CBOR Object Signing and Encryption (COSE) Key Thumbprint
draft-ietf-cose-key-thumbprint-06

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-cose-key-thumbprint and RFC 9679, changed IESG state to RFC Published)

[Ballot comment]
I agree with Eric Vyncke's comments. Also, much thanks to Joel Jaeggli for his OpsDir review: https://datatracker.ietf.org/doc/review-ietf-cose-key-thumbprint-04-opsdir-lc-jaeggli-2024-04-14/

In addition, I have some nits:
1: I found "The resulting value is the COSE Key Thumbprint with H of the COSE Key." to be very difficult to parse -- perhaps you can drop "with H of the COSE Key."? Actually, I'm not entirely sure what the sentence is trying to convey, other than that the result is the thumbprint...


I'm also not sure if the first sentence in the security considerations section is strictly true:
7.  Security Considerations

  A COSE Key Thumbprint will only uniquely identify a particular key if
  a single unambiguous COSE Key representation for that key is defined
  and used when computing the COSE Key Thumbprint.

The implication of "only *uniquely* identify a particular key" makes it sound like if you used some other representation, then you might identify some other key (which, I *guess* might be true if the other representation didn't include the key :-)).
Is "correctly" perhaps a better word than "uniquely"? Or have I completely misunderstood?

[Ballot comment]
Section 2: If COSE keys are specifically public asymmetric keys and/or symmetric keys, you could mention that here.  It becomes partially apparent throughout the reading of the draft, but it would be nice if it was up front. 

Section 5.3: The second sentence is trivially true.  The question is whether a different kind of key can use the thumbprint algorithm.  Perhaps the second should say, 'Any party in possession of a key that is represented as a COSE Keys can use...'

Section 5.6, para 4?, last sentence:  For error handling:  It seems like there should be a MUST or at least a SHOULD instead of the current 'will need to'.

[Ballot comment]
Section 5.3: The second sentence is trivially true.  The question is whether a different kind of key can use the thumbprint algorithm.  Perhaps the second should say, 'Any party in possession of a key that is represented as a COSE Keys can use...'

Section 5.4:  This is just an observation, no change required (because the section is already complex):  SPKI is for the public key, COSE keys (in this document) aren't specified to be public, or symmetric.  So possibly a bit of apples to oranges in terms of 'keys'.  I would not change this section.  If COSE keys are specifically one of these types - public, or symmetric, you could mention that earlier in the draft (maybe in terminology). 

Section 5.6, para 4?, last sentence:  For error handling:  It seems like there should be a MUST or at least a SHOULD instead of the current 'will need to'.

[Ballot comment]
Thanks for the work done on this short but useful document.

I have two comments though, feel free to ignore:

In the abstract, it is not obvious at first read that the cryptographic hash is the "thumbprint"

In the text, sometimes the COSE keys are surrounded by double quotes, sometimes they are not.

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-cose-key-thumbprint-04. If any part of this review is inaccurate, please let us know.

IANA has a question about each of the actions requested in the IANA Considerations section of this document.

IANA understands that, upon approval of this document, there are two actions which we must complete.

First, in the CWT Confirmation Methods registry in the CBOR Web Token (CWT) Claims registry group located at:

https://www.iana.org/assignments/cwt/

a single new registration will be made as follows:

Confirmation Method Name: ckt
Confirmation Method Description: COSE Key Thumbprint
JWT Confirmation Method Name: jkt
Confirmation Key: [ TBD-at-Registration ]
Confirmation Value Type: binary string
Change Controller: IESG
Reference: [ RFC-to-be ]

IANA Question --> In the past, the IESG has preferred that the IETF be used as the change controller (a document is in process). Can this be changed?

As this document requests a registration in an Expert Review or Specification Required (see RFC 8126) registry, we have initiated the required Expert Review via a separate request. This review must be completed before the document's IANA state can be changed to "IANA OK."

Second, in the OAuth URI Registry in the OAuth Parameters registry group located at:

https://www.iana.org/assignments/oauth-parameters/

a single new registration will be made as follows:

URN: urn:ietf:params:oauth:ckt
Common Name: COSE Key Thumbprint URI
Change Controller: IESG
Reference: [ RFC-to-be ]

IANA Question --> Once again, the IESG has preferred that the IETF be used as the change controller (a document is in process). Can this be changed?

As this document requests a registration in an Expert Review or Specification Required (see RFC 8126) registry, we have initiated the required Expert Review via a separate request. This review must be completed before the document's IANA state can be changed to "IANA OK."

