OAuth 2.0 Rich Authorization Requests
RFC 9396
| Document | Type |
RFC
- Proposed Standard
(May 2023)
Was
draft-ietf-oauth-rar
(oauth WG)
|
|
|---|---|---|---|
| Authors | Torsten Lodderstedt , Justin Richer , Brian Campbell | ||
| Last updated | 2023-05-30 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| IESG | Responsible AD | Roman Danyliw | |
| Send notices to | (None) |
RFC 9396
Internet Engineering Task Force (IETF) T. Lodderstedt
Request for Comments: 9396 yes.com
Category: Standards Track J. Richer
ISSN: 2070-1721 Bespoke Engineering
B. Campbell
Ping Identity
May 2023
OAuth 2.0 Rich Authorization Requests
Abstract
This document specifies a new parameter authorization_details that is
used to carry fine-grained authorization data in OAuth messages.
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/rfc9396.
Copyright Notice
Copyright (c) 2023 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
1.1. Conventions and Terminology
2. Request Parameter "authorization_details"
2.1. Authorization Details Types
2.2. Common Data Fields
3. Authorization Request
3.1. Relationship to the "scope" Parameter
3.2. Relationship to the "resource" Parameter
4. Authorization Response
5. Authorization Error Response
6. Token Request
6.1. Comparing Authorization Details
7. Token Response
7.1. Enriched Authorization Details in Token Response
8. Token Error Response
9. Resource Servers
9.1. JWT-Based Access Tokens
9.2. Token Introspection
10. Metadata
11. Implementation Considerations
11.1. Using Authorization Details in a Certain Deployment
11.2. Minimal Implementation Support
11.3. Use of Machine-Readable Type Schemas
11.4. Large Requests
12. Security Considerations
13. Privacy Considerations
14. IANA Considerations
14.1. OAuth Parameters Registration
14.2. JSON Web Token Claims Registration
14.3. OAuth Token Introspection Response Registration
14.4. OAuth Authorization Server Metadata Registration
14.5. OAuth Dynamic Client Registration Metadata Registration
14.6. OAuth Extensions Error Registration
15. References
15.1. Normative References
15.2. Informative References
Appendix A. Additional Examples
A.1. OpenID Connect
A.2. Remote Electronic Signing
A.3. Access to Tax Data
A.4. eHealth
Acknowledgements
Authors' Addresses
1. Introduction
"The OAuth 2.0 Authorization Framework" [RFC6749] defines the scope
parameter that allows OAuth clients to specify the requested scope,
i.e., the limited capability, of an access token. This mechanism is
sufficient to implement static scenarios and coarse-grained
authorization requests, such as "give me read access to the resource
owner's profile." However, it is not sufficient to specify fine-
grained authorization requirements, such as "please let me transfer
an amount of 45 Euros to Merchant A" or "please give me read access
to directory A and write access to file X."
This specification introduces a new parameter authorization_details
that allows clients to specify their fine-grained authorization
requirements using the expressiveness of JSON [RFC8259] data
structures.
For example, an authorization request for a credit transfer
(designated as "payment initiation" in several open banking
initiatives) can be represented using a JSON object like this:
{
"type": "payment_initiation",
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant A",
"creditorAccount": {
"bic":"ABCIDEFFXXX",
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
Figure 1: Example of an Authorization Request for a Credit Transfer
This object contains detailed information about the intended payment,
such as amount, currency, and creditor, that is required to inform
the user and obtain their consent. The authorization server (AS) and
the respective resource server (RS) (providing the payment initiation
API) will together enforce this consent.
For a comprehensive discussion of the challenges arising from new use
cases in the open banking and electronic signing spaces, see
[Transaction-Auth].
In addition to facilitating custom authorization requests, this
specification also introduces a set of common data type fields for
use across different APIs.
1.1. Conventions and Terminology
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.
This specification uses the terms "access token", "refresh token",
"authorization server" (AS), "resource server" (RS), "authorization
endpoint", "authorization request", "authorization response", "token
endpoint", "grant type", "access token request", "access token
response", and "client" defined by "The OAuth 2.0 Authorization
Framework" [RFC6749].
2. Request Parameter "authorization_details"
The request parameter authorization_details contains, in JSON
notation, an array of objects. Each JSON object contains the data to
specify the authorization requirements for a certain type of
resource. The type of resource or access requirement is determined
by the type field, which is defined as follows:
type: An identifier for the authorization details type as a string.
The value of the type field determines the allowable contents of
the object that contains it. The value is unique for the
described API in the context of the AS. This field is REQUIRED.
An authorization_details array MAY contain multiple entries of the
same type.
Figure 2 shows an authorization_details of type payment_initiation
using the example data shown above:
[
{
"type": "payment_initiation",
"actions": [
"initiate",
"status",
"cancel"
],
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant A",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
Figure 2: Example of "authorization_details" for a Credit Transfer
Figure 3 shows a combined request asking for access to account
information and permission to initiate a payment:
[
{
"type": "account_information",
"actions": [
"list_accounts",
"read_balances",
"read_transactions"
],
"locations": [
"https://example.com/accounts"
]
},
{
"type": "payment_initiation",
"actions": [
"initiate",
"status",
"cancel"
],
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant A",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
Figure 3: Example of "authorization_details" for a Combined Request
The JSON objects with type fields of account_information and
payment_initiation represent the different authorization_details to
be used by the AS to ask for consent.
| Note: The AS will make this data subsequently available to the
| respective RSs (see Section 9).
2.1. Authorization Details Types
The AS controls the interpretation of the value of the type parameter
as well as the object fields that the type parameter allows.
