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OAuth 2.0 Delegated Authorization
draft-li-oauth-delegated-authorization-02

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Document	Type	This is an older version of an Internet-Draft whose latest revision state is "Active".
	Authors	Li Ruochen , Haiguang Wang , Peter Chunchi Liu , Tieyan Li
	Last updated	2026-07-06
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draft-li-oauth-delegated-authorization-02

oauth R. Li
Internet-Draft H. Wang
Intended status: Informational Huawei Int. Pte Ltd
Expires: 7 January 2027 C. Liu
Huawei Technologies
T. Li
Huawei Int. Pte Ltd
6 July 2026

OAuth 2.0 Delegated Authorization
draft-li-oauth-delegated-authorization-02

Abstract

Delegated authorization enables a client to delegate a subset of its
granted privileges to a subordinate access token (also known as a
delegated access token). This mechanism allows the client to
securely delegate authorization to another application while
maintaining fine-grained control over delegated permissions.

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://liuchunchi.github.io/li-oauth-delegated-authorization/draft-
li-oauth-delegated-authorization.html. Status information for this
document may be found at https://datatracker.ietf.org/doc/draft-li-
oauth-delegated-authorization/.

Discussion of this document takes place on the WG Working Group
mailing list (mailto:oauth@ietf.org), which is archived at
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https://www.ietf.org/mailman/listinfo/oauth/.

Source for this draft and an issue tracker can be found at
https://github.com/liuchunchi/li-oauth-delegated-authorization.

Status of This Memo

This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
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This Internet-Draft will expire on 7 January 2027.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Protected Resource Metadata Discovery . . . . . . . . . . . . 7
5.1. The delegated_resources Metadata Field . . . . . . . . . 8
5.2. The authorization_requirements Metadata Field . . . . . . 8
5.3. Metadata Example . . . . . . . . . . . . . . . . . . . . 10
6. Delegation Tokens and Delegated Access Tokens . . . . . . . . 12
6.1. Delegation Tokens . . . . . . . . . . . . . . . . . . . . 12
6.1.1. Top Level Delegation Token . . . . . . . . . . . . . 13
6.2. Delegated Access Tokens . . . . . . . . . . . . . . . . . 14
7. Acquiring Delegation Tokens . . . . . . . . . . . . . . . . . 14
7.1. Authorization Code Grant . . . . . . . . . . . . . . . . 14
7.2. Other Grant Types . . . . . . . . . . . . . . . . . . . . 15
8. Creating Delegated Access Tokens . . . . . . . . . . . . . . 15
9. Using Delegated Access Tokens . . . . . . . . . . . . . . . . 16
10. Verification of Delegated Access Tokens . . . . . . . . . . . 16
10.1. Local Verification . . . . . . . . . . . . . . . . . . . 16
10.2. Token Introspection . . . . . . . . . . . . . . . . . . 17
11. Privacy Considerations . . . . . . . . . . . . . . . . . . . 17
11.1. Privacy Benefits . . . . . . . . . . . . . . . . . . . . 17
11.2. Relationship to Token Exchange . . . . . . . . . . . . . 18
11.3. Trade-offs . . . . . . . . . . . . . . . . . . . . . . . 18
12. Security Considerations . . . . . . . . . . . . . . . . . . . 18

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13. Operational Considerations . . . . . . . . . . . . . . . . . 19
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
14.1. OAuth Parameters Registry . . . . . . . . . . . . . . . 20
14.2. OAuth Access Token Types Registry . . . . . . . . . . . 20
14.3. HTTP Field Name Registry . . . . . . . . . . . . . . . . 20
14.4. OAuth Protected Resource Metadata Registry . . . . . . . 21
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
15.1. Normative References . . . . . . . . . . . . . . . . . . 21
15.2. Informative References . . . . . . . . . . . . . . . . . 24
Appendix A. Token Format . . . . . . . . . . . . . . . . . . . . 24
A.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 24
A.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . . . 26
Appendix B. Integration with Step-Up Authorization . . . . . . . 27
Appendix C. Use Cases . . . . . . . . . . . . . . . . . . . . . 28
C.1. Delegating Subset of Access Rights to Specialized AI
Agents . . . . . . . . . . . . . . . . . . . . . . . . . 28
C.2. Third-Party Analytics Platform Integrated in an Enterprise
SaaS . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29

1. Introduction

OAuth 2.0 [RFC6749] provides a framework for authorizing third-party
applications to access protected resources on behalf of a resource
owner. However, in existing implementations, access tokens issued to
clients often contain excessive permissions that exceed actual
requirements, creating security vulnerabilities and potential data
exposure risks.

This specification extends OAuth 2.0 with a delegated authorization
framework that enables clients to create subordinate access tokens
with restricted permissions. This approach addresses the problem of
over-privileged access tokens by implementing a token-chain
architecture that decouples the initial authorization from the final
resource access, allowing delegated tokens to be created and used
flexibly.

2. Requirements Language

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.

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3. Terminology

This specification uses the following terms defined in OAuth 2.0
[RFC6749]: authorization server, client, resource server, and
resource owner. A resource server can also act as a client when it
accesses one or more downstream resource servers. This document
refers to such an entity as an intermediary resource server: it is
downstream from the client that invokes it, and acts as a client when
making requests to resource servers that are farther downstream in
the call chain. Intermediary resource servers can be chained.

The following additional terms are used throughout this document:

*Intermediary Resource Server*: A resource server that receives a
request from a client and, to serve that request, acts as an OAuth
client when accessing one or more downstream resource servers. It
is downstream from its caller and upstream from the resource
servers it invokes. A downstream resource server can itself be an
intermediary resource server when it invokes another resource
server farther downstream in the call chain.

