Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)
draft-ietf-oauth-proof-of-possession-11

[Ballot comment]

- Figure 1 and the discussion thereof: you talk all the time here
about "a symmetric key" so I think you ought add a footnote like
bit of text that says something like "note that there ought be
more than one key involved here, derived from the key exchanged
at (0) via a KDF." I kinda wish that all that had been covered in
one document but I guess that's part of the PoP arch doc, which
is for later.

- 3.1 says "outside the scope of this specification": just
wondering - does that phrase occur in all OAuth RFCs? (only
kidding, honest:-)

- section 4, para 2: replay can also be avoided if a sub-key is
derived from a shared secret that is specific to the instance of
the PoP demonstration.

- section 6: DE guidance - I think we ought tell the DEs that the
specification of a new thing needs to explicitly describe the
security properties of using the new thing.

- I didn't see a response to the secdir review [1] but that was
maybe sent to the wrong places.

  [1] https://www.ietf.org/mail-archive/web/secdir/current/msg06266.html

[Ballot comment]
The Abstract and Introduction both say something like this:

  This specification defines how a JSON Web Token (JWT) [JWT] can
  declare that the presenter of the JWT possesses a key and that the
  recipient can cryptographically confirm that the presenter possesses
  that key.

The JWT doesn't declare that the presenter possesses the key; it declares that the presenter *must* possess the key... yes?  Shouldn't this say that?:

NEW
  This specification defines how a JSON Web Token (JWT) [JWT] can
  declare that the presenter of the JWT must possess a key and how
  the recipient can cryptographically confirm that the presenter
  possesses that key.
END

(Also notice change from "that" to "how".)

  This
  specification defines how to communicate key confirmation key
  information in JWTs.

"key confirmation key information" seems odd and hard to follow.  I think "key information used in key confirmation" is a better way to say it.  But perhaps the sentence as a whole could be better phrased.  Does something like this work?:

NEW
  This specification defines how to imbed into the JWT the key
  information that is used in key confirmation.
END

-- Section 2 --
Minor, very unimportant point: There's no reason to put, for example, "(JWT)", when the citation "[JWT]" immediately follows it.  I suggest just using the citation to provide the abbreviation, and eliminating "(JWT)", "(JWK)", and "(JWE)".  But very unimportant; do, or don't, and no need to respond to this item.

-- Section 3 --

  The issuer of a JWT declares that the presenter possesses a
  particular key and that the recipient can cryptographically confirm
  proof-of-possession of the key by the presenter by including a "cnf"
  (confirmation) claim in the JWT whose value is a JSON object.

I was convinced that this wasn't right until I read it for about the eighth time.  It sounds like the recipient includes the "cnf" claim in the JWT, when it's actually the issuer.  That happens when long sentences have too many qualifiers strung together.  How about this?:

NEW
  By including a "cnf" (confirmation) claim in a JWT, the issuer
  of the JWT declares that the presenter possesses a particular key,
  and that the recipient can cryptographically confirm that the
  presenter has proof-of-possession of that key.  The value in the
  cnf claim is a JSON object, and members in that object identify
  the proof-of-possession key.
END

-- Section 3.5 --

  The protocol used to acquire the resource MUST provide integrity
  protection; an HTTP GET request to retrieve the JWK Set MUST use
  Transport Layer Security (TLS) [RFC5246]; and the identity of the
  server MUST be validated, as per Section 6 of RFC 6125 [RFC6125].

Little editorial punctuational nonsense: I would make the first semicolon a colon instead (or perhaps a period), and I would then make the second semicolon a comma.

-- Section 4 --
In the last paragraph, can you provide a reference for "audience restriction"?

-- Section 6 --
Can we get this fixed in all the OAuth and JOSE documents?  It's getting old having to make the same comment for every document:  We should not be trying to set up IANA processes in our IANA Considerations.  The fourth and sixth paragraphs aren't appropriate here: IANA coordinates and tracks registration requests, and all requests should go to IANA.  IANA will contact the DEs, not the other way around.  The authors have seen this comment from me before....

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

IANA has completed its review of draft-ietf-oauth-proof-of-possession-08.txt. If any part of this review is inaccurate, please let us know.

