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Versions: 00 draft-ietf-oauth-dyn-reg-management

OAuth Working Group                                       J. Richer, Ed.
Internet-Draft                                     The MITRE Corporation
Intended status: Standards Track                              J. Bradley
Expires: February 28, 2014                                 Ping Identity
                                                                M. Jones
                                                               Microsoft
                                                             M. Machulak
                                                    Newcastle University
                                                         August 27, 2013


       OAuth 2.0 Dynamic Client Registration Management Protocol
                draft-richer-oauth-dyn-reg-management-00

Abstract

   This specification defines methods for a dynamically registered OAuth
   2.0 client to manage its registration through an OAuth 2.0 protected
   web API as well as extended client metadata attributes.

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 http://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 February 28, 2014.

Copyright Notice

   Copyright (c) 2013 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
   (http://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



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.3.  Protocol Flow . . . . . . . . . . . . . . . . . . . . . .   3
     1.4.  Registration Tokens and Client Credentials  . . . . . . .   5
       1.4.1.  Credential Rotation . . . . . . . . . . . . . . . . .   6
   2.  Client Metadata . . . . . . . . . . . . . . . . . . . . . . .   7
     2.1.  Human Readable Client Metadata  . . . . . . . . . . . . .   8
   3.  Client Configuration Endpoint . . . . . . . . . . . . . . . .  10
     3.1.  Forming the Client Configuration Endpoint URL . . . . . .  10
     3.2.  Client Read Request . . . . . . . . . . . . . . . . . . .  10
     3.3.  Client Update Request . . . . . . . . . . . . . . . . . .  11
     3.4.  Client Delete Request . . . . . . . . . . . . . . . . . .  14
   4.  Responses . . . . . . . . . . . . . . . . . . . . . . . . . .  15
     4.1.  Client Information Response . . . . . . . . . . . . . . .  15
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  18
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  19
   Appendix B.  Document History . . . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  24

1.  Introduction

   In some use-case scenarios, it is desirable or necessary to allow
   OAuth 2.0 clients to obtain authorization from an OAuth 2.0
   authorization server without requiring the two parties to interact
   beforehand.  Nevertheless, for the authorization server to accurately
   and securely represent to end-users which client is seeking
   authorization to access the end-user's resources, a method for
   automatic and unique registration of clients is needed.  The OAuth
   2.0 authorization framework does not define how the relationship
   between the client and the authorization server is initialized, or
   how a given client is assigned a unique client identifier.
   Historically, this has happened out-of-band from the OAuth 2.0
   protocol.

   This specification extends the OAuth 2.0 Core Dynamic Client
   Registration [DynReg] specification (which provides a method for
   OAuth 2.0 clients to be registered dynamically with an authorization
   server) and defines a mechanism for the client to present the
   authorization server with a set of extended metadata, such as a



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   display name and icon to be presented to the user during the
   authorization step.  This draft also provides a mechanism for the
   client to read and update this information after the initial
   registration action.  This draft protects these actions through the
   use of an OAuth 2.0 bearer access token that is issued to the client
   during registration explicitly for this purpose.

1.1.  Notational Conventions

   The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
   'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
   document are to be interpreted as described in [RFC2119].

   Unless otherwise noted, all the protocol parameter names and values
   are case sensitive.

1.2.  Terminology

   This specification uses the terms "Access Token", "Refresh Token",
   "Authorization Code", "Authorization Grant", "Authorization Server",
   "Authorization Endpoint", "Client", "Client Identifier", "Client
   Secret", "Protected Resource", "Resource Owner", "Resource Server",
   and "Token Endpoint" defined by OAuth 2.0 [RFC6749].

   This specification defines the following additional terms:

   Client Configuration Endpoint  OAuth 2.0 endpoint through which
      registration information for a registered client can be managed.
      This URL for this endpoint is returned by the authorization server
      in the client information response.

   Registration Access Token  OAuth 2.0 bearer token issued by the
      authorization server through the client registration endpoint that
      is used to authenticate the caller when accessing the client's
      registration information at the client configuration endpoint.
      This access token is associated with a particular registered
      client.

