One document matched: draft-ietf-oauth-v2-bearer-10.xml


<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE rfc SYSTEM 'rfc2629.dtd'>
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>

<rfc category='std' ipr='trust200902' docName='draft-ietf-oauth-v2-bearer-10'>
  <?rfc strict='yes' ?>
  <?rfc toc='yes' ?>
  <?rfc tocdepth='3' ?>
  <?rfc symrefs='yes' ?>
  <?rfc sortrefs='yes' ?>
  <?rfc compact='yes' ?>
  <?rfc subcompact='no' ?>

  <front>
    <title abbrev='OAuth 2.0 Bearer Tokens'>The OAuth 2.0 Authorization Protocol: Bearer Tokens</title>

    <author fullname="Michael B. Jones" surname="Jones" initials="M.B."> <!-- role="editor" -->
      <organization>Microsoft</organization>
      <address>
        <email>mbj@microsoft.com</email>
        <uri>http://self-issued.info/</uri>
      </address>
    </author>
    <author fullname='Dick Hardt' surname='Hardt' initials='D'>
      <organization>independent</organization>
      <address>
        <email>dick.hardt@gmail.com</email>
        <uri>http://dickhardt.org/</uri>
      </address>
    </author>
    <author fullname='David Recordon' surname='Recordon' initials='D'>
      <organization>Facebook</organization>
      <address>
        <email>dr@fb.com</email>
        <uri>http://www.davidrecordon.com/</uri>
      </address>
    </author>

    <date year="2011" month="October" day="19" />

    <abstract>
      <t>
        This specification describes how to use bearer tokens in HTTP
        requests to access OAuth 2.0 protected resources.  Any party
        in possession of a bearer token (a "bearer") can use it to get
        access to granted resources (without demonstrating possession
        of a cryptographic key).  To prevent misuse, the bearer token
        MUST be protected from disclosure in storage and in transport.
      </t>
    </abstract>
  </front>

  <middle>

    <section title='Introduction'>
      <t>
        OAuth enables clients to access protected resources by
        obtaining an access token, which is defined in <xref
        target="I-D.ietf-oauth-v2"/> as "a string representing an access
        authorization issued to the client", rather than using the
        resource owner's credentials directly.
      </t>
      <t>
        Tokens are issued to clients by an authorization server with the approval of
        the resource owner. The client uses the access token to access the protected resources
        hosted by the resource server. This specification describes how to make protected resource
        requests when the OAuth access token is a bearer token.
      </t>
      <t>
        This specification defines the use of bearer tokens with OAuth
        over <xref target='RFC2616'>HTTP</xref> using <xref
        target='RFC5246'>TLS</xref>. Other specifications may extend
        it for use with other transport protocols.
      </t>

      <section title='Notational Conventions'>
        <t>
          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 <xref target='RFC2119' />.
        </t>
        <t>
          This document uses the Augmented Backus-Naur Form (ABNF)
          notation of <xref target='I-D.ietf-httpbis-p1-messaging' />,
          which is based upon the Augmented Backus-Naur Form (ABNF)
          notation of <xref target='RFC5234' />. Additionally, the
          following rules are included
	  from <xref target='I-D.ietf-httpbis-p7-auth' />: b64token, auth-param, and realm;
	  from <xref target='I-D.ietf-httpbis-p1-messaging' />: quoted-string;
	  and from <xref target='RFC3986' />: URI-Reference.
        </t>
        <t>
          Unless otherwise noted, all the protocol parameter names and values are case sensitive.
        </t>
      </section>

      <section title='Terminology'>
        <t>
          <list style='hanging'>
            <t hangText="Bearer Token">
              <vspace />
              A security token with the property that any party in
              possession of the token (a "bearer") can use the token
              in any way that any other party in possession of it can.
              Using a bearer token does not require a bearer to prove
              possession of cryptographic key material
              (proof-of-possession).
            </t>
          </list>
        </t>
        <t>
          All other terms are as defined in <xref target="I-D.ietf-oauth-v2" />.
        </t>
      </section>

