OAuth 2.0 Rich Authorization Requests
draft-ietf-oauth-rar-03
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (oauth WG) | |
|---|---|---|---|
| Authors | Torsten Lodderstedt , Justin Richer , Brian Campbell | ||
| Last updated | 2020-10-18 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html xml htmlized pdfized bibtex | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-oauth-rar-03
Web Authorization Protocol T. Lodderstedt
Internet-Draft yes.com
Intended status: Standards Track J. Richer
Expires: 21 April 2021 Bespoke Engineering
B. Campbell
Ping Identity
18 October 2020
OAuth 2.0 Rich Authorization Requests
draft-ietf-oauth-rar-03
Abstract
This document specifies a new parameter "authorization_details" that
is used to carry fine grained authorization data in the OAuth
authorization request.
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-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 21 April 2021.
Copyright Notice
Copyright (c) 2020 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 Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Lodderstedt, et al. Expires 21 April 2021 [Page 1]
Internet-Draft oauth-rar October 2020
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions and Terminology . . . . . . . . . . . . . . . 4
2. Request parameter "authorization_details" . . . . . . . . . . 4
2.1. Authorization data elements types . . . . . . . . . . . . 5
2.2. Authorization Data Types . . . . . . . . . . . . . . . . 8
2.3. Relationship to "scope" parameter . . . . . . . . . . . . 9
2.3.1. Scope value "openid" and "claims" parameter . . . . . 9
2.4. Relationship to "resource" parameter . . . . . . . . . . 9
2.4.1. Authorization Request . . . . . . . . . . . . . . . . 10
2.4.2. Token Request . . . . . . . . . . . . . . . . . . . . 10
3. Using "authorization_details" . . . . . . . . . . . . . . . . 12
3.1. Authorization Request . . . . . . . . . . . . . . . . . . 12
3.2. Authorization Request Processing . . . . . . . . . . . . 15
3.3. Token Request . . . . . . . . . . . . . . . . . . . . . . 16
3.4. Token Response . . . . . . . . . . . . . . . . . . . . . 16
3.4.1. Enriched authorization details in Token Response . . 17
3.5. Token Content . . . . . . . . . . . . . . . . . . . . . . 20
3.6. Token Introspection Request . . . . . . . . . . . . . . . 22
3.7. Token Introspection Response . . . . . . . . . . . . . . 22
4. Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5. Implementation Considerations . . . . . . . . . . . . . . . . 24
6. Security Considerations . . . . . . . . . . . . . . . . . . . 24
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 24
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
10. Normative References . . . . . . . . . . . . . . . . . . . . 25
11. Informative References . . . . . . . . . . . . . . . . . . . 26
Appendix A. Additional Examples . . . . . . . . . . . . . . . . 28
A.1. OpenID Connect . . . . . . . . . . . . . . . . . . . . . 28
A.2. Remote Electronic Signing . . . . . . . . . . . . . . . . 29
A.3. Access to Tax Data . . . . . . . . . . . . . . . . . . . 30
A.4. eHealth . . . . . . . . . . . . . . . . . . . . . . . . . 31
Appendix B. Document History . . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35
1. Introduction
The OAuth 2.0 authorization framework [RFC6749] defines the parameter
"scope" that allows OAuth clients to specify the requested scope,
i.e., the permission, 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" but it is not sufficient to specify fine-grained
authorization requirements, such as "please let me make a payment
with the amount of 45 Euros" or "please give me read access to folder
A and write access to file X".
Lodderstedt, et al. Expires 21 April 2021 [Page 2]
Internet-Draft oauth-rar October 2020
This draft introduces a new parameter "authorization_details" that
allows clients to specify their fine-grained authorization
requirements using the expressiveness of JSON data structures.
For example, a request for payment authorization can be represented
using a JSON object like this:
{
"type": "payment_initiation",
"locations": [
"https://example.com/payments"
],
"instructedAmount": {
"currency": "EUR",
"amount": "123.50"
},
"creditorName": "Merchant123",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
This object contains detailed information about the intended payment,
such as amount, currency, and creditor, that are required to inform
the user and obtain her consent. The AS and the respective 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-authorization].
In addition to facilitating custom authorization requests, this draft
also introduces a set of common data type fields for use across
different APIs.
