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379</style><link rel="Contents" href="#rfc.toc">
380      <link rel="Author" href="#rfc.authors">
381      <link rel="Copyright" href="#rfc.copyrightnotice">
382      <link rel="Index" href="#rfc.index">
383      <link rel="Chapter" title="1 Introduction" href="#rfc.section.1">
384      <link rel="Chapter" title="2 Access Authentication Framework" href="#rfc.section.2">
385      <link rel="Chapter" title="3 Status Code Definitions" href="#rfc.section.3">
386      <link rel="Chapter" title="4 Header Field Definitions" href="#rfc.section.4">
387      <link rel="Chapter" title="5 IANA Considerations" href="#rfc.section.5">
388      <link rel="Chapter" title="6 Security Considerations" href="#rfc.section.6">
389      <link rel="Chapter" title="7 Acknowledgments" href="#rfc.section.7">
390      <link rel="Chapter" href="#rfc.section.8" title="8 References">
391      <link rel="Appendix" title="A Changes from RFCs 2616 and 2617" href="#rfc.section.A">
392      <link rel="Appendix" title="B Collected ABNF" href="#rfc.section.B">
393      <link rel="Appendix" title="C Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.C">
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395      <link rel="schema.dct" href="http://purl.org/dc/terms/">
396      <meta name="dct.creator" content="Fielding, R.">
397      <meta name="dct.creator" content="Gettys, J.">
398      <meta name="dct.creator" content="Mogul, J.">
399      <meta name="dct.creator" content="Frystyk, H.">
400      <meta name="dct.creator" content="Masinter, L.">
401      <meta name="dct.creator" content="Leach, P.">
402      <meta name="dct.creator" content="Berners-Lee, T.">
403      <meta name="dct.creator" content="Lafon, Y.">
404      <meta name="dct.creator" content="Reschke, J. F.">
405      <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p7-auth-latest">
406      <meta name="dct.issued" scheme="ISO8601" content="2011-08-26">
407      <meta name="dct.replaces" content="urn:ietf:rfc:2616">
408      <meta name="dct.abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 7 of the seven-part specification that defines the protocol referred to as &#34;HTTP/1.1&#34; and, taken together, obsoletes RFC 2616. Part 7 defines the HTTP Authentication framework.">
409      <meta name="description" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 7 of the seven-part specification that defines the protocol referred to as &#34;HTTP/1.1&#34; and, taken together, obsoletes RFC 2616. Part 7 defines the HTTP Authentication framework.">
410   </head>
411   <body>
412      <table class="header">
413         <tbody>
414            <tr>
415               <td class="left">HTTPbis Working Group</td>
416               <td class="right">R. Fielding, Editor</td>
417            </tr>
418            <tr>
419               <td class="left">Internet-Draft</td>
420               <td class="right">Adobe</td>
421            </tr>
422            <tr>
423               <td class="left">Obsoletes: <a href="http://tools.ietf.org/html/rfc2616">2616</a> (if approved)
424               </td>
425               <td class="right">J. Gettys</td>
426            </tr>
427            <tr>
428               <td class="left">Updates: <a href="http://tools.ietf.org/html/rfc2617">2617</a> (if approved)
429               </td>
430               <td class="right">Alcatel-Lucent</td>
431            </tr>
432            <tr>
433               <td class="left">Intended status: Standards Track</td>
434               <td class="right">J. Mogul</td>
435            </tr>
436            <tr>
437               <td class="left">Expires: February 27, 2012</td>
438               <td class="right">HP</td>
439            </tr>
440            <tr>
441               <td class="left"></td>
442               <td class="right">H. Frystyk</td>
443            </tr>
444            <tr>
445               <td class="left"></td>
446               <td class="right">Microsoft</td>
447            </tr>
448            <tr>
449               <td class="left"></td>
450               <td class="right">L. Masinter</td>
451            </tr>
452            <tr>
453               <td class="left"></td>
454               <td class="right">Adobe</td>
455            </tr>
456            <tr>
457               <td class="left"></td>
458               <td class="right">P. Leach</td>
459            </tr>
460            <tr>
461               <td class="left"></td>
462               <td class="right">Microsoft</td>
463            </tr>
464            <tr>
465               <td class="left"></td>
466               <td class="right">T. Berners-Lee</td>
467            </tr>
468            <tr>
469               <td class="left"></td>
470               <td class="right">W3C/MIT</td>
471            </tr>
472            <tr>
473               <td class="left"></td>
474               <td class="right">Y. Lafon, Editor</td>
475            </tr>
476            <tr>
477               <td class="left"></td>
478               <td class="right">W3C</td>
479            </tr>
480            <tr>
481               <td class="left"></td>
482               <td class="right">J. Reschke, Editor</td>
483            </tr>
484            <tr>
485               <td class="left"></td>
486               <td class="right">greenbytes</td>
487            </tr>
488            <tr>
489               <td class="left"></td>
490               <td class="right">August 26, 2011</td>
491            </tr>
492         </tbody>
493      </table>
494      <p class="title">HTTP/1.1, part 7: Authentication<br><span class="filename">draft-ietf-httpbis-p7-auth-latest</span></p>
495      <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1>
496      <p>The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information
497         systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 7 of the
498         seven-part specification that defines the protocol referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
499      </p> 
500      <p>Part 7 defines the HTTP Authentication framework.</p>
501      <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1>
502      <p>Discussion of this draft should take place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org), which is archived
503         at &lt;<a href="http://lists.w3.org/Archives/Public/ietf-http-wg/">http://lists.w3.org/Archives/Public/ietf-http-wg/</a>&gt;.
504      </p> 
505      <p>The current issues list is at &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/report/3">http://tools.ietf.org/wg/httpbis/trac/report/3</a>&gt; and related documents (including fancy diffs) can be found at &lt;<a href="http://tools.ietf.org/wg/httpbis/">http://tools.ietf.org/wg/httpbis/</a>&gt;.
506      </p> 
507      <p>The changes in this draft are summarized in <a href="#changes.since.16" title="Since draft-ietf-httpbis-p7-auth-16">Appendix&nbsp;C.18</a>.
508      </p>
509      <h1><a id="rfc.status" href="#rfc.status">Status of This Memo</a></h1>
510      <p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
511      <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute
512         working documents as Internet-Drafts. The list of current Internet-Drafts is at <a href="http://datatracker.ietf.org/drafts/current/">http://datatracker.ietf.org/drafts/current/</a>.
513      </p>
514      <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other
515         documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work
516         in progress”.
517      </p>
518      <p>This Internet-Draft will expire on February 27, 2012.</p>
519      <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1>
520      <p>Copyright © 2011 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
521      <p>This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights
522         and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License
523         text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified
524         BSD License.
525      </p>
526      <p>This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November
527         10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to
528         allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s)
529         controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative
530         works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate
531         it into languages other than English.