      <section title='Overview'>
        <t>
          OAuth provides a method for clients to access a protected resource on behalf of a
          resource owner. In the general case,
	  before a client can access a protected resource, it must first obtain
          an authorization grant from the resource owner and then exchange the authorization grant for
          an access token.
	  The access token represents the grant's scope, duration, and
	  other attributes granted by the authorization grant. The
	  client accesses the protected resource by presenting the
	  access token to the resource server.
	  In some cases, a client can directly present its own
	  credentials to an authorization server to obtain an access
	  token without having to first obtain an authorization grant from a
	  resource owner.
        </t>
        <t>
          The access token provides an abstraction layer, replacing different authorization
          constructs (e.g. username and password, assertion) for a single token understood by the
          resource server. This abstraction enables issuing access tokens valid for a short time
          period, as well as removing the resource server's need to understand a wide range of
          authentication schemes.
        </t>
        <figure title='Abstract Protocol Flow' anchor='Figure-1'>
          <artwork>
<![CDATA[+--------+                               +---------------+
|        |--(A)- Authorization Request ->|   Resource    |
|        |                               |     Owner     |
|        |<-(B)-- Authorization Grant ---|               |
|        |                               +---------------+
|        |
|        |        Authorization Grant &  +---------------+
|        |--(C)--- Client Credentials -->| Authorization |
| Client |                               |     Server    |
|        |<-(D)----- Access Token -------|               |
|        |                               +---------------+
|        |
|        |                               +---------------+
|        |--(E)----- Access Token ------>|    Resource   |
|        |                               |     Server    |
|        |<-(F)--- Protected Resource ---|               |
+--------+                               +---------------+]]>
          </artwork>
        </figure>
        <t>
          The abstract flow illustrated in <xref target='Figure-1' /> describes the overall
          OAuth 2.0 protocol architecture. The following steps are specified within this
          document:

          <list>
            <t>
              E) The client makes a protected resource request to the resource server by presenting
              the access token.
            </t>
            <t>
              F) The resource server validates the access token, and if valid, serves the request.
            </t>
          </list>
        </t>
      </section>
    </section>

    <section title='Authenticated Requests'>
      <t>
	Clients MAY use bearer tokens to make authenticated requests
	to access protected resources.  This section defines three
	methods of sending bearer access tokens in resource requests
	to resource servers.  Clients MUST NOT use more than one
	method to transmit the token in each request
      </t>

      <section title='The Authorization Request Header Field' anchor='authz-header'>
        <t>
	  When sending the access token in the <spanx
	  style='verb'>Authorization</spanx> request header field
	  defined by <xref target='I-D.ietf-httpbis-p7-auth' />, the
	  client uses the <spanx style='verb'>Bearer</spanx>
	  authentication scheme to transmit the access token.
        </t>
        <figure>
          <preamble>
            For example:
          </preamble>
          <artwork>
<![CDATA[GET /resource HTTP/1.1
Host: server.example.com
Authorization: Bearer vF9dft4qmT]]>
          </artwork>
        </figure>
        <t>
          The <spanx style='verb'>Authorization</spanx> header field uses the framework defined by
          <xref target='I-D.ietf-httpbis-p7-auth' /> follows:
        </t>
        <figure>
          <artwork>
<![CDATA[credentials = "Bearer" 1*SP b64token]]>
          </artwork>
        </figure>
	<t>
	  Clients SHOULD make authenticated requests with a bearer
	  token using the <spanx style='verb'>Authorization</spanx>
	  request header field with the <spanx
	  style='verb'>Bearer</spanx> HTTP authorization scheme.
	  Resource servers MUST support this method.
	</t>
      </section>

      <section title='Form-Encoded Body Parameter' anchor='body-param'>
        <t>
          When sending the access token in the HTTP request
          entity-body, the client adds the access token to the request
          body using the <spanx style='verb'>access_token</spanx>
          parameter.  The client MUST NOT use this method unless
	  all of the following conditions are met:
          <list style='symbols'>
            <t>
              The HTTP request entity-body is single-part.
            </t>
            <t>
              The entity-body follows the encoding requirements of the
              <spanx style='verb'>application/x-www-form-urlencoded</spanx> content-type as
              defined by <xref target='W3C.REC-html401-19991224' />.
            </t>
            <t>
              The HTTP request entity-header includes the <spanx style='verb'>Content-Type</spanx>
              header field set to <spanx style='verb'>application/x-www-form-urlencoded</spanx>.
            </t>
            <t>
              The HTTP request method is one for which the request
              body has defined semantics.  In particular,
              this means that the <spanx style='verb'>GET</spanx>
              method MUST NOT be used.
            </t>
          </list>
        </t>
        <t>
          The entity-body MAY include other request-specific
          parameters, in which case, the <spanx
          style='verb'>access_token</spanx> parameter MUST be properly
          separated from the request-specific parameters using <spanx
          style='verb'>&</spanx> character(s) (ASCII code 38).
        </t>
        <figure>
          <preamble>
            For example, the client makes the following HTTP request using transport-layer
            security:
          </preamble>
          <artwork>
<![CDATA[POST /resource HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded

access_token=vF9dft4qmT]]>
          </artwork>
        </figure>
	<t>
	  The <spanx style='verb'>application/x-www-form-urlencoded</spanx>
	  method SHOULD NOT be used except in application contexts
	  where participating browsers do not have access to the
	  <spanx style='verb'>Authorization</spanx> request header
	  field.  Resource servers MAY support this method.
	</t>
      </section>

      <section title='URI Query Parameter' anchor='query-param'>
        <t>
          When sending the access token in the HTTP request URI, the client adds the access
          token to the request URI query component as defined by <xref target='RFC3986' /> using
          the <spanx style='verb'>access_token</spanx> parameter.
        </t>
        <figure>
          <preamble>
            For example, the client makes the following HTTP request using transport-layer
            security:
          </preamble>
          <artwork>
<![CDATA[GET /resource?access_token=vF9dft4qmT HTTP/1.1
Host: server.example.com]]>
          </artwork>
        </figure>
        <t>
          The HTTP request URI query can include other
          request-specific parameters, in which case, the <spanx
          style='verb'>access_token</spanx> parameter MUST be properly
          separated from the request-specific parameters using <spanx
          style='verb'>&</spanx> character(s) (ASCII code 38).
        </t>
        <figure>
          <preamble>
            For example:
          </preamble>
          <artwork>
<![CDATA[https://server.example.com/resource?x=y&access_token=vF9dft4qmT&p=q]]>
          </artwork>
        </figure>
	<t>
	  Because of the <xref target="sec-con">Security
	  Considerations</xref> associated with the URI method, it
	  SHOULD NOT be used unless it is the only feasible method.
	  Resource servers MAY support this method.
	</t>
      </section>

    </section>

    <section title='The WWW-Authenticate Response Header Field' anchor='authn-header'>
      <t>
	If the protected resource request does not include
	authentication credentials or does not contain an access
	token that enables access to the protected resource,
	the resource server MUST include the HTTP <spanx
	style='verb'>WWW-Authenticate</spanx> response header field;
	it MAY include it in response to other conditions as well.
	The <spanx style='verb'>WWW-Authenticate</spanx> header
	field uses the framework defined by
	<xref target='I-D.ietf-httpbis-p7-auth' /> as follows:
      </t>
      <figure>
	<artwork>
<![CDATA[challenge       = "Bearer" [ 1*SP 1#param ]

param           = realm / scope /
                  error / error-desc / error-uri /
                  auth-param

scope           = "scope" "=" <"> scope-val *( SP scope-val ) <">
scope-val       = 1*scope-val-char
scope-val-char  = %x21 / %x23-5B / %x5D-7E
  ; HTTPbis P1 qdtext except whitespace, restricted to US-ASCII

error           = "error" "=" quoted-string
error-desc      = "error_description" "=" <"> *error-desc-char <">
error-desc-char = SP / VCHAR
error-uri       = "error_uri" "=" <"> URI-reference <">]]>
	</artwork>
      </figure>
      <t>
	The <spanx style='verb'>scope</spanx> attribute is a space-delimited list of scope values
	indicating the required scope of the access token for accessing the requested resource.
	The <spanx style='verb'>scope</spanx> attribute MUST NOT appear more than once.
	The <spanx style='verb'>scope</spanx> value is intended for
	programmatic use and is not meant to be displayed to
	end users.
      </t>
      <t>
	If the protected resource request included an access token and failed authentication, the
	resource server SHOULD include the <spanx style='verb'>error</spanx> attribute to provide
	the client with the reason why the access request was declined. The parameter value is
	described in <xref target='resource-error-codes' />.
	In addition, the resource server MAY include the <spanx
	style='verb'>error_description</spanx> attribute to provide
	developers a human-readable explanation that is not meant
	to be displayed to end users.
	It also MAY include
	the <spanx style='verb'>error_uri</spanx> attribute with
	an absolute URI identifying a human-readable web page explaining the error.
	The <spanx style='verb'>error</spanx>, <spanx style='verb'>error_description</spanx>, and
	<spanx style='verb'>error_uri</spanx> attribute MUST NOT appear more than once.

