Web Authorization Protocol J. Richer
Internet-Draft Bespoke Engineering
Intended status: Informational B. Campbell
Expires: 31 August 2025 Ping Identity
D. Saxe
Beyond Identity
27 February 2025
Deferred Key Binding for OAuth
draft-richer-oauth-tmb-claim-00
Abstract
Sometimes you want to get a token that's tied to a public key but you
can't prove possession of that public key. That's when you need to
trust me, bruh.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://jricher.github.io/draft-richer-oauth-tmb-claim/draft-richer-
oauth-tmb-claim.html. Status information for this document may be
found at https://datatracker.ietf.org/doc/draft-richer-oauth-tmb-
claim/.
Discussion of this document takes place on the Web Authorization
Protocol Working Group mailing list (mailto:oauth@ietf.org), which is
archived at https://mailarchive.ietf.org/arch/browse/oauth/.
Subscribe at https://www.ietf.org/mailman/listinfo/oauth/.
Source for this draft and an issue tracker can be found at
https://github.com/jricher/draft-richer-oauth-tmb-claim.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on 31 August 2025.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Token Meta-key Binding Claim . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Normative References . . . . . . . . . . . . . . . . . . . . 3
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The JWT confirmation claim "cnf" [RFC7800] allows an RS to determine
PoP semantics for a token. However, methods like mTLS [RFC8705] and
DPoP [RFC9449] assume that the requester of that token can prove
possession of the key that is bound to the token. Sometimes that's
just too hard, and so here we define a claim to allow a requester to
ask for a token that is bound to a key that the requester cannot,
does not want to, or does not feel like proving possession of at the
time of request.
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2. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Token Meta-key Binding Claim
The token meta-key binding "tmb" claim is passed in an OAuth token
request parameter of the same name. Its value is the form-encoded
value that the requester wants the confirmation claim to be in the
issued token. If the requester is making a DPoP or mTLS request, any
keys there MUST be ignored.
The same parameter can be used in a token exchange request, with the
same results.
If the issued token is a JWT, the value of the "tmb" claim is copied
to the "cnf" claim of the resulting token. If the token is
introspected, the value of "tmb" is returned in the "cnf" claim of
the introspection response.
The requester SHOULD give the resulting token to the holder of the
key represented in the "tmb" claim.
The presenter of the token MUST prove possession of the key in the
resulting "cnf" claim using the appropriate key validation method for
the type of token.
4. Security Considerations
The security of this specification is entirely based on trust. If
you have trust issues, it's not going to be secure.
5. IANA Considerations
This document registers the "tmb" claim to the IANA JWT Claims
registry and OAuth request parameter.
6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
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[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
Possession Key Semantics for JSON Web Tokens (JWTs)",
RFC 7800, DOI 10.17487/RFC7800, April 2016,
<https://www.rfc-editor.org/rfc/rfc7800>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8705] Campbell, B., Bradley, J., Sakimura, N., and T.
Lodderstedt, "OAuth 2.0 Mutual-TLS Client Authentication
and Certificate-Bound Access Tokens", RFC 8705,
DOI 10.17487/RFC8705, February 2020,
<https://www.rfc-editor.org/rfc/rfc8705>.
[RFC9449] Fett, D., Campbell, B., Bradley, J., Lodderstedt, T.,
Jones, M., and D. Waite, "OAuth 2.0 Demonstrating Proof of
Possession (DPoP)", RFC 9449, DOI 10.17487/RFC9449,
September 2023, <https://www.rfc-editor.org/rfc/rfc9449>.
Acknowledgments
TODO acknowledge.
Authors' Addresses
Justin Richer
Bespoke Engineering
Email: ietf@justin.richer.org
Brian Campbell
Ping Identity
Email: bcampbell@pingidentity.com
Dean Saxe
Beyond Identity
Email: dean@thesax.es
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