OAuth Working Group                                          N. Sakimura
Internet-Draft                                 Nomura Research Institute
Intended status: Standards Track                              J. Bradley
Expires: August 3, 17, 2017                                   Ping Identity
                                                        January 30,
                                                       February 13, 2017

The OAuth 2.0 Authorization Framework: JWT Secured Authorization Request
                                 (JAR)
                       draft-ietf-oauth-jwsreq-11
                       draft-ietf-oauth-jwsreq-12

Abstract

   The authorization request in OAuth 2.0 described in RFC 6749 utilizes
   query parameter serialization, which means that Authorization Request
   parameters are encoded in the URI of the request and sent through
   user agents such as web browsers.  While it is easy to implement, it
   means that (a) the communication through the user agents are not
   integrity protected and thus the parameters can be tainted, and (b)
   the source of the communication is not authenticated.  Because of
   these weaknesses, several attacks to the protocol have now been put
   forward.

   This document introduces the ability to send request parameters in a
   JSON Web Token (JWT) instead, which allows the request to be JWS signed
   with JSON Web Signature (JWS) and/or JWE encrypted with JSON Web
   Encryption (JWE) so that the integrity, source authentication and
   confidentiality property of the Authorization Request is attained.
   The request can be sent by value or by reference.

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
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   This Internet-Draft will expire on August 3, 17, 2017.

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   5
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
     2.1.  Request Object  . . . . . . . . . . . . . . . . . . . . .   6
     2.2.  Request Object URI  . . . . . . . . . . . . . . . . . . .   6
   3.  Symbols and abbreviated terms . . . . . . . . . . . . . . . .   6
   4.  Request Object  . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  Authorization Request . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Passing a Request Object by Value . . . . . . . . . . . .   9
     5.2.  Passing a Request Object by Reference . . . . . . . . . .  10
       5.2.1.  URL Referencing the Request Object  . . . . . . . . .  12
       5.2.2.  Request using the "request_uri" Request Parameter . .  13
       5.2.3.  Authorization Server Fetches Request Object . . . . .  13
   6.  Validating JWT-Based Requests . . . . . . . . . . . . . . . .  13
     6.1.  Encrypted Request Object  . . . . . . . . . . . . . . . .  13
     6.2.  JWS Signed Request Object . . . . . . . . . . . . . . . .  14
     6.3.  Request Parameter Assembly and Validation . . . . . . . .  14
   7.  Authorization Server Response . . . . . . . . . . . . . . . .  14
   8.  TLS Requirements  . . . . . . . . . . . . . . . . . . . . . .  14
   9.  IANA  Considerations  . . . . . . . . . . . . . . . . . . . .  15
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  15
     10.1.  Choice of Algorithms . . . . . . . . . . . . . . . . . .  15
     10.2.  Choice of Parameters to include in the Request Object  .  15
     10.3.  Request Source Authentication  . . . . . . . . . . . . .  16
     10.4.  Explicit Endpoints . . . . . . . . . . . . . . . . . . .  16
   11. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  17
     11.1.  Collection limitation  . . . . . . . . . . . . . . . . .  17
     11.2.  Disclosure Limitation  . . . . . . . . . . . . . . . . .  18
       11.2.1.  Request Disclosure . . . . . . . . . . . . . . . . .  18
       11.2.2.  Tracking using Request Object URI  . . . . . . . . .  18
   12. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  19
   13. Revision History  . . . . . . . . . . . . . . . . . . . . . .  19
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  22  23
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  22  24
     14.2.  Informative References . . . . . . . . . . . . . . . . .  24  25
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  24  25

1.  Introduction

   The Authorization Request in OAuth 2.0 [RFC6749] utilizes query
   parameter serialization and is typically sent through user agents
   such as web browsers.

   For example, the parameters "response_type", "client_id", "state",
   and "redirect_uri" are encoded in the URI of the request:

       GET /authorize?response_type=code&client_id=s6BhdRkqt3&state=xyz
       &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
       Host: server.example.com

   While it is easy to implement, the encoding in the URI does not allow
   application layer security with confidentiality and integrity
   protection to be used.  While TLS is used to offer communication
   security between the Client and the user-agent and as well as the user-agent user-
   agent and the Authorization Server, TLS sessions are terminated in
   the user-
   agent. user-agent.  In addition, TLS sessions may be terminated
   prematurely at some middlebox (such as a load balancer).

   As the result, the Authorization Request of [RFC6749] has a property
   that
   shortcomings in that:

   (a)  the communication through the user agents are not integrity
        protected and thus the parameters can be tainted (integrity
        protection failure); failure)

   (b)  the source of the communication is not authenticated (source
        authentication failure); and failure)

   (c)  the communication through the user agents can be monitored
        (containment / confidentiality failure).

   Because of

   Due to these inherent weaknesses, several attacks against the
   protocol, such as Redirection URI rewriting, has have been discovered. identified.

   The use of application layer security mitigates these issues.

   In addition, it

   The use of application layer security allows requests to be prepared
   by a third party so that a client application cannot request more
   permissions than previously agreed.  This offers an additional degree
   of privacy protection.

   Furthermore, the request by reference allows the reduction of over-
   the- wire
   the-wire overhead.

   The JWT [RFC7519] encoding has been chosen because of

   (1)  its close relationship with JSON, which is used as OAuth's
        response format; format

   (2)  its developer friendliness due to its textual nature; nature

   (3)  its relative compactness compared to XML; XML

   (4)  its development status that it is an RFC and so is its
        associated signing and encryption methods as [RFC7515] and
        [RFC7516];
        [RFC7516]

   (5)  the relative ease of JWS and JWE compared to XML Signature and
        Encryption.

   The parameters "request" and "request_uri" are introduced as
   additional authorization request parameters for the OAuth 2.0
   [RFC6749] flows.  The "request" parameter is a JSON Web Token (JWT)
   [RFC7519] whose JWT Claims Set holds the JSON encoded OAuth 2.0
   authorization request parameters.  This JWT is integrity protected
   and source authenticated using JWS.

