Internet-Draft | oauth-rar | September 2021 |
Lodderstedt, et al. | Expires 16 March 2022 | [Page] |
- Workgroup:
- Web Authorization Protocol
- Internet-Draft:
- draft-ietf-oauth-rar-07
- Published:
- Intended Status:
- Standards Track
- Expires:
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 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 16 March 2022.¶
Copyright Notice
Copyright (c) 2021 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.¶
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 transfer an amount of 45 Euros to Merchant A"
or "please give me read access to folder A and write access to file X".¶
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, 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": { "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] or by specifying authorization details with a single location only in the token request, it enables the AS to issue RS-specific structured access tokens that only contain the permissions applicable to the respective RS.¶
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": "Merchant A", "creditorAccount": { "iban": "DE02100100109307118603" }, "remittanceInformationUnstructured": "Ref Number Merchant" } ]¶
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": "Merchant A", "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
.¶
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:¶
-
Backchannel Authentication Requests as defined in [OpenID.CIBA].¶
In case of a authorization requests as defined in [RFC6749], implementors MAY consider to use pushed authorization requests [I-D.ietf-oauth-par] to improve to security, privacy, and reliability of the flow. See Section 13, Section 14, and Section 12.4 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 the following 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%22remittance InformationUnstructured%22%3A%22RefNumberMerchant%22%7D%5D HTTP/1.1 Host: server.example.com¶
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 this example, the client wants to get access to account information and intiate 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" } ]¶
3.1. 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 uses only one form of requirement 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 "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.¶
5. Authorization Error Response
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 or elements
with invalid values or if required elements are missing, the AS MUST abort processing and respond with an error invalid_authorization_details
to the client.¶
6. Token Request
The authorization_details
token request parameter can be used to specify the authorization details 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
, ...) or the client's policy (in case of grant type client_credential
) 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
).¶
7. 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.¶
The authorization details assigned to the access token issued in a token response are determined by the authorization_detail
parameter of the corresponding token request. If the client does not specify the authorization_detail
token request parameters, the AS determines the resulting authorization details at its discretion. The authorization server MAY consider the values of other parameters such as resource
and scope
if they are present during this processing, and the details of such considerations are outside the scope of this specification.¶
The AS MAY omit values in the authorization_details
to the client in the token Response if these are deemed of no intended use for the client.¶
For our running example, this would look like this:¶
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": "Merchant A", "creditorAccount": { "iban": "DE02100100109307118603" }, "remittanceInformationUnstructured": "Ref Number Merchant" } ] }¶
8. Token Error Response
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
, elements
with invalid values, or if required elements are missing, the AS MUST abort processing and respond with an error invalid_authorization_details
to the client.¶
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
element to access tokens in 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 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 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://www.someorg.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" } }¶
In this case, the AS added the following example claims:¶
-
sub
: conveys the user on which behalf the client is asking for payment initation¶ -
txn
: transaction id used to trace the transaction across the services of providerexample.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 fielduser_role
conveys the role the user has with respect to this particular account. In this case, they is the owner. This data is used for access control at the payment API (the RS).¶
9.2. Token Introspection
In the 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).¶
The token introspection 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 initiation example RS:¶
{ "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" } }¶
10. Metadata
The AS publishes the list of authorization details types it supports using the metadata parameter authorization_details_types_supported
, which is a JSON array.¶
Clients announce the authorization data types they use in the new dynamic client registration parameter authorization_details_types
.¶
The registration of authorization data types with the AS is out of scope of this draft.¶
11. 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 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 what such an authorization data type could look like.¶
12. Implementation Considerations
12.2. Minimal product support
Products supporting this specification should provide the following basic functions:¶
-
Support advertisement of supported authorization details types in OAuth server metadata¶
-
Accept
authorization_details
parameter in authorization requests including basic syntax check for compliance 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 resource servers (similar to scope values). This should work with any grant type, especially
authorization_code
andrefresh_token
.¶
Processing and presentation of authorization details will vary significantly among different authorization data types. Products should therefore support customization of the respective behavior. In particular, products should¶
-
allow deployments to determine presentation of the authorization details¶
-
allow deployments to modify requested authorization details in the user consent process, e.g. adding fields¶
-
allow deployments to merge requested and pre-existing authorization details¶
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.¶
12.3. Use of Machine-readable Type Schemas
Products 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 id 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 point to a machine-readable schema format, or that any party in the system (such as the client, AS, or RS) dereference or process the contents of the type
field in any specific way.¶
12.4. Large requests
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 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¶
13. 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] in conjunction with [I-D.ietf-oauth-par] 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.¶
14. 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 [I-D.ietf-oauth-par] and 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 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 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 MUST take into consideration the privacy implications when sharing authorization details with the client or resource servers. The AS SHOULD share this data with those parties on a "need to know" basis.¶
15. 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 draft.¶
We would also like to thank Vladimir Dzhuvinov, Takahiko Kawasaki, Daniel Fett, Dave Tonge, Travis Spencer, Jørgen Binningsbø, Aamund Bremer, Steinar Noem, Francis Pouatcha, Jacob Ideskog, and Aaron Parecki for their valuable feedback to this draft.¶
16. IANA Considerations
16.1. JSON Web Token Claims Registration
This specification requests registration of the following value in the IANA "JSON Web Token Claims Registry" established by [RFC7519].¶
- Claim Name:
-
authorization_details
¶ - Claim Description:
-
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.¶ - Change Controller:
-
IESG¶
- Specification Document(s):
16.3. OAuth Dynamic Client Registration Metadata
This specification requests registration of the following value in the IANA "OAuth Dynamic Client Registration Metadata" registry of [IANA.OAuth.Parameters] established by [RFC7591].¶
- Metadata Name:
-
authorization_details_types
¶ - Metadata Description:
-
Indicates what authorization details types the client uses.¶
- Change Controller:
-
IESG¶
- Specification Document(s):
-
Section 10 of [[ this document ]]¶
16.4. OAuth Extensions Error registry
This specification requests registration of the following value in the IANA "OAuth Extensions Error registry" registry of [IANA.OAuth.Parameters] established by [RFC6749].¶
17. Normative References
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [RFC8414]
- Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0 Authorization Server Metadata", RFC 8414, DOI 10.17487/RFC8414, , <https://www.rfc-editor.org/info/rfc8414>.
