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Versions: 00 01 02 03 04 05                                             
Web Authorization Protocol                                T. Lodderstedt
Internet-Draft                                                   yes.com
Intended status: Standards Track                               J. Richer
Expires: 16 November 2021                            Bespoke Engineering
                                                             B. Campbell
                                                           Ping Identity
                                                             15 May 2021


                 OAuth 2.0 Rich Authorization Requests
                        draft-ietf-oauth-rar-05

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 November 2021.

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.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Conventions and Terminology . . . . . . . . . . . . . . .   4
   2.  Request parameter "authorization_details" . . . . . . . . . .   4
     2.1.  Authorization data elements types . . . . . . . . . . . .   6
     2.2.  Authorization Data Types  . . . . . . . . . . . . . . . .  10
   3.  Authorization Request . . . . . . . . . . . . . . . . . . . .  11
     3.1.  Relationship to "scope" parameter . . . . . . . . . . . .  13
     3.2.  Relationship to "resource" parameter  . . . . . . . . . .  14
   4.  Authorization Response  . . . . . . . . . . . . . . . . . . .  14
   5.  Authorization Error Response  . . . . . . . . . . . . . . . .  14
   6.  Token Request . . . . . . . . . . . . . . . . . . . . . . . .  14
     6.1.  Comparing authorization details . . . . . . . . . . . . .  15
     6.2.  Interaction with the resource parameter . . . . . . . . .  17
   7.  Token Response  . . . . . . . . . . . . . . . . . . . . . . .  18
     7.1.  Enriched authorization details in Token Response  . . . .  19
   8.  Token Error Response  . . . . . . . . . . . . . . . . . . . .  22
   9.  Resource Servers  . . . . . . . . . . . . . . . . . . . . . .  23
     9.1.  JWT-based Access Tokens . . . . . . . . . . . . . . . . .  23
     9.2.  Token Introspection . . . . . . . . . . . . . . . . . . .  25
   10. Metadata  . . . . . . . . . . . . . . . . . . . . . . . . . .  26
   11. Scope value "openid" and "claims" parameter . . . . . . . . .  27
   12. Implementation Considerations . . . . . . . . . . . . . . . .  27
     12.1.  Using authorization details in a certain deployment  . .  27
     12.2.  Minimal product support  . . . . . . . . . . . . . . . .  27
     12.3.  Use of Machine-readable Type Schemas . . . . . . . . . .  28
     12.4.  Large requests . . . . . . . . . . . . . . . . . . . . .  29
   13. Security Considerations . . . . . . . . . . . . . . . . . . .  30
   14. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  30
   15. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  31
   16. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  31
     16.1.  JSON Web Token Claims Registration . . . . . . . . . . .  31
     16.2.  OAuth Authorization Server Metadata  . . . . . . . . . .  31
     16.3.  OAuth Dynamic Client Registration Metadata . . . . . . .  31
     16.4.  OAuth Extensions Error registry  . . . . . . . . . . . .  32
   17. Normative References  . . . . . . . . . . . . . . . . . . . .  32
   18. Informative References  . . . . . . . . . . . . . . . . . . .  32
   Appendix A.  Additional Examples  . . . . . . . . . . . . . . . .  34
     A.1.  OpenID Connect  . . . . . . . . . . . . . . . . . . . . .  34
     A.2.  Remote Electronic Signing . . . . . . . . . . . . . . . .  36
     A.3.  Access to Tax Data  . . . . . . . . . . . . . . . . . . .  37
     A.4.  eHealth . . . . . . . . . . . . . . . . . . . . . . . . .  38
   Appendix B.  Document History . . . . . . . . . . . . . . . . . .  41
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  43






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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".

   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.



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   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 specifing authorization details with a single location only in
   the token request, it enables the AS to mint 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:















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   [
      {
         "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"
      }
   ]

   This example shows a combined request asking for access to account
   information and permission to initiate a payment:


























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   [
      {
         "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.

   "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.



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   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.

   The value of the "type" field determines the allowable contents of
   the object which contains it.  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
   for use by a given API definition.  The allowable values of all
   elements are determined by the API being protected.

   "locations":  An array of strings representing the location of the
      resource or resource server.  These strings are typically URIs
      identifying the location of the RS.

   "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 element types are used in combination, the permissions
   the client requests is the cartesian product of the values.  That is
   to say, the object represents a request for all "action" values
   listed within the object to be used at all "locations" values listed
   within the object for all "datatype" 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 reading the photos and writing the
   contacts.










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   [
      {
         "type": "customer_information",
         "locations": [
            "https://example.com/customers",
         ]
         "actions": [
            "read",
            "write"
         ],
         "datatypes": [
            "contacts",
            "photos"
         ]
      }
   ]

   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.





























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   [
      {
         "type": "customer_information",
         "locations": [
            "https://example.com/customers"
         ],
         "actions": [
            "read"
         ],
         "datatypes": [
            "contacts"
         ]
      },
      {
         "type": "customer_information",
         "locations": [
            "https://example.com/customers"
         ],
         "actions": [
            "write"
         ],
         "datatypes": [
            "photos"
         ]
      }
   ]

   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 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.  The second access request includes
   the "actions" and "identifier" fields specified here as well as the
   API-specific "currency" field.













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       "resources": [
           {
               "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"
           }
       ]

   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.

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.



