draft-ietf-oauth-jwt-introspection-response.xml

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<rfc category="std" docName="draft-ietf-oauth-jwt-introspection-response-11"
     ipr="trust200902">
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  <!-- ***** FRONT MATTER ***** -->

  <front>
    <!--
			The abbreviated title is used in the page header - it is only
			necessary if the full title is longer than 39 characters
		-->

    <title abbrev="JWT Response">JWT Response for OAuth Token Introspection</title>

    <author fullname="Torsten Lodderstedt" initials="T." role="editor"
            surname="Lodderstedt">
      <organization>yes.com AG</organization>

      <address>
        <email>torsten@lodderstedt.net</email>

        <!-- uri and facsimile elements may also be added -->
      </address>
      </author>
          
    <author fullname="Vladimir Dzhuvinov" initials="V." 
            surname="Dzhuvinov">
      <organization>Connect2id Ltd.</organization>

      <address>
        <email>vladimir@connect2id.com</email>

        <!-- uri and facsimile elements may also be added -->
      </address>
    </author>

    <date day="20" month="June" year="2021" />

    <!-- Meta-data Declarations -->

    <area>Security Area</area>

    <workgroup>Open Authentication Protocol</workgroup>

    <!--
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			individual submissions. If this element is not present, the default
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    <keyword>token introspection</keyword>
    
    <keyword>JWT</keyword>

    <keyword>oauth2</keyword>

    <!--
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    <abstract>
      <t>This specification proposes an additional JSON Web Token (JWT) secured response
      for OAuth 2.0 Token Introspection.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="Introduction" title="Introduction">
      <t><xref target="RFC7662">OAuth 2.0 Token Introspection</xref> specifies a 
      method for a protected resource to query an OAuth 2.0 authorization server 
      to determine the state of an access token and obtain data associated with
      the access token. This enables deployments to implement opaque access
      tokens in an interoperable way.</t>
      <t>The introspection response, as specified in <xref target="RFC7662">OAuth
      2.0 Token Introspection</xref>, is a plain JSON object.
      However, there are use cases where the resource server requires stronger
      assurance that the authorization server issued the token introspection 
      response for an access token, including cases where the authorization server 
      assumes liability for the content of the token introspection response. 
      An example is a resource server using verified person data to create certificates, 
      which in turn are used to create qualified electronic signatures.</t>
      <t>In such use cases it may be useful or even required to return a
      signed <xref target="RFC7519">JWT</xref> as the introspection response. 
      This specification extends the token introspection endpoint with the capability 
      to return responses as JWTs.</t>
      </section>
      
       <section anchor="RNC" title="Requirements Notation and Conventions">
<t>
  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL"
  in this document are to be interpreted as described in
  BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/>
  when, and only when, they appear in all capitals, as shown here.
</t>
    </section>
    
    <section anchor="as-rs-relationship" title="Resource Server Management">
    <t>The authorization server (AS) and the resource server (RS) maintain a strong two-way trust relationship.
    The resource server relies on the authorization server to obtain authorization,
    user and other data as input to its access control decisions and service delivery.
    The authorization server relies on the resource server to handle the provided data
    appropriately.</t> 
    <t>In the context of this specification, the token introspection endpoint is used to convey
    such security data and potentially also privacy sensitive data related to an access
    token.</t>
    <t>In order to process the introspection requests in a secure and
    privacy-preserving manner, the authorization server MUST be able to identify, 
    authenticate and authorize resource servers.</t>
    <t>The authorization server MAY additionally encrypt the token introspection response JWTs.
    If encryption is used the authorization server is provisioned with encryption keys and
    algorithms for the RS.</t>
    <t>The authorization server MUST be able to determine whether an RS is the
    audience for a particular access token and what data it is entitled to receive,
    otherwise the RS is not authorized to obtain data for the access token.
    The AS has the discretion how to fulfil this requirement. The AS could, for example,
    maintain a mapping between scope values and resource servers.</t>
    <t>The requirements given above imply that the authorization server
    maintains credentials and other configuration data for each RS.</t>
    <t>One way is by utilizing dynamic client registration <xref target="RFC7591"/>
    and treating every RS as an OAuth client. In this case, the authorization server
    is assumed to at least maintain a "client_id" and a "token_endpoint_auth_method"
    with complementary authentication method metadata, such as "jwks" or "client_secret".
    In cases where the AS needs to acquire consent to transmit data to a RS, the following
    client metadata fields are recommended: "client_name", "client_uri", "contacts",
    "tos_uri", "policy_uri".</t>
    <t>The AS MUST restrict the use of client credentials by a RS to the calls
    it requires, e.g. the AS MAY restrict such a client to call
    the token introspection endpoint only. How the AS implements this restriction
    is beyond the scope of this specification.</t>
    <t>This specification further introduces client metadata to manage the
    configuration options required to sign and encrypt token introspection 
    response JWTs.</t>
    </section>