IANA has a question about one 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 IANA must complete.

First, in the JSON Web Token Claims subregistry of the JSON Web Token (JWT) registry located at:

http://www.iana.org/assignments/jwt/

a single new token claim will be registered as follows:

Claim Name: cnf
Claim Description: Confirmation
Change Controller: IESG
Reference: Section 3.1 of [ RFC-to-be ]

As this document requests registrations in an Expert Review or Specification Required (see RFC 5226) registry, we will initiate the required Expert Review via a separate request. Expert review will need to be completed before your document can be approved for publication as an RFC.

Second, a new registry will be created called the JWT Confirmation Methods registry. This registry is to be managed via Specification Required as defined in RFC 5226. IANA notes the registration requirements noted in Section 6 of [ RFC-to-be ].

IANA QUESTION -> Where should this new registry be located? Is it a néw registry on the IANA Matrix or is it a subregistry of an existing registry? If it is a subregistry of an existing registry, in which registry will it be contained?

The new registry has four initial registrations as follows:

Confirmation Method Value: "jwk"
Confirmation Method Description: JSON Web Key Representing Public Key
Change Controller: IESG
Specification Document(s): Section 3.2 of [ RFC-to-be ]

Confirmation Method Value: "jwe"
Confirmation Method Description: Encrypted JSON Web Key
Change Controller: IESG
Specification Document(s): Section 3.3 of [ RFC-to-be ]

Confirmation Method Value: "kid"
Confirmation Method Description: Key Identifier
Change Controller: IESG
Specification Document(s): Section 3.4 of [ RFC-to-be ]

Confirmation Method Value: "jku"
Confirmation Method Description: JWK Set URL
Change Controller: IESG
Specification Document(s): Section 3.5 of [ RFC-to-be ]

IANA understands that the two actions above are the only ones 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 only to confirm what actions will be performed. 

Thank you,

Sabrina Tanamal
IANA Specialist
ICANN

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: Kathleen.Moriarty.ietf@gmail.com, oauth@ietf.org, kepeng.lkp@alibaba-inc.com, draft-ietf-oauth-proof-of-possession@ietf.org, oauth-chairs@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)) to Proposed Standard


The IESG has received a request from the Web Authorization Protocol WG
(oauth) to consider the following document:
- 'Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)'
  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
ietf@ietf.org mailing lists by 2015-12-16. 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 how to express a declaration in a JSON Web
  Token (JWT) that the presenter of the JWT possesses a particular key
  and that the recipient can cryptographically confirm proof-of-
  possession of the key by the presenter.  Being able to prove
  possession of a key is also sometimes described as the presenter
  being a holder-of-key.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-oauth-proof-of-possession/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-oauth-proof-of-possession/ballot/


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

Shepherd Writeup for "Proof-of-Possession Key Semantics for JSON Web
Tokens (JWTs)"
draft-ietf-oauth-proof-of-possession-06

1. Summary

The document shepherd is Kepeng Li. The responsible Area Director is
Kathleen Moriarty.

  This specification defines how to express a declaration in a JSON Web
  Token (JWT) that the presenter of the JWT possesses a particular key
  and that the recipient can cryptographically confirm proof-of-
  possession of the key by the presenter.  This property is also
  sometimes described as the presenter being a holder-of-key.


This specification is a Standards Track RFC describing a solution
component described in the OAuth 2.0 Proof-of-Possession architecture
(see draft-ietf-oauth-pop-architecture).

2. Review and Consensus

The document was developed by the working group based on the
requirements and architecture described in
draft-ietf-oauth-pop-architecture.
There is strong consensus behind this work.

This document contains an IANA consideration section and requires
registration into an existing registry and a new registry to be created.

The document contains JSON examples, which have been validated using
JSONLint.
One example is only a JSON snippet and does not contain valid JSON.

3. Intellectual Property

Each author has confirmed conformance with BCP 78/79. There are no IPR
disclosures on the document.

http://www.ietf.org/mail-archive/web/oauth/current/msg15005.html
http://www.ietf.org/mail-archive/web/oauth/current/msg15004.html
http://www.ietf.org/mail-archive/web/oauth/current/msg15001.html

4. Other Points

All normative references have been finalized.