532      </p>
533      <hr class="noprint">
534      <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
535      <ul class="toc">
536         <li>1.&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul>
537               <li>1.1&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
538               <li>1.2&nbsp;&nbsp;&nbsp;<a href="#notation">Syntax Notation</a><ul>
539                     <li>1.2.1&nbsp;&nbsp;&nbsp;<a href="#core.rules">Core Rules</a></li>
540                  </ul>
541               </li>
542            </ul>
543         </li>
544         <li>2.&nbsp;&nbsp;&nbsp;<a href="#access.authentication.framework">Access Authentication Framework</a><ul>
545               <li>2.1&nbsp;&nbsp;&nbsp;<a href="#challenge.and.response">Challenge and Response</a></li>
546               <li>2.2&nbsp;&nbsp;&nbsp;<a href="#protection.space">Protection Space (Realm)</a></li>
547               <li>2.3&nbsp;&nbsp;&nbsp;<a href="#authentication.scheme.registry">Authentication Scheme Registry</a><ul>
548                     <li>2.3.1&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.authentication.schemes">Considerations for New Authentication Schemes</a></li>
549                  </ul>
550               </li>
551            </ul>
552         </li>
553         <li>3.&nbsp;&nbsp;&nbsp;<a href="#status.code.definitions">Status Code Definitions</a><ul>
554               <li>3.1&nbsp;&nbsp;&nbsp;<a href="#status.401">401 Unauthorized</a></li>
555               <li>3.2&nbsp;&nbsp;&nbsp;<a href="#status.407">407 Proxy Authentication Required</a></li>
556            </ul>
557         </li>
558         <li>4.&nbsp;&nbsp;&nbsp;<a href="#header.field.definitions">Header Field Definitions</a><ul>
559               <li>4.1&nbsp;&nbsp;&nbsp;<a href="#header.authorization">Authorization</a></li>
560               <li>4.2&nbsp;&nbsp;&nbsp;<a href="#header.proxy-authenticate">Proxy-Authenticate</a></li>
561               <li>4.3&nbsp;&nbsp;&nbsp;<a href="#header.proxy-authorization">Proxy-Authorization</a></li>
562               <li>4.4&nbsp;&nbsp;&nbsp;<a href="#header.www-authenticate">WWW-Authenticate</a></li>
563            </ul>
564         </li>
565         <li>5.&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
566               <li>5.1&nbsp;&nbsp;&nbsp;<a href="#authentication.scheme.registration">Authenticaton Scheme Registry</a></li>
567               <li>5.2&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Status Code Registration</a></li>
568               <li>5.3&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Header Field Registration</a></li>
569            </ul>
570         </li>
571         <li>6.&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul>
572               <li>6.1&nbsp;&nbsp;&nbsp;<a href="#auth.credentials.and.idle.clients">Authentication Credentials and Idle Clients</a></li>
573            </ul>
574         </li>
575         <li>7.&nbsp;&nbsp;&nbsp;<a href="#acks">Acknowledgments</a></li>
576         <li>8.&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
577               <li>8.1&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
578               <li>8.2&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
579            </ul>
580         </li>
581         <li><a href="#rfc.authors">Authors' Addresses</a></li>
582         <li>A.&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616">Changes from RFCs 2616 and 2617</a></li>
583         <li>B.&nbsp;&nbsp;&nbsp;<a href="#collected.abnf">Collected ABNF</a></li>
584         <li>C.&nbsp;&nbsp;&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>
585               <li>C.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.1">Since RFC 2616</a></li>
586               <li>C.2&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.2">Since draft-ietf-httpbis-p7-auth-00</a></li>
587               <li>C.3&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.3">Since draft-ietf-httpbis-p7-auth-01</a></li>
588               <li>C.4&nbsp;&nbsp;&nbsp;<a href="#changes.since.02">Since draft-ietf-httpbis-p7-auth-02</a></li>
589               <li>C.5&nbsp;&nbsp;&nbsp;<a href="#changes.since.03">Since draft-ietf-httpbis-p7-auth-03</a></li>
590               <li>C.6&nbsp;&nbsp;&nbsp;<a href="#changes.since.04">Since draft-ietf-httpbis-p7-auth-04</a></li>
591               <li>C.7&nbsp;&nbsp;&nbsp;<a href="#changes.since.05">Since draft-ietf-httpbis-p7-auth-05</a></li>
592               <li>C.8&nbsp;&nbsp;&nbsp;<a href="#changes.since.06">Since draft-ietf-httpbis-p7-auth-06</a></li>
593               <li>C.9&nbsp;&nbsp;&nbsp;<a href="#changes.since.07">Since draft-ietf-httpbis-p7-auth-07</a></li>
594               <li>C.10&nbsp;&nbsp;&nbsp;<a href="#changes.since.08">Since draft-ietf-httpbis-p7-auth-08</a></li>
595               <li>C.11&nbsp;&nbsp;&nbsp;<a href="#changes.since.09">Since draft-ietf-httpbis-p7-auth-09</a></li>
596               <li>C.12&nbsp;&nbsp;&nbsp;<a href="#changes.since.10">Since draft-ietf-httpbis-p7-auth-10</a></li>
597               <li>C.13&nbsp;&nbsp;&nbsp;<a href="#changes.since.11">Since draft-ietf-httpbis-p7-auth-11</a></li>
598               <li>C.14&nbsp;&nbsp;&nbsp;<a href="#changes.since.12">Since draft-ietf-httpbis-p7-auth-12</a></li>
599               <li>C.15&nbsp;&nbsp;&nbsp;<a href="#changes.since.13">Since draft-ietf-httpbis-p7-auth-13</a></li>
600               <li>C.16&nbsp;&nbsp;&nbsp;<a href="#changes.since.14">Since draft-ietf-httpbis-p7-auth-14</a></li>
601               <li>C.17&nbsp;&nbsp;&nbsp;<a href="#changes.since.15">Since draft-ietf-httpbis-p7-auth-15</a></li>
602               <li>C.18&nbsp;&nbsp;&nbsp;<a href="#changes.since.16">Since draft-ietf-httpbis-p7-auth-16</a></li>
603            </ul>
604         </li>
605         <li><a href="#rfc.index">Index</a></li>
606      </ul>
607      <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a>&nbsp;<a id="introduction" href="#introduction">Introduction</a></h1>
608      <p id="rfc.section.1.p.1">This document defines HTTP/1.1 access control and authentication. It includes the relevant parts of <cite title="Hypertext Transfer Protocol -- HTTP/1.1" id="rfc.xref.RFC2616.1">RFC 2616</cite> with only minor changes, plus the general framework for HTTP authentication, as previously defined in "HTTP Authentication:
609         Basic and Digest Access Authentication" (<a href="#RFC2617" id="rfc.xref.RFC2617.1"><cite title="HTTP Authentication: Basic and Digest Access Authentication">[RFC2617]</cite></a>).
