JSON Web Token (JWT) Response for OAuth Token Introspection
RFC 9701



Internet Engineering Task Force (IETF) T. Lodderstedt, Ed.
Request for Comments: 9701 yes.com AG
Category: Standards Track V. Dzhuvinov
ISSN: 2070-1721 Connect2id Ltd.
 January 2025

 JSON Web Token (JWT) Response for OAuth Token Introspection

Abstract

 This specification proposes an additional response secured by JSON
 Web Token (JWT) for OAuth 2.0 Token Introspection.

Status of This Memo

 This is an Internet Standards Track document.

 This document is a product of the Internet Engineering Task Force
 (IETF). It represents the consensus of the IETF community. It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG). Further information on
 Internet Standards is available in Section 2 of RFC 7841.

 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc9701.

Copyright Notice

 Copyright (c) 2025 IETF Trust and the persons identified as the
 document authors. All rights reserved.

 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.

Table of Contents

 1. Introduction
 2. Requirements Notation
 3. Resource Server Management
 4. Requesting a JWT Response
 5. JWT Response
 6. Client Metadata
 7. Authorization Server Metadata
 8. Security Considerations
 8.1. Cross-JWT Confusion
 8.2. Token Data Leakage
 9. Privacy Considerations
 10. IANA Considerations
 10.1. OAuth Dynamic Client Registration Metadata Registration
 10.1.1. Registry Contents
 10.2. OAuth Authorization Server Metadata Registration
 10.2.1. Registry Contents
 10.3. Media Type Registration
 10.3.1. Registry Contents
 10.4. JWT Claim Registration
 10.4.1. Registry Contents
 11. References
 11.1. Normative References
 11.2. Informative References
 Acknowledgements
 Authors' Addresses

1. Introduction

 "OAuth 2.0 Token Introspection" [RFC7662] specifies a method for a
 protected resource to query an OAuth 2.0 authorization server to
 determine the state of an access token and obtain data associated
 with the access token. This enables deployments to implement opaque
 access tokens in an interoperable way.

 The introspection response, as specified in "OAuth 2.0 Token
 Introspection" [RFC7662], is a plain JSON object. However, there are
 use cases where the resource server requires stronger assurance that
 the authorization server issued the token introspection response for
 an access token, including cases where the authorization server
 assumes liability for the content of the token introspection
 response. An example is a resource server using verified personal
 data to create certificates, which in turn are used to create
 qualified electronic signatures.

 In such use cases, it may be useful or even required to return a
 signed JWT [RFC7519] as the introspection response. This
 specification extends the token introspection endpoint with the
 capability to return responses as JWTs.

2. Requirements Notation

 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. Resource Server Management

 The authorization server (AS) and the resource server (RS) maintain a
 strong, two-way trust relationship. The resource server relies on
 the authorization server to obtain authorization, user, and other
 data as input to its access control decisions and service delivery.
 The authorization server relies on the resource server to handle the
 provided data appropriately.

 In the context of this specification, the token introspection
 endpoint is used to convey such security data and potentially also
 privacy-sensitive data related to an access token.

 In order to process the introspection requests in a secure and
 privacy-preserving manner, the authorization server MUST be able to
 identify, authenticate, and authorize resource servers.

 The AS MAY additionally encrypt the token introspection response
 JWTs. If encryption is used, the AS is provisioned with encryption
 keys and algorithms for the RS.

 The AS MUST be able to determine whether an RS is the audience for a
 particular access token and what data it is entitled to receive;
 otherwise, the RS is not authorized to obtain data for the access
 token. The AS has the discretion of how to fulfill this requirement.
 The AS could, for example, maintain a mapping between scope values
 and RSs.

 The requirements given above imply that the AS maintains credentials
 and other configuration data for each RS.

 One way is by utilizing dynamic client registration [RFC7591] and
 treating every RS as an OAuth client. In this case, the AS is
 assumed to at least maintain a "client_id" and a
 "token_endpoint_auth_method" with complementary authentication method
 metadata, such as "jwks" or "client_secret". In cases where the AS
 needs to acquire consent to transmit data to an RS, the following
 client metadata fields are recommended: "client_name", "client_uri",
 "contacts", "tos_uri", and "policy_uri".