      </t>
      <figure>
	<preamble>
	  For example, in response to a protected resource request without authentication:
	</preamble>
	<artwork>
<![CDATA[HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example"]]>
          </artwork>
        </figure>
        <figure>
          <preamble>
            And in response to a protected resource request with an authentication attempt using an
            expired access token:
          </preamble>
          <artwork>
<![CDATA[HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example",
                  error="invalid_token",
                  error_description="The access token expired"]]>
	</artwork>
      </figure>

      <section title='Error Codes' anchor='resource-error-codes'>
	<t>
	  When a request fails, the resource server responds using the appropriate HTTP status
	  code (typically, 400, 401, or 403), and includes one of the following error codes in
	  the response:

	  <list style='hanging' hangIndent='6'>
	    <t hangText='invalid_request'>
	      <vspace />
	      The request is missing a required parameter, includes an unsupported parameter or
	      parameter value, repeats the same parameter, uses more than one method for
	      including an access token, or is otherwise malformed. The resource server SHOULD
	      respond with the HTTP 400 (Bad Request) status code.
	    </t>
	    <t hangText='invalid_token'>
	      <vspace />
	      The access token provided is expired, revoked, malformed, or invalid for other
	      reasons. The resource SHOULD respond with the HTTP 401 (Unauthorized) status
	      code. The client MAY request a new access token and retry the protected resource
	      request.
	    </t>
	    <t hangText='insufficient_scope'>
	      <vspace />
	      The request requires higher privileges than provided by the access token. The
	      resource server SHOULD respond with the HTTP 403 (Forbidden) status code and MAY
	      include the <spanx style='verb'>scope</spanx> attribute with the scope necessary to
	      access the protected resource.
	    </t>
	  </list>
	</t>
	<t>
	  If the request lacks any authentication information (i.e. the client was unaware
	  authentication is necessary or attempted using an unsupported authentication method),
	  the resource server SHOULD NOT include an error code or other error information.
	</t>
	<figure>
	  <preamble>
	    For example:
	  </preamble>
	  <artwork>
<![CDATA[HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example"]]>
	  </artwork>
	</figure>
      </section>

    </section>

    <section title='Security Considerations' anchor="sec-con">

      <t>
	This section describes the relevant security threats regarding
	token handling when using bearer tokens and describes how to
	mitigate these threats.
      </t>

      <section title="Security Threats" anchor="threats">

	<t>
	  The following list presents several common threats against
	  protocols utilizing some form of tokens. This list of
	  threats is based on NIST Special Publication 800-63 <xref
	  target="NIST800-63"/>. Since this document builds on the
	  OAuth 2.0 specification, we exclude a discussion of threats
	  that are described there or in related documents.
	</t>

	<t>
	  <list style="hanging">
	    <t hangText="Token manufacture/modification:">
	      An attacker may generate a bogus token or modify the
	      token contents (such as the authentication or attribute
	      statements) of an existing token, causing the resource
	      server to grant inappropriate access to the client.
	      For example, an attacker may modify the token to extend
	      the validity period; a malicious client may modify the
	      assertion to gain access to information that they
	      should not be able to view.
	    </t>
	    <t hangText="Token disclosure:">
	      Tokens may contain authentication and attribute
	      statements that include sensitive information.
	    </t>
	    <t hangText="Token redirect:">
	      An attacker uses a token generated for consumption by 
	      one resource server to gain access to a different
	      resource server that mistakenly believes the token to be
	      for it.
	    </t>
	    <t hangText="Token replay:">
	      An attacker attempts to use a token that has already
	      been used with that resource server in the past.
	    </t>
	  </list> 
	</t>
      </section> 

