Skip to main content

JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and Authorization Grants
draft-ietf-oauth-jwt-bearer-05

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7523.
Authors Michael B. Jones , Brian Campbell , Chuck Mortimore
Last updated 2013-03-29
RFC stream Internet Engineering Task Force (IETF)
Formats
Reviews
Additional resources Mailing list discussion
Stream WG state WG Document
Document shepherd (None)
IESG IESG state Became RFC 7523 (Proposed Standard)
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to (None)
draft-ietf-oauth-jwt-bearer-05
OAuth Working Group                                           M.B. Jones
Internet-Draft                                                 Microsoft
Intended status: Standards Track                             B. Campbell
Expires: September 30, 2013                                Ping Identity
                                                            C. Mortimore
                                                              Salesforce
                                                          March 29, 2013

  JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and
                          Authorization Grants
                     draft-ietf-oauth-jwt-bearer-05

Abstract

   This specification defines the use of a JSON Web Token (JWT) Bearer
   Token as a means for requesting an OAuth 2.0 access token as well as
   for use as a means of client authentication.

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 September 30, 2013.

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
   include Simplified BSD License text as described in Section 4.e of

Jones, et al.          Expires September 30, 2013               [Page 1]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   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  . . . . . . . . . . . . . . . . .   4
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  HTTP Parameter Bindings for Transporting Assertions . . . . .   4
     2.1.  Using JWTs as Authorization Grants  . . . . . . . . . . .   4
     2.2.  Using JWTs for Client Authentication  . . . . . . . . . .   5
   3.  JWT Format and Processing Requirements  . . . . . . . . . . .   6
     3.1.  Authorization Grant Processing  . . . . . . . . . . . . .   7
     3.2.  Client Authentication Processing  . . . . . . . . . . . .   7
   4.  Authorization Grant Example . . . . . . . . . . . . . . . . .   8
   5.  Interoperability Considerations . . . . . . . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Sub-Namespace Registration of urn:ietf:params:oauth
           :grant-type:jwt-bearer  . . . . . . . . . . . . . . . . .   9
     7.2.  Sub-Namespace Registration of urn:ietf:params:oauth
           :client-assertion-type:jwt-bearer . . . . . . . . . . . .  10
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  11
   Appendix B.  Document History . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   JSON Web Token (JWT) [JWT] is a JavaScript Object Notation (JSON)
   [RFC4627] based security token encoding that enables identity and
   security information to be shared across security domains.  A
   security token is generally issued by an identity provider and
   consumed by a relying party that relies on its content to identify
   the token's subject for security related purposes.

   The OAuth 2.0 Authorization Framework [RFC6749] provides a method for
   making authenticated HTTP requests to a resource using an access
   token.  Access tokens are issued to third-party clients by an
   authorization server (AS) with the (sometimes implicit) approval of
   the resource owner.  In OAuth, an authorization grant is an abstract
   term used to describe intermediate credentials that represent the
   resource owner authorization.  An authorization grant is used by the
   client to obtain an access token.  Several authorization grant types
   are defined to support a wide range of client types and user
   experiences.  OAuth also allows for the definition of new extension

Jones, et al.          Expires September 30, 2013               [Page 2]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   grant types to support additional clients or to provide a bridge
   between OAuth and other trust frameworks.  Finally, OAuth allows the
   definition of additional authentication mechanisms to be used by
   clients when interacting with the authorization server.

   The Assertion Framework for OAuth 2.0 Client Authentication and
   Authorization Grants [I-D.ietf-oauth-assertions] specification is an
   abstract extension to OAuth 2.0 that provides a general framework for
   the use of Assertions (a.k.a.  Security Tokens) as client credentials
   and/or authorization grants with OAuth 2.0.  This specification
   profiles the Assertion Framework for OAuth 2.0 Client Authentication
   and Authorization Grants [I-D.ietf-oauth-assertions] specification to
   define an extension grant type that uses a JSON Web Token (JWT)
   Bearer Token to request an OAuth 2.0 access token as well as for use
   as client credentials.  The format and processing rules for the JWT
   defined in this specification are intentionally similar, though not
   identical, to those in the closely related SAML 2.0 Profile for OAuth
   2.0 Client Authentication and Authorization Grants
   [I-D.ietf-oauth-saml2-bearer] specification.