However, the value of the type parameter is also generally documented
and intended to be used by developers. It is RECOMMENDED that API
designers choose type values that are easily copied without
ambiguity. For example, some glyphs have multiple Unicode code
points for the same visual character, and a developer could
potentially type a different character than what the AS has defined.
Possible means of reducing potential confusion are limiting the value
to ASCII [RFC0020] characters, providing a machine-readable listing
of data type values, or instructing developers to copy and paste
directly from the documentation.
If an application or API is expected to be deployed across different
servers, such as the case in an open standard, the API designer is
RECOMMENDED to use a collision-resistant namespace under their
control, such as a URI that the API designer controls.
The following example shows how an implementation could utilize the
namespace https://scheme.example.org/ to ensure collision-resistant
type values.
{
"type": "https://scheme.example.org/files",
"locations": [
"https://example.com/files"
],
"permissions": [
{
"path": "/myfiles/A",
"access": [
"read"
]
},
{
"path": "/myfiles/A/X",
"access": [
"read",
"write"
]
}
]
}
Figure 4: Example of "authorization_details" with a URL as Type
Identifier
2.2. Common Data Fields
This specification defines a set of common data fields that are
designed to be usable across different types of APIs. This
specification does not require the use of these common fields by an
API definition but, instead, provides them as reusable generic
components for API designers to make use of. The allowable values of
all fields are determined by the API being protected, as defined by a
particular "type" value.
locations: An array of strings representing the location of the
resource or RS. These strings are typically URIs identifying the
location of the RS. This field can allow a client to specify a
particular RS, as discussed in Section 12.
actions: An array of strings representing the kinds of actions to be
taken at the resource.
datatypes: An array of strings representing the kinds of data being
requested from the resource.
identifier: A string identifier indicating a specific resource
available at the API.
privileges: An array of strings representing the types or levels of
privilege being requested at the resource.
When different common data fields are used in combination, the
permissions the client requests are the product of all the values.
The object represents a request for all actions values listed within
the object to be used at all locations values listed within the
object for all datatypes values listed within the object. In the
following example, the client is requesting read and write access to
both the contacts and photos belonging to customers in a
customer_information API. If this request is granted, the client
would assume it would be able to use any combination of rights
defined by the API, such as read access to the photos and write
access to the contacts.
[
{
"type": "customer_information",
"locations": [
"https://example.com/customers"
],
"actions": [
"read",
"write"
],
"datatypes": [
"contacts",
"photos"
]
}
]
Figure 5: Example of "authorization_details" with Common Data Fields
If the client wishes to have finer control over its access, it can
send multiple objects. In this example, the client is asking for
read access to the contacts and write access to the photos in the
same API endpoint. If this request is granted, the client would not
be able to write to the contacts.
[
{
"type": "customer_information",
"locations": [
"https://example.com/customers"
],
"actions": [
"read"
],
"datatypes": [
"contacts"
]
},
{
"type": "customer_information",
"locations": [
"https://example.com/customers"
],
"actions": [
"write"
],
"datatypes": [
"photos"
]
}
]
Figure 6: Example of "authorization_details" with Common Data
Fields in Multiple Objects
An API MAY define its own extensions, subject to the type of the
respective authorization object. It is anticipated that API
designers will use a combination of common data fields defined in
this specification as well as fields specific to the API itself. The
following non-normative example shows the use of both common and API-
specific fields as part of two different fictitious API type values.
The first access request includes the actions, locations, and
datatypes fields specified here as well as the API-specific
geolocation field, indicating access to photos taken at the given
coordinates. The second access request includes the actions and
identifier fields specified here as well as the API-specific currency
fields.
[
{
"type":"photo-api",
"actions":[
"read",
"write"
],
"locations":[
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes":[
"metadata",
"images"
],
"geolocation":[
{
"lat":-32.364,
"lng":153.207
},
{
"lat":-35.364,
"lng":158.207
}
]
},
{
"type":"financial-transaction",
"actions":[
"withdraw"
],
"identifier":"account-14-32-32-3",
"currency":"USD"
}
]
Figure 7: Example of "authorization_details" Using Common and
Extension Data Fields
If this request is approved, the resulting access token's access
rights will be the union of the requested types of access for each of
the two APIs, just as above.
3. Authorization Request
The authorization_details authorization request parameter can be used
to specify authorization requirements in all places where the scope
parameter is used for the same purpose, examples include:
* authorization requests as specified in [RFC6749]
* device authorization requests as specified in [RFC8628]
* backchannel authentication requests as defined in [OID-CIBA]
In case of authorization requests as defined in [RFC6749],
implementers MAY consider using pushed authorization requests
[RFC9126] to improve the security, privacy, and reliability of the
flow. See Sections 12, 13, and 11.4 for details.
Parameter encoding is determined by the respective context. In the
context of an authorization request according to [RFC6749], the
parameter is encoded using the application/x-www-form-urlencoded
format of the serialized JSON as shown in Figure 8, using the example
from Section 2 (line breaks for display purposes only):
GET /authorize?response_type=code
&client_id=s6BhdRkqt3
&state=af0ifjsldkj
&redirect_uri=https%3A%2F%2Fclient.example.org%2Fcb
&code_challenge_method=S256
&code_challenge=K2-ltc83acc4h0c9w6ESC_rEMTJ3bwc-uCHaoeK1t8U
&authorization_details=%5B%7B%22type%22%3A%22account%5Finfo
rmation%22%2C%22actions%22%3A%5B%22list%5Faccounts%22%2C%22
read%5Fbalances%22%2C%22read%5Ftransactions%22%5D%2C%22loca
tions%22%3A%5B%22https%3A%2F%2Fexample%2Ecom%2Faccounts%22%
5D%7D%2C%7B%22type%22%3A%22payment%5Finitiation%22%2C%22act
ions%22%3A%5B%22initiate%22%2C%22status%22%2C%22cancel%22%5
D%2C%22locations%22%3A%5B%22https%3A%2F%2Fexample%2Ecom%2Fp
ayments%22%5D%2C%22instructedAmount%22%3A%7B%22currency%22%
3A%22EUR%22%2C%22amount%22%3A%22123%2E50%22%7D%2C%22credito
rName%22%3A%22Merchant%20A%22%2C%22creditorAccount%22%3A%7B
%22iban%22%3A%22DE02100100109307118603%22%7D%2C%22remittanc
eInformationUnstructured%22%3A%22Ref%20Number%20Merchant%22
%7D%5D HTTP/1.1
Host: server.example.com
Figure 8: Example of Authorization Request with
"authorization_details"
Based on the data provided in the authorization_details parameter,
the AS will ask the user for consent to the requested access
permissions.