610      </p>
611      <p id="rfc.section.1.p.2">HTTP provides several <em class="bcp14">OPTIONAL</em> challenge-response authentication mechanisms which can be used by a server to challenge a client request and by a client to
612         provide authentication information. The "basic" and "digest" authentication schemes continue to be specified in <cite title="HTTP Authentication: Basic and Digest Access Authentication" id="rfc.xref.RFC2617.2">RFC 2617</cite>.
613      </p>
614      <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a>&nbsp;<a id="intro.requirements" href="#intro.requirements">Requirements</a></h2>
615      <p id="rfc.section.1.1.p.1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
616         in this document are to be interpreted as described in <a href="#RFC2119" id="rfc.xref.RFC2119.1"><cite title="Key words for use in RFCs to Indicate Requirement Levels">[RFC2119]</cite></a>.
617      </p>
618      <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the "MUST" or "REQUIRED" level requirements for the
619         protocols it implements. An implementation that satisfies all the "MUST" or "REQUIRED" level and all the "SHOULD" level requirements
620         for its protocols is said to be "unconditionally compliant"; one that satisfies all the "MUST" level requirements but not
621         all the "SHOULD" level requirements for its protocols is said to be "conditionally compliant".
622      </p>
623      <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a id="notation" href="#notation">Syntax Notation</a></h2>
624      <p id="rfc.section.1.2.p.1">This specification uses the ABNF syntax defined in <a href="p1-messaging.html#notation" title="Syntax Notation">Section 1.2</a> of <a href="#Part1" id="rfc.xref.Part1.1"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> (which extends the syntax defined in <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> with a list rule). <a href="#collected.abnf" title="Collected ABNF">Appendix&nbsp;B</a> shows the collected ABNF, with the list rule expanded.
625      </p>
626      <p id="rfc.section.1.2.p.2">The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="http://tools.ietf.org/html/rfc5234#appendix-B.1">Appendix B.1</a>: ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), HEXDIG
627         (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit sequence of data), SP (space), VCHAR (any visible USASCII character),
628         and WSP (whitespace).
629      </p>
630      <h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a id="core.rules" href="#core.rules">Core Rules</a></h3>
631      <p id="rfc.section.1.2.1.p.1">The core rules below are defined in <a href="#Part1" id="rfc.xref.Part1.2"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>:
632      </p>
633      <div id="rfc.figure.u.1"></div><pre class="inline">  <a href="#core.rules" class="smpl">BWS</a>           = &lt;BWS, defined in <a href="#Part1" id="rfc.xref.Part1.3"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
634  <a href="#core.rules" class="smpl">OWS</a>           = &lt;OWS, defined in <a href="#Part1" id="rfc.xref.Part1.4"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
635  <a href="#core.rules" class="smpl">quoted-string</a> = &lt;quoted-string, defined in <a href="#Part1" id="rfc.xref.Part1.5"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#field.rules" title="Common Field ABNF Rules">Section 3.2.3</a>&gt;
636  <a href="#core.rules" class="smpl">token</a>         = &lt;token, defined in <a href="#Part1" id="rfc.xref.Part1.6"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#field.rules" title="Common Field ABNF Rules">Section 3.2.3</a>&gt;
637</pre><h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="access.authentication.framework" href="#access.authentication.framework">Access Authentication Framework</a></h1>
638      <h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a>&nbsp;<a id="challenge.and.response" href="#challenge.and.response">Challenge and Response</a></h2>
639      <p id="rfc.section.2.1.p.1">HTTP provides a simple challenge-response authentication mechanism that can be used by a server to challenge a client request
640         and by a client to provide authentication information. It uses an extensible, case-insensitive token to identify the authentication
641         scheme, followed by additional information necessary for achieving authentication via that scheme. The latter can either be
642         a comma-separated list of attribute-value pairs or a single sequence of characters capable of holding base64-encoded information.
643      </p>
644      <div id="rfc.figure.u.2"></div><pre class="inline"><span id="rfc.iref.a.1"></span><span id="rfc.iref.a.2"></span><span id="rfc.iref.g.1"></span><span id="rfc.iref.g.2"></span><span id="rfc.iref.b.1"></span><span id="rfc.iref.g.3"></span>  auth-scheme    = <a href="#core.rules" class="smpl">token</a>
645 
646  auth-param     = <a href="#core.rules" class="smpl">token</a> <a href="#core.rules" class="smpl">BWS</a> "=" <a href="#core.rules" class="smpl">BWS</a> ( <a href="#core.rules" class="smpl">token</a> / <a href="#core.rules" class="smpl">quoted-string</a> )
647
648  b64token       = 1*( <a href="#notation" class="smpl">ALPHA</a> / <a href="#notation" class="smpl">DIGIT</a> /
649                       "-" / "." / "_" / "~" / "+" / "/" ) *"="
650</pre><p id="rfc.section.2.1.p.3">The "b64token" syntax allows the 66 unreserved URI characters (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>), plus a few others, so that it can hold a base64, base64url (URL and filename safe alphabet), base32, or base16 (hex) encoding,
651         with or without padding, but excluding whitespace (<a href="#RFC4648" id="rfc.xref.RFC4648.1"><cite title="The Base16, Base32, and Base64 Data Encodings">[RFC4648]</cite></a>).
652      </p>
653      <p id="rfc.section.2.1.p.4">The 401 (Unauthorized) response message is used by an origin server to challenge the authorization of a user agent. This response <em class="bcp14">MUST</em> include a WWW-Authenticate header field containing at least one challenge applicable to the requested resource.
654      </p>
655      <p id="rfc.section.2.1.p.5">The 407 (Proxy Authentication Required) response message is used by a proxy to challenge the authorization of a client and <em class="bcp14">MUST</em> include a Proxy-Authenticate header field containing at least one challenge applicable to the proxy for the requested resource.
656      </p>
657      <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.c.1"></span><span id="rfc.iref.g.4"></span>  <a href="#challenge.and.response" class="smpl">challenge</a>   = <a href="#challenge.and.response" class="smpl">auth-scheme</a> [ 1*<a href="#notation" class="smpl">SP</a> ( <a href="#challenge.and.response" class="smpl">b64token</a> / #<a href="#challenge.and.response" class="smpl">auth-param</a> ) ]
658</pre><div class="note" id="rfc.section.2.1.p.7">
659         <p> <b>Note:</b> User agents will need to take special care in parsing the WWW-Authenticate and Proxy-Authenticate header field values because
660            they can contain more than one challenge, or if more than one of each is provided, since the contents of a challenge can itself
661            contain a comma-separated list of authentication parameters.
662         </p>
663      </div>
664      <div class="note" id="rfc.section.2.1.p.8">
665         <p> <b>Note:</b> Many browsers fail to parse challenges containing unknown schemes. A workaround for this problem is to list well-supported
666            schemes (such as "basic") first.