      <section title="Threat Mitigation" anchor="mitigation"> 

	<t>
	  A large range of threats can be mitigated by protecting the
	  contents of the token by using a digital signature or a
	  Message Authentication Code (MAC).
	  Alternatively, a bearer token can contain a reference to
	  authorization information, rather than encoding the
	  information directly. Such references MUST be infeasible for
	  an attacker to guess; using a reference may require an extra
	  interaction between a server and the token issuer to resolve
	  the reference to the authorization information.
	  The mechanics of such an interaction are not defined by this
	  specification.
	</t>
	<t>
	  This document does not specify the encoding or the contents
	  of the token; hence detailed recommendations for token
	  integrity protection are outside the scope of this document.
	  We assume that the token integrity protection is sufficient
	  to prevent the token from being modified.
	</t>
	<t>
	  To deal with token redirect, it is important for the
	  authorization server to include the identity of the intended
	  recipients (the audience), typically a single resource
	  server (or a list of resource servers), in the token.
	  Restricting the use of the token to a specific scope is also
	  recommended.
	</t>
	<t>
	  To provide protection against token disclosure,
	  confidentiality protection is applied via <xref
	  target='RFC5246'>TLS</xref> with a
	  ciphersuite that offers confidentiality protection.  This
	  requires that the communication interaction between the
	  client and the authorization server, as well as the
	  interaction between the client and the resource server,
	  utilize confidentiality protection.
	  Since TLS is mandatory to
	  implement and to use with this specification, it is the
	  preferred approach for preventing token disclosure via the
	  communication channel. For those cases where the client
	  is prevented from observing the contents of the token, token
	  encryption MUST be applied in addition to the usage of TLS
	  protection.
	</t>
	<t>
	  To deal with token capture and replay,
	  the following recommendations are
	  made: First, the lifetime of the token MUST be limited by
	  putting a validity time field inside the protected part of
	  the token.  Note that using short-lived (one hour or less)
	  tokens reduces the impact of them being
	  leaked.  Second, confidentiality protection of the exchanges
	  between the client and the authorization server and between
	  the client and the resource server MUST be applied, for instance,
	  through the use of <xref target='RFC5246'>TLS</xref>.  As a
	  consequence, no eavesdropper along the communication path is
	  able to observe the token exchange. Consequently, such an
	  on-path adversary cannot replay the token.
	  Furthermore, when
	  presenting the token to a resource server, the client MUST
	  verify the identity of that resource server, as per <xref target="RFC2818" />.
	  Note that the
	  client MUST validate the TLS certificate chain when making
	  these requests to protected resources.  Presenting the token
	  to an unauthenticated and unauthorized resource server or
	  failing to validate the certificate chain will allow
	  adversaries to steal the token and gain unauthorized access
	  to protected resources.
	</t>
      </section> 
 
      <section title="Summary of Recommendations">
	<t>
	  <list style="hanging">
	    <t hangText="Safeguard bearer tokens">
	      Client implementations MUST ensure that bearer tokens
	      are not leaked to unintended parties, as they will be
	      able to use them to gain access to protected resources.
	      This is the primary security consideration when using
	      bearer tokens and underlies all the more
	      specific recommendations that follow.
	    </t>
	    <t hangText="Validate SSL certificate chains">
	      The client MUST validate the TLS certificate chain when
	      making requests to protected resources.  Failing to do
	      so may enable DNS hijacking attacks to steal the token
	      and gain unintended access.
	    </t>
	    <t hangText="Always use TLS (https)">
	      Clients MUST always use <xref target='RFC5246'>TLS</xref>
	      (https) or equivalent transport security when making requests
	      with bearer tokens.  Failing to do so exposes the token
	      to numerous attacks that could give attackers unintended
	      access.
	    </t>
	    <t hangText="Don't store bearer tokens in cookies">
	      Implementations MUST NOT store bearer tokens within
	      cookies that can be sent in the clear (which is the
	      default transmission mode for cookies).
	      Implementations that do store bearer tokens in cookies
	      MUST take precautions against cross site request forgery.
	    </t>
	    <t hangText="Issue short-lived bearer tokens">
	      Token servers SHOULD issue short-lived (one hour or
	      less) bearer tokens, particularly when issuing tokens to
	      clients that run within a web browser or other
	      environments where information leakage may occur.  Using
	      short-lived bearer tokens can reduce the impact of them
	      being leaked.
	    </t>
	    <t hangText="Issue scoped bearer tokens">
	      Token servers SHOULD issue bearer tokens that contain an audience
	      restriction, scoping their use to the intended relying
	      party or set of relying parties.
	    </t>
	    <t hangText="Don't pass bearer tokens in page URLs">
	      Bearer tokens SHOULD NOT be passed in page URLs (for
	      example as query string parameters). Instead, bearer
	      tokens SHOULD be passed in HTTP message headers or
	      message bodies for which confidentiality measures are
	      taken. Browsers, web servers, and other software may not
	      adequately secure URLs in the browser history, web
	      server logs, and other data structures. If bearer tokens
	      are passed in page URLs, attackers might be able to
	      steal them from the history data, logs, or other
	      unsecured locations.
	    </t>
	  </list>
	</t>
      </section>
    </section>