   The JWT [RFC7519] can be passed to the authorization endpoint by
   reference, in which case the parameter "request_uri" is used instead
   of the "request".

   Using JWT [RFC7519] as the request encoding instead of query
   parameters has several advantages:

   (a)  (integrity protection) The request can be signed so that the
        integrity of the request can be checked; checked.

   (b)  (source authentication) The request can be signed so that the
        signer can be authenticated; authenticated.

   (c)  (confidentiality protection) The request can be encrypted so
        that end-to-end confidentiality can be provided even if the TLS
        connection is terminated at one point or another; and another.

   (d)  (collection minimization) The request can be signed by a third
        party attesting that the authorization request is compliant with
        a certain policy.  For example, a request can be pre-examined by
        a third party that all the personal data requested is strictly
        necessary to perform the process that the end-user asked for,
        and statically signed by that third party.  The client would
        then send the request along with dynamic parameters such as
        "state".  The authorization server then examines the signature
        and shows the conformance status to the end-user, who would have
        some assurance as to the legitimacy of the request when
        authorizing it.  In some cases, it may even be desirable to skip
        the authorization dialogue under such circumstances.

   There are a few cases that request by reference is useful such as:

   1.  When it is desirable to reduce the size of transmitted request.
       The use of application layer security increases the size of the
       request, particularly when public key cryptography is used.

   2.  The client can make a signed Request Object and put it in a place
       that the Authorization Server can access.  This may just be done
       by a client utility or other process, so that the private key
       does not have to reside on the client, simplifying programming.
       The downside of it is that the signed portion just become a
       token.

   3.  When the server wants the requests to be cacheable: cacheable.  The
       "request_uri" may include a SHA-256 hash of the contents of the
       resources referenced by the Request Object URI.  With this, the
       server knows if the resource has changed without fetching it, so
       it does not have to re-fetch the same content, which is a win as
       well.  This is explained in Section 5.2.

   4.  When the client does not want to do the crypto: crypto.  The
       Authorization Server may provide an endpoint to accept the
       Authorization Request through direct communication with the
       Client so that the Client is authenticated and the channel is TLS
       protected.

   This capability is in use by OpenID Connect [OpenID.Core].

1.1.  Requirements Language

   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].

2.  Terminology

   For the purposes of this specification, the following terms and
   definitions in addition to what is defined in OAuth 2.0 Framework
   [RFC6749], JSON Web Signature [RFC7515], and JSON Web Encryption
   [RFC7519] apply.

2.1.  Request Object

   JWT [RFC7519] that holds an OAuth 2.0 authorization request as JWT
   Claims Set

2.2.  Request Object URI

   Absolute URI from which the Request Object (Section 2.1) can be
   obtained

3.  Symbols and abbreviated terms

   The following abbreviations are common to this specification.

   JSON  Javascript Object Notation

   JWT  JSON Web Token

   JWS  JSON Web Signature

   JWE  JSON Web Encryption

   URI  Uniform Resource Identifier

   URL  Uniform Resource Locator

   WAP  Wireless Application Protocol

4.  Request Object

   A Request Object (Section 2.1) is used to provide authorization
   request parameters for an OAuth 2.0 authorization request.  It
   contains OAuth 2.0 [RFC6749] authorization request parameters
   including extension parameters.  The parameters are represented as
   the JWT claims.  Parameter names and string values MUST be included
   as JSON strings.  Since it is a JWT, JSON strings MUST be represented
   in UTF-8.  Numerical values MUST be included as JSON numbers.  It MAY
   include any extension parameters.  This JSON [RFC7159] constitutes
   the JWT Claims Set defined in JWT [RFC7519].  The JWT Claims Set is
   then signed, encrypted, or signed and encrypted. or encrypted or both.

   To sign, JSON Web Signature (JWS) [RFC7515] is used.  The result is a
   JWS signed JWT [RFC7519].  If signed, the Authorization Request
   Object SHOULD contain the Claims "iss" (issuer) and "aud" (audience)
   as members, with their semantics being the same as defined in the JWT
   [RFC7519] specification.

   To encrypt, JWE [RFC7516] is used.  Unless the algorithm used in JWE
   allows for the source to be authenticated, JWS signature SHOULD also
   be applied so that the source authentication can be done.  When both
   signature and encryption are being applied, the JWT MUST be signed
   then encrypted as advised in the section 11.2 of [RFC7519].  The
   result is a Nested JWT, as defined in [RFC7519].

   The Authorization Request Object MAY be sent by value as described in
   Section 5.1 or by reference as described in Section 5.2.

   Required OAuth 2.0 Authorization Request parameters that are not
   included in the Request Object MUST be sent as query parameters.  If
   a required parameter is missing from both the query parameters and
   the Request Object, the request is malformed.

   "request" and "request_uri" parameters MUST NOT be included in
   Request Objects.

   If the parameter exists in both the query string and the
   Authorization Request Object, the values in the Request Object take
   precedence.  This means that if it intends to use a cached request
   object, it cannot include parameters such as "state" that are
   expected to differ in every request.  It is fine recommended to include
   them in the request object if it is going to be prepared afresh every
   time.

   The following is a non-normative an example of the Claims in a Request Object before
   base64url encoding and signing.  Note that it includes extension
   variables such as "nonce" and "max_age".