Most notably, the field "locations" allows a client to specify where
it intends to use a certain authorization, i.e., it is now possible
to unambiguously assign permissions to resource servers. In
situations with multiple resource servers, this prevents unintended
client authorizations (e.g. a "read" scope value potentially
applicable for an email as well as a cloud service). In combination
with the "resource" token request parameter as specified in [RFC8707]
it enables the AS to mint RS-specific structured access tokens that
only contain the permissions applicable to the respective RS.
Lodderstedt, et al. Expires 21 April 2021 [Page 3]
Internet-Draft oauth-rar October 2020
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", "resource server", "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.
This example shows the specification of authorization details using
the payment authorization object shown above:
[
{
"type": "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"
}
]
Lodderstedt, et al. Expires 21 April 2021 [Page 4]
Internet-Draft oauth-rar October 2020
This example 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": "Merchant123",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
The JSON objects with "type" fields of "account_information" and
"payment_initiation" represent the different authorization data to be
used by the AS to ask for consent and MUST subsequently also be made
available to the respective resource servers. The array MAY contain
several elements of the same "type".
2.1. Authorization data elements types
The allowable contents of the authorization details object are
determined by the "type" parameter.
Lodderstedt, et al. Expires 21 April 2021 [Page 5]
Internet-Draft oauth-rar October 2020
"type": The type of authorization data as a string. This field MAY
define which other elements are allowed in the request. This
element is REQUIRED.
This field MUST be compared using an exact byte match of the string
value against known types by the AS. The AS MUST ensure that there
is no collision between different authorization data types that it
supports. The AS MUST NOT do any collation or normalization of data
types during comparison.
This draft defines a set of common data elements that are designed to
be usable across different types of APIs. These data elements MAY be
combined in different ways depending on the needs of the API. All
data elements are OPTIONAL.
"locations": An array of strings representing the location of the
resource or resource server. This is typically composed of URIs.
"actions": An array of strings representing the kinds of actions to
be taken at the resource. The values of the strings are
determined by the API being protected.
"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.
When different element types are used in combination, the permissions
the client requests is the cartesian product of the values. In the
following example
[
{
"type": "customer_information",
"locations": [
"https://example.com/customers",
]
"actions": [
"read",
"write"
],
"datatypes": [
"contacts",
"photos"
]
}
]
Lodderstedt, et al. Expires 21 April 2021 [Page 6]
Internet-Draft oauth-rar October 2020
the client is requesting read and write access to both the contacts
and photos belonging to customers in a customer information API. If
the client wishes to have finer control over its access, it can send
multiple objects. For example:
[
{
"type": "customer_information",
"locations": [
"https://example.com/customers"
],
"actions": [
"read"
],
"datatypes": [
"contacts"
]
},
{
"type": "customer_information",
"locations": [
"https://example.com/customers"
],
"actions": [
"write"
],
"datatypes": [
"photos"
]
}
]
The client is asking for read access to the contacts and write access
to the photos in the same API endpoint.
An API MAY define its own extensions, subject to the "type" of the
respective authorization object. It is assumed that the full
structure of each of the authorization objects is tailored to the
needs of a certain application, API, or resource type, and can
contain a mix of general-purpose and api-specific elements within the
structure. The example structures shown above are based on certain
kinds of APIs that can be found in the Open Banking space.
Lodderstedt, et al. Expires 21 April 2021 [Page 7]
Internet-Draft oauth-rar October 2020
2.2. Authorization Data Types
Interpretation of the value of the "type" parameter, and the object
elements that the "type" parameter allows, is under the control of
the AS. 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 depending than what the AS has
defined. Possible means of reducing potential confusion are limiting
the value to ASCII characters, providing a machine-readable listing
of data type values, or instructing developers to copy and paste
directly from 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
element names.
{
"type": "https://scheme.example.org/files",
"locations": [
"https://example.com/files"
],
"permissions": [
{
"path": "/myfiles/A",
"access": [
"read"
]
},
{
"path": "/myfiles/A/X",
"access": [
"read",
"write"
]
}
]
}
Lodderstedt, et al. Expires 21 April 2021 [Page 8]
Internet-Draft oauth-rar October 2020
2.3. Relationship to "scope" parameter
"authorization_details" and "scope" can be used in the same
authorization request for carrying independent authorization
requirements.
The AS MUST consider 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.
It is RECOMMENDED that a given API use only one form of requirement
specification.
When gathering user consent, the AS MUST present the merged set of
requirements represented by the authorization request.