1.3.  Protocol Flow

   This extends the flow in the core dynamic registration [DynReg]
   specification as follows:









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          +--------(A)- Initial Access Token
          |
          v
    +-----------+                                      +---------------+
    |           |--(B)- Client Registration Request -->|    Client     |
    |           |                                      | Registration  |
    |           |<-(C)- Client Information Response ---|   Endpoint    |
    |           |                                      +---------------+
    |           |
    |           |                                      +---------------+
    | Client or |--(D)- Read or Update Request ------->|               |
    | Developer |                                      |               |
    |           |<-(E)- Client Information Response ---|    Client     |
    |           |                                      | Configuration |
    |           |                                      |   Endpoint    |
    |           |                                      |               |
    |           |--(F)- Delete Request --------------->|               |
    |           |                                      |               |
    |           |<-(G)- Delete Confirmation -----------|               |
    +-----------+                                      +---------------+



   Figure 1: Abstract Protocol Flow


   The abstract OAuth 2.0 Client dynamic registration flow illustrated
   in Figure 1 describes the interaction between the client or developer
   and the two endpoints defined in this specification and its parent.
   This figure does not demonstrate error conditions.  This flow
   includes the following steps:

   (A)
      Optionally, the client or developer is issued an initial access
      token for use with the client registration endpoint.  The method
      by which the initial access token is issued to the client or
      developer is out of scope for this specification.

   (B)
      The client or developer calls the client registration endpoint
      with its desired registration metadata, optionally including the
      initial access token from (A) if one is required by the
      authorization server.

   (C)
      The authorization server registers the client and returns the
      client's registered metadata, a client identifier that is unique
      at the server, a set of client credentials such as a client secret



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      if applicable for this client, a URI pointing to the client
      configuration endpoint, and a registration access token to be used
      when calling the client configuration endpoint.

   (D)
      The client or developer optionally calls the client configuration
      endpoint with a read or update request using the registration
      access token issued in (C).  An update request contains all of the
      client's registered metadata.

   (E)
      The authorization server responds with the client's current
      configuration, potentially including a new registration access
      token and a new set of client credentials such as a client secret
      if applicable for this client.  If a new registration access token
      is issued, it replaces the token issued in (C) for all subsequent
      calls to the client configuration endpoint.

   (F)
      The client or developer optionally calls the client configuration
      endpoint with a delete request using the registration access token
      issued in (C).

   (G)
      The authorization server deprovisions the client and responds with
      a confirmation that the deletion has taken place.

1.4.  Registration Tokens and Client Credentials

   Throughout the course of the dynamic registration protocol, there are
   three different classes of credentials in play, each with different
   properties and targets.

   o  The initial access token is optionally used by the client or
      developer at the registration endpoint.  This is an OAuth 2.0
      token that is used to authorize the initial client registration
      request.  The content, structure, generation, and validation of
      this token are out of scope for this specification.  The
      authorization server can use this token to verify that the
      presenter is allowed to dynamically register new clients.  This
      token may be shared between multiple instances of a client to
      allow them to each register separately, thereby letting the
      authorization server use this token to tie multiple instances of
      registered clients (each with their own distinct client
      identifier) back to the party to whom the initial access token was
      issued, usually an application developer.  This token should be
      used only at the client registration endpoint.




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   o  The registration access token is used by the client or developer
      at the client configuration endpoint and represents the holder's
      authorization to manage the registration of a client.  This is an
      OAuth 2.0 bearer token that is issued from the client registration
      endpoint in response to a client registration request and is
      returned in a client information response.  The registration
      access token is uniquely bound to the client identifier and is
      required to be presented with all calls to the client
      configuration endpoint.  The registration access token should be
      protected and should not be shared between instances of a client
      (otherwise, one instance could change or delete registration
      values for all instances of the client).  The registration access
      token can be rotated through the use of the client read and update
      methods on the client configuration endpoint.  The registration
      access token should be used only at the client configuration
      endpoint.

   o  The client credentials (such as "client_secret") are optional
      depending on the type of client and are used to retrieve OAuth
      tokens.  Client credentials are most often bound to particular
      instances of a client and should not be shared between instances.
      Note that since not all types of clients have client credentials,
      they cannot be used to manage client registrations at the client
      configuration endpoint.  The client credentials can be rotated
      through the use of the client read and update methods on the
      client configuration endpoint.  The client credentials can not be
      used for authentication at the client registration endpoint or at
      the client configuration endpoint.

1.4.1.  Credential Rotation

   The Authorization Server MAY rotate the client's registration access
   token and/or client credentials (such as a "client_secret")
   throughout the lifetime of the client.  The client can discovery that
   these values have changed by reading the client information response
   returned from either a read or update request to the client
   configuration endpoint.  The client's current registration access
   token and client credentials (if applicable) MUST be included in this
   response.

   The registration access token SHOULD be rotated only in response to a
   read or update request to the client configuration endpoint, at which
   point the new registration access token is returned to the client and
   the old registration access token SHOULD be discarded by both
   parties.  If the registration access token to expire or be rotated
   outside of such requests, the client or developer may be locked out
   of managing the client's configuration.