*Target Resource Server*: The resource server that receives a
delegated access token from an upstream intermediary resource
server for a particular downstream request and hosts the protected
resource requested in that hop. This role is relative to a
particular request: a target resource server for one hop can also
act as an intermediary resource server for a subsequent downstream
hop. It is downstream from the intermediary resource servers that
precede it in that call chain.

*Delegation Token*: A token issued by the authorization server for
the client that enables the client to create delegated access
tokens.

*Delegated Access Token*: A token created by the client using the
delegation token, with permissions being a subset of the
delegation token's privileges and a more limited lifespan.

*Delegation Key*: A cryptographic key bound to the delegation token,
used by the client to sign delegated access tokens. The
delegation key is presented in the token request as the
delegation_key parameter.

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4. Overview

The delegated authorization framework introduces a hierarchical token
structure where a client can obtain a delegation token from an
authorization server and use it to issue subordinate access tokens
with reduced permissions. This enables fine-grained access control
while maintaining the security properties of the original
authorization grant.

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Figure 1: Delegated Authorization Framework Architecture

1. The client requests authorization from the resource owner. The
client indicates in the authorization request that the requested
authorization grant is for delegated authorization.

2. The client receives an authorization grant.

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3. The client requests a delegation token by authenticating with the
authorization server and presenting the authorization grant and
its delegation key as defined in Section 3.

4. The authorization server authenticates the client and validates
the authorization grant, and if valid, issues a delegation token.

5. The client calls an intermediary resource server's API,
presenting the delegated access token generated from the
delegation token. The delegated access token is issued by the
client using the delegation key. The intermediary resource
server can request protected resources from one or more
downstream resource servers by presenting the delegated access
token. A downstream resource server can itself be an
intermediary resource server for a subsequent downstream request.

6. A target resource server for a downstream request validates the
delegated access token, and if valid, serves the resource.
Responses propagate back through the intermediary resource
servers, each of which can optionally transform a downstream
response into a service-specific response, and ultimately return
a response to the client.

Both delegation token and delegated access token can be JSON Web
Tokens (JWTs) [RFC7519] or CBOR Web Tokens (CWTs) [RFC8392].

5. Protected Resource Metadata Discovery

Before the client retrieves a delegation token and generates a
delegated access token for an intermediary resource server, the
client needs to determine the permissions required by that resource
server for its own protected resources, the permissions required when
accessing downstream resource servers, and the identity of those
downstream resource servers. Such information can be manually
configured into the client, or it can be dynamically discovered using
OAuth 2.0 Protected Resource Metadata [RFC9728].

Each resource server publishes its metadata at the standard well-
known URI as defined in [RFC9728]. The metadata describes the
resource server as a protected resource. A client can determine that
a resource server is an intermediary resource server when the
metadata contains the delegated_resources key. The
delegated_resources metadata field identifies any downstream resource
servers the publishing resource server accesses and the authorization
capabilities for each. If a downstream resource server is itself an
intermediary resource server, the client can also retrieve that
resource server's metadata to discover subsequent downstream
requirements.

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The authorization_requirements metadata field identifies the
authorization requirements for specific endpoints or operations. A
client can use this field to request a delegation token and create
delegated access tokens with the minimum permissions needed for the
intended request. Discovery of protected resource metadata,
including use of the WWW-Authenticate resource_metadata parameter,
follows [RFC9728].

5.1. The delegated_resources Metadata Field

This specification defines a new protected resource metadata field,
delegated_resources, that indicates the downstream resource servers
and the authorization capabilities the publishing resource server
needs for each.

*delegated_resources*: JSON object mapping downstream protected
resource identifiers (as defined in [RFC9728]) to the
authorization capabilities for each. Each downstream resource
value is a JSON object containing the following members:

*authorization_target*: OPTIONAL. String identifying the
protected resource to which the listed scopes_supported or
authorization_details_types_supported apply. The value self
indicates the downstream protected resource identified by the
corresponding delegated_resources key. Any other value is a
protected resource identifier as defined in [RFC9728]. If
omitted, the default value is self.

*scopes_supported*: OPTIONAL. JSON array of scope values
[RFC6749] that the publishing resource server may need at the
authorization_target.

*authorization_details_types_supported*: OPTIONAL. JSON array of
authorization details types [RFC9396] that the publishing
resource server may need at the authorization_target.

A downstream resource value MUST contain at least one of
scopes_supported or authorization_details_types_supported.

5.2. The authorization_requirements Metadata Field

This specification defines a new protected resource metadata field,
authorization_requirements, that indicates the authorization
requirements for specific endpoints or operations of the publishing
resource server. The requirements can describe permissions needed at
the publishing resource server itself, permissions delegated to
downstream resource servers, or both.

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*authorization_requirements*: JSON array of authorization
requirement objects. Each object describes one endpoint or
operation and the permissions required to access it. The
following members are defined:

*methods*: OPTIONAL. JSON array of HTTP methods to which this
requirement applies. If omitted, the requirement applies
independent of HTTP method.

*path*: OPTIONAL. Absolute path or path template identifying the
endpoint to which this requirement applies. If omitted, the
requirement applies to the operation as otherwise identified by
the object.

*operation*: OPTIONAL. String identifying an application-level
operation to which this requirement applies. This member is
intended for APIs where the authorization requirement is
associated with a named action rather than only with an HTTP
path. The syntax and semantics of the operation identifier are
deployment specific. For HTTP APIs where the method and path
uniquely identify the protected action, methods and path are
preferred.