667         </p>
668      </div>
669      <p id="rfc.section.2.1.p.9">A user agent that wishes to authenticate itself with an origin server — usually, but not necessarily, after receiving a 401
670         (Unauthorized) — <em class="bcp14">MAY</em> do so by including an Authorization header field with the request.
671      </p>
672      <p id="rfc.section.2.1.p.10">A client that wishes to authenticate itself with a proxy — usually, but not necessarily, after receiving a 407 (Proxy Authentication
673         Required) — <em class="bcp14">MAY</em> do so by including a Proxy-Authorization header field with the request.
674      </p>
675      <p id="rfc.section.2.1.p.11">Both the Authorization field value and the Proxy-Authorization field value consist of credentials containing the authentication
676         information of the client for the realm of the resource being requested. The user agent <em class="bcp14">MUST</em> choose to use one of the challenges with the strongest auth-scheme it understands and request credentials from the user based
677         upon that challenge.
678      </p>
679      <div id="rfc.figure.u.4"></div><pre class="inline"><span id="rfc.iref.c.2"></span><span id="rfc.iref.g.5"></span>  <a href="#challenge.and.response" class="smpl">credentials</a> = <a href="#challenge.and.response" class="smpl">auth-scheme</a> [ 1*<a href="#notation" class="smpl">SP</a> ( <a href="#challenge.and.response" class="smpl">b64token</a> / #<a href="#challenge.and.response" class="smpl">auth-param</a> ) ]
680</pre><p id="rfc.section.2.1.p.13">If the origin server does not wish to accept the credentials sent with a request, it <em class="bcp14">SHOULD</em> return a 401 (Unauthorized) response. The response <em class="bcp14">MUST</em> include a WWW-Authenticate header field containing at least one (possibly new) challenge applicable to the requested resource.
681      </p>
682      <p id="rfc.section.2.1.p.14">If a proxy does not accept the credentials sent with a request, it <em class="bcp14">SHOULD</em> return a 407 (Proxy Authentication Required). The response <em class="bcp14">MUST</em> include a Proxy-Authenticate header field containing a (possibly new) challenge applicable to the proxy for the requested
683         resource.
684      </p>
685      <p id="rfc.section.2.1.p.15">The HTTP protocol does not restrict applications to this simple challenge-response mechanism for access authentication. Additional
686         mechanisms <em class="bcp14">MAY</em> be used, such as encryption at the transport level or via message encapsulation, and with additional header fields specifying
687         authentication information. However, such additional mechanisms are not defined by this specification.
688      </p>
689      <p id="rfc.section.2.1.p.16">Proxies <em class="bcp14">MUST</em> forward the WWW-Authenticate and Authorization headers unmodified and follow the rules found in <a href="#header.authorization" id="rfc.xref.header.authorization.1" title="Authorization">Section&nbsp;4.1</a>.
690      </p>
691      <div id="rfc.iref.p.1"></div>
692      <div id="rfc.iref.r.1"></div>
693      <h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a>&nbsp;<a id="protection.space" href="#protection.space">Protection Space (Realm)</a></h2>
694      <p id="rfc.section.2.2.p.1">The authentication parameter realm is reserved for use by authentication schemes that wish to indicate the scope of protection:</p>
695      <div id="rfc.figure.u.5"></div><pre class="inline"><span id="rfc.iref.r.2"></span><span id="rfc.iref.r.3"></span><span id="rfc.iref.g.6"></span>  realm       = "realm" <a href="#core.rules" class="smpl">BWS</a> "=" <a href="#core.rules" class="smpl">BWS</a> realm-value
696  realm-value = quoted-string
697</pre><p id="rfc.section.2.2.p.3">A <dfn>protection space</dfn> is defined by the canonical root URI (the scheme and authority components of the effective request URI; see <a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.7"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) of the server being accessed, in combination with the realm value if present. These realms allow the protected resources
698         on a server to be partitioned into a set of protection spaces, each with its own authentication scheme and/or authorization
699         database. The realm value is a string, generally assigned by the origin server, which can have additional semantics specific
700         to the authentication scheme. Note that there can be multiple challenges with the same auth-scheme but different realms.
701      </p>
702      <p id="rfc.section.2.2.p.4">The protection space determines the domain over which credentials can be automatically applied. If a prior request has been
703         authorized, the same credentials <em class="bcp14">MAY</em> be reused for all other requests within that protection space for a period of time determined by the authentication scheme,
704         parameters, and/or user preference. Unless otherwise defined by the authentication scheme, a single protection space cannot
705         extend outside the scope of its server.
706      </p>
707      <h2 id="rfc.section.2.3"><a href="#rfc.section.2.3">2.3</a>&nbsp;<a id="authentication.scheme.registry" href="#authentication.scheme.registry">Authentication Scheme Registry</a></h2>
708      <p id="rfc.section.2.3.p.1">The HTTP Authentication Scheme Registry defines the name space for the authentication schemes in challenges and credentials.</p>
709      <p id="rfc.section.2.3.p.2">Registrations <em class="bcp14">MUST</em> include the following fields:
710      </p>
711      <ul>
712         <li>Authentication Scheme Name</li>
713         <li>Pointer to specification text</li>
714         <li>Notes (optional)</li>
715      </ul>
716      <p id="rfc.section.2.3.p.3">Values to be added to this name space are subject to IETF review (<a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
717      </p>
718      <p id="rfc.section.2.3.p.4">The registry itself is maintained at &lt;<a href="http://www.iana.org/assignments/http-authschemes">http://www.iana.org/assignments/http-authschemes</a>&gt;.
719      </p>
720      <h3 id="rfc.section.2.3.1"><a href="#rfc.section.2.3.1">2.3.1</a>&nbsp;<a id="considerations.for.new.authentication.schemes" href="#considerations.for.new.authentication.schemes">Considerations for New Authentication Schemes</a></h3>
721      <p id="rfc.section.2.3.1.p.1">There are certain aspects of the HTTP Authentication Framework that put constraints on how new authentication schemes can
722         work:
723      </p>
724      <p id="rfc.section.2.3.1.p.2"> </p>
725      <ul>
726         <li>
727            <p>Authentication schemes need to be compatible with the inherent constraints of HTTP; for instance, that messages need to keep
728               their semantics when inspected in isolation, thus an authentication scheme can not bind information to the TCP session over
729               which the message was received (see <a href="p1-messaging.html#message-orientation-and-buffering" title="Message Orientation and Buffering">Section 2.2</a> of <a href="#Part1" id="rfc.xref.Part1.8"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>).
730            </p>
731         </li>
732         <li>
733            <p>The authentication parameter "realm" is reserved for defining Protection Spaces as defined in <a href="#protection.space" title="Protection Space (Realm)">Section&nbsp;2.2</a>. New schemes <em class="bcp14">MUST NOT</em> use it in a way incompatible with that definition.
734            </p>
735         </li>
736         <li>
737            <p>The "b64token" notation was introduced for compatibility with existing authentication schemes and can only be used once per
738               challenge/credentials. New schemes thus ought to use the "auth-param" syntax instead, because otherwise future extensions
739               will be impossible.