| Note: The user may also grant a subset of the requested
| authorization details.
In Figure 9, the client wants to get access to account information
and initiate a payment:
[
{
"type": "account_information",
"actions": [
"list_accounts",
"read_balances",
"read_transactions"
],
"locations": [
"https://example.com/accounts"
]
},
{
"type": "payment_initiation",
"actions": [
"initiate",
"status",
"cancel"
],
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant A",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
Figure 9: URL Decoded "authorization_details"
3.1. Relationship to the "scope" Parameter
authorization_details and scope can be used in the same authorization
request for carrying independent authorization requirements.
Combined use of authorization_details and scope is supported by this
specification in part to allow existing OAuth-based applications to
incrementally migrate towards using authorization_details
exclusively. It is RECOMMENDED that a given API use only one form of
requirement specification.
The AS MUST process both sets of requirements in combination with
each other for the given authorization request. The details of how
the AS combines these parameters are specific to the APIs being
protected and outside the scope of this specification.
When gathering user consent, the AS MUST present the merged set of
requirements represented by the authorization request.
If the resource owner grants the client the requested access, the AS
will issue tokens to the client that are associated with the
respective authorization_details (and scope values, if applicable).
3.2. Relationship to the "resource" Parameter
The resource authorization request parameter, as defined in
[RFC8707], can be used to further determine the resources where the
requested scope can be applied. The resource parameter does not have
any impact on the way the AS processes the authorization_details
authorization request parameter.
4. Authorization Response
This specification does not define extensions to the authorization
response.
5. Authorization Error Response
The AS MUST refuse to process any unknown authorization details type
or authorization details not conforming to the respective type
definition. The AS MUST abort processing and respond with an error
invalid_authorization_details to the client if any of the following
are true of the objects in the authorization_details structure:
* contains an unknown authorization details type value,
* is an object of known type but containing unknown fields,
* contains fields of the wrong type for the authorization details
type,
* contains fields with invalid values for the authorization details
type, or
* is missing required fields for the authorization details type.
6. Token Request
The authorization_details token request parameter can be used to
specify the authorization details that a client wants the AS to
assign to an access token. The AS checks whether the underlying
grant (in case of grant types authorization_code, refresh_token,
etc.) or the client's policy (in case of grant type
client_credentials) allows the issuance of an access token with the
requested authorization details. Otherwise, the AS refuses the
request with the error code invalid_authorization_details (similar to
invalid_scope).
6.1. Comparing Authorization Details
Many actions in the OAuth protocol allow the AS and RS to make
security decisions based on whether the request is asking for "more"
or "less" than a previous, existing request. For example, upon
refreshing a token, the client can ask for a new access token with
"fewer permissions" than had been previously authorized by the
resource owner. The requested access token will convey the reduced
permissions, but the resource owner's previous authorization is
unchanged by such requests. Since the semantics of the fields in the
authorization_details will be implementation specific to a given API
or set of APIs, there is no standardized mechanism to compare two
arbitrary authorization detail requests. An AS should not rely on
simple object comparison in most cases, as the intersection of some
fields within a request could have side effects on the access rights
granted, depending on how the API has been designed and deployed.
This is a similar effect to the scope values used with some APIs.
When comparing a new request to an existing request, an AS can use
the same processing techniques as used in granting the request in the
first place to determine if a resource owner needs to authorize the
request. The details of this comparison are dependent on the
definition of the type of authorization request and outside the scope
of this specification, but common patterns can be applied.
This shall be illustrated using our running example. The example
authorization request in Section 3, if approved by the user, resulted
in the issuance of an authorization code associated with the
privileges to:
* list accounts,
* access the balance of one or more accounts,
* access the transactions of one or more accounts, and
* initiate, check the status of, and cancel a payment.
The client could now request the AS to issue an access token assigned
with the privilege to just access a list of accounts as follows:
[
{
"type": "account_information",
"actions": [
"list_accounts"
],
"locations": [
"https://example.com/accounts"
]
}
]
Figure 10: Example of "authorization_details" Reduced Privileges
The example API is designed such that each field used by the
account_information type contains additive rights, with each value
within the actions and locations arrays specifying a different
element of access. To make a comparison in this instance, the AS
would perform the following steps:
* verify that the authorization code issued in the previous step
contains an authorization details object of type
account_information,
* verify whether the approved list of actions contains
list_accounts, and
* verify whether the locations value includes only previously
approved locations.
If all checks succeed, the AS would issue the requested access token
with the reduced set of access.