     {
      "iss": "s6BhdRkqt3",
      "aud": "https://server.example.com",
      "response_type": "code id_token",
      "client_id": "s6BhdRkqt3",
      "redirect_uri": "https://client.example.org/cb",
      "scope": "openid",
      "state": "af0ifjsldkj",
      "nonce": "n-0S6_WzA2Mj",
      "max_age": 86400
     }

   Signing it with the "RS256" algorithm results in this Request Object
   value (with line wraps within values for display purposes only):

     eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ew0KICJpc3MiOiAiczZCaGRSa3
     F0MyIsDQogImF1ZCI6ICJodHRwczovL3NlcnZlci5leGFtcGxlLmNvbSIsDQogInJl
     c3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsDQogImNsaWVudF9pZCI6ICJzNk
     JoZFJrcXQzIiwNCiAicmVkaXJlY3RfdXJpIjogImh0dHBzOi8vY2xpZW50LmV4YW1w
     bGUub3JnL2NiIiwNCiAic2NvcGUiOiAib3BlbmlkIiwNCiAic3RhdGUiOiAiYWYwaW
     Zqc2xka2oiLA0KICJub25jZSI6ICJuLTBTNl9XekEyTWoiLA0KICJtYXhfYWdlIjog
     ODY0MDAsDQogImNsYWltcyI6IA0KICB7DQogICAidXNlcmluZm8iOiANCiAgICB7DQ
     ogICAgICJnaXZlbl9uYW1lIjogeyJlc3NlbnRpYWwiOiB0cnVlfSwNCiAgICAgIm5p
     Y2tuYW1lIjogbnVsbCwNCiAgICAgImVtYWlsIjogeyJlc3NlbnRpYWwiOiB0cnVlfS
     wNCiAgICAgImVtYWlsX3ZlcmlmaWVkIjogeyJlc3NlbnRpYWwiOiB0cnVlfSwNCiAg
     ICAgInBpY3R1cmUiOiBudWxsDQogICAgfSwNCiAgICJpZF90b2tlbiI6IA0KICAgIH
     sNCiAgICAgImdlbmRlciI6IG51bGwsDQogICAgICJiaXJ0aGRhdGUiOiB7ImVzc2Vu
     dGlhbCI6IHRydWV9LA0KICAgICAiYWNyIjogeyJ2YWx1ZXMiOiBbInVybjptYWNlOm
     luY29tbW9uOmlhcDpzaWx2ZXIiXX0NCiAgICB9DQogIH0NCn0.nwwnNsk1-Zkbmnvs
     F6zTHm8CHERFMGQPhos-EJcaH4Hh-sMgk8ePrGhw_trPYs8KQxsn6R9Emo_wHwajyF
     KzuMXZFSZ3p6Mb8dkxtVyjoy2GIzvuJT_u7PkY2t8QU9hjBcHs68PkgjDVTrG1uRTx
     0GxFbuPbj96tVuj11pTnmFCUR6IEOXKYr7iGOCRB3btfJhM0_AKQUfqKnRlrRscc8K
     ol-cSLWoYE9l5QqholImzjT_cMnNIznW9E7CDyWXTsO70xnB4SkG6pXfLSjLLlxmPG
     iyon_-Te111V8uE83IlzCYIb_NMXvtTIVc1jpspnTSD7xMbpL-2QgwUsAlMGzw

   The following RSA public key, represented in JWK format, can be used
   to validate the Request Object signature in this and subsequent
   Request Object examples (with line wraps within values for display
   purposes only):

     {
      "kty":"RSA",
      "kid":"k2bdc",
      "n":"y9Lqv4fCp6Ei-u2-ZCKq83YvbFEk6JMs_pSj76eMkddWRuWX2aBKGHAtKlE5P
           7_vn__PCKZWePt3vGkB6ePgzAFu08NmKemwE5bQI0e6kIChtt_6KzT5OaaXDF
           I6qCLJmk51Cc4VYFaxgqevMncYrzaW_50mZ1yGSFIQzLYP8bijAHGVjdEFgZa
           ZEN9lsn_GdWLaJpHrB3ROlS50E45wxrlg9xMncVb8qDPuXZarvghLL0HzOuYR
           adBJVoWZowDNTpKpk2RklZ7QaBO7XDv3uR7s_sf2g-bAjSYxYUGsqkNA9b3xV
           W53am_UZZ3tZbFTIh557JICWKHlWj5uzeJXaw",
      "e":"AQAB"
     }

5.  Authorization Request

   The client constructs the authorization request URI by adding one of
   the following parameters but not both to the query component of the
   authorization endpoint URI using the "application/x-www-form-
   urlencoded" format:

   request  The Request Object (Section 2.1) that holds authorization
      request parameters stated in section 4 of OAuth 2.0 [RFC6749].

   request_uri  The absolute URL that points to the Request Object
      (Section 2.1) that holds authorization request parameters stated
      in section 4 of OAuth 2.0 [RFC6749].

   The client directs the resource owner to the constructed URI using an
   HTTP redirection response, or by other means available to it via the
   user-agent.

   For example, the client directs the end user's user-agent to make the
   following HTTPS request:

   GET /authz?request=eyJhbG..AlMGzw HTTP/1.1
   Host: server.example.com

   The value for the request parameter is abbreviated for brevity.

   The authorization request object MUST be either one of the following:

   (a)  JWS signed; or signed

   (b)  JWE encrypted (when symmetric keys are being used); or used)

   (c)  JWS signed and JWE encrypted. encrypted

   When the Request Object is used, the OAuth 2.0 request parameter
   values contained in the JWS Signed and/or JWE Encrypted JWT supersede
   those passed using the OAuth 2.0 request syntax.  Parameters MAY also
   be passed using the OAuth 2.0 request syntax even when a Request
   Object is used in the cases such as (a) to achieve backward
   compatibility with [RFC6749] or (b) to enable a cached, pre-signed
   (and possibly pre-encrypted) Request Object value to be used
   containing the fixed request parameters, while parameters that can
   vary with each request, such as "state" and "nonce" of OpenID
   Connect, are passed as OAuth 2.0 parameters.  In such case, one needs
   to carefully assess the risk associated with it as unprotected
   parameters would create additional attack surfaces.  See Section 10.2
   as well.

5.1.  Passing a Request Object by Value

   The Client sends the Authorization Request as a Request Object to the
   Authorization Endpoint as the "request" parameter value.