740            </p>
741         </li>
742         <li>
743            <p>Authentication schemes need to document whether they are usable in origin-server authentication (i.e., using WWW-Authenticate),
744               and/or proxy authentication (i.e., using Proxy-Authenticate).
745            </p>
746         </li>
747         <li>
748            <p>The credentials carried in an Authorization header field are specific to the User Agent, and therefore have the same effect
749               on HTTP caches as the "private" Cache-Control response directive, within the scope of the request they appear in.
750            </p>
751            <p>Therefore, new authentication schemes which choose not to carry credentials in the Authorization header (e.g., using a newly
752               defined header) will need to explicitly disallow caching, by mandating the use of either Cache-Control request directives
753               (e.g., "no-store") or response directives (e.g., "private").
754            </p>
755         </li>
756      </ul>
757      <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a id="status.code.definitions" href="#status.code.definitions">Status Code Definitions</a></h1>
758      <div id="rfc.iref.15"></div>
759      <div id="rfc.iref.s.1"></div>
760      <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="status.401" href="#status.401">401 Unauthorized</a></h2>
761      <p id="rfc.section.3.1.p.1">The request requires user authentication. The response <em class="bcp14">MUST</em> include a WWW-Authenticate header field (<a href="#header.www-authenticate" id="rfc.xref.header.www-authenticate.1" title="WWW-Authenticate">Section&nbsp;4.4</a>) containing a challenge applicable to the target resource. The client <em class="bcp14">MAY</em> repeat the request with a suitable Authorization header field (<a href="#header.authorization" id="rfc.xref.header.authorization.2" title="Authorization">Section&nbsp;4.1</a>). If the request already included Authorization credentials, then the 401 response indicates that authorization has been
762         refused for those credentials. If the 401 response contains the same challenge as the prior response, and the user agent has
763         already attempted authentication at least once, then the user <em class="bcp14">SHOULD</em> be presented the representation that was given in the response, since that representation might include relevant diagnostic
764         information.
765      </p>
766      <div id="rfc.iref.16"></div>
767      <div id="rfc.iref.s.2"></div>
768      <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a>&nbsp;<a id="status.407" href="#status.407">407 Proxy Authentication Required</a></h2>
769      <p id="rfc.section.3.2.p.1">This code is similar to 401 (Unauthorized), but indicates that the client ought to first authenticate itself with the proxy.
770         The proxy <em class="bcp14">MUST</em> return a Proxy-Authenticate header field (<a href="#header.proxy-authenticate" id="rfc.xref.header.proxy-authenticate.1" title="Proxy-Authenticate">Section&nbsp;4.2</a>) containing a challenge applicable to the proxy for the target resource. The client <em class="bcp14">MAY</em> repeat the request with a suitable Proxy-Authorization header field (<a href="#header.proxy-authorization" id="rfc.xref.header.proxy-authorization.1" title="Proxy-Authorization">Section&nbsp;4.3</a>).
771      </p>
772      <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1>
773      <p id="rfc.section.4.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to authentication.</p>
774      <div id="rfc.iref.a.3"></div>
775      <div id="rfc.iref.h.1"></div>
776      <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="header.authorization" href="#header.authorization">Authorization</a></h2>
777      <p id="rfc.section.4.1.p.1">The "Authorization" header field allows a user agent to authenticate itself with a server — usually, but not necessarily,
778         after receiving a 401 (Unauthorized) response. Its value consists of credentials containing information of the user agent
779         for the realm of the resource being requested.
780      </p>
781      <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.7"></span>  <a href="#header.authorization" class="smpl">Authorization</a> = <a href="#challenge.and.response" class="smpl">credentials</a>
782</pre><p id="rfc.section.4.1.p.3">If a request is authenticated and a realm specified, the same credentials <em class="bcp14">SHOULD</em> be valid for all other requests within this realm (assuming that the authentication scheme itself does not require otherwise,
783         such as credentials that vary according to a challenge value or using synchronized clocks).
784      </p>
785      <p id="rfc.section.4.1.p.4">When a shared cache (see <a href="p6-cache.html#shared.and.non-shared.caches">Section 1.2</a> of <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) receives a request containing an Authorization field, it <em class="bcp14">MUST NOT</em> return the corresponding response as a reply to any other request, unless one of the following specific exceptions holds:
786      </p>
787      <p id="rfc.section.4.1.p.5"> </p>
788      <ol>
789         <li>If the response includes the "s-maxage" cache-control directive, the cache <em class="bcp14">MAY</em> use that response in replying to a subsequent request. But (if the specified maximum age has passed) a proxy cache <em class="bcp14">MUST</em> first revalidate it with the origin server, using the header fields from the new request to allow the origin server to authenticate
790            the new request. (This is the defined behavior for s-maxage.) If the response includes "s-maxage=0", the proxy <em class="bcp14">MUST</em> always revalidate it before re-using it.
791         </li>
792         <li>If the response includes the "must-revalidate" cache-control directive, the cache <em class="bcp14">MAY</em> use that response in replying to a subsequent request. But if the response is stale, all caches <em class="bcp14">MUST</em> first revalidate it with the origin server, using the header fields from the new request to allow the origin server to authenticate
793            the new request.
794         </li>
795         <li>If the response includes the "public" cache-control directive, it <em class="bcp14">MAY</em> be returned in reply to any subsequent request.
796         </li>
797      </ol>
798      <div id="rfc.iref.p.2"></div>
799      <div id="rfc.iref.h.2"></div>
800      <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a id="header.proxy-authenticate" href="#header.proxy-authenticate">Proxy-Authenticate</a></h2>
801      <p id="rfc.section.4.2.p.1">The "Proxy-Authenticate" header field consists of a challenge that indicates the authentication scheme and parameters applicable
802         to the proxy for this effective request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.9"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). It <em class="bcp14">MUST</em> be included as part of a 407 (Proxy Authentication Required) response.
803      </p>
804      <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.8"></span>  <a href="#header.proxy-authenticate" class="smpl">Proxy-Authenticate</a> = 1#<a href="#challenge.and.response" class="smpl">challenge</a>
805</pre><p id="rfc.section.4.2.p.3">Unlike WWW-Authenticate, the Proxy-Authenticate header field applies only to the current connection and <em class="bcp14">SHOULD NOT</em> be passed on to downstream clients. However, an intermediate proxy might need to obtain its own credentials by requesting
806         them from the downstream client, which in some circumstances will appear as if the proxy is forwarding the Proxy-Authenticate
807         header field.
808      </p>
809      <div id="rfc.iref.p.3"></div>
810      <div id="rfc.iref.h.3"></div>
811      <h2 id="rfc.section.4.3"><a href="#rfc.section.4.3">4.3</a>&nbsp;<a id="header.proxy-authorization" href="#header.proxy-authorization">Proxy-Authorization</a></h2>
812      <p id="rfc.section.4.3.p.1">The "Proxy-Authorization" header field allows the client to identify itself (or its user) to a proxy which requires authentication.
