Using Counter Modes with Encapsulating Security Payload (ESP) and Authentication Header (AH) to Protect Group Traffic
draft-ietf-msec-ipsec-group-counter-modes-06

[Ballot comment]
#1: Sec 2:

It is the basis for several modes of operation that combine
  encryption, including CCM and GCM.

combine with what?  I assume you mean "combine authentication with encryption, including CCM and GCM."

[Ballot discuss]
This one is a DISCUSS-DISCUSS (i.e., no action required for authors). 

I'd like to understand why this counter mode ID is on standards track when the last one (draft-ietf-ipsecme-aes-ctr-ikev2) had to go through as informational.

These are regular DISCUSSes:

#2: From SECDIR review:

Please add a normative reference to draft-ietf-msec-gdoi-update-06 that references how to distribute the SIDs.

#3: Section 4:

  If the entire set of sender identifiers has been
  exhausted, the GKMS MUST refuse to allow new group members to
  join.

If the GKMS got in this situation by using a small SID wouldn't another idea be to switch to a bigger SID?  This obviously wouldn't work for the 16 but would for the 8 and 12 bit SIDs.

[Ballot comment]
A review by Ari Keränen:

4. Group Key Management Conventions

    o  When a GKMS determines that a particular group member is no longer
      a part of the group, then it MAY re-allocate any sender identifier
      associated with that group member for use with new group member.
      In this case, the GKMS MUST first delete and replace any active AH
      or ESP SAs with which the SID may have been used.


How does the "delete and replace" happen in practice if the GKMS is a
different entity than the one with the active AH or SA?


    A GKMS MUST support a group member notifying the GCKS that its IV
    space will soon be exhausted and requires a new SA to be distributed.
    A group member SHOULD notify the GCKS in advance of its IV space
    being exhausted.  A GCKS MAY choose to ignore this notification based
    on policy (e.g., if the group member appears to be asking for new SAs
    so frequent as to negatively affect group communications).

Ignoring the IV space exhaustion notifications probably has some
security implications worth noting in the security considerations sections.

[Ballot comment]
I support Alexey's DISCUSS. "MUST support" is ambiguous. and the following SHOULD/MAY combination is so loose, it is unclear what a compliant implementation MUST support.

[Ballot discuss]
This is a fine document, but I have one question:

4.  Group Key Management Conventions

  A GKMS MUST support a group member notifying the GCKS that its IV
  space will soon be exhausted and requires a new SA to be distributed.

Excuse my ignorance of the subject, but I would like to understand how this MUST can be achieved and whether any protocol extensions are needed to implement this requirement.

  A group member SHOULD notify the GCKS in advance of its IV space
  being exhausted.  A GCKS MAY choose to ignore this notification based
  on policy (e.g., if the group member appears to be asking for new SAs
  so frequent as to negatively affect group communications).

[Ballot discuss]
This is a fine document, but I have one question:

4.  Group Key Management Conventions

  A GKMS MUST support a group member notifying the GCKS that its IV
  space will soon be exhausted and requires a new SA to be distributed.

Excuse my ignorance of the subject, but I would like to understand how this MUST can be achieved and if any protocol extensions are needed to implement this requirement.

  A group member SHOULD notify the GCKS in advance of its IV space
  being exhausted.  A GCKS MAY choose to ignore this notification based
  on policy (e.g., if the group member appears to be asking for new SAs
  so frequent as to negatively affect group communications).

(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?

Vincent Roca is the shepherd. I have reviewed this document.
I think it's ready for IESG review.


(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, reviews received from:
Alfred Hoenes (-04 version, Jan 2010) 2nd WG LC
Sheela Rowles (-02 version, Jan 2009) 1st WG LC
David L. Black (-02 version, Dec 2008) 1st WG LC
George Gross (individual I-D, Feb 2007)
Those reviews are fine and the main comments addressed as far
as I can tell.


(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?

No.


(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.

After having read the document, I don't have any major comment.
I'll just send an email to the authors (with you in CC) with a few
very minor comments.
There's no IPR disclosure.


(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 seems to be a WG consensus.
(1.f) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarize 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
http://www.ietf.org/ID-Checklist.html 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? If the document
does not already indicate its intended status at the top of
the first page, please indicate the intended status here.

Yes, I've checked nits. There's an easy to correct issue regarding the
boilerplate version (from Sept 2009), and document may lack a disclaimer
for pre-RFC5378 work.


(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].

There's a normative/informative split that seems appropriate, and
no particular normative dependency.


(1.i) Has the Document Shepherd verified that the document's IANA
Considerations 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 [RFC2434]. If the
document describes an Expert Review process, has the Document
Shepherd conferred with the Responsible Area Director so that
the IESG can appoint the needed Expert during IESG Evaluation?

No IANA section and no need for any such section.


(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?

Non applicable.

(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.

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

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?

Personnel
Who is the Document Shepherd for this document? Who is the
Responsible Area Director? If the document requires IANA
experts(s), insert 'The IANA Expert(s) for the registries
in this document are .'

Technical Summary

Counter modes have been defined for block ciphers such as the
Advanced Encryption Standard (AES). Counter modes use a counter,
which is typically assumed to be incremented by a single sender.
This memo describes the use of counter modes when applied to the
Encapsulating Security Payload (ESP) and Authentication Header (AH)
in multiple-sender group applications.


Working Group Summary

One of the main comments received (Alfred Hoenes) concerns the
need to make the proposal compatible with any AES-like block ciphers
(it was previously restricted to AES). It has been addressed.
There was no controversial issue.


Document Quality

The document is small and easy to read.
I am not aware of the existence of an implementation but it's
likely one will be done, if not already the case.

Personnel

Shepherd: Vincent Roca
AD: Tim Polk