*scopes*: OPTIONAL. JSON array of scope values [RFC6749]
required for the identified endpoint or operation at the
publishing resource server.

*authorization_details_types*: OPTIONAL. JSON array of
authorization details types [RFC9396] required or accepted for
the identified endpoint or operation at the publishing resource
server.

*authorization_details*: OPTIONAL. JSON array of authorization
detail objects [RFC9396] that describe the required permissions
for the identified endpoint or operation at the publishing
resource server. This member can be used when the
authorization details type alone is not sufficient to describe
the minimum required permission.

*delegated_resources*: OPTIONAL. JSON object mapping downstream

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protected resource identifiers to delegated authorization
requirement objects. This member describes permissions that
the publishing resource server needs to receive in a delegated
access token in order to call the specified downstream resource
servers while serving the identified local endpoint or
operation. Each delegated authorization requirement object MAY
contain authorization_target, with the same semantics as in the
delegated_resources metadata field, and identifies required
permissions using scopes, authorization_details_types, or
authorization_details.

A top-level authorization requirement object MUST identify an
endpoint or operation using path, operation, or both. Each top-level
authorization requirement object MUST contain at least one of scopes,
authorization_details_types, authorization_details, or
delegated_resources. Each delegated authorization requirement object
MUST contain at least one of scopes, authorization_details_types, or
authorization_details. The authorization_requirements field is
optional. Resource servers MAY omit it when authorization
requirements are dynamic, confidential, or better conveyed through an
authorization challenge.

When both path and operation are present, path identifies the
endpoint and operation further identifies the action within that
endpoint.

The authorization_requirements metadata is self-declared discovery
information. It does not replace access control enforcement by
resource servers, and clients MUST NOT assume that possession of the
indicated permissions guarantees access to the identified endpoint or
operation.

5.3. Metadata Example

The following is a non-normative example of a resource server
publishing protected resource metadata that describes both its
downstream resource server capabilities and endpoint-specific
authorization requirements:

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{
"resource": "https://analytics.example.com",
"scopes_supported": ["openid", "analytics:summary"],
"authorization_servers": ["https://idp.example.com"],

"delegated_resources": {
"https://crm.example.com": {
"authorization_target": "self",
"scopes_supported": ["read:contacts", "read:reports"],
"authorization_details_types_supported": ["data"]
}
},

"authorization_requirements": [
{
"methods": ["GET"],
"path": "/summary",
"scopes": ["analytics:summary"]
},
{
"methods": ["GET"],
"path": "/reports/contacts",
"delegated_resources": {
"https://crm.example.com": {
"scopes": ["read:contacts"],
"authorization_details_types": ["data"]
}
}
},
{
"methods": ["GET"],
"path": "/reports/monthly",
"delegated_resources": {
"https://crm.example.com": {
"authorization_target": "https://reports.example.com",
"scopes": ["read:reports"]
}
}
}
]
}

In this example the resource server (https://analytics.example.com)
indicates that it supports its own analytics:summary scope and that
it may need access to the CRM resource server
(https://crm.example.com) with the read:contacts and read:reports
scopes. The authorization_requirements field further indicates that
GET /summary requires the local analytics:summary scope, GET

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/reports/contacts requires a delegated access token that covers the
CRM read:contacts scope and data-type authorization details, and GET
/reports/monthly requires a delegated access token presented to CRM
that covers the read:reports scope at https://reports.example.com.

The client uses this information, and optionally the metadata of
downstream intermediary resource servers, to:

1. Request a delegation token from the authorization server with
appropriate permissions (see Section 7).

2. Create delegated access tokens with the correct permissions,
audience, and downstream resource identifiers (see Section 8).

6. Delegation Tokens and Delegated Access Tokens

This section defines the properties of delegation tokens and
delegated access tokens. The delegated authorization framework uses
a hierarchical token structure where tokens form a chain: a
delegation token can be used to create subordinate tokens, which can
either be another delegation token (to continue the chain) or a
delegated access token (to access protected resources). The top-
level token in the chain is issued by the authorization server, while
subordinate tokens are created by clients.

6.1. Delegation Tokens

A delegation token is a token that can be used to create subordinate
tokens. It contains a max_delegation_depth claim that limits the
maximum length of the delegation chain.

*delegation_key*: The cryptographic key bound to the delegation
token, used by the client to sign subordinate tokens (either
another delegation token or a delegated access token). The value
is a JSON object representing the public key, using key format as
defined in [RFC7517]. This claim MUST be present in delegation
tokens. The corresponding private key is held by the client and
used to create subordinate tokens. Subordinate tokens MUST
include the parent delegation token in the delegation_token claim,
creating a verifiable chain from the top-level token to the
subordinate token.

*max_delegation_depth*: OPTIONAL. Integer value indicating the
maximum depth of the delegation chain. If not present, the
delegation chain is unrestricted. When a client creates a
subordinate token from a delegation token:

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* If the parent delegation token has a max_delegation_depth value,
the subordinate delegation token MUST have a max_delegation_depth
value smaller than the parent's value.

* If the parent delegation token does not have a
max_delegation_depth value, the subordinate delegation token MAY
set any max_delegation_depth value.

When max_delegation_depth reaches 1, the subordinate token MUST be a
delegated access token (no further delegation is allowed).

The scope / authorization_details, aud, exp, and nbf claims MAY be
present in delegation tokens and can be reduced in subordinate
tokens.