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2.  Client Metadata

   Many OAuth 2.0 clients wish to register different kinds of client
   metadata to facilitate authorization and usage of the protected API.
   This specification extends the list of client metadata defined in
   OAuth 2.0 Core Client Dynamic Registration [DynReg] with the
   following fields:

   client_name
      Human-readable name of the client to be presented to the user.  If
      omitted, the authorization server MAY display the raw "client_id"
      value to the user instead.  It is RECOMMENDED that clients always
      send this field.  The value of this field MAY be internationalized
      as described in Human Readable Client Metadata (Section 2.1).

   client_uri
      URL of the homepage of the client.  If present, the server SHOULD
      display this URL to the end user in a clickable fashion.  It is
      RECOMMENDED that clients always send this field.  The value of
      this field MUST point to a valid web page.  The value of this
      field MAY be internationalized as described in Human Readable
      Client Metadata (Section 2.1).

   logo_uri
      URL that references a logo for the client.  If present, the server
      SHOULD display this image to the end user during approval.  The
      value of this field MUST point to a valid image file.  The value
      of this field MAY be internationalized as described in Human
      Readable Client Metadata (Section 2.1).

   scope
      Space separated list of scope values (as described in OAuth 2.0
      Section 3.3 [RFC6749]) that the client can use when requesting
      access tokens.  The semantics of values in this list is service
      specific.  If omitted, an authorization server MAY register a
      Client with a default set of scopes.

   contacts
      Array of email addresses for people responsible for this client.
      The authorization server MAY make these addresses available to end
      users for support requests for the client.  An authorization
      server MAY use these email addresses as identifiers for an
      administrative page for this client.

   tos_uri
      URL that points to a human-readable Terms of Service document for
      the client.  The Authorization Server SHOULD display this URL to
      the end-user if it is given.  The Terms of Service usually



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      describe a contractual relationship between the end-user and the
      client that the end-user accepts when authorizing the client.  The
      value of this field MUST point to a valid web page.  The value of
      this field MAY be internationalized as described in Human Readable
      Client Metadata (Section 2.1).

   policy_uri
      URL that points to a human-readable Policy document for the
      client.  The authorization server SHOULD display this URL to the
      end-user if it is given.  The policy usually describes how an end-
      user's data will be used by the client.  The value of this field
      MUST point to a valid web page.  The value of this field MAY be
      internationalized as described in Human Readable Client Metadata
      (Section 2.1).

   jwks_uri
      URL for the Client's JSON Web Key Set [JWK] document representing
      the client's public keys.  The value of this field MUST point to a
      valid JWK Set. These keys MAY be used for higher level protocols
      that require signing or encryption.

   software_id
      A identifier for the software that comprises a client.  Unlike
      "client_id", which is issued by the authorization server and
      generally varies between instances, the "software_id" is asserted
      by the client software and is intended to be shared between all
      copies of the client software.  The value for this field MAY be a
      UUID [RFC4122].  The identifier SHOULD NOT change when software
      version changes or when a new installation instance is detected.
      Authorization servers MUST treat this field as self-asserted by
      the client and MUST NOT make any trusted decisions on the value of
      this field alone.

   software_version
      A version identifier for the software that comprises a client.
      The value of this field is a string that is intended to be
      compared using string equality matching.  The value of the
      "software_version" SHOULD change on any update to the client
      software.  Authorization servers MUST treat this field as self-
      asserted by the client and MUST NOT make any trusted decisions on
      the value of this field alone.

2.1.  Human Readable Client Metadata

   Human-readable client metadata values and client metadata values that
   reference human-readable values MAY be represented in multiple
   languages and scripts.  For example, the values of fields such as
   "client_name", "tos_uri", "policy_uri", "logo_uri", and "client_uri"



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   might have multiple locale-specific values in some client
   registrations.

   To specify the languages and scripts, BCP47 [RFC5646] language tags
   are added to client metadata member names, delimited by a #
   character.  Since JSON member names are case sensitive, it is
   RECOMMENDED that language tag values used in Claim Names be spelled
   using the character case with which they are registered in the IANA
   Language Subtag Registry [IANA.Language].  In particular, normally
   language names are spelled with lowercase characters, region names
   are spelled with uppercase characters, and languages are spelled with
   mixed case characters.  However, since BCP47 language tag values are
   case insensitive, implementations SHOULD interpret the language tag
   values supplied in a case insensitive manner.  Per the
   recommendations in BCP47, language tag values used in metadata member
   names should only be as specific as necessary.  For instance, using
   "fr" might be sufficient in many contexts, rather than "fr-CA" or
   "fr-FR".

   For example, a client could represent its name in English as
   ""client_name#en": "My Client"" and its name in Japanese as
   ""client_name#ja-Jpan-JP":
   "\u30AF\u30E9\u30A4\u30A2\u30F3\u30C8\u540D"" within the same
   registration request.  The authorization server MAY display any or
   all of these names to the resource owner during the authorization
   step, choosing which name to display based on system configuration,
   user preferences or other factors.