 The AS MUST restrict the use of client credentials by an RS to the
 calls it requires, e.g., the AS MAY restrict such a client to call
 the token introspection endpoint only. How the AS implements this
 restriction is beyond the scope of this specification.

 This specification further introduces client metadata to manage the
 configuration options required to sign and encrypt token
 introspection response JWTs.

4. Requesting a JWT Response

 An RS requests a JWT introspection response by sending an
 introspection request with an Accept HTTP header field set to
 "application/token-introspection+jwt".

 The AS MUST authenticate the caller at the token introspection
 endpoint. Authentication can utilize client authentication methods
 or a separate access token that is issued to the RS and identifies
 the RS as the subject.

 The following is a non-normative example request, with the RS
 authenticating with a private key JWT:

 POST /introspect HTTP/1.1
 Host: as.example.com
 Accept: application/token-introspection+jwt
 Content-Type: application/x-www-form-urlencoded

 token=2YotnFZFEjr1zCsicMWpAA&
 client_assertion_type=
 urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer&
 client_assertion=PHNhbWxwOl[...omitted for brevity...]ZT

5. JWT Response

 The introspection endpoint responds with a JWT, setting the Content-
 Type HTTP header field to "application/token-introspection+jwt" and
 the JWT typ ("type") header parameter to "token-introspection+jwt".

 The JWT MUST include the following top-level claims:

 iss
 MUST be set to the issuer URL of the authorization server.

 aud
 MUST identify the resource server receiving the token
 introspection response.

 iat
 MUST be set to the time when the introspection response was
 created by the authorization server

 token_introspection
 A JSON object containing the members of the token introspection
 response, as specified in [RFC7662], Section 2.2. The separation
 of the introspection response members into a dedicated JSON object
 containing a JWT claim is intended to prevent conflict and
 confusion with top-level JWT claims that may bear the same name.

 If the access token is invalid, expired, revoked, or not intended
 for the calling resource server (audience), the authorization
 server MUST set the value of the active member in the
 token_introspection claim to false and MUST NOT include other
 members. Otherwise, the active member is set to true.

 The AS SHOULD narrow down the scope value to the scopes relevant
 to the particular RS.

 As specified in Section 2.2 of [RFC7662], implementations MAY
 extend the token introspection response with service-specific
 claims. In the context of this specification, such claims will be
 added as top-level members of the token_introspection claim.

 Token introspection response parameter names intended to be used
 across domains MUST be registered in the "OAuth Token
 Introspection Response" registry [IANA.OAuth.Token.Introspection]
 defined by [RFC7662].

 When the AS acts as a provider of resource owner identity claims
 to the RS, the AS determines, based on its RS-specific policy,
 what identity claims to return in the token introspection
 response. The AS MUST ensure the release of any privacy-sensitive
 data is legally based (see Section 9).

 Further content of the introspection response is determined by the
 RS-specific policy at the AS.

 The JWT MAY include other claims, including those from the "JSON Web
 Token Claims" registry established by [RFC7519]. The JWT SHOULD NOT
 include the sub and exp claims, as an additional measure to prevent
 misuse of the JWT as an access token (see Section 8.1).

 Note: Although the JWT format is widely used as an access token
 format, the JWT returned in the introspection response is not an
 alternative representation of the introspected access token and is
 not intended to be used as an access token.

 This specification registers the "application/token-
 introspection+jwt" media type, which is used as the value of the typ
 ("type") header parameter of the JWT to indicate that the payload is
 a token introspection response.

 The JWT is cryptographically secured as specified in [RFC7519].

 Depending on the specific resource server policy, the JWT is either
 signed or signed and encrypted. If the JWT is signed and encrypted,
 it MUST be a Nested JWT, as defined in JWT [RFC7519].

 Note: An AS compliant with this specification MUST refuse to serve
 introspection requests that don't authenticate the caller and return
 an HTTP status code 400. This is done to ensure token data is
 released to legitimate recipients only and prevent downgrading to
 [RFC7662] behavior (see Section 8.2).