*scope* / *authorization_details*: The scope (as defined in
[RFC8693]) or authorization details (as defined in [RFC9396]) of
the delegation token. When creating a subordinate token, the
client MAY reduce the scope or authorization_details to a subset
of the parent token's permissions.

*aud*: The audience of the delegation token. When creating a
subordinate token, the client MAY narrow the audience to a subset
of the parent token's audience.

*exp*: The expiration time of the delegation token. When creating a
subordinate token, the client MUST set an expiration time that is
no later than the parent token's expiration time.

*nbf*: The not-before time of the delegation token. When creating a
subordinate token, the client MAY set a not-before time that is
later than the parent token's not-before time.

6.1.1. Top Level Delegation Token

The top-level delegation token is issued by the authorization server
and MAY contain the iss, sub, and jti claims. If present, these
claims apply to the entire token chain. These claims MUST NOT be
present in subordinate delegation tokens or delegated access tokens.

*iss*: The issuer of the delegation token. This claim applies to
all subordinate tokens in the chain.

*sub*: The subject of the delegation token, typically representing
the resource owner or the client. This claim applies to all
subordinate tokens in the chain.

*jti*: Unique identifier for the delegation token. This claim

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applies to all subordinate tokens in the chain.

Subordinate delegation tokens and delegated access tokens MUST NOT
include the iss, sub, or jti claims. Verifiers (resource servers)
SHALL consider these claims from the top-level delegation token when
validating the entire token chain.

6.2. Delegated Access Tokens

A delegated access token is a token used to access protected
resources. It cannot be used to create subordinate tokens.

The scope, aud, exp, and nbf claims in delegated access tokens follow
the same rules as in delegation tokens, as described in Section 6.1.

*max_delegation_depth*: Delegated access tokens do not need to
include a max_delegation_depth claim, even if the parent
delegation token has one. If a delegated access token includes
max_delegation_depth, its value MUST be 0.

7. Acquiring Delegation Tokens

The client requests a delegation token using standard OAuth 2.0 grant
types with additional parameters to distinguish delegation requests
from standard token requests.

7.1. Authorization Code Grant

For authorization code grant type, the client MUST include a
delegation=true parameter in the authorization request to indicate
that the client is requesting a delegation token instead of an OAuth
2.0 access token.

Additionally, the authorization request MUST include either a scope
parameter (as defined in [RFC6749] Section 3.3), an
authorization_details parameter (as defined in "Rich Authorization
Requests" [RFC9396]), or both, that define the permissions granted to
the requested delegation token.

In the token request, the client MUST include a delegation_key
parameter with the value of the delegation key. The delegation key
is a public key for digital signature.

Additionally, the client MAY include in the token request either a
scope parameter, an authorization_details parameter, or both. The
client MAY also include a delegation=true parameter in the token
request.

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In the token response, the authorization server MUST include an
access_token attribute whose value is the delegation token, and MUST
include a token_type attribute valued "Delegation", and MAY include a
refresh_token attribute which is the refresh token for obtaining a
new delegation token via the refresh token grant.

Other procedures of the authorization code grant are as described in
[RFC6749]. Use of Proof Key for Code Exchange (PKCE) [RFC7636] is
RECOMMENDED.

7.2. Other Grant Types

Other OAuth 2.0 grant types, such as the refresh token grant or
client credentials grant, MAY support delegated authorization by
including the delegation and delegation_key parameters when
applicable. The authorization server MUST validate that the client
is authorized to request delegation tokens using the given grant
type.

8. Creating Delegated Access Tokens

The client creates delegated access tokens by:

1. Validating the delegation token's validity and permissions.

2. Generating a subordinate access token with (optionally) reduced
privileges.

3. Applying cryptographic protection using the delegation key
(digital signature).

The client MUST include the delegation token in the delegation_token
attribute of the delegated access token.

The client MUST ensure that the delegated access token's scope,
lifetime, audience, and other claims do not exceed those of the
delegation token. The client MAY generate single-use delegated
access tokens that the resource server or authorization server only
consider valid when validating it for the first time.

The client is RECOMMENDED to "sender-constrain" the delegated access
tokens by binding the delegated access tokens with public keys or
certificates where the corresponding private keys are held by the
resource servers that will present those tokens, via techniques
similar to OAuth 2.0 mTLS [RFC8705] or OAuth 2.0 DPoP [RFC9449].

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9. Using Delegated Access Tokens

When the client accesses an intermediary resource server endpoint
that requires downstream access, the client MUST include the
delegated access token as a bearer token [RFC6750] in the Delegated-
Authorization header. The delegated access token is used by
downstream resource servers to verify requests from upstream
intermediary resource servers. The Delegated-Authorization header
MAY be used in combination with an Authorization header used by the
intermediary resource server to verify the request from the client.

For example:

GET /dp-resource HTTP/1.1
Host: analytics.example.com
Authorization: Bearer mF_9.B5g1234
Delegated-Authorization: Bearer mF_9.B5f-4.1JqM

Upon receiving a request with a Delegated-Authorization header, the
intermediary resource server can send downstream requests to one or
more resource servers for the respective protected resources. For
each such downstream request, the invoked resource server is the
target resource server for that hop and can itself act as an
intermediary resource server for subsequent downstream requests. The
intermediary resource server MUST include the received delegated
access token as a bearer token in the Authorization header.

For example:

GET /target-resource HTTP/1.1
Host: resource.example.com
Authorization: Bearer mF_9.B5f-4.1JqM

10. Verification of Delegated Access Tokens

Resource servers verify delegated access tokens through either local
validation using pre-configured public keys or remote validation via
token introspection [RFC7662] at the authorization server.

