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 target is BCP which is indicated in the header. According to 
RFC1818 BCP are used to publish relevant technical information 
endorsed by the IETF community.  This document recommend 
not to use weak ciphers. This could fall under the BCP. In addition 
rfc6649 "Deprecate DES, RC4-HMAC-EXP, and Other Weak 
Cryptographic Algorithms in Kerberos" has BCP as a status.   

The draft updates  RFC 3961  and obsoletes RFC 4757. This is mentioned 
in the header, abstract and introduction. 

(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.

The 3DES and RC4 encryption types are steadily weakening in
cryptographic strength, and the deprecation process should be begun
for their use in Kerberos.  Accordingly, RFC 4757 is moved to
Obsolete status, as none of the encryption types it specifies should
be used, and RFC 3961 is updated to note the deprecation of the
triple-DES encryption types.

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 

No controversy. 

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?

This does not apply here. 

My understanding is implementations are likely to implement
the draft, especially with the "SHOULD NOT" recommendation.

Both co-authors expect to start the deprecation process which is slow
to achieve as there is now a long deployment history. A deprecation 
will not remove the actual software  implementation right away, but 
progressively disable it.


  Who is the Document Shepherd? Who is the Responsible Area

Daniel Migault is the shepherd, Eric Rescola is the AD 

(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.

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

No. The document has been written and supported by major implementations
 of Kerberos, and has benefited from a significant number of reviews.

(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.

This does not apply here. 

(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. 

(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.

Both co-authors state they are not aware of any IPR. 

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


(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?   


(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 latest version provides teh following nits: 

  Checking nits according to :

  -- The draft header indicates that this document obsoletes RFC4757, but the
     abstract doesn't seem to directly say this.  It does mention RFC4757
     though, so this could be OK.

  -- The draft header indicates that this document updates RFC3961, but the
     abstract doesn't seem to directly say this.  It does mention RFC3961
     though, so this could be OK.

MGLT: This is OK, the abstract mentions: """Accordingly, RFC 4757 is moved to
   Obsolete status, as none of the encryption types it specifies should
   be used, and RFC 3961 is updated to note the deprecation of the
   triple-DES encryption types."""

This is probably due to the space between RFC and the number. 

  Miscellaneous warnings:

     (Using the creation date from RFC3961, updated by this document, for
     RFC5378 checks: 2004-02-11)

  -- The document seems to lack a disclaimer for pre-RFC5378 work, but may
     have content which was first submitted before 10 November 2008.  If you
     have contacted all the original authors and they are all willing to grant
     the BCP78 rights to the IETF Trust, then this is fine, and you can ignore
     this comment.  If not, you may need to add the pre-RFC5378 disclaimer. 
     (See the Legal Provisions document at for more information.)

MGLT: I do not think this applies here as well. There is no copy past from the pre-RFC5378 work.

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

This does not apply here. 

(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. 


(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.

The current document obsoletes: 4757 and updates: 3961. This is mentioned 
in the abstract and in the header and the introduction.

(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 IANA section is consequent with body of the text. 

Encryption types 5, 7, 16, and 23 are deprecated, with this document
as the reference. We checked with IANA whether the reference should
be the reference introducing the registry entry or the one deprecating 
it. From there response, there is no specific rule for it. Having the 
reference deprecating the entry is fine. 

Note that the the IANA is also requested to  update status checksum  
types 1, 2, 3, 4, 5, 6, and 8 that are deprecated, with RFC 6649.  

(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.

Standards Action for standards-track RFCs; non-standards-track 
RFCs must be reviewed by an expert. The proposed expert is Ken Raeburn. 

(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.

This does not apply here.