   This document defines how a JSON Web Token (JWT) Bearer Token can be
   used to request an access token when a client wishes to utilize an
   existing trust relationship, expressed through the semantics of (and
   digital signature or keyed message digest calculated over) the JWT,
   without a direct user approval step at the authorization server.  It
   also defines how a JWT can be used as a client authentication
   mechanism.  The use of a security token for client authentication is
   orthogonal to and separable from using a security token as an
   authorization grant.  They can be used either in combination or
   separately.  Client authentication using a JWT is nothing more than
   an alternative way for a client to authenticate to the token endpoint
   and must be used in conjunction with some grant type to form a
   complete and meaningful protocol request.  JWT authorization grants
   may be used with or without client authentication or identification.
   Whether or not client authentication is needed in conjunction with a
   JWT authorization grant, as well as the supported types of client
   authentication, are policy decisions at the discretion of the
   authorization server.

   The process by which the client obtains the JWT, prior to exchanging
   it with the authorization server or using it for client
   authentication, is out of scope.

Jones, et al.          Expires September 30, 2013               [Page 3]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

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 RFC 2119 [RFC2119].

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

1.2.  Terminology

   All terms are as defined in The OAuth 2.0 Authorization Framework
   [RFC6749], the Assertion Framework for OAuth 2.0 Client
   Authentication and Authorization Grants [I-D.ietf-oauth-assertions],
   and the JSON Web Token (JWT) [JWT] specifications.

2.  HTTP Parameter Bindings for Transporting Assertions

   The Assertion Framework for OAuth 2.0 Client Authentication and
   Authorization Grants [I-D.ietf-oauth-assertions] specification
   defines generic HTTP parameters for transporting Assertions (a.k.a.
   Security Tokens) during interactions with a token endpoint.  This
   section defines specific parameters and treatments of those
   parameters for use with JWT bearer tokens.

2.1.  Using JWTs as Authorization Grants

   To use a Bearer JWT as an authorization grant, use an access token
   request as defined in Section 4 of the Assertion Framework for OAuth
   2.0 Client Authentication and Authorization Grants
   [I-D.ietf-oauth-assertions] specification with the following specific
   parameter values and encodings.

   The value of the "grant_type" parameter MUST be
   "urn:ietf:params:oauth:grant-type:jwt-bearer".

   The value of the "assertion" parameter MUST contain a single JWT.

   The "scope" parameter may be used, as defined in the Assertion
   Framework for OAuth 2.0 Client Authentication and Authorization
   Grants [I-D.ietf-oauth-assertions] specification, to indicate the
   requested scope.

   Authentication of the client is optional, as described in
   Section 3.2.1 of OAuth 2.0 [RFC6749] and consequently, the
   "client_id" is only needed when a form of client authentication that
   relies on the parameter is used.

Jones, et al.          Expires September 30, 2013               [Page 4]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   The following non-normative example demonstrates an Access Token
   Request with a JWT as an authorization grant (with extra line breaks
   for display purposes only):

     POST /token.oauth2 HTTP/1.1
     Host: as.example.com
     Content-Type: application/x-www-form-urlencoded

     grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer
     &assertion=eyJhbGciOiJFUzI1NiJ9.
     eyJpc3Mi[...omitted for brevity...].
     J9l-ZhwP[...omitted for brevity...]

2.2.  Using JWTs for Client Authentication

   To use a JWT Bearer Token for client authentication, use the
   following parameter values and encodings.

   The value of the "client_assertion_type" parameter MUST be
   "urn:ietf:params:oauth:client-assertion-type:jwt-bearer".

   The value of the "client_assertion" parameter MUST contain a single
   JWT.

   The following non-normative example demonstrates client
   authentication using a JWT during the presentation of an
   authorization code grant in an Access Token Request (with extra line
   breaks for display purposes only):

     POST /token.oauth2 HTTP/1.1
     Host: as.example.com
     Content-Type: application/x-www-form-urlencoded

     grant_type=authorization_code&
     code=vAZEIHjQTHuGgaSvyW9hO0RpusLzkvTOww3trZBxZpo&
     client_assertion_type=urn%3Aietf%3Aparams%3Aoauth%3A
     client-assertion-type%3Ajwt-bearer&
     client_assertion=eyJhbGciOiJSUzI1NiJ9.
     eyJpc3Mi[...omitted for brevity...].
     cC4hiUPo[...omitted for brevity...]