	<section anchor="jwt_request" title="Requesting a JWT Response">
    
	<t>A resource server requests a JWT introspection response by sending an introspection request
    with an <spanx style="verb">Accept</spanx> HTTP header field set to
    "application/token-introspection+jwt".</t>

    <t>The AS MUST authenticate the caller at the token introspection endpoint. Authentication can
    utilize client authentication methods or a separate access token issued to the resource server
    and identifying it as subject.</t>

    <t>The following is a non-normative example request, with the resource
    server authenticating with a private key JWT:</t>

	  <t>
	  	<figure>
          <artwork><![CDATA[POST /introspect HTTP/1.1
Host: as.example.com
Accept: application/token-introspection+jwt
Content-Type: application/x-www-form-urlencoded

token=2YotnFZFEjr1zCsicMWpAA&
client_assertion_type=
 urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer&
client_assertion=PHNhbWxwOl[...omitted for brevity...]ZT]]></artwork>
        </figure>
	  </t>

	</section>
	
    <section anchor="jwt_response" title="JWT Response">
    
     <t>The introspection endpoint responds with a JWT, setting the
     <spanx style="verb">Content-Type</spanx> HTTP header field to
     "application/token-introspection+jwt" and the JWT <spanx style="verb">typ</spanx>
     ("type") header parameter to "token-introspection+jwt".</t>

     <t>The JWT MUST include the following top-level claims:
     <list hangIndent="8" style="hanging">
         <t hangText="iss">MUST be set to the issuer URL of the authorization
         server.</t>
         <t hangText="aud">MUST identify the resource server receiving the token
         introspection response.</t>
         <t hangText="iat">MUST be set to the time when the introspection response
         was created by the authorization server.</t>
         <t hangText="token_introspection">A JSON object containing the members
         of the token introspection response as specified in <xref target="RFC7662"/>, section 2.2.
         The separation of the introspection response members into
         a dedicated containing JWT claim is intended to prevent conflict and confusion
         with top-level JWT claims that may bear the same name.
         <vspace blankLines="1" />
         If the access token is invalid, expired, revoked, or not intended for the
         calling resource server (audience), the authorization server MUST set the value of the
         <spanx style="verb">active</spanx> member in the <spanx style="verb">token_introspection</spanx>
         claim to <spanx style="verb">false</spanx> and MUST NOT include other members.
         Otherwise, the <spanx style="verb">active</spanx> member is set to <spanx style="verb">true</spanx>.
         <vspace blankLines="1" />
         The AS SHOULD narrow down the <spanx style="verb">scope</spanx> value to the scopes
         relevant to the particular RS.
         <vspace blankLines="1" />
         As specified in section 2.2 of <xref target="RFC7662"/>, implementations MAY extend the
         token introspection response with service-specific claims. In the context of this
         specification, such claims will be added as top-level members of the
         <spanx style="verb">token_introspection</spanx> claim.
         <vspace blankLines="1" />
         Token introspection response parameter names intended to be used across domains MUST be
         registered in the <xref target="IANA.OAuth.Token.Introspection">OAuth Token Introspection
         Response registry</xref> defined by <xref target="RFC7662"/>.
         <vspace blankLines="1" />
         When the AS acts as a provider of resource owner
         identity claims to the RS, the AS determines based on its RS-specific policy what
         identity claims to return in the token introspection response.
         The AS MUST ensure the release of any privacy-sensitive data is legally based (see
         <xref target="privacy"/>).
         <vspace blankLines="1" />
         Further content of the introspection response is determined by the RS-specific
         policy at the AS.</t>
     </list>
     </t>

     <t>The JWT MAY include other claims, including those from the "JSON Web Token Claims"
     registry established by <xref target="RFC7519"/>. The JWT SHOULD NOT include the
     <spanx style="verb">sub</spanx> and <spanx style="verb">exp</spanx> claims,
     as an additional prevention against misuse of the JWT as an access token (see
     <xref target="Cross-JWT_Confusion"/>).</t>
          