10.1. Local Verification

The resource server verifies delegated access tokens by:

1. The resource server is pre-configured with the authorization
server's public key, or it fetches the public key via the
authorization server's JWKS endpoint [RFC7517].

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2. Checking the digital signature of the delegation token (part of
the delegated access token) against the authorization server's
public key.

3. Checking the digital signature of the delegated access token
against the delegation key bound to the delegation token.

4. Verifying the delegated access token's permissions and validity
are within the scope of the delegation token.

5. Verifying the delegated access token is within validity period,
and the delegated access token's permissions cover the resource
request.

10.2. Token Introspection

The resource server sends the delegated access token to the
authorization server via the token introspection endpoint [RFC7662].
The authorization server verifies the delegated access token against
its keys.

11. Privacy Considerations

This section describes the privacy properties of the local delegation
approach defined in this specification.

11.1. Privacy Benefits

When a client creates delegated access tokens locally using a
delegation token, the authorization server only observes the initial
delegation token request. After that, the client can independently
issue subordinate tokens without further authorization server
interaction. This provides the following privacy benefits:

* *Minimized Authorization Server Visibility*: The authorization
server does not learn which intermediary resource servers are
authorized to access downstream resource servers, what resources
they access, or when they access them.

* *No Access Pattern Correlation*: The authorization server cannot
track usage patterns or correlate activities across different
resource servers.

* *Reduced Data Collection*: The authorization server stores only
metadata about the initial delegation token, not about each
delegated access token.

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* *Network Traffic Reduction*: Fewer network round-trips to the
authorization server reduce exposure to network surveillance.

11.2. Relationship to Token Exchange

Token Exchange [RFC8693] provides a mechanism for delegating access
by having the client exchange one token for another at the
authorization server. That approach requires authorization server
involvement for each delegation event, which necessarily exposes
delegation metadata to the authorization server. The local
delegation approach in this specification performs delegation
entirely on the client side after the initial token issuance,
providing an alternative with different privacy characteristics.

11.3. Trade-offs

While local delegation provides significant privacy benefits,
implementations should consider:

* *Client Responsibility*: The client must securely protect the
delegation key and properly enforce delegation rules.

* *Auditability*: Deployments requiring delegation event audits can
implement client-side logging rather than relying on authorization
server monitoring.

* *Revocation*: If a delegation key is compromised, the
authorization server may need to revoke the entire delegation
token.

12. Security Considerations

This specification extends OAuth 2.0 to support delegated
authorization through hierarchical token issuance. While this
enables fine-grained privilege delegation, it also introduces new
trust and security considerations.

* Delegation tokens MUST NOT be sent to resource servers without
subordinate delegated access tokens. Resource servers and
authorization servers MUST NOT treat delegation tokens as regular
OAuth access tokens.

* Clients MUST protect the delegation key, as compromise allows an
attacker to mint valid delegated access tokens within the scope of
the delegation token.

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* Delegated access tokens SHOULD have short lifetimes and be bound
to specific audiences, methods, and sender keys (e.g., via DPoP or
mTLS) to mitigate replay and token leakage risks. Resource
servers MUST validate both the delegation token and the delegated
access token, ensuring the latter does not exceed the former’s
permissions.

* Token introspection CAN be used in scenarios where the tokens are
kept opaque from the resource servers. If employed, token
introspection responses MUST NOT reveal sensitive internal
information. Authorization servers SHOULD enforce rate limiting
and audit token issuance and validation activities.

* Protected resource metadata published by resource servers is self-
declared. Clients and authorization servers SHOULD verify that
delegated access tokens remain within the intended scope of
delegation. Clients SHOULD not trust delegated_resources or
authorization_requirements metadata from untrusted resource
servers without independent verification of the resource server's
identity and authorization requirements.

13. Operational Considerations

Deployments of this specification should consider the following
operational aspects:

* *Key Management*: Clients MUST securely store and rotate
delegation keys. Authorization servers SHOULD support key
rotation for delegation tokens and provide mechanisms to revoke
compromised keys.

* *Token Lifetimes*: Delegation tokens SHOULD have longer lifetimes
than delegated access tokens to reduce authorization server load,
and SHOULD be refreshable using refresh tokens.

* *Metadata Caching*: Protected resource metadata published by
resource servers at /.well-known/oauth-protected-resource can be
cached by clients; a reasonable default TTL (e.g., 24 hours) is
RECOMMENDED.

* *Error Handling*: Resource servers SHOULD provide clear error
responses (e.g., invalid token, insufficient scope) without
exposing implementation details.

* *Interoperability*: Implementers SHOULD ensure compatibility with
existing OAuth 2.0 features such as PKCE, Rich Authorization
Requests, and sender-constrained tokens.

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14. IANA Considerations

14.1. OAuth Parameters Registry

This specification registers the following parameters in the "OAuth
Parameters" registry:

*Delegation:*

* *Name*: delegation

* *Parameter Usage Location*: authorization request, token request

* *Change Controller*: IETF

* *Reference*: [this document]

*Delegation Key:*

* *Name*: delegation_key

* *Parameter Usage Location*: token request

* *Change Controller*: IETF

* *Reference*: [this document]

14.2. OAuth Access Token Types Registry

This specification registers the following parameters in the "OAuth
Access Token Types" registry:

* *Name*: Delegation

* *Additional Token Endpoint Response Parameters*: (none)

* *HTTP Authentication Scheme(s)*: Bearer

* *Change Controller*: IETF

* *Reference*: [this document]

14.3. HTTP Field Name Registry

This specification registers the following parameters in the
"Hypertext Transfer Protocol (HTTP) Field Name" registry:

* *Field Name*: Delegated-Authorization

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* *Status*: permanent

* *Structured Type*: (none)

* *Reference*: [this document]

14.4. OAuth Protected Resource Metadata Registry

This specification registers the following entry in the "OAuth
Protected Resource Metadata" registry defined in [RFC9728]:

* *Metadata Name*: delegated_resources

* *Metadata Description*: JSON object mapping downstream protected
resource identifiers to the authorization capabilities for each.
Each downstream resource value contains authorization_target and
either scopes_supported or authorization_details_types_supported,
indicating permissions that may be needed at that authorization
target.