Jones, et al.          Expires September 30, 2013               [Page 5]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

3.  JWT Format and Processing Requirements

   In order to issue an access token response as described in OAuth 2.0
   [RFC6749] or to rely on a JWT for client authentication, the
   authorization server MUST validate the JWT according to the criteria
   below.  Application of additional restrictions and policy are at the
   discretion of the authorization server.

   1.   The JWT MUST contain an "iss" (issuer) claim that contains a
        unique identifier for the entity that issued the JWT.

   2.   The JWT MUST contain a "sub" (subject) claim identifying the
        subject of the transaction.  The subject MAY identify the
        resource owner for whom the access token is being requested.

        a.  When using a JWT as an authorization grant, the subject
            SHOULD identify an authorized accessor for whom the access
            token is being requested (typically the resource owner, or
            an authorized delegate).

        b.  For client authentication, the subject MUST be the
            "client_id" of the OAuth client.

   3.   The JWT MUST contain an "aud" (audience) claim containing a
        value that identifies the authorization server as an intended
        audience.  The token endpoint URL of the authorization server
        MAY be used as a value for an "aud" element to identify the
        authorization server as an intended audience of the JWT.  JWTs
        that do not identify the authorization server as an intended
        audience MUST be rejected.

   4.   The JWT MUST contain an "exp" (expiration) claim that limits the
        time window during which the JWT can be used.  The authorization
        server MUST verify that the expiration time has not passed,
        subject to allowable clock skew between systems, and reject
        expired JWTs.  The authorization server MAY reject JWTs with an
        "exp" claim value that is unreasonably far in the future.

   5.   The JWT MAY contain an "nbf" (not before) claim that identifies
        the time before which the token MUST NOT be accepted for
        processing.

   6.   The JWT MAY contain an "iat" (issued at) claim that identifies
        the time at which the JWT was issued.  The authorization server
        MAY reject JWTs with an "iat" claim value that is unreasonably
        far in the past.

Jones, et al.          Expires September 30, 2013               [Page 6]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   7.   The JWT MAY contain a "jti" (JWT ID) claim that provides a
        unique identifier for the token.  The authorization server MAY
        ensure that JWTs are not replayed by maintaining the set of used
        "jti" values for the length of time for which the JWT would be
        considered valid based on the applicable "exp" instant.

   8.   The JWT MAY contain other claims.

   9.   The JWT MUST be digitally signed or have a keyed message digest
        applied by the issuer.  The authorization server MUST reject
        JWTs with an invalid signature or keyed message digest.

   10.  The authorization server MUST verify that the JWT is valid in
        all other respects per JSON Web Token (JWT) [JWT].

3.1.  Authorization Grant Processing

   JWT authorization grants may be used with or without client
   authentication or identification.  Whether or not client
   authentication is needed in conjunction with a JWT authorization
   grant, as well as the supported types of client authentication, are
   policy decisions at the discretion of the authorization server.
   However, if client credentials are present in the request, the
   authorization server MUST validate them.

   If the JWT is not valid, or the current time is not within the
   token's valid time window for use, the authorization server MUST
   construct an error response as defined in OAuth 2.0 [RFC6749].  The
   value of the "error" parameter MUST be the "invalid_grant" error
   code.  The authorization server MAY include additional information
   regarding the reasons the JWT was considered invalid using the
   "error_description" or "error_uri" parameters.

   For example:

     HTTP/1.1 400 Bad Request
     Content-Type: application/json
     Cache-Control: no-store

     {
      "error":"invalid_grant",
      "error_description":"Audience validation failed"
     }

3.2.  Client Authentication Processing

Jones, et al.          Expires September 30, 2013               [Page 7]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   If the client JWT is not valid, or its subject confirmation
   requirements cannot be met, the authorization server MUST construct
   an error response as defined in OAuth 2.0 [RFC6749].  The value of
   the "error" parameter MUST be the "invalid_client" error code.  The
   authorization server MAY include additional information regarding the
   reasons the JWT was considered invalid using the "error_description"
   or "error_uri" parameters.