Note that this comparison is relevant to this specific API type
definition. A different API type definition could have different
processing rules. For example, an actions value could subsume the
rights associated with another actions value. For example, if a
client initially asks for a token with write access, this implies
both read and write access to this API:
[
{
"type": "example_api",
"actions": [
"write"
]
}
]
Figure 11: Example of "authorization_details" Requesting "write"
Access to an API
Later, that same client makes a refresh request for read access:
[
{
"type": "example_api",
"actions": [
"read"
]
}
]
Figure 12: Example of "authorization_details" Requesting "read"
Access to an API
The AS would compare the type value and the actions value to
determine that the read access is already covered by the write access
previously granted to the client.
This same API could be designed with a possible value for privileges
of admin, used in this example to denote that the resulting token is
allowed to perform any of the functions on the resources. If that
client is then granted such admin privileges to the API, the
authorization_details would be as follows:
[
{
"type": "example_api",
"privileges": [
"admin"
]
}
]
Figure 13: Example of "authorization_details" with "admin" Access
to an API
The AS would compare the type value and find that the privileges
value subsumes any aspects of read or write access that had been
granted to the client previously. Note that other API definitions
can use privileges such that values do not subsume one another.
The next example shows how the client can use the common data element
locations (see Section 2.2) to request the issuance of an access
token restricted to a certain RS. In our running example, the client
may ask for all permissions of the approved grant of type
payment_initiation applicable to the RS residing at
https://example.com/payments as follows:
[
{
"type": "payment_initiation",
"locations": [
"https://example.com/payments"
]
}
]
Figure 14: Example of "authorization_details" Requesting an
Audience-Restricted Access Token
7. Token Response
In addition to the token response parameters as defined in [RFC6749],
the AS MUST also return the authorization_details as granted by the
resource owner and assigned to the respective access token.
The authorization details assigned to the access token issued in a
token response are determined by the authorization_details parameter
of the corresponding token request. If the client does not specify
the authorization_details token request parameters, the AS determines
the resulting authorization_details at its discretion.
The AS MAY omit values in the authorization_details to the client.
For our running example, it would look like this:
HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
{
"access_token": "2YotnFZFEjr1zCsicMWpAA",
"token_type": "example",
"expires_in": 3600,
"refresh_token": "tGzv3JOkF0XG5Qx2TlKWIA",
"authorization_details": [
{
"type": "payment_initiation",
"actions": [
"initiate",
"status",
"cancel"
],
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant A",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
}
Figure 15: Example Token Response
7.1. Enriched Authorization Details in Token Response
The authorization details attached to the access token MAY differ
from what the client requests. In addition to the user authorizing
less than what the client requested, there are some use cases where
the AS enriches the data in an authorization details object. Whether
enrichment is allowed and specifics of how it works are necessarily
part of the definition of the respective authorization details type.
As one example, a client may ask for access to account information
but leave the decision about the specific accounts it will be able to
access to the user. During the course of the authorization process,
the user would select the subset of their accounts that they want to
allow the client to access. As one design option to convey the
selected accounts, the AS could add this information to the
respective authorization details object.
In that example, the requested authorization_details parameter might
look like the following. In this example, the empty arrays serve as
placeholders for where data will be added during enrichment by the
AS. This example is illustrative only and is not intended to suggest
a preference for designing the specifics of any authorization details
type this way.
"authorization_details": [
{
"type": "account_information",
"access": {
"accounts": [],
"balances": [],
"transactions": []
},
"recurringIndicator":true
}
]
Figure 16: Example of Requested "authorization_details"
The AS then would expand the authorization details object and add the
respective account identifiers.
HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
{
"access_token":"2YotnFZFEjr1zCsicMWpAA",
"token_type":"example",
"expires_in":3600,
"refresh_token":"tGzv3JokF0XG5Qx2TlKWIA",
"authorization_details":[
{
"type":"account_information",
"access":{
"accounts":[
{
"iban":"DE2310010010123456789"
},
{
"maskedPan":"123456xxxxxx1234"
}
],
"balances":[
{
"iban":"DE2310010010123456789"
}
],
"transactions":[
{
"iban":"DE2310010010123456789"
},
{
"maskedPan":"123456xxxxxx1234"
}
]
},
"recurringIndicator":true
}
]
}
Figure 17: Example of Enriched "authorization_details"
For another example, the client is asking for access to a medical
record but does not know the record number at request time. In this
example, the client specifies the type of access it wants but doesn't
specify the location or identifier of that access.
{
"authorization_details": [
{
"type": "medical_record",
"sens": [ "HIV", "ETH", "MART" ],
"actions": [ "read" ],
"datatypes": [ "Patient", "Observation", "Appointment" ]
}
]}
Figure 18: Example of Requested "authorization_details"
When the user interacts with the AS, they select which of the medical
records they are responsible for giving to the client. This
information gets returned with the access token.
{
"access_token":"2YotnFZFEjr1zCsicMWpAA",
"token_type":"example",
"expires_in":3600,
"refresh_token":"tGzv3JokF0XG5Qx2TlKWIA",
"authorization_details":[
{
"type": "medical_record",
"sens": [ "HIV", "ETH", "MART" ],
"actions": [ "read" ],
"datatypes": [ "Patient", "Observation", "Appointment" ],
"identifier": "patient-541235",
"locations": [ "https://records.example.com/" ]
}
]
}
Figure 19: Example of Enriched "authorization_details"
| Note: The client needs to be aware upfront of the possibility
| that a certain authorization details object can be enriched.
| It is assumed that this property is part of the definition of
| the respective authorization details type.
8. Token Error Response
The Token Error Response MUST conform to the rules given in
Section 5.
9. Resource Servers
In order to enable the RS to enforce the authorization details as
approved in the authorization process, the AS MUST make this data
available to the RS. The AS MAY add the authorization_details field
to access tokens in JSON Web Token (JWT) format or to token
introspection responses.
9.1. JWT-Based Access Tokens
If the access token is a JWT [RFC7519], the AS is RECOMMENDED to add
the authorization details object, filtered to the specific audience,
as a top-level claim.