We understand that these are the only actions required to 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 meant only to confirm the list of actions that will be performed.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Sr. Specialist

The following Last Call announcement was sent out (ends 2024-04-02):

From: The IESG
To: IETF-Announce
CC: cose-chairs@ietf.org, cose@ietf.org, draft-ietf-cose-key-thumbprint@ietf.org, michael_b_jones@hotmail.com, paul.wouters@aiven.io
Reply-To: last-call@ietf.org
Sender:
Subject: CORRECTED Last Call:  (CBOR Object Signing and Encryption (COSE) Key Thumbprint) to Proposed Standard


The IESG has received a request from the CBOR Object Signing and Encryption
WG (cose) to consider the following document: - 'CBOR Object Signing and
Encryption (COSE) Key Thumbprint'
  as Proposed Standard

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
last-call@ietf.org mailing lists by 2024-04-02. 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


  This specification defines a method for computing a hash value over a
  COSE Key. It defines which fields in a COSE Key structure are used in
  the hash computation, the method of creating a canonical form of the
  fields, and how to hash the byte sequence.  The resulting hash value
  can be used for identifying or selecting a key that is the subject of
  the thumbprint.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-cose-key-thumbprint/



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


The document contains these normative downward references.
See RFC 3967 for additional information:
    rfc9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms (Informational - Internet Engineering Task Force (IETF))
    rfc6755: An IETF URN Sub-Namespace for OAuth (Informational - Internet Engineering Task Force (IETF))

The following Last Call announcement was sent out (ends 2024-04-02):

From: The IESG
To: IETF-Announce
CC: cose-chairs@ietf.org, cose@ietf.org, draft-ietf-cose-key-thumbprint@ietf.org, michael_b_jones@hotmail.com, paul.wouters@aiven.io
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (CBOR Object Signing and Encryption (COSE) Key Thumbprint) to Proposed Standard


The IESG has received a request from the CBOR Object Signing and Encryption
WG (cose) to consider the following document: - 'CBOR Object Signing and
Encryption (COSE) Key Thumbprint'
  as Proposed Standard

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
last-call@ietf.org mailing lists by 2024-03-26. 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


  This specification defines a method for computing a hash value over a
  COSE Key. It defines which fields in a COSE Key structure are used in
  the hash computation, the method of creating a canonical form of the
  fields, and how to hash the byte sequence.  The resulting hash value
  can be used for identifying or selecting a key that is the subject of
  the thumbprint.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-cose-key-thumbprint/



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


The document contains these normative downward references.
See RFC 3967 for additional information:
    rfc9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms (Informational - Internet Engineering Task Force (IETF))
    rfc6755: An IETF URN Sub-Namespace for OAuth (Informational - Internet Engineering Task Force (IETF))

Shepherd write-up for draft-ietf-cose-key-thumbprint-04 by Michael B. Jones
===========================================================================

Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?

It reached broad agreement.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?

There was nothing particularly controversial.

Questions were asked about whether the hash algorithm identifier in the URI representation should come from the IANA "Named Information Hash Algorithm" registry or the IANA "COSE Algorithms" registry.  The former seems appropriate, since it defines a string representation of the hash algorithm, which is needed in this context, whereas the latter does not.  I'll also note that, for the forseeable future, the string used will likely nearly always be "sha-256", so questions of what algorithms are supported are fairly moot.

3. 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 publicly available.)

No

4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as RFC 7942 recommends) or elsewhere
(where)?

This is not a protocol document.  That said, there are implementations of this functionality deployed by Transmute for SCITT and by Isobe Kohei for his "TEEP" TAM server.  These were reported on the COSE mailing list.

Additional Reviews

5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.

Some of the SCITT participants and some of the users of the closely-related JWK Thumbprint specification [RFC 7638] authors have reviewed the specification.

It would be nice to have confirmation from an independent implementation or two that their computations match the example in the specification.

6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

IANA reviews have not yet taken place.  That said, I'm a designated expert, and the registration request looks fine to me.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?

The document contains no YANG module.

8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.

The document does not utilize formal language.

Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?

Yes

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?

I'm not aware of any such issues in this document.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

Proposed Standard is being requested.  The specification normatively describes how to prepare CBOR data as input to a cryptographic hash function, therefore this is an appropriate document type.

12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.

The authors are aware of no intellectual property pertaining to this specification.

13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.

Yes

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.

[IANA.Hash.Algorithms] should be a normative reference, since its use is required for implementation.  Other than that, all the references are appropriately categorized.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?

None

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?

No

19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.

No

20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see RFC 8126).

The IANA actions are clearly described and appropriate.

