registry -
Domain Name System Security (DNSSEC) Algorithm Numbers - should have
[ RFC-to-be ] as a reference for the entire registry.

IANA understands that this is the only action that must be completed upon
approval of this document.

Note: The actions 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 what actions will be performed.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Subject: Last Call:  (Applicability Statement: DNS Security (DNSSEC) DNSKEY Algorithm Implementation Status) to Best Current Practice


The IESG has received a request from the DNS Extensions WG (dnsext) to
consider the following document:
- 'Applicability Statement: DNS Security (DNSSEC) DNSKEY Algorithm
  Implementation Status'
  as Best Current
Practice

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 2012-07-11. 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 DNS Security Extensions (DNSSEC) requires the use of
  cryptographic algorithm suites for generating digital signatures over
  DNS data.  There is currently an IANA registry for these algorithms
  that lacks the recommended implementation status of each algorithm.
  This document provides an applicability statement on algorithm
  implementation status for DNSSEC component software.  This document
  lists each algorithm's status based on the current reference.  In the
  case that an algorithm is specified without an implementation status,
  this document assigns one.  This document updates RFCs 2536, 2539,
  3110, 4034, 4398, 5155, 5702, and 5933.

Note that this document responds to the objections raised against
draft-ietf-dnsext-dnssec-registry-fixes-08; the earlier document was
split into this document and draft-ietf-dnsext-dnssec-registry-update.
The implementation status information published in this document was
originally published in draft-ietf-dnsext-dnssec-registry-fixes-08,
which made a novel and controversial use of the IANA registry.  That
approach was too controversial, so this document publishes that
information separately.

The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-dnsext-dnssec-algo-imp-status/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-dnsext-dnssec-algo-imp-status/ballot/


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

Submission write-up for draft-ietf-dnsext-dnssec-algo-imp-status-03.
Template date 2012-02-24

(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?

    BCP

(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 DNS Security Extensions (DNSSEC) requires the use of
  cryptographic algorithm suites for generating digital signatures
  over DNS data.  There is currently an IANA registry for these
  algorithms that it lacks the recommended implementation status of
  each algorithm.  This document provides an applicability statement
  on algorithm implementation status for DNSSEC component software.
  This document lists each algorithm's status based on the current
  reference.  In the case that an algorithm is specified without an
  implementation status, this document assigns one.  The document
  updates RFCs 2536, 2539, 3110, 4034, 4398, 5155, 5702, and 5933.

Working Group Summary

    The intended effect of this draft was originally captured in
    draft-ietf-dnsext-dnssec-registry-fixes-08, which made a novel and
    controversial use of the IANA registry.  That approach was too
    controversial, and so the WG split the document into two parts.
    This draft is one of them.

    The present approach was far less controversial than the previous
    one, and nobody has raised any objection to the current text.

Document Quality

    The draft does not specify a protocol of any kind, but it does
    make a recommendation in favour of some algorithms that are so far
    not widely deployed. 

    The discussion of dnssec-registry-fixes led to the approach
    instantiated in this draft. 

Personnel

  Who is the Document Shepherd? Who is the Responsible Area
  Director?

    Andrew Sullivan is the Document Shepherd, and Ralph Droms 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.

    The shepherd reviewed the document for content, to make sure that
    it was in keeping with the WG's consensus, to ensure that its
    references were correct, and to ensure that it addressed previous
    objections to the approach adopted in dnssec-registry-fixes.  The
    document is ready.

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

    No.  There was adequate discussion of the draft, and a significant
    amount of it had to do with whether a particular word was the
    right one. 

(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, except that the IESG should confirm that the approach in the
    draft meets its objections to the predecessor draft.

(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.

    The IESG should confirm that the approach in the draft meets its
    objections to the predecessor draft.  Otherwise, none.

(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 appear to be no objections.  The WG has previously lamented
    the problem that figuring out what is a conforming DNSSEC
    validator or server implementation has been hard because of the
    lack this draft seeks to address.

(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 http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

  Nits all pass.  The nits tool says that two updates are missing
  from the header, but I can see them.

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

    N/A

(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.

    No.

(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.

    This draft is intended to update a number of others.  They are all
    listed.
   
(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).

    The document does not actually change or create any IANA registry,
    but it requests addition of itself as a reference from the
    relevant registry.

(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.

    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.

    N/A.