* *Change Controller*: IETF

* *Specification Document(s)*: [this document]

* *Metadata Name*: authorization_requirements

* *Metadata Description*: JSON array describing authorization
requirements for specific endpoints or operations of the protected
resource. Each entry can identify local requirements using
scopes, authorization_details_types, or authorization_details, and
can identify downstream delegated requirements using
delegated_resources. Within delegated_resources,
authorization_target distinguishes the protected resource to which
the listed permissions apply.

* *Change Controller*: IETF

* *Specification Document(s)*: [this document]

15. References

15.1. 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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[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>.

[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
Framework: Bearer Token Usage", RFC 6750,
DOI 10.17487/RFC6750, October 2012,
<https://www.rfc-editor.org/rfc/rfc6750>.

[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/rfc/rfc7515>.

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

[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/rfc/rfc7517>.

[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>.

[RFC7636] Sakimura, N., Ed., Bradley, J., and N. Agarwal, "Proof Key
for Code Exchange by OAuth Public Clients", RFC 7636,
DOI 10.17487/RFC7636, September 2015,
<https://www.rfc-editor.org/rfc/rfc7636>.

[RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection",
RFC 7662, DOI 10.17487/RFC7662, October 2015,
<https://www.rfc-editor.org/rfc/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/rfc/rfc8174>.

[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/rfc/rfc8259>.

[RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392,
May 2018, <https://www.rfc-editor.org/rfc/rfc8392>.

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[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/rfc/rfc8414>.

[RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers
(URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019,
<https://www.rfc-editor.org/rfc/rfc8615>.

[RFC8693] Jones, M., Nadalin, A., Campbell, B., Ed., Bradley, J.,
and C. Mortimore, "OAuth 2.0 Token Exchange", RFC 8693,
DOI 10.17487/RFC8693, January 2020,
<https://www.rfc-editor.org/rfc/rfc8693>.

[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>.

[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/rfc/rfc9110>.

[RFC9396] Lodderstedt, T., Richer, J., and B. Campbell, "OAuth 2.0
Rich Authorization Requests", RFC 9396,
DOI 10.17487/RFC9396, May 2023,
<https://www.rfc-editor.org/rfc/rfc9396>.

[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>.

[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/rfc/rfc9700>.

[RFC9728] Jones, M.B., Hunt, P., and A. Parecki, "OAuth 2.0
Protected Resource Metadata", RFC 9728,
DOI 10.17487/RFC9728, April 2025,
<https://www.rfc-editor.org/rfc/rfc9728>.

[I-D.lombardo-oauth-step-up-authz-challenge-proto]
Lombardo, J., Babeanu, A., Zehavi, Y., and G. Fletcher,
"OAuth 2.0 step-up authorization challenge proto", Work in

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Progress, Internet-Draft, draft-lombardo-oauth-step-up-
authz-challenge-proto-02, 30 June 2025,
<https://datatracker.ietf.org/doc/html/draft-lombardo-
oauth-step-up-authz-challenge-proto-02>.

15.2. Informative References

[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/rfc/rfc8792>.

Appendix A. Token Format

The example tokens in this section are shown in Flattened JSON
Serialization [RFC7515] [RFC7516], un-base64url-encoded and with
comments for ease of reading. When used as JWTs [RFC7519], they
should be represented in Compact Serialization [RFC7515] [RFC7516].
Similarly, they can be represented as CWTs [RFC8392].

A.1. Example 1

In this example, the delegation token is a JWS token signed with
HS256, and the delegated access token is a JWS token signed with
RS256.

*Delegation Token*:

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{
"protected": {
"_comment": "to be base64url-encoded",
"alg": "HS256",
"typ": "JWT",
"kid": "as-key-1"
},
"payload": {
"_comment": "to be base64url-encoded",
"iss": "https://as1.example.com",
"sub": "user@example.com",
"aud": "https://res1.example.com",
"iat": 1772177588,
"exp": 1774769588,
"scope": "email:read email:send",
"delegation_key": {
"kty": "RSA",
"n": "0Z5t3Rwhfz4MJxdNzg2I6Bsf9H_3kcMKtH6iwJsLV2DKO1MVcHb6wsxHZpqRePjm5Q1-pImr4pT67hCHyAR6kS4QbTrBZcjSe8lsvZIiifiBVWZxz8ZAfdj6EFSOWhFLZ0GVqe9NMslwX1hHOwmhRmMjGjexISPsZk5qN3gwqmD36H1GS-rE-cWlXI9f4pVcCdYqE0rfhZ7hDn5mrpWWY8wJuQa2jFqX-Fhyvt_Zh-qaa5Wp8cLJPS_ceAcLeS5mOYE58beelp51PuCDpq7a9fN4K_EpcSD7Ay0GrJxgN_VcLA7DgOAuU6zYDzk2KnmQ3qz35Tj5hy8jDHgF1AaSTw",
"e": "AQAB"
}
},
"signature": "SBwdWhy4dissabBRoyyxMxRuVUbsFYv_1HZFeROLh5A"
}