   The following is a non-normative an example of an Authorization Request using the
   "request" parameter (with line wraps within values for display
   purposes only):

     https://server.example.com/authorize?
       request=eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ew0KICJpc3MiOiA
       iczZCaGRSa3F0MyIsDQogImF1ZCI6ICJodHRwczovL3NlcnZlci5leGFtcGxlLmN
       vbSIsDQogInJlc3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsDQogImNsaWV
       udF9pZCI6ICJzNkJoZFJrcXQzIiwNCiAicmVkaXJlY3RfdXJpIjogImh0dHBzOi8
       vY2xpZW50LmV4YW1wbGUub3JnL2NiIiwNCiAic2NvcGUiOiAib3BlbmlkIiwNCiA
       ic3RhdGUiOiAiYWYwaWZqc2xka2oiLA0KICJub25jZSI6ICJuLTBTNl9XekEyTWo
       iLA0KICJtYXhfYWdlIjogODY0MDAsDQogImNsYWltcyI6IA0KICB7DQogICAidXN
       lcmluZm8iOiANCiAgICB7DQogICAgICJnaXZlbl9uYW1lIjogeyJlc3NlbnRpYWw
       iOiB0cnVlfSwNCiAgICAgIm5pY2tuYW1lIjogbnVsbCwNCiAgICAgImVtYWlsIjo
       geyJlc3NlbnRpYWwiOiB0cnVlfSwNCiAgICAgImVtYWlsX3ZlcmlmaWVkIjogeyJ
       lc3NlbnRpYWwiOiB0cnVlfSwNCiAgICAgInBpY3R1cmUiOiBudWxsDQogICAgfSw
       NCiAgICJpZF90b2tlbiI6IA0KICAgIHsNCiAgICAgImdlbmRlciI6IG51bGwsDQo
       gICAgICJiaXJ0aGRhdGUiOiB7ImVzc2VudGlhbCI6IHRydWV9LA0KICAgICAiYWN
       yIjogeyJ2YWx1ZXMiOiBbInVybjptYWNlOmluY29tbW9uOmlhcDpzaWx2ZXIiXX0
       NCiAgICB9DQogIH0NCn0.nwwnNsk1-ZkbmnvsF6zTHm8CHERFMGQPhos-EJcaH4H
       h-sMgk8ePrGhw_trPYs8KQxsn6R9Emo_wHwajyFKzuMXZFSZ3p6Mb8dkxtVyjoy2
       GIzvuJT_u7PkY2t8QU9hjBcHs68PkgjDVTrG1uRTx0GxFbuPbj96tVuj11pTnmFC
       UR6IEOXKYr7iGOCRB3btfJhM0_AKQUfqKnRlrRscc8Kol-cSLWoYE9l5QqholImz
       jT_cMnNIznW9E7CDyWXTsO70xnB4SkG6pXfLSjLLlxmPGiyon_-Te111V8uE83Il
       zCYIb_NMXvtTIVc1jpspnTSD7xMbpL-2QgwUsAlMGzw

5.2.  Passing a Request Object by Reference

   The "request_uri" Authorization Request parameter enables OAuth
   authorization requests to be passed by reference, rather than by
   value.  This parameter is used identically to the "request"
   parameter, other than that the Request Object value is retrieved from
   the resource at the specified URL, rather than passed by value.

   When the "request_uri" parameter is used, the OAuth 2.0 authorization
   request parameter values contained in the referenced JWT supersede
   those passed using the OAuth 2.0 request syntax.  Parameters MAY also
   be passed using the OAuth 2.0 request syntax even when a Request
   Object is used in the cases such as (a) to achieve backward
   compatibility with [RFC6749] or (b) to enable a cached, pre-signed
   (and possibly pre-encrypted) Request Object value to be used
   containing the fixed request parameters, while parameters that can
   vary with each request, such as "state" and "nonce" of OpenID
   Connect, are passed as OAuth 2.0 parameters.  In such case, one needs
   to carefully assess the risk associated with it as unprotected
   parameters would create additional attack surfaces.  See Section 10.2
   as well.

   Servers MAY cache the contents of the resources referenced by Request
   Object URIs.  If the contents of the referenced resource could ever
   change, the URI SHOULD include the base64url encoded SHA-256 hash as
   defined in RFC6234 [RFC6234] of the referenced resource contents as
   the fragment component of the URI.  If the fragment value used for a
   URI changes, it signals the server that any cached value for that URI
   with the old fragment value is no longer valid.

   The entire Request URI MUST NOT exceed 512 ASCII characters.  There
   are three reasons for this restriction.

   1.  Many WAP / feature phones do not accept large payloads.  The
       restriction is typically either 512 or 1024 ASCII characters.

   2.  The maximum URL length supported by older versions of Internet
       Explorer is 2083 ASCII characters.

   3.  On a slow connection such as 2G mobile connection, a large URL
       would cause the slow response and therefore the use of such is
       not advisable from the user experience point of view.

   The contents of the resource referenced by the URL MUST be a Request
   Object.  The scheme used in the "request_uri" value MUST be "https",
   unless the target Request Object is signed in a way that is
   verifiable by the Authorization Server.  The "request_uri" value MUST
   be reachable by the Authorization Server, and SHOULD be reachable by
   the Client.

   The following is a non-normative an example of the contents of a Request Object
   resource that can be referenced by a "request_uri" (with line wraps
   within values for display purposes only):

     eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ew0KICJpc3MiOiAiczZCaGRSa3
     F0MyIsDQogImF1ZCI6ICJodHRwczovL3NlcnZlci5leGFtcGxlLmNvbSIsDQogInJl
     c3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsDQogImNsaWVudF9pZCI6ICJzNk
     JoZFJrcXQzIiwNCiAicmVkaXJlY3RfdXJpIjogImh0dHBzOi8vY2xpZW50LmV4YW1w
     bGUub3JnL2NiIiwNCiAic2NvcGUiOiAib3BlbmlkIiwNCiAic3RhdGUiOiAiYWYwaW
     Zqc2xka2oiLA0KICJub25jZSI6ICJuLTBTNl9XekEyTWoiLA0KICJtYXhfYWdlIjog
     ODY0MDAsDQogImNsYWltcyI6IA0KICB7DQogICAidXNlcmluZm8iOiANCiAgICB7DQ
     ogICAgICJnaXZlbl9uYW1lIjogeyJlc3NlbnRpYWwiOiB0cnVlfSwNCiAgICAgIm5p
     Y2tuYW1lIjogbnVsbCwNCiAgICAgImVtYWlsIjogeyJlc3NlbnRpYWwiOiB0cnVlfS
     wNCiAgICAgImVtYWlsX3ZlcmlmaWVkIjogeyJlc3NlbnRpYWwiOiB0cnVlfSwNCiAg
     ICAgInBpY3R1cmUiOiBudWxsDQogICAgfSwNCiAgICJpZF90b2tlbiI6IA0KICAgIH
     sNCiAgICAgImdlbmRlciI6IG51bGwsDQogICAgICJiaXJ0aGRhdGUiOiB7ImVzc2Vu
     dGlhbCI6IHRydWV9LA0KICAgICAiYWNyIjogeyJ2YWx1ZXMiOiBbInVybjptYWNlOm
     luY29tbW9uOmlhcDpzaWx2ZXIiXX0NCiAgICB9DQogIH0NCn0.nwwnNsk1-Zkbmnvs
     F6zTHm8CHERFMGQPhos-EJcaH4Hh-sMgk8ePrGhw_trPYs8KQxsn6R9Emo_wHwajyF
     KzuMXZFSZ3p6Mb8dkxtVyjoy2GIzvuJT_u7PkY2t8QU9hjBcHs68PkgjDVTrG1uRTx
     0GxFbuPbj96tVuj11pTnmFCUR6IEOXKYr7iGOCRB3btfJhM0_AKQUfqKnRlrRscc8K
     ol-cSLWoYE9l5QqholImzjT_cMnNIznW9E7CDyWXTsO70xnB4SkG6pXfLSjLLlxmPG
     iyon_-Te111V8uE83IlzCYIb_NMXvtTIVc1jpspnTSD7xMbpL-2QgwUsAlMGzw

5.2.1.  URL Referencing the Request Object

   The Client stores the Request Object resource either locally or
   remotely at a URL the Authorization Server can access.  The URL MUST
   be HTTPS URL.  This URL is the Request Object URI, "request_uri".

   It is possible for the Request Object to include values that are to
   be revealed only to the Authorization Server.  As such, the
   "request_uri" MUST have appropriate entropy for its lifetime.  It is
   RECOMMENDED that it be removed if it is known that it will not be
   used again or after a reasonable timeout unless access control
   measures are taken.

   Unless the access to the "request_uri" over TLS provides adequate
   authentication of the source of the Request Object, the Request
   Object MUST be JWS Signed.

   The following is a non-normative an example of a Request Object URI value (with line
   wraps within values for display purposes only):

     https://client.example.org/request.jwt#
       GkurKxf5T0Y-mnPFCHqWOMiZi4VS138cQO_V7PZHAdM

5.2.2.  Request using the "request_uri" Request Parameter

   The Client sends the Authorization Request to the Authorization
   Endpoint.

   The following is a non-normative an example of an Authorization Request using the
   "request_uri" parameter (with line wraps within values for display
   purposes only):

     https://server.example.com/authorize?
       response_type=code%20id_token
       &client_id=s6BhdRkqt3
       &request_uri=https%3A%2F%2Fclient.example.org%2Frequest.jwt
       %23GkurKxf5T0Y-mnPFCHqWOMiZi4VS138cQO_V7PZHAdM
       &state=af0ifjsldkj

5.2.3.  Authorization Server Fetches Request Object

   Upon receipt of the Request, the Authorization Server MUST send an
   HTTP "GET" request to the "request_uri" to retrieve the referenced
   Request Object, unless it is already cached, and parse it to recreate
   the Authorization Request parameters.

   Note that the client SHOULD use a unique URI for each request
   containing distinct parameters values, or otherwise prevent the
   Authorization Server from caching the "request_uri".

   The following is a non-normative an example of this fetch process:

     GET /request.jwt HTTP/1.1
     Host: client.example.org

6.  Validating JWT-Based Requests

6.1.  Encrypted Request Object

   The Authorization Server MUST decrypt the JWT in accordance with the
   JSON Web Encryption [RFC7516] specification.  If the result is a
   signed request object, signature validation MUST be performed as
   defined in Section 6.2 as well.

   If decryption fails, the Authorization Server MUST return an
   "invalid_request_object" error.

6.2.  JWS Signed Request Object

   To perform JWS signature validation of a JSON Web Signature Validation, [RFC7515]
   signed request object, the "alg" Header Parameter in
   the its JOSE Header
   MUST match the value of the pre-registered algorithm.  The signature
   MUST be validated against the appropriate key for that "client_id"
   and algorithm.

   If signature validation fails, the Authorization Server MUST return
   an "invalid_request_object" error.

6.3.  Request Parameter Assembly and Validation

   The Authorization Server MUST assemble the set of Authorization
   Request parameters to be used from the Request Object value and the
   OAuth 2.0 Authorization Request parameters (minus the "request" or
   "request_uri" parameters).  If the same parameter exists both in the
   Request Object and the OAuth Authorization Request parameters, the
   parameter in the Request Object is used.  Using the assembled set of
   Authorization Request parameters, the Authorization Server then
   validates the request as specified in OAuth 2.0 [RFC6749].

7.  Authorization Server Response

   Authorization Server Response is created and sent to the client as in
   Section 4 of OAuth 2.0 [RFC6749] .

   In addition, this document uses these additional error values:

   invalid_request_uri  The "request_uri" in the Authorization Request
      returns an error or contains invalid data.

   invalid_request_object  The request parameter contains an invalid
      Request Object.

   request_not_supported  The Authorization Server does not support the
      use of the "request" parameter.

   request_uri_not_supported  The Authorization Server does not support
      the use of the "request_uri" parameter.

8.  TLS Requirements

   Client implementations supporting the Request Object URI method MUST
   support TLS following Recommendations for Secure Use of Transport
   Layer Security (TLS) and Datagram Transport Layer Security (DTLS)
   [RFC7525].

   To protect against information disclosure and tampering,
   confidentiality protection MUST be applied using TLS with a cipher
   suite that provides confidentiality and integrity protection.