 The following is a non-normative example response (with line breaks
 for display purposes only):

 HTTP/1.1 200 OK
 Content-Type: application/token-introspection+jwt

 eyJraWQiOiJ3RzZEIiwidHlwIjoidG9rZW4taW50cm9zcGVjdGlvbitqd3QiLCJhbGc
 iOiJSUzI1NiJ9.eyJpc3MiOiJodHRwczovL2FzLmV4YW1wbGUuY29tLyIsImF1ZCI6I
 mh0dHBzOi8vcnMuZXhhbXBsZS5jb20vcmVzb3VyY2UiLCJpYXQiOjE1MTQ3OTc4OTIs
 InRva2VuX2ludHJvc3BlY3Rpb24iOnsiYWN0aXZlIjp0cnVlLCJpc3MiOiJodHRwczo
 vL2FzLmV4YW1wbGUuY29tLyIsImF1ZCI6Imh0dHBzOi8vcnMuZXhhbXBsZS5jb20vcm
 Vzb3VyY2UiLCJpYXQiOjE1MTQ3OTc4MjIsImV4cCI6MTUxNDc5Nzk0MiwiY2xpZW50X
 2lkIjoicGFpQjJnb28wYSIsInNjb3BlIjoicmVhZCB3cml0ZSBkb2xwaGluIiwic3Vi
 IjoiWjVPM3VwUEM4OFFyQWp4MDBkaXMiLCJiaXJ0aGRhdGUiOiIxOTgyLTAyLTAxIiw
 iZ2l2ZW5fbmFtZSI6IkpvaG4iLCJmYW1pbHlfbmFtZSI6IkRvZSIsImp0aSI6InQxRm
 9DQ2FaZDRYdjRPUkpVV1ZVZVRaZnNLaFczMENRQ3JXRERqd1h5NncifX0.przJMU5Gh
 mNzvwtt1Sr-xa9xTkpiAg5IshbQsRiRVP_7eGR1GHYrNwQh84kxOkHCyje2g5WSRcYo
 sGEVIiC-eoPJJ-qBwqwSlgx9JEeCDw2W5DjrblOI_N0Jvsq_dUeOyoWVMqlOydOBhKN
 Y0smBrI4NZvEExucOm9WUJXMuJtvq1gBes-0go5j4TEv9sOP9uu81gqWTr_LOo6pgT0
 tFFyZfWC4kbXPXiQ2YT6mxCiQRRNM-l9cBdF6Jx6IOrsfFhBuYdYQ_mlL19HgDDOFal
 eyqmru6lKlASOsaE8dmLSeKcX91FbG79FKN8un24iwIDCbKT9xlUFl54xWVShNDFA

 The example response JWT header contains the following JSON document:

 {
 "typ": "token-introspection+jwt",
 "alg": "RS256",
 "kid": "wG6D"
 }

 The example response JWT payload contains the following JSON
 document:

 {
 "iss":"https://as.example.com/",
 "aud":"https://rs.example.com/resource",
 "iat":1514797892,
 "token_introspection":
 {
 "active":true,
 "iss":"https://as.example.com/",
 "aud":"https://rs.example.com/resource",
 "iat":1514797822,
 "exp":1514797942,
 "client_id":"paiB2goo0a",
 "scope":"read write dolphin",
 "sub":"Z5O3upPC88QrAjx00dis",
 "birthdate":"1982-02-01",
 "given_name":"John",
 "family_name":"Doe",
 "jti":"t1FoCCaZd4Xv4ORJUWVUeTZfsKhW30CQCrWDDjwXy6w"
 }
 }

6. Client Metadata

 The authorization server determines the algorithm to secure the JWT
 for a particular introspection response. This decision can be based
 on registered metadata parameters for the resource server, supplied
 via dynamic client registration [RFC7591] with the resource server
 acting as a client, as specified below.

 The parameter names follow the pattern established by OpenID Connect
 Dynamic Client Registration [OpenID.Registration] for configuring
 signing and encryption algorithms for JWT responses at the UserInfo
 endpoint.