   If any human-readable field is sent without a language tag, parties
   using it MUST NOT make any assumptions about the language, character
   set, or script of the string value, and the string value MUST be used
   as-is wherever it is presented in a user interface.  To facilitate
   interoperability, it is RECOMMENDED that clients and servers use a
   human-readable field without any language tags in addition to any
   language-specific fields, and it is RECOMMENDED that any human-
   readable fields sent without language tags contain values suitable
   for display on a wide variety of systems.

   Implementer's Note: Many JSON libraries make it possible to reference
   members of a JSON object as members of an object construct in the
   native programming environment of the library.  However, while the
   "#" character is a valid character inside of a JSON object's member
   names, it is not a valid character for use in an object member name
   in many programming environments.  Therefore, implementations will
   need to use alternative access forms for these claims.  For instance,
   in JavaScript, if one parses the JSON as follows, "var j =
   JSON.parse(json);", then the member "client_name#en-us" can be
   accessed using the JavaScript syntax "j["client_name#en-us"]".



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3.  Client Configuration Endpoint

   The client configuration endpoint is an OAuth 2.0 protected resource
   that is provisioned by the server to facilitate viewing, updating,
   and deleting a client's registered information.  The location of this
   endpoint is communicated to the client through the
   "registration_client_uri" member of the Client Information Response
   (Section 4.1).  The client MUST use its registration access token in
   all calls to this endpoint as an OAuth 2.0 Bearer Token [RFC6750].

   Operations on this endpoint are switched through the use of different
   HTTP methods [RFC2616].  If an authorization server does not support
   a particular method on the client configuration endpoint, it MUST
   respond with the appropriate error code.

3.1.  Forming the Client Configuration Endpoint URL

   The authorization server MUST provide the client with the fully
   qualified URL in the "registration_client_uri" element of the Client
   Information Response (Section 4.1).  The authorization server MUST
   NOT expect the client to construct or discover this URL on its own.
   The client MUST use the URL as given by the server and MUST NOT
   construct this URL from component pieces.

   Depending on deployment characteristics, the client configuration
   endpoint URL may take any number of forms.  It is RECOMMENDED that
   this endpoint URL be formed through the use of a server-constructed
   URL string which combines the client registration endpoint's URL and
   the issued "client_id" for this client, with the latter as either a
   path parameter or a query parameter.  For example, a client with the
   client identifier "s6BhdRkqt3" could be given a client configuration
   endpoint URL of "https://server.example.com/register/s6BhdRkqt3"
   (path parameter) or of "https://server.example.com/
   register?client_id=s6BhdRkqt3" (query parameter).  In both of these
   cases, the client simply uses the URL as given by the authorization
   server.

   These common patterns can help the server to more easily determine
   the client to which the request pertains, which MUST be matched
   against the client to which the registration access token was issued.
   If desired, the server MAY simply return the client registration
   endpoint URL as the client configuration endpoint URL and change
   behavior based on the authentication context provided by the
   registration access token.

3.2.  Client Read Request





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   To read the current configuration of the client on the authorization
   server, the client makes an HTTP GET request to the client
   configuration endpoint, authenticating with its registration access
   token.

   Following is a non-normative example request (with line wraps for
   display purposes only):

   GET /register/s6BhdRkqt3 HTTP/1.1
   Accept: application/json
   Host: server.example.com
   Authorization: Bearer reg-23410913-abewfq.123483



   Upon successful read of the information for a currently active
   client, the authorization server responds with an HTTP 200 OK with
   content type of "application/json" and a payload as described in
   Client Information Response (Section 4.1).  Some values in the
   response, including the "client_secret" and
   "registration_access_token", MAY be different from those in the
   initial registration response.  If the authorization server includes
   a new client secret and/or registration access token in its response,
   the client MUST immediately discard its previous client secret and/or
   registration access token.  The value of the "client_id" MUST NOT
   change from the initial registration response.

   If the registration access token used to make this request is not
   valid, the server MUST respond with an error as described in OAuth
   Bearer Token Usage [RFC6750].

   If the client does not exist on this server, the server MUST respond
   with HTTP 401 Unauthorized and the registration access token used to
   make this request SHOULD be immediately revoked.

   If the client does not have permission to read its record, the server
   MUST return an HTTP 403 Forbidden.

3.3.  Client Update Request

   This operation updates a previously-registered client with new
   metadata at the authorization server.  This request is authenticated
   by the registration access token issued to the client.