     <t>Note: Although the JWT format is widely used as an access token format, the JWT
     returned in the introspection response is not an alternative representation of 
     the introspected access token and is not intended to be used as an access token.</t>
     
     <t>This specification registers the "application/token-introspection+jwt" media type, 
     which is used as value of the <spanx style="verb">typ</spanx> ("type") header
     parameter of the JWT to indicate that the payload is a token introspection response.</t>

     <t>The JWT is cryptographically secured as specified in <xref target="RFC7519"/>.</t>

     <t>Depending on the specific resource server policy the JWT is either
     signed, or signed and encrypted. If the JWT is signed and encrypted it
     MUST be a Nested JWT, as defined in <xref target="RFC7519">JWT</xref>.</t>

     <t>Note: An AS compliant with this specification MUST refuse to serve introspection
     requests that don't authenticate the caller, and return an HTTP status code 400. This is
     done to ensure token data is released to legitimate recipients only and prevent
     downgrading to <xref target="RFC7662"/> behavior (see
     <xref target="token_data_leakage"/>).</t>
      
     <t>The following is a non-normative example response
     (with line breaks for display purposes only):</t>

	 <t>
	  	<figure>
          <artwork><![CDATA[HTTP/1.1 200 OK
Content-Type: application/token-introspection+jwt

eyJraWQiOiJ3RzZEIiwidHlwIjoidG9rZW4taW50cm9zcGVjdGlvbitqd3QiLCJhbGc
iOiJSUzI1NiJ9.eyJpc3MiOiJodHRwczovL2FzLmV4YW1wbGUuY29tLyIsImF1ZCI6I
mh0dHBzOi8vcnMuZXhhbXBsZS5jb20vcmVzb3VyY2UiLCJpYXQiOjE1MTQ3OTc4OTIs
InRva2VuX2ludHJvc3BlY3Rpb24iOnsiYWN0aXZlIjp0cnVlLCJpc3MiOiJodHRwczo
vL2FzLmV4YW1wbGUuY29tLyIsImF1ZCI6Imh0dHBzOi8vcnMuZXhhbXBsZS5jb20vcm
Vzb3VyY2UiLCJpYXQiOjE1MTQ3OTc4MjIsImV4cCI6MTUxNDc5Nzk0MiwiY2xpZW50X
2lkIjoicGFpQjJnb28wYSIsInNjb3BlIjoicmVhZCB3cml0ZSBkb2xwaGluIiwic3Vi
IjoiWjVPM3VwUEM4OFFyQWp4MDBkaXMiLCJiaXJ0aGRhdGUiOiIxOTgyLTAyLTAxIiw
iZ2l2ZW5fbmFtZSI6IkpvaG4iLCJmYW1pbHlfbmFtZSI6IkRvZSIsImp0aSI6InQxRm
9DQ2FaZDRYdjRPUkpVV1ZVZVRaZnNLaFczMENRQ3JXRERqd1h5NncifX0.przJMU5Gh
mNzvwtt1Sr-xa9xTkpiAg5IshbQsRiRVP_7eGR1GHYrNwQh84kxOkHCyje2g5WSRcYo
sGEVIiC-eoPJJ-qBwqwSlgx9JEeCDw2W5DjrblOI_N0Jvsq_dUeOyoWVMqlOydOBhKN
Y0smBrI4NZvEExucOm9WUJXMuJtvq1gBes-0go5j4TEv9sOP9uu81gqWTr_LOo6pgT0
tFFyZfWC4kbXPXiQ2YT6mxCiQRRNM-l9cBdF6Jx6IOrsfFhBuYdYQ_mlL19HgDDOFal
eyqmru6lKlASOsaE8dmLSeKcX91FbG79FKN8un24iwIDCbKT9xlUFl54xWVShNDFA]]></artwork>
        </figure>	
        </t>
        <t>
        The example response JWT header contains the following JSON document:
        </t>
        <t>
        <figure>
          <artwork><![CDATA[{
  "typ": "token-introspection+jwt",
  "alg": "RS256",
  "kid": "wG6D"
}]]></artwork>
        </figure>
        </t>
        <t>
        The example response JWT payload contains the following JSON document:
        </t>
        <t>
        <figure>
          <artwork><![CDATA[{
  "iss":"https://as.example.com/",
  "aud":"https://rs.example.com/resource",
  "iat":1514797892,
  "token_introspection":
     {
        "active":true,
        "iss":"https://as.example.com/",
        "aud":"https://rs.example.com/resource",
        "iat":1514797822,
        "exp":1514797942,
        "client_id":"paiB2goo0a",
        "scope":"read write dolphin",
        "sub":"Z5O3upPC88QrAjx00dis",
        "birthdate":"1982-02-01",
        "given_name":"John",
        "family_name":"Doe",
        "jti":"t1FoCCaZd4Xv4ORJUWVUeTZfsKhW30CQCrWDDjwXy6w"
     }
}]]></artwork>
        </figure>