The AS will typically also add further claims to the JWT that the RS
requires request processing, e.g., user ID, roles, and transaction-
specific data. What claims the particular RS requires is defined by
the RS-specific policy with the AS.
The following shows the contents of an example JWT for the payment
initiation example above:
{
"iss": "https://as.example.com",
"sub": "24400320",
"aud": "a7AfcPcsl2",
"exp": 1311281970,
"acr": "psd2_sca",
"txn": "8b4729cc-32e4-4370-8cf0-5796154d1296",
"authorization_details": [
{
"type": "https://scheme.example.com/payment_initiation",
"actions": [
"initiate",
"status",
"cancel"
],
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant A",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
],
"debtorAccount": {
"iban": "DE40100100103307118608",
"user_role": "owner"
}
}
Figure 20: Example of "authorization_details" in JWT-Based Access
Token
In this case, the AS added the following example claims to the JWT-
based access token:
sub: indicates the user for which the client is asking for payment
initiation.
txn: transaction id used to trace the transaction across the
services of provider example.com
debtorAccount: API-specific field containing the debtor account. In
the example, this account was not passed in the
authorization_details but was selected by the user during the
authorization process. The field user_role conveys the role the
user has with respect to this particular account. In this case,
they are the owner. This data is used for access control at the
payment API (the RS).
9.2. Token Introspection
Token introspection [RFC7662] provides a means for an RS to query the
AS to determine information about an access token. If the AS
includes authorization detail information for the token in its
response, the information MUST be conveyed with authorization_details
as a top-level member of the introspection response JSON object. The
authorization_details member MUST contain the same structure defined
in Section 2, potentially filtered and extended for the RS making the
introspection request.
Here is an example introspection response for the payment initiation
example:
{
"active": true,
"sub": "24400320",
"aud": "s6BhdRkqt3",
"exp": 1311281970,
"acr": "psd2_sca",
"txn": "8b4729cc-32e4-4370-8cf0-5796154d1296",
"authorization_details": [
{
"type": "https://scheme.example.com/payment_initiation",
"actions": [
"initiate",
"status",
"cancel"
],
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant123",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
],
"debtorAccount": {
"iban": "DE40100100103307118608",
"user_role": "owner"
}
}
Figure 21: Example of "authorization_details" in Introspection
Response
10. Metadata
To advertise its support for this feature, the supported list of
authorization details types is included in the AS metadata response
[RFC8414] using the metadata parameter
authorization_details_types_supported, which is a JSON array.
This is illustrated by the following example:
{
...
"authorization_details_types_supported":[
"payment_initiation",
"account_information"
]
}
Figure 22: Example of Server Metadata about the Supported
Authorization Details
Clients MAY indicate the authorization details types they will use
when requesting authorization with the client registration metadata
parameter authorization_details_types, which is a JSON array.
This is illustrated by the following example:
{
...
"authorization_details_types":[
"payment_initiation"
]
}
Figure 23: Example of Server Metadata about Authorization Details
The registration of authorization details types with the AS is
outside the scope of this specification.
11. Implementation Considerations
11.1. Using Authorization Details in a Certain Deployment
Using authorization details in a certain deployment will require the
following steps:
* Define authorization details types.
* Publish authorization details types in the OAuth server metadata.
* Determine how authorization details are shown to the user in the
user consent prompt.
* If needed, enrich authorization details in the user consent
process (e.g., add selected accounts or set expirations).
* If needed, determine how authorization details are reflected in
access token content or introspection responses.
* Determine how the RSs process the authorization details or token
data derived from authorization details.
* If needed, entitle clients to use certain authorization details
types.
11.2. Minimal Implementation Support
General AS implementations supporting this specification should
provide the following basic functions:
* Support advertisement of supported authorization details types in
OAuth server metadata
* Accept the authorization_details parameter in authorization
requests in conformance with this specification
* Support storage of consented authorization details as part of a
grant
* Implement default behavior for adding authorization details to
access tokens and token introspection responses in order to make
them available to RSs (similar to scope values). This should work
with any grant type, especially authorization_code and
refresh_token.
Processing and presentation of authorization details will vary
significantly among different authorization details types.
Implementations should therefore support customization of the
respective behavior. In particular, implementations should allow
deployments to:
* determine presentation of the authorization details;
* modify requested authorization details in the user consent
process, e.g., adding fields; and
* merge requested and preexisting authorization details.
One approach to supporting such customization would be to have a
mechanism allowing the registration of extension modules, each of
them responsible for rendering the respective user consent and any
transformation needed to provide the data needed to the RS by way of
structured access tokens or token introspection responses.
11.3. Use of Machine-Readable Type Schemas
Implementations might allow deployments to use machine-readable
schema languages for defining authorization details types to
facilitate creating and validating authorization details objects
against such schemas. For example, if an authorization details type
were defined using JSON Schemas [JSON.Schema], the JSON Schema
identifier could be used as type value in the respective
authorization details objects.
Note, however, that type values are identifiers understood by the AS
and, to the extent necessary, the client and RS. This specification
makes no assumption that a type value would point to a machine-
readable schema format or that any party in the system (such as the
client, AS, or RS) would dereference or process the contents of the
type field in any specific way.
11.4. Large Requests
Authorization request URIs containing authorization_details in a
request parameter or a request object can become very long.