   The client sends an HTTP PUT to the client configuration endpoint
   with a content type of "application/json".  The HTTP entity payload
   is a JSON [RFC4627] document consisting of a JSON object and all
   parameters as top- level members of that JSON object.



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   This request MUST include all fields described in Client Metadata
   (Section 2) as returned to the client from a previous register, read,
   or update operation.  The client MUST NOT include the
   "registration_access_token", "registration_client_uri",
   "client_secret_expires_at", or "client_id_issued_at" fields described
   in Client Information Response (Section 4.1).

   Valid values of client metadata fields in this request MUST replace,
   not augment, the values previously associated with this client.
   Omitted fields MUST be treated as null or empty values by the server.

   The client MUST include its "client_id" field in the request, and it
   MUST be the same as its currently-issued client identifier.  If the
   client includes the "client_secret" field in the request, the value
   of this field MUST match the currently-issued client secret for that
   client.  The client MUST NOT be allowed to overwrite its existing
   client secret with its own chosen value.

   For all metadata fields, the authorization server MAY replace any
   invalid values with suitable default values, and it MUST return any
   such fields to the client in the response.

   For example, a client could send the following request to the client
   registration endpoint to update the client registration in the above
   example with new information:


























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   Following is a non-normative example request (with line wraps for
   display purposes only):

   PUT /register/s6BhdRkqt3 HTTP/1.1
   Accept: application/json
   Host: server.example.com
   Authorization: Bearer reg-23410913-abewfq.123483

   {
    "client_id":"s6BhdRkqt3",
    "client_secret": "cf136dc3c1fc93f31185e5885805d",
    "redirect_uris":["https://client.example.org/callback",
       "https://client.example.org/alt"],
    "scope": "read write dolphin",
    "grant_types": ["authorization_code", "refresh_token"]
    "token_endpoint_auth_method": "client_secret_basic",
    "jwks_uri": "https://client.example.org/my_public_keys.jwks"
    "client_name":"My New Example",
    "client_name#fr":"Mon Nouvel Exemple",
    "logo_uri":"https://client.example.org/newlogo.png"
    "logo_uri#fr":"https://client.example.org/fr/newlogo.png"
   }


   Upon successful update, the authorization server responds with an
   HTTP 200 OK Message with content type "application/json" and a
   payload as described in Client Information Response (Section 4.1).
   Some values in the response, including the "client_secret" and
   r"egistration_access_token", MAY be different from those in the
   initial registration response.  If the authorization server includes
   a new client secret and/or registration access token in its response,
   the client MUST immediately discard its previous client secret and/or
   registration access token.  The value of the "client_id" MUST NOT
   change from the initial registration response.

   If the registration access token used to make this request is not
   valid, the server MUST respond with an error as described in OAuth
   Bearer Token Usage [RFC6750].

   If the client does not exist on this server, the server MUST respond
   with HTTP 401 Unauthorized, and the registration access token used to
   make this request SHOULD be immediately revoked.

   If the client is not allowed to update its records, the server MUST
   respond with HTTP 403 Forbidden.

   If the client attempts to set an invalid metadata field and the
   authorization server does not set a default value, the authorization



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   server responds with an error as described in Client Registration
   Error Response [DynReg].

3.4.  Client Delete Request

   To deprovision itself on the authorization server, the client makes
   an HTTP DELETE request to the client configuration endpoint.  This
   request is authenticated by the registration access token issued to
   the client.

   Following is a non-normative example request (with line wraps for
   display purposes only):

   DELETE /register/s6BhdRkqt3 HTTP/1.1
   Host: server.example.com
   Authorization: Bearer reg-23410913-abewfq.123483



   A successful delete action will invalidate the "client_id",
   "client_secret", and "registration_access_token" for this client,
   thereby preventing the "client_id" from being used at either the
   authorization endpoint or token endpoint of the authorization server.
   The authorization server SHOULD immediately invalidate all existing
   authorization grants and currently-active tokens associated with this
   client.

   If a client has been successfully deprovisioned, the authorization
   server responds with an HTTP 204 No Content message.

   If the server does not support the delete method, the server MUST
   respond with an HTTP 405 Not Supported.

   If the registration access token used to make this request is not
   valid, the server MUST respond with an error as described in OAuth
   Bearer Token Usage [RFC6750].

   If the client does not exist on this server, the server MUST respond
   with HTTP 401 Unauthorized and the registration access token used to
   make this request SHOULD be immediately revoked.

   If the client is not allowed to delete itself, the server MUST
   respond with HTTP 403 Forbidden.

   Following is a non-normative example response:






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   HTTP/1.1 204 No Content
   Cache-Control: no-store
   Pragma: no-cache



4.  Responses

   In response to certain requests from the client to either the client
   registration endpoint or the client configuration endpoint as
   described in this specification, the authorization server sends the
   following response bodies.