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   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"
            ]
         }
      ]
   }

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 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 using the
   example from Section 2 (line breaks for display purposes only):



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  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%22Merchant123%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.  In this example, the client wants to get access to
   account information and intiate a payment:



























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   [
      {
         "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"
      }
   ]

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.




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   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.

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 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 error code
   "invalid_authorization_details" (similar to "invalid_scope").










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6.1.  Comparing authorization details

   Many actions in the OAuth protocol allow the AS and RS to make
   security decisions based on whether or not 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.  Since the nature of an authorization details request
   is based solely on the API or APIs that it is describing, there is
   not a simple means of comparing any two arbitrary authorization
   details requests.  Authorization servers should not rely on simple
   object comparison in most cases, as the intersection of some elements
   within a request could have side effects in 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.

   However, when comparing a new request to an existing request,
   authorization servers 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

   *  to initiate 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:












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   [
      {
         "type":"account_information",
         "actions":[
            "list_accounts"
         ],
         "locations":[
            "https://example.com/accounts"
         ]
      }
   ]

   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:

   *  compare that the authorization code issued in the previous step
      contains an authorization details object of type
      "account_information"

   *  compare whether the approved list of actions contains
      "list_account", and

   *  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, the value of an "action" could
   subsume the rights associated with another "action" value.  For
   example, if a client initially asks for a token with "write" access,
   which implies both read and write access to this API:

   [
       {
           "type": "example_api",
           "actions": [
               "write"
           ]
       }
   ]

   Later that same client makes a refresh request for "read" access:



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   [
       {
           "type": "example_api",
           "actions": [
               "read"
           ]
       }
   ]

   The AS would compare the "type" value and the "action" value to
   determine that the "read" access is already covered by the "write"
   access previously granted to the client.

6.2.  Interaction with the resource parameter

   The "resource" token request parameter as defined in [RFC8707] MAY be
   used in the token request to request the creation of an audience
   restricted access token (as recommended in
   [I-D.ietf-oauth-security-topics]).  If the client uses this
   parameter, the AS MUST consider the audience restriction defined by
   the "locations" elements of the "authorization_details" 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" token request parameter value.  The authorization
      server MUST compare both values using an exact byte match of the
      string values.

   For example the following token request selects authorization details
   applicable for the resource server represented by the URI
   "https://example.com/payments".











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   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

   Using the example given above, this request would result in the
   assignment of the "payment_initiation" authorization details object
   from Section 2 to the access token to be issued (see below).

7.  Token Response

   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 as well as any related parameters
   such as "resource" and "scope".  If the client does not specify any
   of those token request parameters, the AS determines the resulting
   authorization details at its discretion.

   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.

   For our running example, this would look like this:























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   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"
         }
      ]
   }

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 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
   they 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.





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   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.


































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   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.







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   {
   "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.

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.





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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 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
   initation example above:






























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   {
      "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

   *  "txn": transaction id used to trace the transaction across the
      services of provider "example.com"









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   *  "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,
      they is the owner.  This data is used for access control at the
      payment API (the RS).

9.2.  Token Introspection

   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).

   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:
































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   {
      "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.





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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 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 what such an authorization
   data type could look like.

12.  Implementation Considerations

12.1.  Using authorization details in a certain deployment

   Using authorization details in a certain deployment will require the
   follwowing 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

   *  (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 resource server(s) process(s) the authorization
      details or token data derived from authorization details

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





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   *  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" and "refresh_token".

   *  If the product supports resource indicators, it should also
      support filtering of the authorization details to be assigned to
      access tokens using the "resource" token request parameter.

   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.






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   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










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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 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 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.







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15.  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, Francis Pouatcha, 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):  Section 2 of this document

16.2.  OAuth Authorization Server Metadata

   This specification requests registration of the following values 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:  IESG
   Specification Document(s):  Section 10 of [[ this document ]]

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



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   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].

   Metadata Name:  "invalid_authorization_details"
   Metadata Description:  indicates invalid
      "authorization_details_parameter"to the client.
   Change Controller:  IESG
   Specification Document(s):  Section 5 of [[ this document ]]

17.  Normative References

   [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>.

   [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>.

   [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>.

   [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>.

   [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>.

18.  Informative References

   [I-D.ietf-oauth-jwsreq]
              Sakimura, N., Bradley, J., and M. B. Jones, "The OAuth 2.0
              Authorization Framework: JWT Secured Authorization Request



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              (JAR)", Work in Progress, Internet-Draft, draft-ietf-
              oauth-jwsreq-34, 8 April 2021,
              <https://tools.ietf.org/html/draft-ietf-oauth-jwsreq-34>.

   [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-07,
              12 April 2021,
              <https://tools.ietf.org/html/draft-ietf-oauth-par-07>.

   [JSON.Schema]
              json-schema.org, "JSON Schema",
              <https://json-schema.org/>.

   [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>.

   [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>.

   [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>.

   [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>.

   [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-18, 13 April 2021, <https://tools.ietf.org/html/
              draft-ietf-oauth-security-topics-18>.

   [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>.




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   [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>.

   [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-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-10, 18 October
              2020, <https://tools.ietf.org/html/draft-ietf-oauth-jwt-
              introspection-response-10>.

   [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>.

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

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]




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   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































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   [
      {
         "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].














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   [
      {
         "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.





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   [
       {
           "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.  They wants to
   look at the electronic patient records of a certain patient and they
   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.









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   "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"



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               }
            ],
            "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






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   *  "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 ]]

   -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
      with "authorization_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




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   *  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"

   *  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




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   *  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




















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