OAuth 2.0 JWT Authorization Grant with DPoP Binding

Internet-Draft	JWT Authorization Grant with DPoP	October 2025
Parecki	Expires 21 April 2026	[Page]

Abstract

This specification defines a new OAuth 2.0 authorization grant type that uses a JSON Web Token (JWT) assertion to request an access token that is bound to a specific key using the Demonstration of Proof-of-Possession (DPoP) mechanism. This provides a higher level of security than a simple bearer token, as the client must prove possession of the key to use the access token.¶

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://drafts.aaronpk.com/oauth-jwt-dpop-grant/draft-parecki-oauth-jwt-dpop-grant.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-parecki-oauth-jwt-dpop-grant/.¶

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/aaronpk/oauth-jwt-dpop-grant.¶

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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This Internet-Draft will expire on 21 April 2026.¶

Copyright Notice

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶

1. Introduction

The JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and Authorization Grants [RFC7523] defines the use of a JWT as an authorization grant, using the grant type urn:ietf:params:oauth:grant-type:jwt-bearer. This grant type describes the use of a JWT authorization grant as a bearer token, which is susceptible to reuse by any party that obtains one.¶

OAuth 2.0 Demonstration of Proof-of-Possession at the Application Layer (DPoP) [RFC9449] defines a mechanism to bind access tokens to a specific cryptographic key. This prevents the token from being used by any party that does not have access to the private key.¶

This specification extends the proof-of-possession concept to the authorization grant itself. It defines a new grant type, urn:ietf:params:oauth:grant-type:jwt-dpop, for cases where the JWT assertion is already bound to a DPoP key. To exchange the assertion for an access token, the client must provide a DPoP proof demonstrating possession of the key to which the assertion is bound. This makes the JWT assertion a sender-constrained credential.¶

3. HTTP Parameter Bindings for Transporting Assertions

The OAuth Assertion Framework [RFC7521] defines generic HTTP parameters for transporting assertions (a.k.a. security tokens) during interactions with a token endpoint. This section defines specific parameters and treatments of those parameters for use with JWT DPoP-Bound Tokens.¶

3.1. Using DPoP-Bound JWTs as Authorization Grants

To use a DPoP-bound JWT as an authorization grant, the client uses an access token request as defined in Section 4 of [RFC7521] with the following specific parameter values and encodings.¶

grant_type:: REQUIRED - The value MUST be urn:ietf:params:oauth:grant-type:jwt-dpop¶
assertion:: REQUIRED - A single JWT, as defined in [RFC7519], that contains a cnf claim as described in Section 4.¶
scope:: OPTIONAL - The scope parameter may be used, as defined in [RFC7521], to indicate the requested scope.¶

Authentication of the client is optional, as described in Section 3.2.1 of [RFC6749] and consequently, the client_id is only needed when a form of client authentication that relies on the parameter is used.¶

The client MUST also include a DPoP header as defined in Section 4 of [RFC9449], which constitutes a proof of possession for the key to which the assertion is bound.¶

The following example demonstrates an access token request with a JWT as an authorization grant (with extra line breaks for display purposes only):¶

POST /token HTTP/1.1
Host: as.example.com
Content-Type: application/x-www-form-urlencoded
DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrI...

grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-dpop
&assertion=eyJhbGciOiJFUzI1NiIsImtpZCI6IjE2In0.
eyJpc3Mi[...omitted for brevity...].
J9l-ZhwP[...omitted for brevity...]

4. JWT Format and Processing Requirements

The authorization server MUST validate the JWT according to the criteria below. Application of additional restrictions and policy are at the discretion of the authorization server.¶

The authorization server MUST validate the DPoP proof in the DPoP header as described in Section 4 of [RFC9449]. The htm claim of the DPoP JWT MUST be POST, and the htu claim must match the token endpoint URL.¶
The authorization server MUST validate the JWT assertion according to the processing rules in Section 3.1 of [RFC7523] and Section 4 of [I-D.ietf-oauth-rfc7523bis].¶
The authorization server MUST verify that the JWT assertion contains a cnf claim as defined in [RFC7800]. This cnf claim MUST contain a jwk property representing a public key.¶
The authorization server MUST verify that the public key in the jwk property of the cnf claim of the JWT assertion exactly matches the public key in the jwk header of the DPoP proof.¶

If any of these validation steps fail, the authorization server MUST return an invalid_grant error response.¶

4.1. Access Token Response

If the request is valid, the authorization server issues an access token. The issued access token SHOULD also be DPoP-bound to the same key from the DPoP proof. In this case, the token_type of the access token MUST be DPoP, and the response MUST include a token_type parameter with the value DPoP. If a bearer token is issued, the token_type MUST be Bearer.¶

6. IANA Considerations

6.1. OAuth URI Registration

This specification requests registration of the following value in the "OAuth URI" registry established by [RFC6755].¶

URN: urn:ietf:params:oauth:grant-type:jwt-dpop¶
Common Name: DPoP-bound JWT Authorization Grant¶
Change Controller: IESG¶
Specification Document(s): this document¶

7. Normative References

[I-D.ietf-oauth-rfc7523bis]: Jones, M. B., Campbell, B., Mortimore, C., and F. Skokan, "Updates to OAuth 2.0 JSON Web Token (JWT) Client Authentication and Assertion-Based Authorization Grants", Work in Progress, Internet-Draft, draft-ietf-oauth-rfc7523bis-03, 7 October 2025, <https://datatracker.ietf.org/doc/html/draft-ietf-oauth-rfc7523bis-03>.
[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>.
[RFC6749]: Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012, <https://www.rfc-editor.org/rfc/rfc6749>.
[RFC6755]: Campbell, B. and H. Tschofenig, "An IETF URN Sub-Namespace for OAuth", RFC 6755, DOI 10.17487/RFC6755, October 2012, <https://www.rfc-editor.org/rfc/rfc6755>.
[RFC7519]: Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, <https://www.rfc-editor.org/rfc/rfc7519>.
[RFC7521]: Campbell, B., Mortimore, C., Jones, M., and Y. Goland, "Assertion Framework for OAuth 2.0 Client Authentication and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521, May 2015, <https://www.rfc-editor.org/rfc/rfc7521>.
[RFC7523]: Jones, M., Campbell, B., and C. Mortimore, "JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and Authorization Grants", RFC 7523, DOI 10.17487/RFC7523, May 2015, <https://www.rfc-editor.org/rfc/rfc7523>.
[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>.
[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>.

OAuth 2.0 JWT Authorization Grant with DPoP Binding

Abstract

About This Document

Status of This Memo

Copyright Notice

Table of Contents

1. Introduction

2. Conventions and Definitions

2.1. Terminology