2.3.1. Scope value "openid" and "claims" parameter
OpenID Connect [OIDC] specifies the JSON-based "claims" request
parameter that can be used to specify the claims a client (acting as
OpenID Connect Relying Party) wishes to receive in a fine-grained and
privacy preserving way as well as assign those claims to a 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 data type for OpenID
Connect. Appendix A.1 gives an example of how such an authorization
data type could look like.
2.4. Relationship to "resource" parameter
The request parameter "resource" as defined in [RFC8707] indicates to
the AS the resource(s) where the client intends to use the access
tokens issued based on a certain grant. This mechanism is a way to
audience-restrict access tokens and to allow the AS to create
resource server specific access tokens. The "authorization_details"
parameter also allows the client to designate the audience of a
certain authorization details object in the respective "locations"
element.
This specification allows a client to use both parameters together in
an authorization request, and it defines how the "resource" parameter
in the token request can be used to assign authorization details to a
certain access token.
Lodderstedt, et al. Expires 21 April 2021 [Page 9]
Internet-Draft oauth-rar October 2020
If used together, the "locations" element within objects of the
"authorization_details" parameter overrides the value of the
"resources" parameter. In the absence of a "locations" element, the
value of the "resources" parameter is applied to the object.
2.4.1. Authorization Request
If a client uses "authorization_details" with "locations" elements
and the "resource" parameter in the same authorization request, the
meaning is as follows:
* for every authorization details object containing a "locations"
element, the intended audience is defined by the "locations"
element only. The "resource" parameter value is not applied.
* for every authorization details object not containing a
"locations" element, this authorization details object is bound to
the audience(s) defined by the "resource" parameter.
The authorization server will consider this audience restriction in
the user consent if needed.
2.4.2. Token Request
If a client uses the "resource" parameter in a token requests, the AS
MUST utilize the data provided in the "locations" elements to filter
the authorization data objects applicable to the respective
resource(s).
The logic is as follows:
* For every authorization details object without a "locations"
element: the authorization server treats it as applicable to all
resources, i.e. it assigns this authorization details object to
the access token.
* For every authorization details object with a "locations" element:
the authorization server adds this object to the access token, if
at least one of the "locations" values exactly matches the
"resource" parameter value. The authorization server MUST compare
both values using an exact byte match of the string values.
This shall be illustrated using an example.
The client has sent an authorization request using the following
example authorization details.
Lodderstedt, et al. Expires 21 April 2021 [Page 10]
Internet-Draft oauth-rar October 2020
[
{
"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": "Merchant123",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
If this client then sends the following token request to the AS,
POST /token HTTP/1.1
Host: as.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&code=SplxlOBeZQQYbYS6WxSbIA
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
&resource=https%3A%2F%2Fexample%2Ecom%2Fpayments
that contains a resource parameter with the value of
"https://example.com/payments", this value will be matched against
the locations elements ("https://example.com/accounts" and
Lodderstedt, et al. Expires 21 April 2021 [Page 11]
Internet-Draft oauth-rar October 2020
"https://example.com/payments") and will select the element of type
"payment_initiation" for inclusion in the access token as illustrated
by the following example JWT content.
{
"iss": "https://as.example.com",
"sub": "24400320",
"aud": "a7AfcPcsl2",
"exp": 1311281970,
...
"authorization_details": [
{
"type": "https://www.someorg.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"
}
],
...
}
3. Using "authorization_details"
3.1. Authorization Request
The 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],
* Access token requests as specified in [RFC6749], if also used as
authorization requests, e.g. in the case of assertion grant types
[RFC7521],
Lodderstedt, et al. Expires 21 April 2021 [Page 12]
Internet-Draft oauth-rar October 2020
* Request objects as specified in [I-D.ietf-oauth-jwsreq],
* Device Authorization Request as specified in [RFC8628],
* Backchannel Authentication Requests as defined in [OpenID.CIBA].
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 the following
example:
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%5Finformati
on%22%2C%22actions%22%3A%5B%22list%5Faccounts%22%2C%22read%5Fbal
ances%22%2C%22read%5Ftransactions%22%5D%2C%22locations%22%3A%5B%
22https%3A%2F%2Fexample%2Ecom%2Faccounts%22%5D%7D%5D HTTP/1.1
Host: server.example.com
Implementors MUST ensure to protect personal identifiable information
in transit. One way is to utilize encrypted request objects as
defined in [I-D.ietf-oauth-jwsreq]. In the context of a request
object, "authorization_details" is added as another top level JSON
element.