	  </t>

    </section>
    
    <section anchor="client_metadata" title="Client Metadata">
      <t>The authorization server determines the algorithm to
      secure the JWT for a particular introspection response. This decision can
      be based on registered metadata parameters for the resource server,
      supplied via dynamic client registration <xref target="RFC7591"/> with the 
      resource server acting as a client, as specified below.</t>
      <t>The parameter names follow the pattern established by
      <xref target="OpenID.Registration">OpenID Connect
      Dynamic Client Registration</xref> for configuring signing and encryption
      algorithms for JWT responses at the UserInfo endpoint.</t>
      <t>The following client metadata parameters are introduced by this
      specification:
		<list hangIndent="8" style="hanging">
      	  <t hangText="introspection_signed_response_alg">OPTIONAL. 
      	  <xref target="RFC7515">JWS</xref> 
      	  algorithm (<spanx style="verb">alg</spanx> value) as defined in 
      	  <xref target="RFC7518">JWA</xref> for signing introspection responses. If
      	  this is specified, the response will be signed using JWS and the 
      	  configured algorithm. The default, if omitted, is <spanx style="verb">RS256</spanx>.</t>
          <t hangText="introspection_encrypted_response_alg">OPTIONAL.
          <xref target="RFC7516">JWE</xref> algorithm (<spanx style="verb">alg</spanx> value) 
          as defined in <xref target="RFC7518">JWA</xref> for content key encryption.
          
          If this is specified, the response will be encrypted using JWE and the 
          configured content encryption algorithm 
          (<spanx style="verb">introspection_encrypted_response_enc</spanx>). The default, 
          if omitted, is that no encryption is performed.
          
          If both signing and 
          encryption are requested, the response will be 
          signed then encrypted, with the result being a Nested JWT, as defined in 
          <xref target="RFC7519">JWT</xref>.</t>
          <t hangText="introspection_encrypted_response_enc">OPTIONAL.
          <xref target="RFC7516">JWE</xref> algorithm (<spanx style="verb">enc</spanx> value) 
          as defined in <xref target="RFC7518">JWA</xref> for content encryption of 
          introspection responses. The default, if omitted, is <spanx style="verb">A128CBC-HS256</spanx>.
          Note: This parameter MUST NOT be specified without setting 
          <spanx style="verb">introspection_encrypted_response_alg</spanx>.</t>
        </list>
      </t>
     <t>Resource servers may register their public encryption keys 
      using the <spanx style="verb">jwks_uri</spanx> or <spanx style="verb">jwks</spanx> 
      metadata parameters.</t>
    </section>    
    
    <section anchor="server_metadata" title="Authorization Server Metadata">
      <t>Authorization servers SHOULD publish the supported algorithms for
      signing and encrypting the JWT of an introspection response by utilizing
      <xref target="RFC8414">OAuth 2.0 Authorization Server Metadata</xref>
      parameters. Resource servers use this data to parametrize their client
      registration requests.</t>
     <t>The following parameters are introduced by this specification: 
		<list hangIndent="8" style="hanging">
				
		<t hangText="introspection_signing_alg_values_supported">
		OPTIONAL. JSON array containing a list of the <xref target="RFC7515">JWS</xref> signing 
		algorithms (<spanx style="verb">alg</spanx> values) as defined in 
		<xref target="RFC7518">JWA</xref> supported by the introspection
		endpoint to sign the response.</t>

		<t hangText="introspection_encryption_alg_values_supported">
		OPTIONAL. JSON array containing a list of the <xref target="RFC7516">JWE</xref> 
		encryption algorithms (<spanx style="verb">alg</spanx> values) as defined in
		<xref target="RFC7518">JWA</xref> supported by the 
		introspection endpoint to encrypt the content encryption key for 
		introspection responses (content key encryption).</t>