Therefore, implementers should consider using the request_uri
parameter as defined in [RFC9101] in combination with the pushed
request object mechanism as defined in [RFC9126] to pass
authorization_details in a reliable and secure manner. Here is an
example of such a pushed authorization request that sends the
authorization request data directly to the AS via an HTTPS-protected
connection:
POST /as/par HTTP/1.1
Host: as.example.com
Content-Type: application/x-www-form-urlencoded
Authorization: Basic czZCaGRSa3F0Mzo3RmpmcDBaQnIxS3REUmJuZlZkbUl3
response_type=code&
client_id=s6BhdRkqt3
&state=af0ifjsldkj
&redirect_uri=https%3A%2F%2Fclient.example.org%2Fcb
&code_challenge_method=S256
&code_challenge=K2-ltc83acc4h0c9w6ESC_rEMTJ3bwc-uCHaoeK1t8U
&authorization_details=%5B%7B%22type%22%3A%22account_information%22
%2C%22actions%22%3A%5B%22list_accounts%22%2C%22read_balances%22%2C%
22read_transactions%22%5D%2C%22locations%22%3A%5B%22https%3A%2F%2Fe
xample.com%2Faccounts%22%5D%7D%2C%7B%22type%22%3A%22payment_initiat
ion%22%2C%22actions%22%3A%5B%22initiate%22%2C%22status%22%2C%22canc
el%22%5D%2C%22locations%22%3A%5B%22https%3A%2F%2Fexample.com%2Fpaym
ents%22%5D%2C%22instructedAmount%22%3A%7B%22currency%22%3A%22EUR%22
%2C%22amount%22%3A%22123.50%22%7D%2C%22creditorName%22%3A%22Merchan
t123%22%2C%22creditorAccount%22%3A%7B%22iban%22%3A%22DE021001001093
07118603%22%7D%2C%22remittanceInformationUnstructured%22%3A%22Ref%2
0Number%20Merchant%22%7D%5D
Figure 24: Example of Large Request including "authorization_details"
12. Security Considerations
The authorization_details parameter is sent through the user agent in
case of an OAuth authorization request, which makes them vulnerable
to modifications by the user. If the integrity of the
authorization_details is a concern, clients MUST protect
authorization_details against tampering and swapping. This can be
achieved by signing the request using signed request objects as
defined in [RFC9101] or using the request_uri authorization request
parameter as defined in [RFC9101] in conjunction with [RFC9126] to
pass the URI of the request object to the AS.
All string comparisons in an authorization_details parameter are to
be done as defined by [RFC8259]. No additional transformation or
normalization is to be done in evaluating equivalence of string
values.
The common data field locations allows a client to specify where it
intends to use a certain authorization, i.e., it is possible to
unambiguously assign permissions to RSs. In situations with multiple
RSs, this prevents unintended client authorizations (e.g., a read
scope value potentially applicable for an email as well as a cloud
service) through audience restriction.
The AS MUST properly sanitize and handle the data passed in the
authorization_details in order to prevent injection attacks.
The Security Considerations of [RFC6749], [RFC7662], and [RFC8414]
also apply.
13. Privacy Considerations
It is especially important for implementers to design and use
authorization details in a privacy-preserving manner.
Any sensitive personal data included in authorization_details must be
prevented from leaking, e.g., through referrer headers.
Implementation options include encrypted request objects as defined
in [RFC9101] or transmission of authorization_details via end-to-end
encrypted connections between client and AS by utilizing [RFC9126]
and the request_uri authorization request parameter as defined in
[RFC9101]. The latter does not require application-level encryption,
but it requires another message exchange between the client and the
AS.
Even if the request data is encrypted, an attacker could use the AS
to learn the user's data by injecting the encrypted request data into
an authorization request on a device under their control and use the
AS's user consent screens to show the (decrypted) user data in the
clear. Implementations need to consider this attack vector and
implement appropriate countermeasures, e.g., by only showing portions
of the data or, if possible, determining whether the assumed user
context is still the same (after user authentication).
The AS needs to take into consideration the privacy implications when
sharing authorization_details with the client or RSs. The AS should
share this data with those parties on a "need to know" basis as
determined by local policy.
14. IANA Considerations
14.1. OAuth Parameters Registration
The following parameter has been registered in the "OAuth Parameters"
registry [IANA.OAuth.Parameters] established by [RFC6749].
Name: authorization_details
Parameter Usage Location: authorization request, token request,
token response
Change Controller: IETF
Reference: RFC 9396
14.2. JSON Web Token Claims Registration
The following value has been registered in the IANA "JSON Web Token
Claims" registry established by [RFC7519].
Claim Name: authorization_details
Claim Description: The claim authorization_details contains a JSON
array of JSON objects representing the rights of the access token.
Each JSON object contains the data to specify the authorization
requirements for a certain type of resource.
Change Controller: IETF
Reference: Section 9.1 of RFC 9396
14.3. OAuth Token Introspection Response Registration
The following value has been registered in the IANA "OAuth Token
Introspection Response" registry established by [RFC7662].
Name: authorization_details
Description: The member authorization_details contains a JSON array
of JSON objects representing the rights of the access token. Each
JSON object contains the data to specify the authorization
requirements for a certain type of resource.
Change Controller: IETF
Reference: Section 9.2 of RFC 9396
14.4. OAuth Authorization Server Metadata Registration
The following values have been registered in the IANA "OAuth
Authorization Server Metadata" registry of [IANA.OAuth.Parameters]
established by [RFC8414].
Metadata Name: authorization_details_types_supported
Metadata Description: JSON array containing the authorization
details types the AS supports
Change Controller: IETF
Reference: Section 10 of RFC 9396
14.5. OAuth Dynamic Client Registration Metadata Registration
The following value has been registered in the IANA "OAuth Dynamic
Client Registration Metadata" registry of [IANA.OAuth.Parameters]
established by [RFC7591].
Client Metadata Name: authorization_details_types
Client Metadata Description: Indicates what authorization details
types the client uses.