Lodderstedt, et al. Expires 21 April 2021 [Page 13]
Internet-Draft oauth-rar October 2020
{
"iss": "s6BhdRkqt3",
"aud": "https://server.example.com",
"response_type": "code",
"client_id": "s6BhdRkqt3",
"redirect_uri": "https://client.example.com/cb",
"state": "af0ifjsldkj",
"code_challenge_method": "S256",
"code_challenge": "K2-ltc83acc4h0c9w6ESC_rEMTJ3bwc-uCHaoeK1t8U",
"authorization_details": [
{
"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": "Merchant123",
"creditorAccount": {
"iban": "DE02100100109307118603"
},
"remittanceInformationUnstructured": "Ref Number Merchant"
}
]
}
Authorization request URIs containing authorization details in a
request parameter or a request object can become very long.
Implementers SHOULD therefore consider using the "request_uri"
parameter as defined in [I-D.ietf-oauth-jwsreq] in combination with
Lodderstedt, et al. Expires 21 April 2021 [Page 14]
Internet-Draft oauth-rar October 2020
the pushed request object mechanism as defined in
[I-D.ietf-oauth-par] 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 a 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
3.2. Authorization Request Processing
Based on the data provided in the "authorization_details" parameter
the AS will ask the user for consent to the requested access
permissions.
The AS MUST refuse to process any unknown authorization data type or
authorization details not conforming to the respective type
definition. If any of the objects in "authorization_details"
contains an unknown authorization data type or an object of known
type but containing unknown elements or elements of the wrong type,
the AS MUST abort processing and respond with an error
"invalid_authorization_details" to the client.
Note: If the authorization request also contained the "scope"
parameter, the AS MUST present the merged set of requirements
represented by the authorization request in the user consent.
Lodderstedt, et al. Expires 21 April 2021 [Page 15]
Internet-Draft oauth-rar October 2020
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).
Note: The AS MUST make the "authorization_details" available to the
respective resource servers. The AS MAY add the
"authorization_details" element to access tokens in JWT format and to
Token Introspection responses (see below).
3.3. Token Request
Clients utilizing authorization details are RECOMMENDED to use the
"resource" token request parameter to allow the AS to issue audience
restricted access tokens as recommended in
[I-D.ietf-oauth-security-topics].
For example the following token request selects authorization details
applicable for the resource server represented by the URI
"https://example.com/payments".
POST /token HTTP/1.1
Host: as.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&code=SplxlOBeZQQYbYS6WxSbIA
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
&resource=https%3A%2F%2Fexample%2Ecom%2Fpayments
3.4. Token Response
In addition to the token response parameters as defined in [RFC6749],
the authorization server MUST also return the authorization details
as granted by the resource owner and assigned to the respective
access token.
This is shown in the following example:
Lodderstedt, et al. Expires 21 April 2021 [Page 16]
Internet-Draft oauth-rar October 2020
HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-cache, no-store
{
"access_token": "2YotnFZFEjr1zCsicMWpAA",
"token_type": "example",
"expires_in": 3600,
"refresh_token": "tGzv3JOkF0XG5Qx2TlKWIA",
"authorization_details": [
{
"type": "https://www.someorg.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"
}
]
}
3.4.1. 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 use cases where the
authorization server enriches the data in an authorization details
object. For example, a client may ask for access to account
information but leave the decision about the accounts it will be able
to access to the user. The user would select the sub set of accounts
she wants the client to entitle to access in the course of the
authorization process. In order to allow the client to determine the
accounts it is entitled to access, the authorization server will add
this information to the respective authorization details object.
Lodderstedt, et al. Expires 21 April 2021 [Page 17]
Internet-Draft oauth-rar October 2020
As an example, the requested authorization detail parameter could
look like this:
"authorization_details": [
{
"type": "account_information",
"access": {
"accounts": [],
"balances": [],
"transactions": []
},
"recurringIndicator":true
}
]
The authorization server then would expand the authorization details
object and add the respective account identifiers.
Lodderstedt, et al. Expires 21 April 2021 [Page 18]
Internet-Draft oauth-rar October 2020
HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-cache, 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
}
]
}
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.