 The following client metadata parameters are introduced by this
 specification:

 introspection_signed_response_alg
 OPTIONAL. "JSON Web Signature (JWS)" [RFC7515] algorithm (alg
 value), as defined in "JSON Web Algorithms (JWA)" [RFC7518], for
 signing introspection responses. If this is specified, the
 response will be signed using JWS and the configured algorithm.
 The default, if omitted, is RS256.

 introspection_encrypted_response_alg
 OPTIONAL. "JSON Web Encryption (JWE)" [RFC7516] algorithm (alg
 value), as defined in JWA [RFC7518], for content key encryption.
 If this is specified, the response will be encrypted using JWE and
 the configured content encryption algorithm
 (introspection_encrypted_response_enc). The default, if omitted,
 is that no encryption is performed. If both signing and
 encryption are requested, the response will be signed then
 encrypted, with the result being a Nested JWT, as defined in JWT
 [RFC7519].

 introspection_encrypted_response_enc
 OPTIONAL. JWE [RFC7516] algorithm (enc value), as defined in JWA
 [RFC7518], for content encryption of introspection responses. The
 default, if omitted, is A128CBC-HS256. Note: This parameter MUST
 NOT be specified without setting
 introspection_encrypted_response_alg.

 Resource servers may register their public encryption keys using the
 jwks_uri or jwks metadata parameters.

7. Authorization Server Metadata

 Authorization servers SHOULD publish the supported algorithms for
 signing and encrypting the JWT of an introspection response by
 utilizing "OAuth 2.0 Authorization Server Metadata" [RFC8414]
 parameters. Resource servers use this data to parametrize their
 client registration requests.

 The following parameters are introduced by this specification:

 introspection_signing_alg_values_supported
 OPTIONAL. JSON array containing a list of the JWS [RFC7515]
 signing algorithms (alg values), as defined in JWA [RFC7518],
 supported by the introspection endpoint to sign the response.

 introspection_encryption_alg_values_supported
 OPTIONAL. JSON array containing a list of the JWE [RFC7516]
 encryption algorithms (alg values), as defined in JWA [RFC7518],
 supported by the introspection endpoint to encrypt the content
 encryption key for introspection responses (content key
 encryption).

 introspection_encryption_enc_values_supported
 OPTIONAL. JSON array containing a list of the JWE [RFC7516]
 encryption algorithms (enc values), as defined in JWA [RFC7518],
 supported by the introspection endpoint to encrypt the response
 (content encryption).

8. Security Considerations

8.1. Cross-JWT Confusion

 The iss and potentially the aud claim of a token introspection JWT
 can resemble those of a JWT-encoded access token. An attacker could
 try to exploit this and pass a JWT token introspection response as an
 access token to the resource server. The typ ("type") JWT header
 "token-introspection+jwt" and the encapsulation of the token
 introspection members, such as sub and scope in the
 token_introspection claim, are intended to prevent such substitution
 attacks. Resource servers MUST therefore check the typ JWT header
 value of received JWT-encoded access tokens and ensure all minimally
 required claims for a valid access token are present.

 Resource servers MUST additionally apply the countermeasures against
 access token replay, as described in [RFC9700].

 JWT confusion and other attacks involving JWTs are discussed in
 [RFC8725].

8.2. Token Data Leakage

 The authorization server MUST use Transport Layer Security (TLS) 1.2
 (or higher), per BCP 195 [RFC9325], in order to prevent token data
 leakage.

 Section 2.1 of [RFC7662] permits requests to the introspection
 endpoint to be authorized with an access token that doesn't identify
 the caller. To prevent introspection of tokens by parties that are
 not the intended consumer, the authorization server MUST require all
 requests to the token introspection endpoint to be authenticated.

9. Privacy Considerations

 The token introspection response can be used to transfer personal
 identifiable information (PII) from the AS to the RS. The AS MUST
 conform to legal and jurisdictional constraints for the data transfer
 before any data is released to a particular RS. The details and
 determining of these constraints vary by jurisdiction and are outside
 the scope of this document.