*Delegated Access Token*:

{
"protected": {
"_comment": "to be base64url-encoded",
"alg": "RS256",
"typ": "JWT",
"kid": "delegation-key-1"
},
"payload": {
"_comment": "to be base64url-encoded",
"sub": "https://dp1.example.com",
"aud": "https://res1.example.com",
"iat": 1772181188,
"exp": 1772184788,
"scope": "email:read",
"delegationToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImFzLWtleS0xIn0.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.SBwdWhy4dissabBRoyyxMxRuVUbsFYv_1HZFeROLh5A"
},
"signature": "df5sTdp6j-ULv3To3yqYFFZWLrY41wu6jpKfsZdjMNMeRH3TXY5nSc-lhdFfJElVGnyCa5Rf9YGlvacGVy84maFCq0zhNTiLL8xBYieCKTAhmMuWZvIUZFBoE1KBj2YXskpnU6CFTKhALbW5lidZSGXdcEnygxwaumpO_AxlYghU8RQrQgF1wAsoDLcoun1-FROuHUzqKGWqYSbXe1lGJ3dTt5ftod7SjGqM2Quz4BvfQMpw82VVGq7YlvRJMuPe4ITUeikFNQ672bvVrjhwHUlglQ9HuFj5iroHqwr6dLtfKVDBtw33A_lCnsWfk4vPWDJ-1fy3Klj4hT_bhBIVJA"
}

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A.2. Example 2

In this example, the delegation token chain consists of three tokens:
a top-level delegation token issued by the authorization server, a
subordinate delegation token created by the client, and a delegated
access token created from the subordinate token. The top-level
delegation token has max_delegation_depth of 3, which allows for two
levels of delegation.

*Top-Level Delegation Token*:

{
"protected": {
"_comment": "to be base64url-encoded",
"alg": "RS256",
"typ": "JWT",
"kid": "as-key-2"
},
"payload": {
"_comment": "to be base64url-encoded",
"iss": "https://as1.example.com",
"sub": "user@example.com",
"aud": "https://res1.example.com",
"iat": 1772177588,
"exp": 1774769588,
"scope": "email:read email:write email:send",
"delegation_key": {
"kty": "RSA",
"n": "3O1EVa-_zsENOhylq99puKjF6NBq8S8Ntw9sufyCB9LrTSs-xRoDQ7X6rYbPEOn5E-6ASZyUW2vFxLacj0Wir05hznlnfRLRTmJhud4im5COfAhuiPeL0Mbs3WFLdBfWVGXSP2O5UNkd7dJ2KqudqxNF81Nrt51RpmPR59pUZS3REfAYgtqhQ07WuCTzd2VpFttPFurDSiWcriyELNdgsT9wap0nyceSVLQgY9ZgR0VvsmHj_LUKie1t5RCjTsaMHJH6x3QI0tjKG9Psbil0ORlhA9WEgOO6E6KOC_StEBnK_Ntb2ArGPDjlNPzTqWOeeev84MM8VXdRzpTLOrRmHQ",
"e": "AQAB"
},
"max_delegation_depth": 3
},
"signature": "p1OjJQ2tASuFPPCXzdbuSHaZiPTF2jM1Z_My2_qPx0IAAJJ5RVo9Km2hFeXjqqGcjkG5wEFxMw_q8JO48O9bVaKNBa1k_-UoBxf5KlMpldMFIUyV4D8Sugshh73iqVii5HW2MY4uS5Gj46GDUcX1NQRg8LW6Wa4zso0SPfIfunXF0dvBG24cCUoIFOr1NzryZ7OcVt9kdC4_uXGoSmjtGl1XsRvgb216fZFuZV0F88zWFsDcBZn4i8qGcBS2XAHjW4jbH7Y1O8dvl2h0afftmNkG2ZgHPl3phj_i-unQsAxhCUI_8MjtfF5iwe586uQw_1iED2IUlEXOgX-Ld5GgTw"
}

*Subordinate Delegation Token*:

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{
"protected": {
"_comment": "to be base64url-encoded",
"alg": "RS256",
"typ": "JWT",
"kid": "delegation-key-2"
},
"payload": {
"_comment": "to be base64url-encoded",
"aud": "https://res1.example.com",
"iat": 1772181188,
"exp": 1772782388,
"max_delegation_depth": 1,
"scope": "email:read email:write",
"delegationToken": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImFzLWtleS0yIn0.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.p1OjJQ2tASuFPPCXzdbuSHaZiPTF2jM1Z_My2_qPx0IAAJJ5RVo9Km2hFeXjqqGcjkG5wEFxMw_q8JO48O9bVaKNBa1k_-UoBxf5KlMpldMFIUyV4D8Sugshh73iqVii5HW2MY4uS5Gj46GDUcX1NQRg8LW6Wa4zso0SPfIfunXF0dvBG24cCUoIFOr1NzryZ7OcVt9kdC4_uXGoSmjtGl1XsRvgb216fZFuZV0F88zWFsDcBZn4i8qGcBS2XAHjW4jbH7Y1O8dvl2h0afftmNkG2ZgHPl3phj_i-unQsAxhCUI_8MjtfF5iwe586uQw_1iED2IUlEXOgX-Ld5GgTw"
},
"signature": "lnf8Wz5M_B4dVTOOjT0aQa0ZSqEbTZVGb1HU_dk1tJ4eCbkCB8lmO0wJXc07Ys8gKqqb3TS4tKUbnwwKo3_Dw3FGYjbDqDE7rBtdc0lqi6fKSecff2ujVCi2U2dLjX78_h7U0LP1XbJuhkjdBYa-_mwiygAXf0j8cilXTigbTWJfgqcziVmkJzl9a_5HJ8HYF5ohdGmVBhOfyRrwGikYoHEQB6Ye_6jwTD_IQsUJe0eYdD4xAdA7C2awZAvhdYduKXit7WSyGuEhbyKopsm6WVZz4BkjWDjcJ2S7Xjb6RxPCGc_nNiAMsGT1nG9MIj-oGYy8gIWPSLEyF_6sk8hiaQ"
}