		<t hangText="introspection_encryption_enc_values_supported">
		OPTIONAL. JSON array containing a list of the <xref target="RFC7516">JWE</xref> 
		encryption algorithms (<spanx style="verb">enc</spanx> values) as defined in
		<xref target="RFC7518">JWA</xref> supported by the introspection
		endpoint to encrypt the response (content encryption).</t>

        </list>
      </t>
    </section>
    
    <section anchor="Security" title="Security Considerations">
     <section anchor="Cross-JWT_Confusion" title="Cross-JWT Confusion">
      <t>The <spanx style="verb">iss</spanx> and potentially the <spanx style="verb">aud</spanx>
      claim of a token introspection JWT can resemble those of a JWT-encoded access token.
      An attacker could try to exploit this and pass a JWT token introspection response as
      an access token to the resource server. The <spanx style="verb">typ</spanx> ("type")
      JWT header "token-introspection+jwt" and the encapsulation of the token introspection members
      such as <spanx style="verb">sub</spanx> and <spanx style="verb">scope</spanx> in
      the <spanx style="verb">token_introspection</spanx> claim is intended to prevent such
      substitution attacks. Resource servers MUST therefore check the <spanx style="verb">typ</spanx>
      JWT header value of received JWT-encoded access tokens and ensure all minimally
      required claims for a valid access token are present.</t>
      
      <t>Resource servers MUST additionally apply the countermeasures against replay 
      as described in <xref target="I-D.ietf-oauth-security-topics"/>, section 3.2.</t>
      <t>JWT Confusion and other attacks involving JWTs are discussed in
      <xref target="I-D.ietf-oauth-jwt-bcp"/>.</t>
           </section>

      <section anchor="token_data_leakage" title="Token Data Leakage">
      <t>The authorization server MUST use Transport Layer Security (TLS) 1.2
      (or higher) per BCP 195 <xref target="RFC7525"/> in order to prevent 
      token data leakage.</t>

      <t>Section 2.1 of <xref target="RFC7662"/> permits requests to the introspection endpoint to
      be authorized with an access token which doesn't identify the caller. To prevent
      introspection of tokens by parties that are not the intended consumer the
      authorization server MUST require all requests to the token introspection endpoint to be
      authenticated.</t>
      </section>

    </section>
    
    <section anchor="privacy" title="Privacy Considerations">
     <t>The token introspection response can be used to transfer personal identifiable 
     information (PII) from the AS to the RS. The AS MUST conform to legal and jurisdictional constraints
     for the data transfer before any data is released to a particular RS. The details and determining
     of these constraints varies by jurisdiction and is outside the scope of this document.</t>
     <t>A commonly found way to establish the legal basis for releasing PII is by explicit user
     consent gathered from the resource owner by the AS during the authorization flow.</t>
     <t>It is also possible that the legal basis is established out of band, for example in
     an explicit contract or by the client gathering the resource owner's consent.</t> 
     <t>If the AS and the RS belong to the same legal entity (1st party scenario), there is
     potentially no need for an explicit user consent but the terms of service and policy
     of the respective service provider MUST be enforced at all times.</t>
     <t>In any case, the AS MUST ensure that the scope of the legal basis is enforced
     throughout the whole process. The AS MUST retain the scope of the legal basis with 
     the access token, e.g. in the scope value, it MUST authenticate the RS, and the AS MUST
     determine the data a resource server is allowed to receive based on the resource server’s identity and 
     suitable token data, e.g. the scope value. </t>
     <t>Implementers should be aware that a token introspection request lets the AS know when the client 
     (and potentially the user) is accessing the RS, which is also an indication of when the user is using 
     the client. If this implication is not acceptable, implementers MUST use other means to relay
     access token data, for example by directly transferring the data needed by the RS within the access
     token.</t>
    </section>
    
    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>We would like to thank Petteri Stenius, Neil Madden, Filip Skokan, Tony 
      Nadalin, Remco Schaar, Justin Richer, Takahiko Kawasaki, Benjamin Kaduk,
      Robert Wilton and Roman Danyliw for their valuable feedback.</t>
    </section>