    <section title='IANA Considerations'>   

      <section title='OAuth Access Token Type Registration'>
        <t>
          This specification registers the following access token type in the OAuth Access Token
          Type Registry.
        </t>

        <section title='The "Bearer" OAuth Access Token Type'>
          <t>
            <list style='hanging'>
              <t hangText='Type name:'>
                <vspace />
                Bearer
              </t>
              <t hangText='Additional Token Endpoint Response Parameters:'>
                <vspace />
                (none)
              </t>
              <t hangText='HTTP Authentication Scheme(s):'>
                <vspace />
                Bearer
              </t>
              <t hangText='Change controller:'>
                <vspace />
                IETF
              </t>
              <t hangText='Specification document(s):'>
                <vspace />
                [[ this document ]]
              </t>
            </list>
          </t>
        </section>
      </section>

      <section title='Authentication Scheme Registration'>
        <t>
          This specification registers the following authentication
          scheme in the Authentication Scheme Registry defined in
          <xref target='I-D.ietf-httpbis-p7-auth' />.
        </t>

        <section title='The "Bearer" Authentication Scheme'>
          <t>
            <list style='hanging'>
              <t hangText='Authentication Scheme Name:'>
                <vspace />
                Bearer
              </t>
              <t hangText='Pointer to specification text:'>
                <vspace />
                [[ this document ]]
              </t>
              <t hangText='Notes (optional):'>
                <vspace />
                (none)
              </t>
            </list>
          </t>
        </section>
      </section>

    </section> 

  </middle>

  <back>

    <references title='Normative References'>

      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml' ?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2616.xml' ?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2818.xml' ?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.3986.xml' ?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.5234.xml' ?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.5246.xml' ?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml4/reference.W3C.REC-html401-19991224.xml' ?>

      <?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-ietf-httpbis-p1-messaging-16.xml'?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-ietf-httpbis-p7-auth-16.xml'?>
      <?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-ietf-oauth-v2-22.xml' ?>

    </references>

    <references title="Informative References">

      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2617.xml' ?>

      <reference anchor="NIST800-63">
        <front>
          <title>NIST Special Publication 800-63-1, INFORMATION SECURITY</title>
          <author fullname="William E. Burr" initials="W." surname="Burr">
            <organization>NIST</organization>
          </author>
          <author fullname="Donna F. Dodson" initials="D." surname="Dodson">
            <organization>NIST</organization>
          </author>
          <author fullname="Ray A. Perlner" initials="R." surname="Perlner">
            <organization>NIST</organization>
          </author>
          <author fullname="W. Timothy Polk" initials="T." surname="Polk">
            <organization>NIST</organization>
          </author>
          <author fullname="Sarbari Gupta" initials="S." surname="Gupta">
            <organization>NIST</organization>
          </author>
          <author fullname="Emad A. Nabbus" initials="E." surname="Nabbus">
            <organization>NIST</organization>
          </author>
          <date month="December" year="2008"/>
        </front>
        <format target="http://csrc.nist.gov/publications/PubsDrafts.html#SP-800-63-Rev.%201" type="HTML"/>
      </reference>

    </references> 

    <section title='Acknowledgements'>
      <t>
        The following people contributed to preliminary versions of this document:
        Blaine Cook (BT), Brian Eaton (Google), Yaron Y. Goland (Microsoft), Brent Goldman (Facebook),
        Raffi Krikorian (Twitter), Luke Shepard (Facebook), and Allen Tom (Yahoo!). The content and
        concepts within are a product of the OAuth community, the WRAP community, and the OAuth Working
        Group.
      </t>
      <t>
        The OAuth Working Group has dozens of very active contributors who proposed ideas and
        wording for this document, including:
        Michael Adams, Amanda Anganes, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah Culver, Bill de hÓra,
        Brian Ellin, Igor Faynberg, George Fletcher, Tim Freeman, Evan Gilbert, Justin Hart,
        John Kemp, Eran Hammer-Lahav, Chasen Le Hara, Michael B. Jones, Torsten Lodderstedt,
	Eve Maler, James Manger, Laurence Miao,
        Chuck Mortimore, Anthony Nadalin, Justin Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre,
        Marius Scurtescu, Naitik Shah, Justin Smith, Jeremy Suriel, Christian Stübner, Paul Tarjan,
        and Franklin Tse.
      </t>
    </section>