Change Controller: IETF
Reference: Section 10 of RFC 9396
14.6. OAuth Extensions Error Registration
The following value has been registered in the IANA "OAuth Extensions
Error Registry" of [IANA.OAuth.Parameters] established by [RFC6749].
Name: invalid_authorization_details
Usage Location: token endpoint, authorization endpoint
Protocol Extension: OAuth 2.0 Rich Authorization Requests
Change Controller: IETF
Reference: Section 5 of RFC 9396
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/info/rfc2119>.
[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>.
[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>.
[RFC8628] Denniss, W., Bradley, J., Jones, M., and H. Tschofenig,
"OAuth 2.0 Device Authorization Grant", RFC 8628,
DOI 10.17487/RFC8628, August 2019,
<https://www.rfc-editor.org/info/rfc8628>.
[RFC8707] Campbell, B., Bradley, J., and H. Tschofenig, "Resource
Indicators for OAuth 2.0", RFC 8707, DOI 10.17487/RFC8707,
February 2020, <https://www.rfc-editor.org/info/rfc8707>.
15.2. Informative References
[CSC] Cloud Signature Consortium, "Architectures and protocols
for remote signature applications", Version 1.0.4.0, June
2019, <https://cloudsignatureconsortium.org/wp-
content/uploads/2020/01/CSC_API_V1_1.0.4.0.pdf>.
[ETSI] ETSI, "Electronic Signatures and Infrastructures (ESI);
Protocols for remote digital signature creation", V1.1.1,
ETSI TS 119 432, March 2019,
<https://www.etsi.org/deliver/
etsi_ts/119400_119499/119432/01.01.01_60/
ts_119432v010101p.pdf>.
[IANA.OAuth.Parameters]
IANA, "OAuth Parameters",
<https://www.iana.org/assignments/oauth-parameters>.
[JSON.Schema]
OpenJS Foundation, "JSON Schema",
<https://json-schema.org/>.
[OID-CIBA] Fernandez, G., Walter, F., Nennker, A., Tonge, D., and B.
Campbell, "OpenID Connect Client-Initiated Backchannel
Authentication Flow - Core 1.0", 1 September 2021,
<https://openid.net/specs/openid-client-initiated-
backchannel-authentication-core-1_0.html>.
[OIDC] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0 incorporating
errata set 1", 8 November 2014,
<https://openid.net/specs/openid-connect-core-1_0.html>.
[RFC0020] Cerf, V., "ASCII format for network interchange", STD 80,
RFC 20, DOI 10.17487/RFC0020, October 1969,
<https://www.rfc-editor.org/info/rfc20>.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/info/rfc6749>.
[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>.
[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/info/rfc8259>.
[RFC9101] Sakimura, N., Bradley, J., and M. Jones, "The OAuth 2.0
Authorization Framework: JWT-Secured Authorization Request
(JAR)", RFC 9101, DOI 10.17487/RFC9101, August 2021,
<https://www.rfc-editor.org/info/rfc9101>.
[RFC9126] Lodderstedt, T., Campbell, B., Sakimura, N., Tonge, D.,
and F. Skokan, "OAuth 2.0 Pushed Authorization Requests",
RFC 9126, DOI 10.17487/RFC9126, September 2021,
<https://www.rfc-editor.org/info/rfc9126>.
[Transaction-Auth]
Lodderstedt, T., "Transaction Authorization or why we need
to re-think OAuth scopes", 20 April 2019,
<https://medium.com/oauth-2/transaction-authorization-or-
why-we-need-to-re-think-oauth-scopes-2326e2038948>.
Appendix A. Additional Examples
A.1. OpenID Connect
OpenID Connect [OIDC] specifies the JSON-based claims request
parameter that can be used to specify the claims a client (acting as
an OpenID Connect Relying Party) wishes to receive in a fine-grained
and privacy-preserving way as well as assign those claims to certain
delivery mechanisms, i.e., ID Token or userinfo response.
The combination of the scope value openid and the additional
parameter claims can be used beside authorization_details in the same
way as every non-OIDC scope value.
Alternatively, there could be an authorization details type for
OpenID Connect. This section gives an example of what such an
authorization details type could look like, but defining this
authorization details type is outside the scope of this
specification.
These hypothetical examples try to encapsulate all details specific
to the OpenID Connect part of an authorization process into an
authorization JSON object.
The top-level fields are based on the definitions given in [OIDC]:
claim_sets: the names of predefined claim sets, replacement for
respective scope values, such as profile
max_age: Maximum Authentication Age
acr_values: requested Authentication Context Class Reference (ACR)
values
claims: the claims JSON structure as defined in [OIDC]
This is a simple request for some claim sets.
[
{
"type": "openid",
"locations": [
"https://op.example.com/userinfo"
],
"claim_sets": [
"email",
"profile"
]
}
]
Figure 25: Example of OpenID Connect Request Utilizing
"authorization_details"
| Note: locations specifies the location of the userinfo endpoint
| since this is the only place where an access token is used by a
| client (Relying Party) in OpenID Connect to obtain claims.
A more sophisticated example is shown in Figure 26.
[
{
"type": "openid",
"locations": [
"https://op.example.com/userinfo"
],
"max_age": 86400,
"acr_values": "urn:mace:incommon:iap:silver",
"claims": {
"userinfo": {
"given_name": {
"essential": true
},
"nickname": null,
"email": {
"essential": true
},
"email_verified": {
"essential": true
},
"picture": null,
"http://example.com/claims/groups": null
},
"id_token": {
"auth_time": {
"essential": true
}
}
}
}
]
Figure 26: Advanced Example of OpenID Connect Request Utilizing
"authorization_details"
A.2. Remote Electronic Signing
The following example is based on the concept laid out for remote
electronic signing in ETSI TS 119 432 [ETSI] and the Cloud Signature
Consortium (CSC) API for remote signature creation [CSC].