   Whenever TLS is used, the identity of the service provider encoded in
   the TLS server certificate MUST be verified using the procedures
   described in Section 6 of [RFC6125].

9.  IANA Considerations

   This specification requests no actions by IANA.

10.  Security Considerations

   In addition to the all the security considerations discussed in OAuth
   2.0 [RFC6819], the security considerations in [RFC7515], [RFC7516],
   and [RFC7518] needs to be considered.  Also, there are several
   academic papers such as [BASIN] that provide useful insight into the
   security properties of protocols like OAuth.

   In consideration of the above, this document advises taking the
   following security considerations into account.

10.1.  Choice of Algorithms

   When sending the authorization request object through "request"
   parameter, it MUST either be signed using JWS [RFC7515] or encrypted
   using JWE [RFC7516] with then considered appropriate algorithm.

10.2.  Choice of Parameters to include in the Request Object

   Unless there is a compelling reason to do otherwise, it is strongly
   recommended to create a request object that covers all the parameters
   so that the entire request is integrity protected.

   This means that the request object is going to be prepared fresh each
   time an authorization request is made and caching cannot be used.  It
   has a performance disadvantage, but where such disadvantage is
   permissible, it should be considered.

   Unless the server and the client have agreed prior to the
   authorization request to use the non-protected parameters, the
   authorization server SHOULD reject a request that is not fully
   integrity protected and source authenticated.  Note that such
   agreement needs to be done in a secure fashion.  For example, the
   developers from the server side and the client side can have a face
   to face meeting to come to such an agreement.

10.3.  Request Source Authentication

   The source of the Authorization Request MUST always be verified.
   There are several ways to do it in this specification.

   (a)  Verifying the JWS Signature of the Request Object.

   (b)  Verifying that the symmetric key for the JWE encryption is the
        correct one if the JWE is using symmetric encryption.

   (c)  Verifying the TLS Server Identity of the Request Object URI.  In
        this case, the Authorization Server MUST know out-of-band that
        the Client uses Request Object URI and only the Client is
        covered by the TLS certificate.  In general, it is not a
        reliable method.

   (c)

   (d)  Authorization Server is providing an endpoint that provides a
        Request Object URI in exchange for a Request Object.  In this
        case, the Authorization Server MUST perform Client
        Authentication to accept the Request Object and bind the Client
        Identifier to the Request Object URI it is providing.  Since
        Request Object URI can be replayed, the lifetime of the Request
        Object URI MUST be short and preferably one-time use.  The
        entropy of the Request Object URI MUST be sufficiently large.
        The adequate shortness of the validity and the entropy of the
        Request Object URI depends on the risk calculation based on the
        value of the resource being protected.  A general guidance for
        the validity time would be less than a minute and the Request
        Object URI is to include a cryptographic random value of 128bit
        or more at the time of the writing of this specification.

   (d)

   (e)  A third party, such as a Trust Framework Provider, provides an
        endpoint that provides a Request Object URI in exchange for a
        Request Object.  The same requirements as (b) above apply.  In
        addition, the Authorization Server MUST know out-of-band that
        the Client utilizes the Trust Framework Operator.

10.4.  Explicit Endpoints

   Although this specification does not require them, research such as
   [BASIN] points out that it is a good practice to explicitly state the
   intended interaction endpoints and the message position in the
   sequence in a tamper evident manner so that the intent of the
   initiator is unambiguous.  The endpoints that come into question in
   this specification are :

   (a)  Protected Resources ("protected_resources"); ("protected_resources")
   (b)  Authorization Endpoint ("authorization_endpoint"); ("authorization_endpoint")

   (c)  Redirection URI ("redirect_uri"); and ("redirect_uri")

   (d)  Token Endpoint ("token_endpoint"). ("token_endpoint")

   While Redirection URI is included, others are not included in the
   Authorization Request Object.  It is probably a good idea to include
   these in it to reduce the attack surface.  An extension specification
   should be created as a preventive measure to address potential
   vulnerabilities that have not yet been identified.

11.  Privacy Considerations

   When the Client is being granted access to a protected resource
   containing personal data, both the Client and the Authorization
   Server need to adhere to Privacy Principles.  ISO/IEC 29100
   [ISO29100] is a freely accessible an International Standard and its Privacy Principles
   are good to follow.

   While ISO/IEC 29100 [ISO29100] is a high-level document that gives
   general guidance, RFC 6973 Privacy Considerations for Internet
   Protocols [RFC6973] gives more specific guidances guidance on the privacy
   consideration for Internet Protocols.  It gives excellent guidances guidance on
   the enhancement of protocol design and implementation.  The provision
   listed in it should be followed.

   Most of the provision would apply to The OAuth 2.0 Authorization
   Framework [RFC6749] and The OAuth 2.0 Authorization Framework: Bearer
   Token Usage [RFC6750] and are not specific to this specification.  In
   what follows, only the specific provisions to this specification are
   noted.

11.1.  Collection limitation

   When the Client is being granted access to a protected resource
   containing personal data, the Client SHOULD limit the collection of
   personal data to that which is within the bounds of applicable law
   and strictly necessary for the specified purpose(s).

   It is often hard for the user to find out if the personal data asked
   for is strictly necessary.  A Trust Framework Provider can help the
   user by examining the Client request and comparing to the proposed
   processing by the Client and certifying the request.  After the
   certification, the Client, when making an Authorization Request, can
   submit Authorization Request to the Trust Framework Provider to
   obtain the Request Object URI.

   Upon receiving such Request Object URI in the Authorization Request,
   the Authorization Server first verifies that the authority portion of
   the Request Object URI is a legitimate one for the Trust Framework
   Provider.  Then, the Authorization Server issues HTTP GET request to
   the Request Object URI.  Upon connecting, the Authorization Server
   MUST verify the server identity represented in the TLS certificate is
   legitimate for the Request Object URI.  Then, the Authorization
   Server can obtain the Request Object, which includes the "client_id"
   representing the Client.

   The Consent screen MUST indicate the Client and SHOULD indicate that
   the request has been vetted by the Trust Framework Operator for the
   adherence to the Collection Limitation principle.