4.  Authorization Grant Example

   Though non-normative, the following examples illustrate what a
   conforming JWT and access token request would look like.

   The example shows a JWT issued and signed by the system entity
   identified as "https://jwt-idp.example.com".  The subject of the JWT
   is identified by email address as "mike@example.com".  The intended
   audience of the JWT is "https://jwt-rp.example.net", which is an
   identifier with which the authorization server identifies itself.
   The JWT is sent as part of an access token request to the
   authorization server's token endpoint at "https://authz.example.net/
   token.oauth2".

   Below is an example JSON object that could be encoded to produce the
   JWT Claims Object for a JWT:

   {"iss":"https://jwt-idp.example.com",
    "sub":"mailto:mike@example.com",
    "aud":"https://jwt-rp.example.net",
    "nbf":1300815780,
    "exp":1300819380,
    "http://claims.example.com/member":true}

   The following example JSON object, used as the header of a JWT,
   declares that the JWT is signed with the ECDSA P-256 SHA-256
   algorithm.

   {"alg":"ES256"}

   To present the JWT with the claims and header shown in the previous
   example as part of an access token request, for example, the client
   might make the following HTTPS request (with extra line breaks for
   display purposes only):

Jones, et al.          Expires September 30, 2013               [Page 8]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

     POST /token.oauth2 HTTP/1.1
     Host: authz.example.net
     Content-Type: application/x-www-form-urlencoded

     grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer
     &assertion=eyJhbGciOiJFUzI1NiJ9.
     eyJpc3Mi[...omitted for brevity...].
     J9l-ZhwP[...omitted for brevity...]

5.  Interoperability Considerations

   Agreement between system entities regarding identifiers, keys, and
   endpoints is required in order to achieve interoperable deployments
   of this profile.  Specific items that require agreement are as
   follows: values for the issuer and audience identifiers, the location
   of the token endpoint, and the key used to apply and verify the
   digital signature or keyed message digest over the JWT.  The exchange
   of such information is explicitly out of scope for this
   specification.  In some cases, additional profiles may be created
   that constrain or prescribe these values or specify how they are to
   be exchanged.  Examples of such profiles include the OAuth 2.0
   Dynamic Client Registration Protocol [I-D.ietf-oauth-dyn-reg], OpenID
   Connect Dynamic Client Registration 1.0 [OpenID.Registration], and
   OpenID Connect Discovery 1.0 [OpenID.Discovery].

6.  Security Considerations

   No additional security considerations apply beyond those described
   within The OAuth 2.0 Authorization Framework [RFC6749], the Assertion
   Framework for OAuth 2.0 Client Authentication and Authorization
   Grants [I-D.ietf-oauth-assertions], and the JSON Web Token (JWT)
   [JWT] specifications.

7.  IANA Considerations

7.1.  Sub-Namespace Registration of urn:ietf:params:oauth:grant-type
      :jwt-bearer

   This specification registers the value "grant-type:jwt-bearer" in the
   IANA urn:ietf:params:oauth registry established in An IETF URN Sub-
   Namespace for OAuth [RFC6755].

   o  URN: urn:ietf:params:oauth:grant-type:jwt-bearer

   o  Common Name: JWT Bearer Token Grant Type Profile for OAuth 2.0

   o  Change controller: IETF

Jones, et al.          Expires September 30, 2013               [Page 9]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   o  Specification Document: [[this document]]

7.2.  Sub-Namespace Registration of urn:ietf:params:oauth:client-
      assertion-type:jwt-bearer

   This specification registers the value "client-assertion-type:jwt-
   bearer" in the IANA urn:ietf:params:oauth registry established in An
   IETF URN Sub-Namespace for OAuth [RFC6755].

   o  URN: urn:ietf:params:oauth:client-assertion-type:jwt-bearer

   o  Common Name: JWT Bearer Token Profile for OAuth 2.0 Client
      Authentication

   o  Change controller: IETF

   o  Specification Document: [[this document]]

8.  References

8.1.  Normative References

   [I-D.ietf-oauth-assertions]
              Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
              "Assertion Framework for OAuth 2.0", draft-ietf-oauth-
              assertions-10 (work in progress), January 2013.