813         Its value consists of credentials containing the authentication information of the user agent for the proxy and/or realm of
814         the resource being requested.
815      </p>
816      <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.9"></span>  <a href="#header.proxy-authorization" class="smpl">Proxy-Authorization</a> = <a href="#challenge.and.response" class="smpl">credentials</a>
817</pre><p id="rfc.section.4.3.p.3">Unlike Authorization, the Proxy-Authorization header field applies only to the next outbound proxy that demanded authentication
818         using the Proxy-Authenticate field. When multiple proxies are used in a chain, the Proxy-Authorization header field is consumed
819         by the first outbound proxy that was expecting to receive credentials. A proxy <em class="bcp14">MAY</em> relay the credentials from the client request to the next proxy if that is the mechanism by which the proxies cooperatively
820         authenticate a given request.
821      </p>
822      <div id="rfc.iref.w.1"></div>
823      <div id="rfc.iref.h.4"></div>
824      <h2 id="rfc.section.4.4"><a href="#rfc.section.4.4">4.4</a>&nbsp;<a id="header.www-authenticate" href="#header.www-authenticate">WWW-Authenticate</a></h2>
825      <p id="rfc.section.4.4.p.1">The "WWW-Authenticate" header field consists of at least one challenge that indicates the authentication scheme(s) and parameters
826         applicable to the effective request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.10"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>).
827      </p>
828      <p id="rfc.section.4.4.p.2">It <em class="bcp14">MUST</em> be included in 401 (Unauthorized) response messages and <em class="bcp14">MAY</em> be included in other response messages to indicate that supplying credentials (or different credentials) might affect the
829         response.
830      </p>
831      <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.10"></span>  <a href="#header.www-authenticate" class="smpl">WWW-Authenticate</a> = 1#<a href="#challenge.and.response" class="smpl">challenge</a>
832</pre><p id="rfc.section.4.4.p.4">User agents are advised to take special care in parsing the WWW-Authenticate field value as it might contain more than one
833         challenge, or if more than one WWW-Authenticate header field is provided, the contents of a challenge itself can contain a
834         comma-separated list of authentication parameters.
835      </p>
836      <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
837      <h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a>&nbsp;<a id="authentication.scheme.registration" href="#authentication.scheme.registration">Authenticaton Scheme Registry</a></h2>
838      <p id="rfc.section.5.1.p.1">The registration procedure for HTTP Authentication Schemes is defined by <a href="#authentication.scheme.registry" title="Authentication Scheme Registry">Section&nbsp;2.3</a> of this document.
839      </p>
840      <p id="rfc.section.5.1.p.2">The HTTP Method Authentication Scheme shall be created at &lt;<a href="http://www.iana.org/assignments/http-authschemes">http://www.iana.org/assignments/http-authschemes</a>&gt;.
841      </p>
842      <h2 id="rfc.section.5.2"><a href="#rfc.section.5.2">5.2</a>&nbsp;<a id="status.code.registration" href="#status.code.registration">Status Code Registration</a></h2>
843      <p id="rfc.section.5.2.p.1">The HTTP Status Code Registry located at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt; shall be updated with the registrations below:
844      </p>
845      <div id="rfc.table.1">
846         <div id="iana.status.code.registration.table"></div>
847         <table class="tt full left" cellpadding="3" cellspacing="0">
848            <thead>
849               <tr>
850                  <th>Value</th>
851                  <th>Description</th>
852                  <th>Reference</th>
853               </tr>
854            </thead>
855            <tbody>
856               <tr>
857                  <td class="left">401</td>
858                  <td class="left">Unauthorized</td>
859                  <td class="left"> <a href="#status.401" id="rfc.xref.status.401.1" title="401 Unauthorized">Section&nbsp;3.1</a>
860                  </td>
861               </tr>
862               <tr>
863                  <td class="left">407</td>
864                  <td class="left">Proxy Authentication Required</td>
865                  <td class="left"> <a href="#status.407" id="rfc.xref.status.407.1" title="407 Proxy Authentication Required">Section&nbsp;3.2</a>
866                  </td>
867               </tr>
868            </tbody>
869         </table>
870      </div>
871      <h2 id="rfc.section.5.3"><a href="#rfc.section.5.3">5.3</a>&nbsp;<a id="header.field.registration" href="#header.field.registration">Header Field Registration</a></h2>
872      <p id="rfc.section.5.3.p.1">The Message Header Field Registry located at &lt;<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>&gt; shall be updated with the permanent registrations below (see <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>):
873      </p>
874      <div id="rfc.table.2">
875         <div id="iana.header.registration.table"></div>
876         <table class="tt full left" cellpadding="3" cellspacing="0">
877            <thead>
878               <tr>
879                  <th>Header Field Name</th>
880                  <th>Protocol</th>
881                  <th>Status</th>
882                  <th>Reference</th>
883               </tr>
884            </thead>
885            <tbody>
886               <tr>
887                  <td class="left">Authorization</td>
888                  <td class="left">http</td>
889                  <td class="left">standard</td>
890                  <td class="left"> <a href="#header.authorization" id="rfc.xref.header.authorization.3" title="Authorization">Section&nbsp;4.1</a>
891                  </td>
892               </tr>
893               <tr>
894                  <td class="left">Proxy-Authenticate</td>
895                  <td class="left">http</td>
896                  <td class="left">standard</td>
897                  <td class="left"> <a href="#header.proxy-authenticate" id="rfc.xref.header.proxy-authenticate.2" title="Proxy-Authenticate">Section&nbsp;4.2</a>
898                  </td>
899               </tr>
900               <tr>
901                  <td class="left">Proxy-Authorization</td>
902                  <td class="left">http</td>
903                  <td class="left">standard</td>
904                  <td class="left"> <a href="#header.proxy-authorization" id="rfc.xref.header.proxy-authorization.2" title="Proxy-Authorization">Section&nbsp;4.3</a>
905                  </td>
906               </tr>
907               <tr>
908                  <td class="left">WWW-Authenticate</td>
909                  <td class="left">http</td>
910                  <td class="left">standard</td>
911                  <td class="left"> <a href="#header.www-authenticate" id="rfc.xref.header.www-authenticate.2" title="WWW-Authenticate">Section&nbsp;4.4</a>
912                  </td>
913               </tr>
914            </tbody>
915         </table>
916      </div>
917      <p id="rfc.section.5.3.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
918      <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
919      <p id="rfc.section.6.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
920         as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does
921         make some suggestions for reducing security risks.