4.1.  Client Information Response

   This specification extends the client information response defined in
   OAuth 2.0 Core Client Dynamic Registration.  The response contains
   the client identifier as well as the client secret, if the client is
   a confidential client.  The response also contains the fully
   qualified URL of the client configuration endpoint for this specific
   client that the client may use to obtain and update information about
   itself.  The response also contains a registration access token that
   is to be used by the client to perform subsequent operations at the
   client configuration endpoint.

   client_id
      REQUIRED.  The unique client identifier, MUST NOT be currently
      valid for any other registered client.

   client_secret
      OPTIONAL.  The client secret.  If issued, this MUST be unique for
      each "client_id".  This value is used by confidential clients to
      authenticate to the token endpoint as described in OAuth 2.0
      [RFC6749] Section 2.3.1.

   client_id_issued_at
      OPTIONAL.  Time at which the Client Identifier was issued.  The
      time is represented as the number of seconds from
      1970-01-01T0:0:0Z as measured in UTC until the date/time.

   client_secret_expires_at
      REQUIRED if "client_secret" is issued.  Time at which the
      "client_secret" will expire or 0 if it will not expire.  The time
      is represented as the number of seconds from 1970-01-01T0:0:0Z as
      measured in UTC until the date/time.

   registration_access_token




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      REQUIRED.  Access token that is used at the client configuration
      endpoint to perform subsequent operations upon the client
      registration.

   registration_client_uri
      REQUIRED.  The fully qualified URL of the client configuration
      endpoint for this client.  The client MUST use this URL as given
      when communicating with the client configuration endpoint.

   Additionally, the Authorization Server MUST return all registered
   metadata (Section 2) about this client, including any fields
   provisioned by the authorization server itself.  The authorization
   server MAY reject or replace any of the client's requested metadata
   values submitted during the registration or update requests and
   substitute them with suitable values.

   The response is an "application/json" document with all parameters as
   top-level members of a JSON object [RFC4627].

   Following is a non-normative example response:

   HTTP/1.1 200 OK
   Content-Type: application/json
   Cache-Control: no-store
   Pragma: no-cache

   {
    "registration_access_token": "reg-23410913-abewfq.123483",
    "registration_client_uri":
       "https://server.example.com/register/s6BhdRkqt3",
    "client_id":"s6BhdRkqt3",
    "client_secret": "cf136dc3c1fc93f31185e5885805d",
    "client_id_issued_at":2893256800
    "client_secret_expires_at":2893276800
    "client_name":"My Example Client",
    "client_name#ja-Jpan-JP":
       "\u30AF\u30E9\u30A4\u30A2\u30F3\u30C8\u540D",
    "redirect_uris":["https://client.example.org/callback",
       "https://client.example.org/callback2"]
    "scope": "read write dolphin",
    "grant_types": ["authorization_code", "refresh_token"]
    "token_endpoint_auth_method": "client_secret_basic",
    "logo_uri": "https://client.example.org/logo.png",
    "jwks_uri": "https://client.example.org/my_public_keys.jwks"
   }






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5.  IANA Considerations

   This specification makes no requests of IANA.

6.  Security Considerations

   Since the client configuration endpoint is an OAuth 2.0 protected
   resource, it SHOULD have some rate limiting on failures to prevent
   the registration access token from being disclosed though repeated
   access attempts.

   The authorization server MUST treat all client metadata as self-
   asserted.  For instance, a rogue client might use the name and logo
   for the legitimate client which it is trying to impersonate.
   Additionally, a rogue client might try to use the software identifier
   or software version of a legitimate client to attempt to associate
   itself on the authorization server instances of the legitimate
   client.  To counteract this, an authorization server needs to take
   steps to mitigate this phishing risk by looking at the entire
   registration request and client configuration.  For instance, an
   authorization server could warn if the domain/site of the logo
   doesn't match the domain/site of redirect URIs.  An authorization
   server could also refuse registration from a known software
   identifier that is requesting different redirect URIs or a different
   client homepage uri.  An authorization server can also present
   warning messages to end users about dynamically registered clients in
   all cases, especially if such clients have been recently registered
   or have not been trusted by any users at the authorization server
   before.

   In a situation where the authorization server is supporting open
   client registration, it must be extremely careful with any URL
   provided by the client that will be displayed to the user (e.g.
   "logo_uri", "tos_uri", "client_uri", and "policy_uri").  For
   instance, a rogue client could specify a registration request with a
   reference to a drive-by download in the "policy_uri".  The
   authorization server SHOULD check to see if the "logo_uri",
   "tos_uri", "client_uri", and "policy_uri" have the same host and
   scheme as the those defined in the array of "redirect_uris" and that
   all of these resolve to valid web pages.