    <!-- Possibly a 'Contributors' section ... -->

    <section anchor="IANA" title="IANA Considerations">  
      
      <section anchor="DynRegReg" title="OAuth Dynamic Client Registration Metadata Registration">
        <t>
          This specification requests registration of the following client metadata definitions
          in the IANA "OAuth Dynamic Client Registration Metadata" registry
          <xref target="IANA.OAuth.Parameters"/>
          established by <xref target="RFC7591"/>:
        </t>

        <section anchor="DynRegContents" title="Registry Contents">
          <t>
            <list style="symbols">
              <t>
                Client Metadata Name: <spanx style="verb">introspection_signed_response_alg</spanx>
              </t>
              <t>
                Client Metadata Description:
                String value indicating the client's desired introspection response 
                signing algorithm.
              </t>
              <t>
                Change Controller: IESG
              </t>
              <t>
                Specification Document(s): <xref target="client_metadata"/> of [[ this specification ]]
              </t>
            </list>
          </t>
          <t>
            <list style="symbols">
              <t>
                Client Metadata Name: <spanx style="verb">introspection_encrypted_response_alg</spanx>
              </t>
              <t>
                Client Metadata Description:
                String value specifying the desired introspection response 
                content key encryption algorithm (alg value).
              </t>
              <t>
                Change Controller: IESG
              </t>
              <t>
                Specification Document(s): <xref target="client_metadata"/> of [[ this specification ]]
              </t>
            </list>
          </t>
          <t>
            <list style="symbols">
              <t>
                Client Metadata Name: <spanx style="verb">introspection_encrypted_response_enc</spanx>
              </t>
              <t>
                Client Metadata Description:
                    String value specifying the desired introspection response 
                content encryption algorithm (enc value).
              </t>
              <t>
                Change Controller: IESG
              </t>
              <t>
                Specification Document(s): <xref target="client_metadata"/> of [[ this specification ]]
              </t>
            </list>
          </t>

        </section>
      </section>
      
      <section anchor="ietf-oauth-discoveryIANA" title="OAuth Authorization Server Metadata Registration">
      <t>
        This specification requests registration of the following values
        in the IANA "OAuth Authorization Server Metadata" registry
        <xref target="IANA.OAuth.Parameters"/> established by <xref target="RFC8414"/>.
      </t>
        <section title="Registry Contents">
          <t>
            <list style='symbols'>
              <t>Metadata Name: <spanx style="verb">introspection_signing_alg_values_supported</spanx></t>
              <t>Metadata Description: JSON array containing a list of algorithms supported 
              by the authorization server for introspection response signing.</t>
              <t>Change Controller: IESG</t>
              <t>Specification Document(s): <xref target="server_metadata"/> of [[ this specification ]]</t>             
            </list>
          </t>
          <t>
            <list style='symbols'>
              <t>Metadata Name: <spanx style="verb">introspection_encryption_alg_values_supported</spanx></t>
              <t>Metadata Description: JSON array containing a list of algorithms supported 
              by the authorization server for introspection response content key encryption (alg value).</t>
              <t>Change Controller: IESG</t>
              <t>Specification Document(s): <xref target="server_metadata"/> of [[ this specification ]]</t>             
            </list>
          </t>
          <t>
            <list style='symbols'>
              <t>Metadata Name: <spanx style="verb">introspection_encryption_enc_values_supported</spanx></t>
              <t>Metadata Description: JSON array containing a list of algorithms supported 
              by the authorization server for introspection response content encryption (enc value).</t>
              <t>Change Controller: IESG</t>
              <t>Specification Document(s): <xref target="server_metadata"/> of [[ this specification ]]</t>             
            </list>
          </t>
        </section>
      </section>     
 