 A commonly found way to establish the legal basis for releasing PII
 is by explicit user consent gathered from the resource owner by the
 AS during the authorization flow.

 It is also possible that the legal basis is established out of band,
 for example, in an explicit contract or by the client gathering the
 resource owner's consent.

 If the AS and the RS belong to the same legal entity (1st party
 scenario), there is potentially no need for an explicit user consent,
 but the terms of service and policy of the respective service
 provider MUST be enforced at all times.

 In any case, the AS MUST ensure that the scope of the legal basis is
 enforced throughout the whole process. The AS MUST retain the scope
 of the legal basis with the access token, e.g., in the scope value,
 it MUST authenticate the RS, and the AS MUST determine the data an RS
 is allowed to receive based on the RS's identity and suitable token
 data, e.g., the scope value.

 Implementers should be aware that a token introspection request lets
 the AS know when the client (and potentially the user) is accessing
 the RS, which is also an indication of when the user is using the
 client. If this implication is not acceptable, implementers MUST use
 other means to relay access token data, for example, by directly
 transferring the data needed by the RS within the access token.

10. IANA Considerations

10.1. OAuth Dynamic Client Registration Metadata Registration

 The following client metadata definitions have been registered in the
 IANA "OAuth Dynamic Client Registration Metadata" registry
 [IANA.OAuth.Parameters] established by [RFC7591]:

10.1.1. Registry Contents

 Client Metadata Name: introspection_signed_response_alg
 Client Metadata Description: String value indicating the client's
 desired introspection response signing algorithm
 Change Controller: IETF
 Reference: Section 6 of RFC 9701

 Client Metadata Name: introspection_encrypted_response_alg
 Client Metadata Description: String value specifying the desired
 introspection response content key encryption algorithm (alg
 value)
 Change Controller: IETF
 Reference: Section 6 of RFC 9701

 Client Metadata Name: introspection_encrypted_response_enc
 Client Metadata Description: String value specifying the desired
 introspection response content encryption algorithm (enc value)
 Change Controller: IETF
 Reference: Section 6 of RFC 9701

10.2. OAuth Authorization Server Metadata Registration

 The following values have been registered in the IANA "OAuth
 Authorization Server Metadata" registry [IANA.OAuth.Parameters]
 established by [RFC8414].

10.2.1. Registry Contents

 Metadata Name: introspection_signing_alg_values_supported
 Metadata Description: JSON array containing a list of algorithms
 supported by the authorization server for introspection response
 signing
 Change Controller: IETF
 Reference: Section 7 of RFC 9701

 Metadata Name: introspection_encryption_alg_values_supported
 Metadata Description: JSON array containing a list of algorithms
 supported by the authorization server for introspection response
 content key encryption (alg value)
 Change Controller: IETF
 Reference: Section 7 of RFC 9701

 Metadata Name: introspection_encryption_enc_values_supported
 Metadata Description: JSON array containing a list of algorithms
 supported by the authorization server for introspection response
 content encryption (enc value)
 Change Controller: IETF
 Reference: Section 7 of RFC 9701

10.3. Media Type Registration

 The "application/token-introspection+jwt" media type has been
 registered in the "Media Types" registry [IANA.MediaTypes] in the
 manner described in [RFC6838]. It can be used to indicate that the
 content is a token introspection response in JWT format.

10.3.1. Registry Contents

 Type name: application

 Subtype name: token-introspection+jwt

 Required parameters: N/A

 Optional parameters: N/A

 Encoding considerations: binary. A token introspection response is
 a JWT; JWT values are encoded as a series of base64url-encoded
 values (with trailing '=' characters removed), some of which may
 be the empty string, separated by period ('.') characters.