922      </p>
923      <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="auth.credentials.and.idle.clients" href="#auth.credentials.and.idle.clients">Authentication Credentials and Idle Clients</a></h2>
924      <p id="rfc.section.6.1.p.1">Existing HTTP clients and user agents typically retain authentication information indefinitely. HTTP/1.1 does not provide
925         a method for a server to direct clients to discard these cached credentials. This is a significant defect that requires further
926         extensions to HTTP. Circumstances under which credential caching can interfere with the application's security model include
927         but are not limited to:
928      </p>
929      <ul>
930         <li>Clients which have been idle for an extended period following which the server might wish to cause the client to reprompt
931            the user for credentials.
932         </li>
933         <li>Applications which include a session termination indication (such as a "logout" or "commit" button on a page) after which
934            the server side of the application "knows" that there is no further reason for the client to retain the credentials.
935         </li>
936      </ul>
937      <p id="rfc.section.6.1.p.2">This is currently under separate study. There are a number of work-arounds to parts of this problem, and we encourage the
938         use of password protection in screen savers, idle time-outs, and other methods which mitigate the security problems inherent
939         in this problem. In particular, user agents which cache credentials are encouraged to provide a readily accessible mechanism
940         for discarding cached credentials under user control.
941      </p>
942      <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="acks" href="#acks">Acknowledgments</a></h1>
943      <p id="rfc.section.7.p.1">This specification takes over the definition of the HTTP Authentication Framework, previously defined in <cite title="HTTP Authentication: Basic and Digest Access Authentication" id="rfc.xref.RFC2617.3">RFC 2617</cite>. We thank John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. Lawrence, Paul J. Leach, Ari Luotonen, and
944         Lawrence C. Stewart for their work on that specification. See <a href="http://tools.ietf.org/html/rfc2617#section-6">Section 6</a> of <a href="#RFC2617" id="rfc.xref.RFC2617.4"><cite title="HTTP Authentication: Basic and Digest Access Authentication">[RFC2617]</cite></a> for further acknowledgements.
945      </p>
946      <p id="rfc.section.7.p.2">See <a href="p1-messaging.html#acks" title="Acknowledgments">Section 12</a> of <a href="#Part1" id="rfc.xref.Part1.11"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for the Acknowledgments related to this document revision.
947      </p>
948      <h1 id="rfc.references"><a id="rfc.section.8" href="#rfc.section.8">8.</a> References
949      </h1>
950      <h2 id="rfc.references.1"><a href="#rfc.section.8.1" id="rfc.section.8.1">8.1</a> Normative References
951      </h2>
952      <table>       
953         <tr>
954            <td class="reference"><b id="Part1">[Part1]</b></td>
955            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:jg@freedesktop.org" title="Alcatel-Lucent Bell Labs">Gettys, J.</a>, <a href="mailto:JeffMogul@acm.org" title="Hewlett-Packard Company">Mogul, J.</a>, <a href="mailto:henrikn@microsoft.com" title="Microsoft Corporation">Frystyk, H.</a>, <a href="mailto:LMM@acm.org" title="Adobe Systems Incorporated">Masinter, L.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, <a href="mailto:timbl@w3.org" title="World Wide Web Consortium">Berners-Lee, T.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-latest">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p1-messaging-latest (work in progress), August&nbsp;2011.
956            </td>
957         </tr>
958         <tr>
959            <td class="reference"><b id="Part6">[Part6]</b></td>
960            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:jg@freedesktop.org" title="Alcatel-Lucent Bell Labs">Gettys, J.</a>, <a href="mailto:JeffMogul@acm.org" title="Hewlett-Packard Company">Mogul, J.</a>, <a href="mailto:henrikn@microsoft.com" title="Microsoft Corporation">Frystyk, H.</a>, <a href="mailto:LMM@acm.org" title="Adobe Systems Incorporated">Masinter, L.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, <a href="mailto:timbl@w3.org" title="World Wide Web Consortium">Berners-Lee, T.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, <a href="mailto:mnot@mnot.net">Nottingham, M., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-latest">HTTP/1.1, part 6: Caching</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p6-cache-latest (work in progress), August&nbsp;2011.
961            </td>
962         </tr>
963         <tr>
964            <td class="reference"><b id="RFC2119">[RFC2119]</b></td>
965            <td class="top"><a href="mailto:sob@harvard.edu" title="Harvard University">Bradner, S.</a>, “<a href="http://tools.ietf.org/html/rfc2119">Key words for use in RFCs to Indicate Requirement Levels</a>”, BCP&nbsp;14, RFC&nbsp;2119, March&nbsp;1997.
966            </td>
967         </tr>
968         <tr>
969            <td class="reference"><b id="RFC5234">[RFC5234]</b></td>
970            <td class="top"><a href="mailto:dcrocker@bbiw.net" title="Brandenburg InternetWorking">Crocker, D., Ed.</a> and <a href="mailto:paul.overell@thus.net" title="THUS plc.">P. Overell</a>, “<a href="http://tools.ietf.org/html/rfc5234">Augmented BNF for Syntax Specifications: ABNF</a>”, STD&nbsp;68, RFC&nbsp;5234, January&nbsp;2008.
971            </td>
972         </tr>
973      </table>
974      <h2 id="rfc.references.2"><a href="#rfc.section.8.2" id="rfc.section.8.2">8.2</a> Informative References
975      </h2>
976      <table>           
977         <tr>
978            <td class="reference"><b id="RFC2616">[RFC2616]</b></td>
979            <td class="top"><a href="mailto:fielding@ics.uci.edu" title="University of California, Irvine">Fielding, R.</a>, <a href="mailto:jg@w3.org" title="W3C">Gettys, J.</a>, <a href="mailto:mogul@wrl.dec.com" title="Compaq Computer Corporation">Mogul, J.</a>, <a href="mailto:frystyk@w3.org" title="MIT Laboratory for Computer Science">Frystyk, H.</a>, <a href="mailto:masinter@parc.xerox.com" title="Xerox Corporation">Masinter, L.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, and <a href="mailto:timbl@w3.org" title="W3C">T. Berners-Lee</a>, “<a href="http://tools.ietf.org/html/rfc2616">Hypertext Transfer Protocol -- HTTP/1.1</a>”, RFC&nbsp;2616, June&nbsp;1999.
980            </td>
981         </tr>
982         <tr>
983            <td class="reference"><b id="RFC2617">[RFC2617]</b></td>
984            <td class="top"><a href="mailto:john@math.nwu.edu" title="Northwestern University, Department of Mathematics">Franks, J.</a>, <a href="mailto:pbaker@verisign.com" title="Verisign Inc.">Hallam-Baker, P.</a>, <a href="mailto:jeff@AbiSource.com" title="AbiSource, Inc.">Hostetler, J.</a>, <a href="mailto:lawrence@agranat.com" title="Agranat Systems, Inc.">Lawrence, S.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, Luotonen, A., and <a href="mailto:stewart@OpenMarket.com" title="Open Market, Inc.">L. Stewart</a>, “<a href="http://tools.ietf.org/html/rfc2617">HTTP Authentication: Basic and Digest Access Authentication</a>”, RFC&nbsp;2617, June&nbsp;1999.