Lodderstedt, et al. Expires 21 April 2021 [Page 19]
Internet-Draft oauth-rar October 2020
{
"authorization_details": [
{
"type": "medical_record",
"sens": [ "HIV", "ETH", "MART" ],
"actions": [ "read" ],
"datatypes": [ "Patient", "Observation", "Appointment" ]
}
]
When the user interacts with the AS, they select which of the medical
records they are responsible for to give 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/" ]
}
]
}
Note: the client needs to be aware upfront of the possibility that a
certain authorization details object can be enriched. It is assumned
that this property is part of the definition of the respective
authorization details type.
3.5. Token Content
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.
If the access token is a JWT [RFC7519], the AS is RECOMMENDED to add
the "authorization_details" object, filtered to the specific
audience, as top-level claim.
Lodderstedt, et al. Expires 21 April 2021 [Page 20]
Internet-Draft oauth-rar October 2020
The AS will typically also add further claims to the JWT the RS
requires for 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
initation 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://www.someorg.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"
}
}
In this case, the AS added the following example claims:
* "sub": conveys the user on which behalf the client is asking for
payment initation
Lodderstedt, et al. Expires 21 April 2021 [Page 21]
Internet-Draft oauth-rar October 2020
* "txn": transaction id used to trace the transaction across the
services of provider "example.com"
* "debtorAccount": API-specific element containing the debtor
account. In the example, this account was not passed in the
authorization details but selected by the user during the
authorization process. The field "user_role" conveys the role the
user has with respect to this particuar account. In this case,
she is the owner. This data is used for access control at the
payment API (the RS).
3.6. Token Introspection Request
In case of opaque access tokens, the data provided to a certain RS is
determined using the RS's identifier with the AS (see
[I-D.ietf-oauth-jwt-introspection-response], section 3).
3.7. Token Introspection Response
The token endpoint response provides the RS with the authorization
details applicable to it as a top-level JSON element along with the
claims the RS requires for request processing.
Here is an example for the payment initation example RS:
Lodderstedt, et al. Expires 21 April 2021 [Page 22]
Internet-Draft oauth-rar October 2020
{
"active": true,
"sub": "24400320",
"aud": "s6BhdRkqt3",
"exp": 1311281970,
"acr": "psd2_sca",
"txn": "8b4729cc-32e4-4370-8cf0-5796154d1296",
"authorization_details": [
{
"type": "https://www.someorg.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"
}
}
4. Metadata
The AS advertises support for "authorization_details" using the
metadata parameter "authorization_details_supported" of type boolean.
The authorization data types supported can be determined using the
metadata parameter "authorization_data_types_supported", which is an
JSON array.
Clients announce the authorization data types they use in the new
dynamic client registration parameter "authorization_data_types".
Lodderstedt, et al. Expires 21 April 2021 [Page 23]
Internet-Draft oauth-rar October 2020
The registration of new authorization data types with the AS is out
of scope of this draft.
5. Implementation Considerations
The scheme and processing will vary significantly among different
authorization data types. Any implementation of this draft is
therefore supposed to allow the customization of the user consent and
the handling of access token data.
One option 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 resource server by way of structured access tokens
or token introspection responses.
6. Security Considerations
Authorization details are sent through the user agent in case of an
OAuth authorization request, which makes them vulnerable to
modifications by the user. In order to ensure their integrity, the
client SHOULD send authorization details in a signed request object
as defined in [I-D.ietf-oauth-jwsreq] or use the "request_uri"
authorization request parameter as defined in [I-D.ietf-oauth-jwsreq]
to pass the URI of the request object to the authorization server.
All strings MUST be compared using the exact byte representation of
the characters as defined by [RFC8259]. This is especially true for
the "type" field, which dictates which other fields and functions are
allowed in the request. The server MUST NOT perform any form of
collation, transformation, or equivalence on the string values.
7. Privacy Considerations
Implementers MUST 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 [I-D.ietf-oauth-jwsreq] or transmission of authorization details
via end-to-end encrypted connections between client and authorization
server by utilizing the "request_uri" authorization request parameter
as defined in [I-D.ietf-oauth-jwsreq].
Even if the request data is encrypted, an attacker could use the
authorization server to learn the user data by injecting the
encrypted request data into an authorization request on a device
Lodderstedt, et al. Expires 21 April 2021 [Page 24]
Internet-Draft oauth-rar October 2020
under his control and use the authorization server's user consent
screens to show the (decrypted) user data in the clear.