   While the client secret can expire, the registration access token
   should not expire while a client is still actively registered.  If
   this token were to expire, a developer or client could be left in a
   situation where they have no means of retrieving or updating the
   client's registration information.  Were that the case, a new
   registration would be required, thereby generating a new client
   identifier.  However, to limit the exposure surface of the



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   registration access token, the registration access token MAY be
   rotated when the developer or client does a read or update operation
   on the client's client configuration endpoint.  As the registration
   access tokens are relatively long-term credentials, and since the
   registration access token is a Bearer token and acts as the sole
   authentication for use at the client configuration endpoint, it MUST
   be protected by the developer or client as described in OAuth 2.0
   Bearer Token Usage [RFC6750].

   If a client is deprovisioned from a server, any outstanding
   registration access token for that client MUST be invalidated at the
   same time.  Otherwise, this can lead to an inconsistent state wherein
   a client could make requests to the client configuration endpoint
   where the authentication would succeed but the action would fail
   because the client is no longer valid.  To prevent accidental
   disclosure from such an erroneous situation, the authorization server
   MUST treat all such requests as if the registration access token was
   invalid (by returning an HTTP 401 Unauthorized error, as described).

7.  Normative References

   [DynReg]   Richer, J., "OAuth 2.0 Core Dynamic Client Registration",
              draft-richer-oauth-dyn-reg-core (work in progress), August
              2013.

   [IANA.Language]
              Internet Assigned Numbers Authority (IANA), "Language
              Subtag Registry", 2005.

   [JWK]      Jones, M., "JSON Web Key (JWK)", draft-ietf-jose-json-web-
              key (work in progress), May 2013.

   [OAuth.JWT]
              Jones, M., Campbell, B., and C. Mortimore, "JSON Web Token
              (JWT) Bearer Token Profiles for OAuth 2.0", draft-ietf-
              oauth-jwt-bearer (work in progress), March 2013.

   [OAuth.SAML2]
              Campbell, B., Mortimore, C., and M. Jones, "SAML 2.0
              Bearer Assertion Profiles for OAuth 2.0", draft-ietf-
              oauth-saml2-bearer (work in progress), March 2013.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2246]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
              RFC 2246, January 1999.




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   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122, July
              2005.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627, July 2006.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [RFC5646]  Phillips, A. and M. Davis, "Tags for Identifying
              Languages", BCP 47, RFC 5646, September 2009.

   [RFC6125]  Saint-Andre, P. and J. Hodges, "Representation and
              Verification of Domain-Based Application Service Identity
              within Internet Public Key Infrastructure Using X.509
              (PKIX) Certificates in the Context of Transport Layer
              Security (TLS)", RFC 6125, March 2011.

   [RFC6749]  Hardt, D., "The OAuth 2.0 Authorization Framework", RFC
              6749, October 2012.

   [RFC6750]  Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
              Framework: Bearer Token Usage", RFC 6750, October 2012.

Appendix A.  Acknowledgments

   The authors thank the OAuth Working Group, the User-Managed Access
   Working Group, and the OpenID Connect Working Group participants for
   their input to this document.  In particular, the following
   individuals have been instrumental in their review and contribution
   to various versions of this document: Amanda Anganes, Derek Atkins,
   Tim Bray, Domenico Catalano, Donald Coffin, Vladimir Dzhuvinov,
   George Fletcher, Thomas Hardjono, Phil Hunt, William Kim, Torsten
   Lodderstedt, Eve Maler, Josh Mandel, Nov Matake, Nat Sakimura,
   Christian Scholz, and Hannes Tschofenig.

Appendix B.  Document History

   [[ to be removed by the RFC editor before publication as an RFC ]]



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   - 00

   o  Partitioned dyn-reg specification into core and management specs

   -14

   o  Added software_id and software_version metadata fields

   o  Added direct references to RFC6750 errors in read/update/delete
      methods

   -13

   o  Fixed broken example text in registration request and in delete
      request

   o  Added security discussion of separating clients of different grant
      types

   o  Fixed error reference to point to RFC6750 instead of RFC6749

   o  Clarified that servers must respond to all requests to
      configuration endpoint, even if it's just an error code

   o  Lowercased all Terms to conform to style used in RFC6750

   -12

   o  Improved definition of Initial Access Token

   o  Changed developer registration scenario to have the Initial Access
      Token gotten through a normal OAuth 2.0 flow

   o  Moved non-normative client lifecycle examples to appendix

   o  Marked differentiating between auth servers as out of scope

   o  Added protocol flow diagram

   o  Added credential rotation discussion

   o  Called out Client Registration Endpoint as an OAuth 2.0 Protected
      Resource

   o  Cleaned up several pieces of text

   -11




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   o  Added localized text to registration request and response
      examples.