      <section anchor="ietf-media-typeIANA" title="Media Type Registration">
      <t>This section registers the "application/token-introspection+jwt" media type
   in the "Media Types" registry <xref target="IANA.MediaTypes"/> in the
   manner described in <xref target="RFC6838"/>, which can be used to indicate that the
   content is a token introspection response in JWT format.</t>
        <section title="Registry Contents">
          <t>
            <list style='symbols'>
              <t>Type name: application</t>
              <t>Subtype name: token-introspection+jwt</t>
   			  <t>Required parameters: N/A</t>
              <t>Optional parameters: N/A</t>
              <t>Encoding considerations: binary; A token introspection response is a JWT; JWT values are
                 encoded as a series of base64url-encoded values (with trailing '='
                 characters removed), some of which may be the empty string,
                 separated by period ('.') characters.</t>
              <t>Security considerations: See Section 7 of this specification</t>
              <t>Interoperability considerations: N/A</t>
              <t>Published specification: Section 4 of this specification</t>
              <t>Applications that use this media type: Applications that produce and consume 
                 OAuth Token Introspection Responses in JWT format</t>
              <t>Fragment identifier considerations: N/A</t>
              <t>Additional information:
                 <list style='symbols'>
                   <t>Magic number(s): N/A</t>
                   <t>File extension(s): N/A</t>
                   <t>Macintosh file type code(s): N/A</t>
                 </list>
              </t>
              <t>Person &amp; email address to contact for further information: Torsten Lodderstedt, 
                 torsten@lodderstedt.net</t>
              <t>Intended usage: COMMON</t>
              <t>Restrictions on usage: none</t>
              <t>Author: Torsten Lodderstedt, torsten@lodderstedt.net</t>
              <t>Change controller: IESG</t>
              <t>Provisional registration?  No</t>              
            </list>
          </t>
        </section>
      </section>

      <section anchor="ietf-jwt-IANA" title="JWT Claim Registration">
      <t>This section registers the "token_introspection" claim in the JSON Web
      Token (JWT) IANA registry <xref target="IANA.JWT"/> in the manner described in
      <xref target="RFC7519"/>.</t>
        <section title="Registry Contents">
          <t>
            <list style='symbols'>
              <t>Claim name: token_introspection</t>
              <t>Claim description: Token introspection response</t>
              <t>Change Controller: IESG</t>
              <t>Specification Document(s): <xref target="jwt_response"/> of [[this specification]]</t>
            </list>
          </t>
        </section>
      </section>

    </section>
    
  </middle>

  <!--  *****BACK MATTER ***** -->

  <back>
    <references title="Normative References">
      <?rfc include="reference.RFC.2119"?>    
      <?rfc include="reference.RFC.6838"?>      
      <?rfc include="reference.RFC.7519"?>
      <?rfc include="reference.RFC.7525"?>
      <?rfc include="reference.RFC.7591"?>
      <?rfc include="reference.RFC.7662"?>
      <?rfc include="reference.RFC.7518"?>
      <?rfc include="reference.RFC.7515"?>
      <?rfc include="reference.RFC.7516"?>
      <?rfc include="reference.RFC.8174"?>
      <?rfc include="reference.RFC.8414"?>
      <?rfc include='http://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.draft-ietf-oauth-jwt-bcp-06.xml'?>
      <?rfc include='http://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.draft-ietf-oauth-security-topics-13.xml'?>
      
       <reference anchor="OpenID.Registration" target="https://openid.net/specs/openid-connect-registration-1_0.html">
        <front>
          <title>OpenID Connect Dynamic Client Registration 1.0 incorporating errata set 1</title>

		  <author fullname="Nat Sakimura">
            <organization>NRI</organization>
          </author>
          <author fullname="John Bradley">
            <organization>Ping Identity</organization>
          </author>
          <author fullname="Mike Jones">
            <organization>Microsoft</organization>
          </author>
          <date day="8" month="Nov" year="2014"/>
        </front>
      </reference>

<reference anchor="IANA.MediaTypes" target="http://www.iana.org/assignments/media-types">
	<front>
	  <title>Media Types</title>
	  <author fullname="IANA">
	    <organization abbrev="ISO">IANA</organization>
	  </author>
          <date/>
	</front>
</reference>

<reference anchor="IANA.JWT" target="https://www.iana.org/assignments/jwt/jwt.xhtml#claims">
	<front>
	  <title>JSON Web Token (JWT) claims registry</title>
	  <author fullname="IANA">
	    <organization abbrev="ISO">IANA</organization>
	  </author>
          <date/>
	</front>
</reference>

    <reference anchor="IANA.OAuth.Token.Introspection" target="https://www.iana.org/assignments/oauth-parameters/oauth-parameters.xhtml#token-introspection-response">
        <front>
          <title>OAuth Token Introspection Response registry</title>
          <author>
            <organization>IANA</organization>
          </author>
          <date/>
        </front>
      </reference>

    </references>

    <references title="Informative References">
          <reference anchor="IANA.OAuth.Parameters" target="http://www.iana.org/assignments/oauth-parameters">
        <front>
          <title>OAuth Parameters</title>
          <author>
            <organization>IANA</organization>
          </author>
          <date/>
        </front>
      </reference>