Implementations MUST consider this attacker vector and implement
appropriate counter measures, e.g. by only showing portions of the
data or, if possible, determing whether the assumed user context is
still the same (after user authentication).
The AS MUST take into consideration the privacy implications when
sharing authorization details with the resource servers. The AS
SHOULD share this data with the resource servers on a "need to know"
basis.
8. Acknowledgements
We would 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 draft.
We would also like to thank Vladimir Dzhuvinov, Takahiko Kawasaki,
Daniel Fett, Dave Tonge, Travis Spencer, Jørgen Binningsbø,
Aamund Bremer, Steinar Noem, and Aaron Parecki for their valuable
feedback to this draft.
9. IANA Considerations
TBD
* "authorization_details" as JWT claim
* "authorization_details_supported" and
"authorization_data_types_supported" as metadata parameters
* "authorization_data_types" as dynamic client registration
parameter
* [[ possibly establish authorization data type registry (and
declare: "type", "actions", "locations", "datatypes",
"identifier", others?) ]]
* [[ register type "openid_claims" on a URL by the OpenID
foundation? ]]
* register invalid_authorization_details to OAuth Extensions Error
Registry
10. Normative References
Lodderstedt, et al. Expires 21 April 2021 [Page 25]
Internet-Draft oauth-rar October 2020
[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>.
[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>.
[RFC7521] Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
"Assertion Framework for OAuth 2.0 Client Authentication
and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521,
May 2015, <https://www.rfc-editor.org/info/rfc7521>.
[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>.
[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>.
[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>.
[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>.
11. Informative References
[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,
<http://openid.net/specs/openid-connect-core-1_0.html>.
[I-D.ietf-oauth-jwt-introspection-response]
Lodderstedt, T. and V. Dzhuvinov, "JWT Response for OAuth
Token Introspection", Work in Progress, Internet-Draft,
draft-ietf-oauth-jwt-introspection-response-09, 25 April
2020, <https://tools.ietf.org/html/draft-ietf-oauth-jwt-
introspection-response-09>.
Lodderstedt, et al. Expires 21 April 2021 [Page 26]
Internet-Draft oauth-rar October 2020
[CSC] Consortium, C. S., "Architectures and protocols for remote
signature applications", 1 June 2019,
<https://cloudsignatureconsortium.org/wp-
content/uploads/2019/07/CSC_API_V1_1.0.4.0.pdf>.
[OpenID.CIBA]
Fernandez, G., Walter, F., Nennker, A., Tonge, D., and B.
Campbell, "OpenID Connect Client Initiated Backchannel
Authentication Flow - Core 1.0", 16 January 2019,
<https://openid.net/specs/openid-client-initiated-
backchannel-authentication-core-1_0.html>.
[I-D.ietf-oauth-par]
Lodderstedt, T., Campbell, B., Sakimura, N., Tonge, D.,
and F. Skokan, "OAuth 2.0 Pushed Authorization Requests",
Work in Progress, Internet-Draft, draft-ietf-oauth-par-04,
18 September 2020,
<https://tools.ietf.org/html/draft-ietf-oauth-par-04>.
[ETSI] ETSI, "ETSI TS 119 432, Electronic Signatures and
Infrastructures (ESI); Protocols for remote digital
signature creation", 20 March 2019,
<https://www.etsi.org/deliver/
etsi_ts/119400_119499/119432/01.01.01_60/
ts_119432v010101p.pdf>.
[I-D.ietf-oauth-security-topics]
Lodderstedt, T., Bradley, J., Labunets, A., and D. Fett,
"OAuth 2.0 Security Best Current Practice", Work in
Progress, Internet-Draft, draft-ietf-oauth-security-
topics-16, 5 October 2020, <https://tools.ietf.org/html/
draft-ietf-oauth-security-topics-16>.
[transaction-authorization]
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>.
[I-D.ietf-oauth-jwsreq]
Sakimura, N., Bradley, J., and M. Jones, "The OAuth 2.0
Authorization Framework: JWT Secured Authorization Request
(JAR)", Work in Progress, Internet-Draft, draft-ietf-
oauth-jwsreq-30, 10 September 2020,
<https://tools.ietf.org/html/draft-ietf-oauth-jwsreq-30>.
Lodderstedt, et al. Expires 21 April 2021 [Page 27]
Internet-Draft oauth-rar October 2020
[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>.
