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Shepherd writeup

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?

The requested type of RFC is Standards Track. This is the appropriated type as
the document describes how to use ChaCha20-Poly1305 Authenticated Encryption in
the Cryptographic Message Syntax. The type is indicated in the header of the

(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

  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.

   This document describes the conventions for using ChaCha20-Poly1305
   Authenticated Encryption in the Cryptographic Message Syntax (CMS).
   ChaCha20-Poly1305 is an authenticated encryption algorithm
   constructed of the ChaCha stream cipher and Poly1305 authenticator.

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

  The draft had no controversy. Reviews revealed minor nits that were corrected.

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?

  CMS is already deployed, and the draft describes how to use a specific
  authenticated encryption algorithm which is expected to be used in the
  future. The purpose of the draft is to keep CMS up to date with security, and
  thus deployed. Reviews did not end with important changes in the protocol.


  Who is the Document Shepherd? Who is the Responsible Area

  The Document Shepherd is Daniel Migault. The responsible Area Director is
  Stephen Farrell.

(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 Document Shepherd reviewed the document and only raised minor nits.

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

   The document was reviewed by 4 persons: Daniel Migault, Rich Salz, Jim
   Schaad, and Peter Gutman. None of them revealed anything other than editing
   comments. The author Russ Housley has also significant experience on CMS. So
   I believe the document has received significant reviews and is ready.

(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. The scope of the document is limited to CMS.

(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.

   I have no issue with the document. It is necessary to update existing
   protocol with up-to-date cryptographic protocol. This is the scope of the
   CURDLE WG, and this document addresses this goal for CMS.

(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.

The author confirms there is no IPR disclosure.

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

Russ Husley confirmed there is no IPR disclosure.

(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?

The consensus is more the strong concurrence of the few individual. I believe
the remaining of the group remain silent as there would be little place for
controversy. The scope of the work is well understood by the WG.

(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.)


(11) Identify any ID nits the Document Shepherd has found in this
document. (See and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be

The output of ldnit is as follows:

** Downref: Normative reference to an Informational RFC: RFC 7539 (ref.

  -- Possible downref: Non-RFC (?) normative reference: ref. 'X680'

  -- Possible downref: Non-RFC (?) normative reference: ref. 'X690'

RFC7539 describes the defines the ChaCha20 stream cipher as well as the use of
the Poly1305 authenticator, both as stand-alone algorithms and as a "combined
mode", or Authenticated Encryption with Associated Data (AEAD) algorithm. This
document does not introduce any new crypto, but is meant to serve as a stable
reference and an implementation guide.  It is a product of the Crypto Forum
Research Group (CFRG).

This document is from the IRTF which does not define standards. The current
document describes the use of this algorithm.

The Downref is justified by RFC3967 as it falls into the following case:
   o  A standards track document may need to refer to a protocol or
      algorithm developed by an external body but modified, adapted, or
      profiled by an IETF informational RFC,

X680 and X690 are non IETF standard but ITU-T standards. CMS values are
generated using ASN.1 [X680], which uses the Basic Encoding Rules (BER) and the
Distinguished Encoding Rules (DER) [X690]. are necessary for the integration of
chacha30-polyy1305 into CMS.

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

The document does not need external formal reviews.

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


(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?


(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.

See 11.

(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.


(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).

   IANA is requested to add the following entry in the SMI Security for
   S/MIME Algorithms (1.2.840.113549. registry:

      TBD1   id-alg-AEADChaCha20Poly1305       [This Document]

   IANA is requested to add the following entry in the SMI Security for
   S/MIME Module Identifier (1.2.840.113549. registry:

      TBD2   id-mod-CMS-AEADChaCha20Poly1305   [This Document]

It is consistent with the document which describes the usage a new algorithm as
well as its associated module. Registries are defined in rfc7107 and the
request described in the document are appropriated. The newly created IANA
registries are identified and detailed in the document. They also have an
appropriated name.

(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.
mentions Russ Housley (primary), Jim Schaad (secondary) as expert.

(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.

The document provides ASN1 syntax. I have not checked the syntax as I do not
have found tools to do so.