    <section title='Document History'>
      <t>
        [[ to be removed by the RFC editor before publication as an RFC ]]
      </t>
      <t>
        -10
        <list style='symbols'>
	  <t>
	    Removed the #auth-param option from Authorization header
	    syntax (leaving only the b64token syntax).
	  </t>
	  <t>
	    Restricted the <spanx style='verb'>scope</spanx> value
	    character set to %x21 / %x23-5B / %x5D-7E (printable ASCII
	    characters excluding double-quote and backslash).
	    Indicated that scope is intended for programmatic use and
	    is not meant to be displayed to end users.
	  </t>
	  <t>
	    Restricted the character set for <spanx
	    style='verb'>error_description</spanx> strings to SP /
	    VCHAR and indicated that they are not meant to be
	    displayed to end users.
	  </t>
	  <t>
	    Included more description in the Abstract, since Hannes
	    Tschofenig indicated that the RFC editor would require
	    this.
	  </t>
          <t>
            Changed "Access Grant" to "Authorization Grant", as was
            done in the core spec.
	  </t>
	  <t>
	    Simplified the introduction to the Authenticated Requests
	    section.
	  </t>
        </list>
      </t>
      <t>
        -09
        <list style='symbols'>
          <t>
            Incorporated working group last call comments.  Specific changes were:
	  </t>
	  <t>
	    Use definitions from <xref
	    target='I-D.ietf-httpbis-p7-auth' /> rather than <xref
	    target='RFC2617' />.
	  </t>
	  <t>
	    Update credentials definition to conform to <xref
	    target='I-D.ietf-httpbis-p7-auth' />.
	  </t>
	  <t>
	    Further clarified that query parameters may occur in any order.
	  </t>
	  <t>
	    Specify that error_description is UTF-8 encoded
	    (matching the core specification).
	  </t>
	  <t>
	    Registered "Bearer" Authentication Scheme in
	    Authentication Scheme Registry defined by
	    <xref target='I-D.ietf-httpbis-p7-auth' />.
	  </t>
          <t>
            Updated references to oauth-v2, httpbis-p1-messaging, and
            httpbis-p7-auth drafts.
	  </t>
	  <t>
	    Other wording improvements not introducing normative changes.
	  </t>
        </list>
      </t>
      <t>
        -08
        <list style='symbols'>
          <t>
            Updated references to oauth-v2 and httpbis drafts.
	  </t>
        </list>
      </t>
      <t>
        -07
        <list style='symbols'>
          <t>
            Added missing comma in error response example.
	  </t>
        </list>
      </t>
      <t>
        -06
        <list style='symbols'>
          <t>
            Changed parameter name <spanx
            style="verb">bearer_token</spanx> to <spanx
            style="verb">access_token</spanx>, per working group
            consensus.
	  </t>
	  <t>
	    Changed HTTP status code for <spanx
	    style="verb">invalid_request</spanx> error code from HTTP
	    401 (Unauthorized) back to HTTP 400 (Bad Request), per
	    input from HTTP working group experts.
	  </t>
        </list>
      </t>
      <t>
        -05
        <list style='symbols'>
	  <t>
	    Removed OAuth Errors Registry, per design team input.
	  </t>
	  <t>
	    Changed HTTP status code for <spanx
	    style="verb">invalid_request</spanx> error code from HTTP
	    400 (Bad Request) to HTTP 401 (Unauthorized) to match HTTP
	    usage [[ change pending working group consensus ]].
	  </t>
	  <t>
	    Added missing quotation marks in error-uri definition.
	  </t>
	  <t>
	    Added note to add language and encoding information to
	    error_description if the core specification does.
	  </t>
	  <t>
	    Explicitly reference the Augmented Backus-Naur Form (ABNF)
	    defined in <xref target='RFC5234' />.
	  </t>
	  <t>
	    Use auth-param instead of repeating its definition, which
	    is ( token "=" ( token / quoted-string ) ).
	  </t>
	  <t>
	    Clarify security considerations about including an
	    audience restriction in the token and include a
	    recommendation to issue scoped bearer tokens in the
	    summary of recommendations.
	  </t>
        </list>
      </t>
      <t>
        -04
        <list style='symbols'>