11.2.  Disclosure Limitation

11.2.1.  Request Disclosure

   This specification allows extension parameters.  These may include
   potentially sensitive information.  Since URI query parameter may
   leak through various means but most notably through referrer and
   browser history, if the authorization request contains a potentially
   sensitive parameter, the Client SHOULD JWE [RFC7516] encrypt the
   request object.

   Where Request Object URI method is being used, if the request object
   contains personally identifiable or sensitive information, the
   "request_uri" SHOULD be used only once, have a short validity period,
   and MUST have large enough entropy deemed necessary with applicable
   security policy unless the Request Object itself is JWE [RFC7516]
   Encrypted.  The adequate shortness of the validity and the entropy of
   the Request Object URI depends on the risk calculation based on the
   value of the resource being protected.  A general guidance for the
   validity time would be less than a minute and the Request Object URI
   is to include a cryptographic random value of 128bit or more at the
   time of the writing of this specification.

11.2.2.  Tracking using Request Object URI

   Even if the protected resource does not include a personally
   identifiable information, it is sometimes possible to identify the
   user through the Request Object URI if persistent per-user Request
   Object URI is used.  A third party may observe it through browser
   history etc. and start correlating the user's activity using it.  It
   is in  In
   a way way, it is a data disclosure as well and should be avoided.

   Therefore, per-user Request Object URI should be avoided.

12.  Acknowledgements

   The following people contributed to the creation of this document in
   the OAuth WG.  (Affiliations at the time of the contribution is are
   used.)

   Sergey Beryozkin, Brian Campbell (Ping Identity), Vladimir Dzhuvinov
   (Connect2id), Michael B.  Jones (Microsoft), Torsten Lodderstedt
   (Deutsche Telecom) Jim Manico, Axel Nenker(Deutsche Telecom), Hannes
   Tschofenig (ARM), Denis Pinkas, Kathleen Moriarty (as AD), and Steve Kent (as
   SECDIR).

   The following people contributed to creating this document through
   the OpenID Connect Core 1.0 [OpenID.Core].

   Brian Campbell (Ping Identity), George Fletcher (AOL), Ryo Itou
   (Mixi), Edmund Jay (Illumila), Michael B.  Jones (Microsoft), Breno
   de Medeiros (Google), Hideki Nara (TACT), Justin Richer (MITRE).

   In addition, the following people contributed to this and previous
   versions through the OAuth Working Group.

   Dirk Balfanz (Google), James H.  Manger (Telstra), John Panzer
   (Google), David Recordon (Facebook), Marius Scurtescu (Google), Luke
   Shepard (Facebook).

13.  Revision History

   -12

   o  fixes #48 - OPSDIR Review : General - delete semicolors after list
      items

   o  fixes #58 - DP Comments for the Last Call

   o  fixes #57 - GENART - Remove "non-normative ... " from examples.

   o  fixes #45 - OPSDIR Review : Introduction - are attacks discovered
      or already opened

   o  fixes #49 - OPSDIR Review : Introduction - Inconsistent colons
      after initial sentence of list items.

   o  fixes #53 - OPSDIR Review : 6.2 JWS Signed Request Object -
      Clarify JOSE Header

   o  fixes #42 - OPSDIR Review : Introduction - readability of 'and' is
      confusing

   o  fixes #50 - OPSDIR Review : Section 4 Request Object - Clarify
      'signed, encrypted, or signed and encrypted'

   o  fixes #39 - OPSDIR Review : Abstract - Explain/Clarify JWS and JWE

   o  fixed #50 - OPSDIR Review : Section 4 Request Object - Clarify
      'signed, encrypted, or signed and encrypted'

   o  fixes #43 - OPSDIR Review : Introduction - 'properties' sounds
      awkward and are not exactly 'properties'

   o  fixes #56 - OPSDIR Review : 12 Acknowledgements - 'contribution
      is' => 'contribution are'

   o  fixes #55 - OPSDIR Review : 11.2.2 Privacy Considerations - ' It
      is in a way' => 'In a way, it is'

   o  fixes #54 - OPSDIR Review : 11 Privacy Considerations - 'and not
      specific' => 'and are not specific'

   o  fixes #51 - OPSDIR Review : Section 4 Request Object - 'It is
      fine' => 'It is recommended'

   o  fixes #47 - OPSDIR Review : Introduction - 'over- the- wire' =>
      'over-the-wire'

   o  fixes #46 - OPSDIR Review : Introduction - 'It allows' => 'The use
      of application security' for

   o  fixes #44 - OPSDIR Review : Introduction - 'has' => 'have'

   o  fixes #41 - OPSDIR Review : Introduction - missing 'is' before
      'typically sent'

   o  fixes #38 - OPSDIR Review : Section 11 - Delete 'freely
      accessible' regarding ISO 29100

   -11

   o  s/bing/being/

   o  Added history for -10

   -10

   o  #20: KM1 -- some wording that is awkward in the TLS section.

   o  #21: KM2 - the additional attacks against OAuth 2.0 should also
      have a pointer

   o  #22: KM3 -- Nit: in the first line of 10.4:

   o  #23: KM4 -- Mention RFC6973 in Section 11 in addition to ISO 29100

   o  #24: SECDIR review: Section 4 -- Confusing requirements for
      sign+encrypt

   o  #25: SECDIR review: Section 6 -- authentication and integrity need
      not be provided if the requestor encrypts the token?

   o  #26: SECDIR Review: Section 10 -- why no reference for JWS
      algorithms?

   o  #27: SECDIR Review: Section 10.2 - how to do the agreement between
      client and server "a priori"?

   o  #28: SECDIR Review: Section 10.3 - Indication on "large entropy"
      and "short lifetime" should be indicated

   o  #29: SECDIR Review: Section 10.3 - Typo

   o  #30: SECDIR Review: Section 10.4 - typos and missing articles

   o  #31: SECDIR Review: Section 10.4 - Clearer statement on the lack
      of endpoint identifiers needed

   o  #32: SECDIR Review: Section 11 - ISO29100 needs to be moved to
      normative reference

   o  #33: SECDIR Review: Section 11 - Better English and Entropy
      language needed

   o  #34: Section 4: Typo

   o  #35: More Acknowledgment

   o  #36: DP - More precise qualification on Encryption needed.