[
{
"type": "sign",
"locations": [
"https://signing.example.com/signdoc"
],
"credentialID": "60916d31-932e-4820-ba82-1fcead1c9ea3",
"documentDigests": [
{
"hash": "sTOgwOm+474gFj0q0x1iSNspKqbcse4IeiqlDg/HWuI=",
"label": "Credit Contract"
},
{
"hash": "HZQzZmMAIWekfGH0/ZKW1nsdt0xg3H6bZYztgsMTLw0=",
"label": "Contract Payment Protection Insurance"
}
],
"hashAlgorithmOID": "2.16.840.1.101.3.4.2.1"
}
]
Figure 27: Example of Electronic Signing
The top-level fields have the following meaning:
credentialID: identifier of the certificate to be used for signing
documentDigests: array containing the hash of every document to be
signed (hash fields). Additionally, the corresponding label field
identifies the respective document to the user, e.g., to be used
in user consent.
hashAlgorithm: algorithm that was used to calculate the hash values
The AS is supposed to ask the user for consent for the creation of
signatures for the documents listed in the structure. The client
uses the access token issued as a result of the process to call the
document signature API at the respective signing service to actually
create the signature. This access token is bound to the client, the
user ID and the hashes (and signature algorithm) as consented by the
user.
A.3. Access to Tax Data
This example is inspired by an API allowing third parties to access
citizen's tax declarations and income statements, for example, to
determine their creditworthiness.
[
{
"type": "tax_data",
"locations": [
"https://taxservice.govehub.no.example.com"
],
"actions":"read_tax_declaration",
"periods": ["2018"],
"duration_of_access": 30,
"tax_payer_id": "23674185438934"
}
]
Figure 28: Example of Tax Data Access
The top-level fields have the following meaning:
periods: the periods the client wants to access
duration_of_access: how long the clients intend to access the data
in days
tax_payer_id: identifier of the taxpayer (if known to the client)
A.4. eHealth
These two examples are inspired by requirements for APIs used in the
Norwegian eHealth system.
In this use case, the physical therapist sits in front of their
computer using a local Electronic Health Records (EHR) system. They
want to look at the electronic patient records of a certain patient,
and they also want to fetch the patient's journal entries in another
system, perhaps at another institution or a national service. Access
to this data is provided by an API.
The information necessary to authorize the request at the API is only
known by the EHR system and must be presented to the API.
In the first example, the authorization details object contains the
identifier of an organization. In this case, the API needs to know
if the given organization has the lawful basis for processing
personal health information to give access to sensitive data.
"authorization_details": {
"type": "patient_record",
"requesting_entity": {
"type": "Practitioner",
"identifier": [
{
"system": "urn:oid:2.16.578.1.12.4.1.4.4",
"value": "1234567"
}],
"practitioner_role": {
"organization": {
"identifier": {
"system": "urn:oid:2.16.578.1.12.4.1.2.101",
"type": "ENH",
"value": "[organizational number]"
}
}
}
}
}
Figure 29: eHealth Example
In the second example, the API requires more information to authorize
the request. In this case, the authorization details object contains
additional information about the health institution and the current
profession the user has at the time of the request. The additional
level of detail could be used for both authorization and data
minimization.
[
{
"type": "patient_record",
"location": "https://fhir.example.com/patient",
"actions": [
"read"
],
"patient_identifier": [
{
"system": "urn:oid:2.16.578.1.12.4.1.4.1",
"value": "12345678901"
}
],
"reason_for_request": "Clinical treatment",
"requesting_entity": {
"type": "Practitioner",
"identifier": [
{
"system": "urn:oid:2.16.578.1.12.4.1.4.4",
"value": "1234567"
}
],
"practitioner_role": {
"organization": {
"identifier": [
{
"system": "urn:oid:2.16.578.1.12.4.1.2.101",
"type": "ENH",
"value": "<organizational number>"
}
],
"type": {
"coding": [
{
"system":
"http://hl7.example.org/fhir/org-type",
"code": "dept",
"display": "Hospital Department"
}
]
},
"name": "Akuttmottak"
},
"profession": {
"coding": [
{
"system": "http://snomed.example.org/sct",
"code": "36682004",
"display": "Physical therapist"
}
]
}
}
}
}
]
Figure 30: Advanced eHealth Example
Description of the fields:
patient_identifier: the identifier of the patient composed of a
system identifier in OID format (namespace) and the actual value
within this namespace.
reason_for_request: the reason why the user wants to access a
certain API.
requesting_entity: specification of the requester by means of
identity, role and organizational context. This data is provided
to facilitate authorization and for auditing purposes.
In this use case, the AS authenticates the requester, who is not the
patient, and approves access based on policies.
Acknowledgements
We would like to thank Daniel Fett, Sebastian Ebling, Dave Tonge,
Mike Jones, Nat Sakimura, and Rob Otto for their valuable feedback
during the preparation of this specification.
We would also like to thank Vladimir Dzhuvinov, Takahiko Kawasaki,
Daniel Fett, Dave Tonge, Travis Spencer, Joergen Binningsboe, Aamund
Bremer, Steinar Noem, Francis Pouatcha, Jacob Ideskog, Hannes
Tschofenig, and Aaron Parecki for their valuable feedback to this
specification.
Authors' Addresses
Torsten Lodderstedt
yes.com
Email: torsten@lodderstedt.net
Justin Richer
Bespoke Engineering
Email: ietf@justin.richer.org
Brian Campbell
Ping Identity
Email: bcampbell@pingidentity.com