21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.

None

Shepherd write-up for draft-ietf-cose-key-thumbprint-04 by Michael B. Jones
===========================================================================

Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?

It reached broad agreement.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?

There was nothing controversial.

3. 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 publicly available.)

No

4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as RFC 7942 recommends) or elsewhere
(where)?

This is not a protocol document.  That said, there are implementations of this functionality deployed by Transmute for SCITT and by Isobe Kohei for his "TEEP" TAM server.  These were reported on the COSE mailing list.

Additional Reviews

5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.

Some of the SCITT participants and some of the users of the closely-related JWK Thumbprint specification [RFC 7638] authors have reviewed the specification.

It would be nice to have confirmation from an independent implementation or two that their computations match the example in the specification.

6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

IANA reviews have not yet taken place.  That said, I'm a designated expert, and the registration request looks fine to me.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?

The document contains no YANG module.

8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.

The document does not utilize formal language.

Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?

Yes

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?

I'm not aware of any such issues in this document.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

Proposed Standard is being requested.  The specification normatively describes how to prepare CBOR data as input to a cryptographic hash function, therefore this is an appropriate document type.

12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.

The authors are aware of no intellectual property pertaining to this specification.

13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.

Yes

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.

[IANA.Hash.Algorithms] should be a normative reference, since its use is required for implementation.  Other than that, all the references are appropriately categorized.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?

None

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?

No

19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.

No

20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see RFC 8126).

The IANA actions are clearly described and appropriate.

21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.

None

Shepherd write-up for draft-ietf-cose-key-thumbprint-04 by Michael B. Jones
===========================================================================

Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?

It reached broad agreement.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?

There was nothing controversial.

3. 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 publicly available.)

No

4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as RFC 7942 recommends) or elsewhere
(where)?

This is not a protocol document.  That said, there are implementations of this functionality deployed by Transmute for SCITT and by Isobe Kohei for his "TEEP" TAM server.  These were reported on the COSE mailing list.

Additional Reviews

5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.

Some of the SCITT participants and some of the users of the closely-related JWK Thumbprint specification [RFC 7638] authors have reviewed the specification.

It would be nice to have confirmation from an independent implementation or two that their computations match the example in the specification.

6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

IANA reviews have not yet taken place.  That said, I'm a designated expert, and the registration request looks fine to me.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?

The document contains no YANG module.

8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.

The document does not utilize formal language.

Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?

Yes

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?

I'm not aware of any such issues in this document.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

Proposed Standard is being requested.  The specification normatively describes how to prepare CBOR data as input to a cryptographic hash function, therefore this is an appropriate document type.

12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.

The authors are aware of no intellectual property pertaining to this specification.

13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.

Yes

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.

[IANA.Hash.Algorithms] should be a normative reference, since its use is required for implementation.  Other than that, all the references are appropriately categorized.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?

None

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?

No

19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.

No

20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see RFC 8126).

The IANA actions are clearly described and appropriate.

21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.

None

Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?

It reached broad agreement.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?

There was nothing controversial.

3. 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 publicly available.)

No

4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as RFC 7942 recommends) or elsewhere
(where)?

This is not a protocol document.  That said, there are implementations of this functionality deployed by Transmute for SCITT and by Isobe Kohei for his "TEEP" TAM server.  These were reported on the COSE mailing list.

Additional Reviews

5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.

Some of the SCITT participants and some of the users of the closely-related JWK Thumbprint specification [RFC 7638] authors have reviewed the specification.

It would be nice to have confirmation from an independent implementation or two that their computations match the example in the specification.

6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

IANA reviews have not yet taken place.  That said, I'm a designated expert, and the registration request looks fine to me.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?

The document contains no YANG module.

8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.

The document does not utilize formal language.

Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?

Yes, with one issue remaining to be fixed.  My individual review at https://mailarchive.ietf.org/arch/msg/cose/pm2JDJq1TaWNzlGa71Ikf6id95A/ identified mismatched ordering between two clauses.

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?

I'm not aware of any such issues in this document.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

Proposed Standard is being requested.  The specification normatively describes how to prepare CBOR data as input to a cryptographic hash function, therefore this is an appropriate document type.

12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.

The authors are aware of no intellectual property pertaining to this specification.

13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.

Yes

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.

The references are appropriately categorized.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?

None

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.

There are (appropriate and necessary) normative references to an informational RFC: "CBOR Object Signing and Encryption (COSE): Initial Algorithms" [RFC 9053].

18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?

No

19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.

No

20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see RFC 8126).

The IANA actions are clearly described and appropriate.

21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.

None