    </references> 
    
    <section anchor="History" title="Document History">
      <t>[[ To be removed from the final specification ]]</t>

      <t>-11<list style="symbols">
          <t>consistent normative language that the AS must authenticate all callers
              to the token introspection endpoint when complying with this specification</t>
          <t>removes text that claims from the JSON Web Token Claims registry may be included
              in the token_introspection claim</t>
          <t>updates the privacy considerations section</t>
          <t>fixes the example BASE64URL encoded JWT payload</t>
      </list>
      </t>

      <t>-10<list style="symbols">
          <t>added requirement to authenticate RS if privacy sensitive data is released</t>
          <t>reworked text on claims from different registries</t>
          <t>added forward reference to privacy considerations to section 5</t>
          <t>added text in privacy considerations regarding client/user tracking</t>
          </list>
      </t>    

      <t>-09<list style="symbols">
          <t>changes the Accept and Content-Type HTTP headers from
          "application/json" to "application/token-introspection+jwt" so they
          match the registered media type</t>
          <t>moves the token introspection response members into a JSON object
          claim named "token_introspection" to provide isolation from the top-level
          JWT-specific claims</t>
          <t>"iss", "aud" and "iat" MUST be present as top-level JWT claims</t>
          <t>the "sub" and "exp" claims SHOULD NOT be used as top-level JWT
          claims as additional prevention against JWT access token substitution
          attacks</t>
          </list>
      </t>
      
	  <t>-08<list style="symbols">
          <t>made difference between introspected access token and 
          introspection response clearer</t>
          <t>defined semantics of JWT claims overlapping between 
          introspected access token and introspection response as JWT</t>
          <t>added section about RS management</t>
          <t>added text about user claims including a privacy considerations section</t>
          <t>removed registration of OpenID Connect claims to "Token 
          Introspection Response" registry and refer to "JWT Claims" registry instead</t>
          <t>added registration of "application/token-introspection+jwt" media type as
          type identifier of token introspection responses in JWT format</t>
          <t>more changed to incorporate IESG review feedback</t>
        </list>
      </t> 
      
	  <t>-07<list style="symbols">
          <t>fixed wrong description of "locale"</t>
          <t>added references for ISO and ITU specifications</t>
        </list>
      </t>     
      
	  <t>-06<list style="symbols">
          <t>replaced reference to RFC 7159 with reference to RFC 8259</t>
        </list>
      </t> 
      
	  <t>-05<list style="symbols">
          <t>improved wording for TLS requirement</t>
          <t>added RFC 2119 boilerplate</t>
          <t>fixed and updated some references</t>
        </list>
      </t> 
      
	  <t>-04<list style="symbols">
          <t>reworked definition of parameters in section 4</t>
          <t>added text on data minimization to security considerations section</t>
          <t>added statement regarding TLS to security considerations section</t>
        </list>
      </t> 
      
	  <t>-03<list style="symbols">
          <t>added registration for OpenID Connect Standard Claims to 
          OAuth Token Introspection Response registry</t>
        </list>
      </t> 
	  <t>-02<list style="symbols">
          <t>updated references</t>
        </list>
      </t> 
	  <t>-01<list style="symbols">
          <t>adapted wording to preclude any accept header except "application/jwt" if 
          encrypted responses are required</t>
          <t>use registered alg value RS256 for default signing algorithm</t>
          <t>added text on claims in the token introspection response</t>
        </list>
      </t>        
	  <t>-00<list style="symbols">
          <t>initial version of the WG draft</t>   
          <t>defined default signing algorithm</t>
          <t>changed behavior in case resource server is set up for encryption</t> 
          <t>Added text on token data leakage prevention to the security considerations</t>
          <t>moved Security Considerations section forward</t>
        </list>
      </t>   
      <t>WG draft</t>
      <t>-01<list style="symbols">
      	  <t>fixed typos in client meta data field names</t>
      	  <t>added OAuth Server Metadata parameters to publish algorithms supported 
      	  for signing and encrypting the introspection response</t>
      	  <t>added registration of new parameters for OAuth Server Metadata
      	  and Client Registration</t>
      	  <t>added explicit request for JWT introspection response</t>
      	  <t>made iss and aud claims mandatory in introspection response</t>
      	  <t>Stylistic and clarifying edits, updates references</t>
        </list></t> 
      <t>-00<list style="symbols">
          <t>initial version</t>
        </list></t>  
        
    </section>	
  </back>
</rfc>