   [JWT]      Jones, M.B., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", draft-ietf-oauth-json-web-token (work in
              progress), December 2012.

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

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

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

   [RFC6755]  Campbell, B. and H. Tschofenig, "An IETF URN Sub-Namespace
              for OAuth", RFC 6755, October 2012.

Jones, et al.          Expires September 30, 2013              [Page 10]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

8.2.  Informative References

   [I-D.ietf-oauth-dyn-reg]
              Richer, J., Bradley, J., Jones, M., and M. Machulak,
              "OAuth 2.0 Dynamic Client Registration Protocol", draft-
              ietf-oauth-dyn-reg-08 (work in progress), March 2013.

   [I-D.ietf-oauth-saml2-bearer]
              Campbell, B. and C. Mortimore, "SAML 2.0 Bearer Assertion
              Profiles for OAuth 2.0", draft-ietf-oauth-saml2-bearer-15
              (work in progress), November 2012.

   [OpenID.Discovery]
              Sakimura, N., Bradley, J., Jones, M.B., and E. Jay,
              "OpenID Connect Discovery 1.0", March 2013.

   [OpenID.Registration]
              Sakimura, N., Bradley, J., and M.B. Jones, "OpenID Connect
              Dynamic Client Registration 1.0", March 2013.

Appendix A.  Acknowledgements

   This profile was derived from SAML 2.0 Profile for OAuth 2.0 Client
   Authentication and Authorization Grants [I-D.ietf-oauth-saml2-bearer]
   by Brian Campbell and Chuck Mortimore.

Appendix B.  Document History

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

   -05

   o  Changed title from "JSON Web Token (JWT) Bearer Token Profiles for
      OAuth 2.0" to "JSON Web Token (JWT) Profile for OAuth 2.0 Client
      Authentication and Authorization Grants" to be more explicit about
      the scope of the document per http://www.ietf.org/mail-archive/web
      /oauth/current/msg11063.html.

   o  Numbered the list of processing rules.

   o  Smallish editorial cleanups to try and improve readability and
      comprehensibility.

   o  Cleaner split out of the processing rules in cases where they
      differ for client authentication and authorization grants.

   o  Clarified the parameters that are used/available for authorization
      grants.

Jones, et al.          Expires September 30, 2013              [Page 11]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

   o  Added Interoperability Considerations section.

   o  Added more explanatory context to the example in Section 4.

   -04

   o  Changed the name of the "prn" claim to "sub" (subject) both to
      more closely align with SAML name usage and to use a more
      intuitive name.

   o  Added seriesInfo information to Internet Draft references.

   -03

   o  Reference RFC 6749 and RFC 6755.

   -02

   o  Add more text to intro explaining that an assertion/JWT grant type
      can be used with or without client authentication/identification
      and that client assertion/JWT authentication is nothing more than
      an alternative way for a client to authenticate to the token
      endpoint

   o  Add examples to Sections 2.1 and 2.2

   o  Update references

   -01

   o  Tracked specification name changes: "The OAuth 2.0 Authorization
      Protocol" to "The OAuth 2.0 Authorization Framework" and "OAuth
      2.0 Assertion Profile" to "Assertion Framework for OAuth 2.0".

   o  Merged in changes between draft-ietf-oauth-saml2-bearer-11 and
      draft-ietf-oauth-saml2-bearer-13.  All changes were strictly
      editorial.

   -00

   o  Created the initial IETF draft based upon draft-jones-oauth-jwt-
      bearer-04 with no normative changes.

Jones, et al.          Expires September 30, 2013              [Page 12]
Internet-Draft        OAuth JWT Assertion Profiles            March 2013

Authors' Addresses

   Michael B. Jones
   Microsoft

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

   Brian Campbell
   Ping Identity Corp.

   Email: brian.d.campbell@gmail.com

   Chuck Mortimore
   Salesforce

   Email: cmortimore@salesforce.com

Jones, et al.          Expires September 30, 2013              [Page 13]