Appendix A. Additional Examples
A.1. OpenID Connect
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 elements are based on the definitions given in [OIDC]:
* "claim_sets": names of predefined claim sets, replacement for
respective scope values, such as "profile"
* "max_age": Maximum Authentication Age
* "acr_values": array of 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"
]
}
]
Note: "locations" specifies the location of the userinfo endpoint
since this is the only place where an access token is used by a
client (RP) in OpenID Connect to obtain claims.
A more sophisticated example is shown in the following
Lodderstedt, et al. Expires 21 April 2021 [Page 28]
Internet-Draft oauth-rar October 2020
[
{
"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.info/claims/groups": null
},
"id_token": {
"auth_time": {
"essential": true
}
}
}
}
]
A.2. Remote Electronic Signing
The following example is based on the concept layed out for remote
electronic signing in ETSI TS 119 432 [ETSI] and the CSC API for
remote signature creation [CSC].
Lodderstedt, et al. Expires 21 April 2021 [Page 29]
Internet-Draft oauth-rar October 2020
[
{
"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"
}
]
The top-level elements 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" elements). Additionally, the corresponding
"label" element identifies the respective document to the user,
e.g. to be used in user consent.
* "hashAlgorithm": algomrithm that was used to calculate the hash
values.
The AS is supposed to ask the user for consent for the creation of
signatues for the documents listed in the structure. The client uses
the access token issued as result of the process to call the sign doc
endpoint 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 credit worthiness.
Lodderstedt, et al. Expires 21 April 2021 [Page 30]
Internet-Draft oauth-rar October 2020
[
{
"type": "tax_data",
"locations": [
"https://taxservice.govehub.no"
],
"actions":"read_tax_declaration",
"periods": ["2018"],
"duration_of_access": 30,
"tax_payer_id": "23674185438934"
}
]
The top-level elements have the following meaning:
* "periods": determines the periods the client wants to access
* "duration_of_access": how long does the client intend to access
the data in days
* "tax_payer_id": identifier of the tax payer (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 her computer
using a local Electronic Health Records (EHR) system. She wants to
look at the electronic patient records of a certain patient and she
also wants to fetch the patients 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.
Lodderstedt, et al. Expires 21 April 2021 [Page 31]
Internet-Draft oauth-rar October 2020
"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]"
}
}
}
}
}
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"
Lodderstedt, et al. Expires 21 April 2021 [Page 32]
Internet-Draft oauth-rar October 2020
}
],
"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.org/fhir/organization-type",
"code": "dept",
"display": "Hospital Department"
}
]
},
"name": "Akuttmottak"
},
"profession": {
"coding": [
{
"system": "http://snomed.info/sct",
"code": "36682004",
"display": "Physical therapist"
}
]
}
}
}
}
]
Description of the elements:
* "patient_identifier": the identifier of the patient composed of a
system identifier in OID format (namespace) and the acutal value
within this namespace.
* "reason_for_request": the reason why the user wants to access a
certain API
Lodderstedt, et al. Expires 21 April 2021 [Page 33]
Internet-Draft oauth-rar October 2020
* "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.
Appendix B. Document History
[[ To be removed from the final specification ]]
-03
* Updated referenes to current revisions or RFC numbers
* Added section about enrichment of authorization details objects by
the AS
* Clarified processing of unknown authorization details parameters
* clarified dependencies between "resource" and
"authorization_details" parameters
-02
* Clarify "type" parameter processing
-01
* Minor fix-up in a few examples
-00 (WG draft)
* initial WG revision
-03
* Reworked examples to illustrate privacy preserving use of
"authorization_details"
* Added text on audience restriction
* Added description of relationship between "scope" and
"authorization_details"
* Added text on token request & response and "authorization_details"
Lodderstedt, et al. Expires 21 April 2021 [Page 34]
Internet-Draft oauth-rar October 2020
* Added text on how authorization details are conveyed to RSs by
JWTs or token endpoint response
* Added description of relationship between "claims" and
"authorization_details"
* Added more example from different sectors
* Clarified string comparison to be byte-exact without collation
-02
* Added Security Considerations
* Added Privacy Considerations
* Added notes on URI size and authorization details
* Added requirement to return the effective authorization details
granted by the resource owner in the token response
* changed "authorization_details" structure from object to array
* added Justin Richer & Brian Campbell as Co-Authors
-00 / -01
* first draft
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
Lodderstedt, et al. Expires 21 April 2021 [Page 35]