	  <t>
	    Edits responding to working group last call feedback on
	    -03.  Specific edits enumerated below.
	  </t>
	  <t>
	    Added Bearer Token definition in Terminology section.
	  </t>
          <t>
            Changed parameter name <spanx
            style="verb">oauth_token</spanx> to <spanx
            style="verb">bearer_token</spanx>.
	  </t>
	  <t>
	    Added realm parameter to <spanx
	    style='verb'>WWW-Authenticate</spanx> response to comply
	    with <xref target='RFC2617' />.
	  </t>
	  <t>
	    Removed "[ RWS 1#auth-param ]" from <spanx
	    style="verb">credentials</spanx> definition since it did
	    not comply with the ABNF in <xref
	    target='I-D.ietf-httpbis-p7-auth' />.
	  </t>
	  <t>
	    Removed restriction that the <spanx
	    style="verb">bearer_token</spanx> (formerly <spanx
	    style="verb">oauth_token</spanx>) parameter be the last
	    parameter in the entity-body and the HTTP request URI
	    query.
	  </t>
	  <t>
	    Do not require WWW-Authenticate Response in a reply to a
	    malformed request, as an HTTP 400 Bad Request response
	    without a WWW-Authenticate header is likely the right
	    response in some cases of malformed requests.
	  </t>
	  <t>
	    Removed OAuth Parameters registry extension.
	  </t>
	  <t>
	    Numerous editorial improvements suggested by working group
	    members.
	  </t>
        </list>
      </t>
      <t>
        -03
        <list style='symbols'>
	  <t>
	    Restored the WWW-Authenticate response header
	    functionality deleted from the framework specification in
	    draft 12 based upon the specification text from draft 11.
	  </t>
	  <t>
	    Augmented the OAuth Parameters registry by adding two
	    additional parameter usage locations: "resource request"
	    and "resource response".
	  </t>
          <t>
            Registered the "oauth_token" OAuth parameter with usage
            location "resource request".
          </t>
          <t>
            Registered the "error" OAuth parameter.
          </t>
	  <t>
	    Created the OAuth Error registry and registered errors.
	  </t>
	  <t>
	    Changed the "OAuth2" OAuth access token type name to
	    "Bearer".
	  </t>
        </list>
      </t>
      <t>
        -02
        <list style='symbols'>
          <t>
            Incorporated feedback received on draft 01.  Most changes
            were to the security considerations section.  No normative
            changes were made.  Specific changes included:
          </t>
	  <t>
	    Changed terminology from "token reuse" to "token capture
	    and replay".
	  </t>
	  <t>
	    Removed sentence "Encrypting the token contents is another
	    alternative" from the security considerations since it was
	    redundant and potentially confusing.
	  </t>
	  <t>
	    Corrected some references to "resource server" to be
	    "authorization server" in the security considerations.
	  </t>
	  <t>
	    Generalized security considerations language about
	    obtaining consent of the resource owner.
	  </t>
	  <t>
	    Broadened scope of security considerations description for
	    recommendation "Don't pass bearer tokens in page URLs".
	  </t>
	  <t>
	    Removed unused reference to OAuth 1.0.
	  </t>
	  <t>
	    Updated reference to framework specification and updated
	    David Recordon's e-mail address.
	  </t>
	  <t>
	    Removed security considerations text on authenticating
	    clients.
	  </t>
	  <t>
	    Registered the "OAuth2" OAuth access token type and
	    "oauth_token" parameter.
	  </t>
        </list>
      </t>
      <t>
        -01
        <list style='symbols'>
          <t>
            First public draft, which incorporates feedback received
            on -00 including enhanced Security Considerations content.
            This version is intended to accompany OAuth 2.0 draft 11.
          </t>
        </list>
      </t>
      <t>
        -00
        <list style='symbols'>
          <t>
            Initial draft based on preliminary version of OAuth 2.0 draft 11.
          </t>
        </list>
      </t>
    </section>     

  </back>

</rfc>

PAFTECH AB 2003-20262026-04-22 22:25:01