 Security considerations: See Section 8 of RFC 9701

 Interoperability considerations: N/A

 Published specification: Section 4 of RFC 9701

 Applications that use this media type: Applications that produce and
 consume OAuth Token Introspection Responses in JWT format

 Fragment identifier considerations: N/A

 Additional information:
 Magic number(s): N/A
 File extension(s): N/A
 Macintosh file type code(s): N/A

 Person & email address to contact for further information:
 Torsten Lodderstedt (torsten@lodderstedt.net)

 Intended usage: COMMON

 Restrictions on usage: none

 Author: Torsten Lodderstedt (torsten@lodderstedt.net)

 Change controller: IETF

10.4. JWT Claim Registration

 The "token_introspection" claim has been registered in the "JSON Web
 Token (JWT)" registry [IANA.JWT] in the manner described in
 [RFC7519].

10.4.1. Registry Contents

 Claim Name: token_introspection
 Claim Description: Token introspection response
 Change Controller: IETF
 Reference: Section 5 of RFC 9701

11. References

11.1. Normative References

 [IANA.JWT] IANA, "JSON Web Token (JWT) Claims",
 <https://www.iana.org/assignments/jwt>.

 [IANA.MediaTypes]
 IANA, "Media Types",
 <http://www.iana.org/assignments/media-types>.

 [IANA.OAuth.Token.Introspection]
 IANA, "OAuth Token Introspection Response",
 <https://www.iana.org/assignments/oauth-parameters>.

 [OpenID.Registration]
 Sakimura, N., Bradley, J., and M. Jones, "OpenID Connect
 Dynamic Client Registration 1.0 incorporating errata set
 1", November 2014, <https://openid.net/specs/openid-
 connect-registration-1_0.html>.

 [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/info/rfc2119>.

 [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
 Specifications and Registration Procedures", BCP 13,
 RFC 6838, DOI 10.17487/RFC6838, January 2013,
 <https://www.rfc-editor.org/info/rfc6838>.

 [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
 Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
 2015, <https://www.rfc-editor.org/info/rfc7515>.

 [RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
 RFC 7516, DOI 10.17487/RFC7516, May 2015,
 <https://www.rfc-editor.org/info/rfc7516>.

 [RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
 DOI 10.17487/RFC7518, May 2015,
 <https://www.rfc-editor.org/info/rfc7518>.

 [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/info/rfc7519>.

 [RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and
 P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol",
 RFC 7591, DOI 10.17487/RFC7591, July 2015,
 <https://www.rfc-editor.org/info/rfc7591>.

 [RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection",
 RFC 7662, DOI 10.17487/RFC7662, October 2015,
 <https://www.rfc-editor.org/info/rfc7662>.

 [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/info/rfc8174>.

 [RFC8414] Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0
 Authorization Server Metadata", RFC 8414,
 DOI 10.17487/RFC8414, June 2018,
 <https://www.rfc-editor.org/info/rfc8414>.

 [RFC8725] Sheffer, Y., Hardt, D., and M. Jones, "JSON Web Token Best
 Current Practices", BCP 225, RFC 8725,
 DOI 10.17487/RFC8725, February 2020,
 <https://www.rfc-editor.org/info/rfc8725>.

 [RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati,
 "Recommendations for Secure Use of Transport Layer
 Security (TLS) and Datagram Transport Layer Security
 (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
 2022, <https://www.rfc-editor.org/info/rfc9325>.

 [RFC9700] Lodderstedt, T., Bradley, J., Labunets, A., and D. Fett,
 "Best Current Practice for OAuth 2.0 Security", BCP 240,
 RFC 9700, DOI 10.17487/RFC9700, January 2025,
 <https://www.rfc-editor.org/info/rfc9700>.

11.2. Informative References

 [IANA.OAuth.Parameters]
 IANA, "OAuth Parameters",
 <http://www.iana.org/assignments/oauth-parameters>.

Acknowledgements

 We would like to thank Petteri Stenius, Neil Madden, Filip Skokan,
 Tony Nadalin, Remco Schaar, Justin Richer, Takahiko Kawasaki,
 Benjamin Kaduk, Robert Wilton, and Roman Danyliw for their valuable
 feedback.

Authors' Addresses

 Torsten Lodderstedt (editor)
 yes.com AG
 Email: torsten@lodderstedt.net

 Vladimir Dzhuvinov
 Connect2id Ltd.
 Email: vladimir@connect2id.com