   -09

   o  Minor Editorial Nits.

   o  Section 10.4 added.

   o  Explicit reference to Security consideration (10.2) added in
      section 5 and section 5.2.

   o  , (add yourself) removed from the acknowledgment.

   -08

   o  Applied changes proposed by Hannes on 2016-06-29 on IETF OAuth
      list recorded as https://bitbucket.org/Nat/oauth-jwsreq/
      issues/12/.

   o  TLS requirements added.

   o  Security Consideration reinforced.

   o  Privacy Consideration added.

   o  Introduction improved.

   -07

   o  Changed the abbrev to OAuth JAR from oauth-jar.

   o  Clarified sig and enc methods.

   o  Better English.

   o  Removed claims from one of the example.

   o  Re-worded the URI construction.

   o  Changed the example to use request instead of request_uri.

   o  Clarified that Request Object parameters take precedence
      regardless of request or request_uri parameters were used.

   o  Generalized the language in 4.2.1 to convey the intent more
      clearly.

   o  Changed "Server" to "Authorization Server" as a clarification.

   o  Stopped talking about request_object_signing_alg.

   o  IANA considerations now reflect the current status.

   o  Added Brian Campbell to the contributors list.  Made the lists
      alphabetic order based on the last names.  Clarified that the
      affiliation is at the time of the contribution.

   o  Added "older versions of " to the reference to IE uri length
      limitations.

   o  Stopped talking about signed or unsigned JWS etc.

   o  1.Introduction improved.

   -06

   o  Added explanation on the 512 chars URL restriction.

   o  Updated Acknowledgements.

   -05

   o  More alignment with OpenID Connect.

   -04

   o  Fixed typos in examples. (request_url -> request_uri, cliend_id ->
      client_id)

   o  Aligned the error messages with the OAuth IANA registry.

   o  Added another rationale for having request object.

   -03

   o  Fixed the non-normative description about the advantage of static
      signature.

   o  Changed the requirement for the parameter values in the request
      itself and the request object from 'MUST MATCH" to 'Req Obj takes
      precedence.

   -02

   o  Now that they are RFCs, replaced JWS, JWE, etc. with RFC numbers.

   -01

   o  Copy Edits.

14.  References
14.1.  Normative References

   [ISO29100]
              "ISO/IEC 29100 Information technology - Security
              techniques - Privacy framework", December 2011,
              <http://standards.iso.org/ittf/PubliclyAvailableStandards/
              c045123_ISO_IEC_29100_2011.zip>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [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, DOI 10.17487/RFC6125, March
              2011, <http://www.rfc-editor.org/info/rfc6125>.

   [RFC6234]  Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
              (SHA and SHA-based HMAC and HKDF)", RFC 6234,
              DOI 10.17487/RFC6234, May 2011,
              <http://www.rfc-editor.org/info/rfc6234>.

   [RFC6749]  Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
              RFC 6749, DOI 10.17487/RFC6749, October 2012,
              <http://www.rfc-editor.org/info/rfc6749>.

   [RFC6750]  Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
              Framework: Bearer Token Usage", RFC 6750,
              DOI 10.17487/RFC6750, October 2012,
              <http://www.rfc-editor.org/info/rfc6750>.

   [RFC6819]  Lodderstedt, T., Ed., McGloin, M., and P. Hunt, "OAuth 2.0
              Threat Model and Security Considerations", RFC 6819,
              DOI 10.17487/RFC6819, January 2013,
              <http://www.rfc-editor.org/info/rfc6819>.

   [RFC6973]  Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
              Morris, J., Hansen, M., and R. Smith, "Privacy
              Considerations for Internet Protocols", RFC 6973,
              DOI 10.17487/RFC6973, July 2013,
              <http://www.rfc-editor.org/info/rfc6973>.

   [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
              2014, <http://www.rfc-editor.org/info/rfc7159>.

   [RFC7515]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
              2015, <http://www.rfc-editor.org/info/rfc7515>.

   [RFC7516]  Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
              RFC 7516, DOI 10.17487/RFC7516, May 2015,
              <http://www.rfc-editor.org/info/rfc7516>.

   [RFC7518]  Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
              DOI 10.17487/RFC7518, May 2015,
              <http://www.rfc-editor.org/info/rfc7518>.

   [RFC7519]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
              <http://www.rfc-editor.org/info/rfc7519>.

   [RFC7525]  Sheffer, Y., Holz, R., and P. Saint-Andre,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
              2015, <http://www.rfc-editor.org/info/rfc7525>.

14.2.  Informative References

   [BASIN]    Basin, D., Cremers, C., and S. Meier, "Provably Repairing
              the ISO/IEC 9798 Standard for Entity Authentication",
              Journal of Computer Security - Security and Trust
              Principles Volume 21 Issue 6, Pages 817-846, November
              2013,
              <https://www.cs.ox.ac.uk/people/cas.cremers/downloads/
              papers/BCM2012-iso9798.pdf>.

   [OpenID.Core]
              Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
              C. Mortimore, "OpenID Connect Core 1.0", OpenID
              Foundation Standards, February 2014,
              <http://openid.net/specs/openid-connect-core-1_0.html>.

Authors' Addresses
   Nat Sakimura
   Nomura Research Institute
   1-6-5 Marunouchi, Marunouchi Kitaguchi Bldg.
   Otemachi Financial City Grand Cube, 1-9-2 Otemachi
   Chiyoda-ku, Tokyo  100-0005  100-0004
   Japan

   Phone: +81-3-5533-2111
   Email: n-sakimura@nri.co.jp
   URI:   http://nat.sakimura.org/

   John Bradley
   Ping Identity
   Casilla 177, Sucursal Talagante
   Talagante, RM
   Chile

   Phone: +44 20 8133 3718
   Email: ve7jtb@ve7jtb.com
   URI:   http://www.thread-safe.com/