- [RFC8707]
- Campbell, B., Bradley, J., and H. Tschofenig, "Resource Indicators for OAuth 2.0", RFC 8707, DOI 10.17487/RFC8707, , <https://www.rfc-editor.org/info/rfc8707>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
- [RFC8628]
- Denniss, W., Bradley, J., Jones, M., and H. Tschofenig, "OAuth 2.0 Device Authorization Grant", RFC 8628, DOI 10.17487/RFC8628, , <https://www.rfc-editor.org/info/rfc8628>.
- [RFC7519]
- Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, , <https://www.rfc-editor.org/info/rfc7519>.
18. Informative References
- [RFC6749]
- Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, , <https://www.rfc-editor.org/info/rfc6749>.
- [OIDC]
- Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, "OpenID Connect Core 1.0 incorporating errata set 1", , <http://openid.net/specs/openid-connect-core-1_0.html>.
- [RFC8259]
- Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, , <https://www.rfc-editor.org/info/rfc8259>.
- Lodderstedt, T., "Transaction Authorization or why we need to re-think OAuth scopes", , <https://medium.com/oauth-2/transaction-authorization-or-why-we-need-to-re-think-oauth-scopes-2326e2038948>.
- [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-10, , <https://datatracker.ietf.org/doc/html/draft-ietf-oauth-par-10>.
- [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-12, , <https://datatracker.ietf.org/doc/html/draft-ietf-oauth-jwt-introspection-response-12>.
- [ETSI]
- ETSI, "ETSI TS 119 432, Electronic Signatures and Infrastructures (ESI); Protocols for remote digital signature creation", , <https://www.etsi.org/deliver/etsi_ts/119400_119499/119432/01.01.01_60/ts_119432v010101p.pdf>.
- [JSON.Schema]
- json-schema.org, "JSON Schema", <https://json-schema.org/>.
- [I-D.ietf-oauth-jwsreq]
- Sakimura, N., Bradley, J., and M. B. Jones, "The OAuth 2.0 Authorization Framework: JWT-Secured Authorization Request (JAR)", Work in Progress, Internet-Draft, draft-ietf-oauth-jwsreq-34, , <https://datatracker.ietf.org/doc/html/draft-ietf-oauth-jwsreq-34>.
- [IANA.OAuth.Parameters]
- IANA, "OAuth Parameters", <http://www.iana.org/assignments/oauth-parameters>.
- [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, , <https://www.rfc-editor.org/info/rfc7591>.
- [OpenID.CIBA]
- Fernandez, G., Walter, F., Nennker, A., Tonge, D., and B. Campbell, "OpenID Connect Client Initiated Backchannel Authentication Flow - Core 1.0", , <https://openid.net/specs/openid-client-initiated-backchannel-authentication-core-1_0.html>.
- [CSC]
- Consortium, C. S., "Architectures and protocols for remote signature applications", , <https://cloudsignatureconsortium.org/wp-content/uploads/2019/07/CSC_API_V1_1.0.4.0.pdf>.
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 asprofile
¶ -
max_age
: Maximum Authentication Age¶ -
acr_values
: array of ACR values¶
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¶
[ { "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 laid out for remote electronic signing in ETSI TS 119 432 [ETSI] and the 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" } ]¶
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 correspondinglabel
element 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 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 creditworthiness.¶
[ { "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:¶
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. They want to look at the electronic patient records of a certain patient and they also want 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.¶
"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" } ], "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 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.¶
Appendix B. Document History
[[ To be removed from the final specification ]]¶
-07¶
-
incorporated review feedback from WGLC¶
-
fixed wording in token introspection section¶
-
added privacy considerations re authorization details in token response¶
-06¶
-
removed use of resource indicators to filter authorization details in token response¶
-05¶
-
added
authorization_details
token request parameter and discussion on authorization details comparison¶ -
added
privileges
field to authorization details (to align with GNAP)¶ -
added IANA text and changed metadata parameter names¶
-
added text about use of machine-readable type schemas, e.g JSON Schema¶
-
added text on how authorization details are determined for access token issued with token response¶
-
added token error response and further error conditions to authorization error response¶
-04¶
-
restructured draft for better readability¶
-
simplified normative text about use of the
resource
parameter withauthorization_details
¶ -
added implementation considerations for deployments and products¶
-
added type union language from GNAP¶
-
added recommendation to use PAR to cope with large requests and for request protection¶
-03¶
-
Updated references 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
andauthorization_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
andauthorization_details
¶ -
Added text on token request & response and
authorization_details
¶ -
Added text on how authorization details are conveyed to RSs by JWTs or token introspection endpoint response¶
-
Added description of relationship between
claims
andauthorization_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¶