*Delegated Access Token*:

{
"protected": {
"_comment": "to be base64url-encoded",
"alg": "RS256",
"typ": "JWT",
"kid": "delegation-key-2-sub"
},
"payload": {
"_comment": "to be base64url-encoded",
"sub": "https://dp1.example.com",
"aud": "https://res1.example.com",
"iat": 1772184788,
"exp": 1772188388,
"scope": "email:read",
"delegationToken": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImRlbGVnYXRpb24ta2V5LTIifQ.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.lnf8Wz5M_B4dVTOOjT0aQa0ZSqEbTZVGb1HU_dk1tJ4eCbkCB8lmO0wJXc07Ys8gKqqb3TS4tKUbnwwKo3_Dw3FGYjbDqDE7rBtdc0lqi6fKSecff2ujVCi2U2dLjX78_h7U0LP1XbJuhkjdBYa-_mwiygAXf0j8cilXTigbTWJfgqcziVmkJzl9a_5HJ8HYF5ohdGmVBhOfyRrwGikYoHEQB6Ye_6jwTD_IQsUJe0eYdD4xAdA7C2awZAvhdYduKXit7WSyGuEhbyKopsm6WVZz4BkjWDjcJ2S7Xjb6RxPCGc_nNiAMsGT1nG9MIj-oGYy8gIWPSLEyF_6sk8hiaQ"
},
"signature": "mn-0y0F3lx0IM-60UsBp1_M7uRhdT28dPqxt6-s1OnjM-obyF-p5XbQV9jI5Q56X4cb3jLl6RkM789ODTGt5y4QNdOA2WhlS0WldSOzYkV1Xj2yrC0mZakYCHTpzzgvfeUjeNj-fDWmtgRb2Lfm6Z6dguT071WQkaIyH4IW5xVxroqbn1tFM07uX3huIV9tC_iS926rWaDW7eQDm1nhhjS_QSgUcTF1eJy7hOjEtzs70iij5bQU-B9nn6OfXdpb1jO5vx3lCSnZfL2h2EaQYK3CbjrflbDnIYKtJ0NMx5D03KRcv_uPlG5HHRL5cuMz8eToKc08rc0Qs5PxDbeqV4A"
}

Appendix B. Integration with Step-Up Authorization

This specification can be used together with step-up authorization
[I-D.lombardo-oauth-step-up-authz-challenge-proto]. When a resource
server returns an insufficient_authorization error, the client can
create a new delegated access token with the required permissions
from its existing delegation token.

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This is particularly useful for AI agents that hold a delegation
token. Upon receiving a step-up authorization challenge, the agent
can automatically create a new delegated access token with the
additional authorization_details required by the resource server,
without requiring the user to re-authenticate.

Resource servers that support both delegated authorization and step-
up challenges SHOULD use the body_instructions parameter to specify
the exact authorization_details or scope required.

Appendix C. Use Cases

C.1. Delegating Subset of Access Rights to Specialized AI Agents

Enterprise Identity and Access Management systems often employ Role
Based Access Control (RBAC) or Attribute Based Access Control (ABAC),
assigning a set of minimal permissions to the employee based on their
role, department, or other attributes. AI Agent can be an employee's
personal assistant, or a virtual employee of a certain department in
general. The permissions delegated to an AI agent CAN be long-term,
but an AI agent MUST NOT directly inherit all its owner's access
rights. Rather, they SHOULD be a subset of its owner, bound to
specific service/API/database/codebase according to its specialty and
dedicated workflow.

Table 1: AI Agents

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C.2. Third-Party Analytics Platform Integrated in an Enterprise SaaS

In this scenario, a corporate customer uses a Software-as-a-Service
(SaaS) Customer Relationship Management (CRM) application. The
customer wishes to gain business insights by granting a specialized
third-party analytics platform limited access to its CRM data.

The CRM application obtains a delegation token from the enterprise's
identity provider. It then creates a narrowly scoped delegated
access token for the analytics service. This token only permits read
access to a predefined, non-sensitive subset of customer data (e.g.,
names and identifiers, but not personal email addresses). The
analytics platform uses this token to pull data, generates an
aggregated business intelligence report, and delivers it back to the
CRM application for the corporate customer to view.

Table 2: Enterprise-SaaS

Authors' Addresses

Ruochen Li
Huawei Int. Pte Ltd
Email: li.ruochen@h-partners.com

Haiguang Wang
Huawei Int. Pte Ltd
Email: wang.haiguang.shieldlab@huawei.com

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Chunchi Peter Liu
Huawei Technologies
Email: liuchunchi@huawei.com

Tieyan Li
Huawei Int. Pte Ltd
Email: Li.Tieyan@huawei.com

Li, et al. Expires 7 January 2027 [Page 30]

OAuth 2.0 Delegated Authorization draft-li-oauth-delegated-authorization-02

OAuth 2.0 Delegated Authorization
draft-li-oauth-delegated-authorization-02