   o  Removed "client_secret_jwt" and "private_key_jwt".

   o  Clarified "tos_uri" and "policy_uri" definitions.

   o  Added the OAuth Token Endpoint Authentication Methods registry for
      registering "token_endpoint_auth_method" metadata values.

   o  Removed uses of non-ASCII characters, per RFC formatting rules.

   o  Changed "expires_at" to "client_secret_expires_at" and "issued_at"
      to "client_id_issued_at" for greater clarity.

   o  Added explanatory text for different credentials (Initial Access
      Token, Registration Access Token, Client Credentials) and what
      they're used for.

   o  Added Client Lifecycle discussion and examples.

   o  Defined Initial Access Token in Terminology section.

   -10

   o  Added language to point out that scope values are service-specific

   o  Clarified normative language around client metadata

   o  Added extensibility to token_endpoint_auth_method using absolute
      URIs

   o  Added security consideration about registering redirect URIs

   o  Changed erroneous 403 responses to 401's with notes about token
      handling

   o  Added example for initial registration credential

   -09

   o  Added method of internationalization for Client Metadata values

   o  Fixed SAML reference

   -08





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   o  Collapsed jwk_uri, jwk_encryption_uri, x509_uri, and
      x509_encryption_uri into a single jwks_uri parameter

   o  Renamed grant_type to grant_types since it's a plural value

   o  Formalized name of "OAuth 2.0" throughout document

   o  Added JWT Bearer Assertion and SAML 2 Bearer Assertion to example
      grant types

   o  Added response_types parameter and explanatory text on its use
      with and relationship to grant_types

   -07

   o  Changed registration_access_url to registration_client_uri

   o  Fixed missing text in 5.1

   o  Added Pragma: no-cache to examples

   o  Changed "no such client" error to 403

   o  Renamed Client Registration Access Endpoint to Client
      Configuration Endpoint

   o  Changed all the parameter names containing "_url" to instead use
      "_uri"

   o  Updated example text for forming Client Configuration Endpoint URL

   -06

   o  Removed secret_rotation as a client-initiated action, including
      removing client secret rotation endpoint and parameters.

   o  Changed _links structure to single value registration_access_url.

   o  Collapsed create/update/read responses into client info response.

   o  Changed return code of create action to 201.

   o  Added section to describe suggested generation and composition of
      Client Registration Access URL.

   o  Added clarifying text to PUT and POST requests to specify JSON in
      the body.




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   o  Added Editor's Note to DELETE operation about its inclusion.

   o  Added Editor's Note to registration_access_url about alternate
      syntax proposals.

   -05

   o  changed redirect_uri and contact to lists instead of space
      delimited strings

   o  removed operation parameter

   o  added _links structure

   o  made client update management more RESTful

   o  split endpoint into three parts

   o  changed input to JSON from form-encoded

   o  added READ and DELETE operations

   o  removed Requirements section

   o  changed token_endpoint_auth_type back to
      token_endpoint_auth_method to match OIDC who changed to match us

   -04

   o  removed default_acr, too undefined in the general OAuth2 case

   o  removed default_max_auth_age, since there's no mechanism for
      supplying a non-default max_auth_age in OAuth2

   o  clarified signing and encryption URLs

   o  changed token_endpoint_auth_method to token_endpoint_auth_type to
      match OIDC

   -03

   o  added scope and grant_type claims

   o  fixed various typos and changed wording for better clarity

   o  endpoint now returns the full set of client information





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   o  operations on client_update allow for three actions on metadata:
      leave existing value, clear existing value, replace existing value
      with new value

   -02

   o  Reorganized contributors and references

   o  Moved OAuth references to RFC

   o  Reorganized model/protocol sections for clarity

   o  Changed terminology to "client register" instead of "client
      associate"

   o  Specified that client_id must match across all subsequent requests

   o  Fixed RFC2XML formatting, especially on lists

   -01

   o  Merged UMA and OpenID Connect registrations into a single document

   o  Changed to form-paramter inputs to endpoint

   o  Removed pull-based registration

   -00

   o  Imported original UMA draft specification

Authors' Addresses

   Justin Richer (editor)
   The MITRE Corporation

   Email: jricher@mitre.org


   John Bradley
   Ping Identity

   Email: ve7jtb@ve7jtb.com








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   Michael B. Jones
   Microsoft

   Email: mbj@microsoft.com
   URI:   http://self-issued.info/


   Maciej Machulak
   Newcastle University

   Email: m.p.machulak@ncl.ac.uk
   URI:   http://ncl.ac.uk/







































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