985            </td>
986         </tr>
987         <tr>
988            <td class="reference"><b id="RFC3864">[RFC3864]</b></td>
989            <td class="top"><a href="mailto:GK-IETF@ninebynine.org" title="Nine by Nine">Klyne, G.</a>, <a href="mailto:mnot@pobox.com" title="BEA Systems">Nottingham, M.</a>, and <a href="mailto:JeffMogul@acm.org" title="HP Labs">J. Mogul</a>, “<a href="http://tools.ietf.org/html/rfc3864">Registration Procedures for Message Header Fields</a>”, BCP&nbsp;90, RFC&nbsp;3864, September&nbsp;2004.
990            </td>
991         </tr>
992         <tr>
993            <td class="reference"><b id="RFC3986">[RFC3986]</b></td>
994            <td class="top"><a href="mailto:timbl@w3.org" title="World Wide Web Consortium">Berners-Lee, T.</a>, <a href="mailto:fielding@gbiv.com" title="Day Software">Fielding, R.</a>, and <a href="mailto:LMM@acm.org" title="Adobe Systems Incorporated">L. Masinter</a>, “<a href="http://tools.ietf.org/html/rfc3986">Uniform Resource Identifier (URI): Generic Syntax</a>”, STD&nbsp;66, RFC&nbsp;3986, January&nbsp;2005.
995            </td>
996         </tr>
997         <tr>
998            <td class="reference"><b id="RFC4648">[RFC4648]</b></td>
999            <td class="top">Josefsson, S., “<a href="http://tools.ietf.org/html/rfc4648">The Base16, Base32, and Base64 Data Encodings</a>”, RFC&nbsp;4648, October&nbsp;2006.
1000            </td>
1001         </tr>
1002         <tr>
1003            <td class="reference"><b id="RFC5226">[RFC5226]</b></td>
1004            <td class="top"><a href="mailto:narten@us.ibm.com" title="IBM">Narten, T.</a> and <a href="mailto:Harald@Alvestrand.no" title="Google">H. Alvestrand</a>, “<a href="http://tools.ietf.org/html/rfc5226">Guidelines for Writing an IANA Considerations Section in RFCs</a>”, BCP&nbsp;26, RFC&nbsp;5226, May&nbsp;2008.
1005            </td>
1006         </tr>
1007      </table>
1008      <div class="avoidbreak">
1009         <h1 id="rfc.authors"><a href="#rfc.authors">Authors' Addresses</a></h1>
1010         <address class="vcard"><span class="vcardline"><span class="fn">Roy T. Fielding</span>
1011               (editor)
1012               <span class="n hidden"><span class="family-name">Fielding</span><span class="given-name">Roy T.</span></span></span><span class="org vcardline">Adobe Systems Incorporated</span><span class="adr"><span class="street-address vcardline">345 Park Ave</span><span class="vcardline"><span class="locality">San Jose</span>, <span class="region">CA</span>&nbsp;<span class="postal-code">95110</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:fielding@gbiv.com"><span class="email">fielding@gbiv.com</span></a></span><span class="vcardline">URI: <a href="http://roy.gbiv.com/" class="url">http://roy.gbiv.com/</a></span></address>
1013         <address class="vcard"><span class="vcardline"><span class="fn">Jim Gettys</span><span class="n hidden"><span class="family-name">Gettys</span><span class="given-name">Jim</span></span></span><span class="org vcardline">Alcatel-Lucent Bell Labs</span><span class="adr"><span class="street-address vcardline">21 Oak Knoll Road</span><span class="vcardline"><span class="locality">Carlisle</span>, <span class="region">MA</span>&nbsp;<span class="postal-code">01741</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:jg@freedesktop.org"><span class="email">jg@freedesktop.org</span></a></span><span class="vcardline">URI: <a href="http://gettys.wordpress.com/" class="url">http://gettys.wordpress.com/</a></span></address>
1014         <address class="vcard"><span class="vcardline"><span class="fn">Jeffrey C. Mogul</span><span class="n hidden"><span class="family-name">Mogul</span><span class="given-name">Jeffrey C.</span></span></span><span class="org vcardline">Hewlett-Packard Company</span><span class="adr"><span class="street-address vcardline">HP Labs, Large Scale Systems Group</span><span class="street-address vcardline">1501 Page Mill Road, MS 1177</span><span class="vcardline"><span class="locality">Palo Alto</span>, <span class="region">CA</span>&nbsp;<span class="postal-code">94304</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:JeffMogul@acm.org"><span class="email">JeffMogul@acm.org</span></a></span></address>
1015         <address class="vcard"><span class="vcardline"><span class="fn">Henrik Frystyk Nielsen</span><span class="n hidden"><span class="family-name">Frystyk</span></span></span><span class="org vcardline">Microsoft Corporation</span><span class="adr"><span class="street-address vcardline">1 Microsoft Way</span><span class="vcardline"><span class="locality">Redmond</span>, <span class="region">WA</span>&nbsp;<span class="postal-code">98052</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:henrikn@microsoft.com"><span class="email">henrikn@microsoft.com</span></a></span></address>
1016         <address class="vcard"><span class="vcardline"><span class="fn">Larry Masinter</span><span class="n hidden"><span class="family-name">Masinter</span><span class="given-name">Larry</span></span></span><span class="org vcardline">Adobe Systems Incorporated</span><span class="adr"><span class="street-address vcardline">345 Park Ave</span><span class="vcardline"><span class="locality">San Jose</span>, <span class="region">CA</span>&nbsp;<span class="postal-code">95110</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:LMM@acm.org"><span class="email">LMM@acm.org</span></a></span><span class="vcardline">URI: <a href="http://larry.masinter.net/" class="url">http://larry.masinter.net/</a></span></address>
1017         <address class="vcard"><span class="vcardline"><span class="fn">Paul J. Leach</span><span class="n hidden"><span class="family-name">Leach</span><span class="given-name">Paul J.</span></span></span><span class="org vcardline">Microsoft Corporation</span><span class="adr"><span class="street-address vcardline">1 Microsoft Way</span><span class="vcardline"><span class="locality">Redmond</span>, <span class="region">WA</span>&nbsp;<span class="postal-code">98052</span></span></span><span class="vcardline">Email: <a href="mailto:paulle@microsoft.com"><span class="email">paulle@microsoft.com</span></a></span></address>
1018         <address class="vcard"><span class="vcardline"><span class="fn">Tim Berners-Lee</span><span class="n hidden"><span class="family-name">Berners-Lee</span><span class="given-name">Tim</span></span></span><span class="org vcardline">World Wide Web Consortium</span><span class="adr"><span class="street-address vcardline">MIT Computer Science and Artificial Intelligence Laboratory</span><span class="street-address vcardline">The Stata Center, Building 32</span><span class="street-address vcardline">32 Vassar Street</span><span class="vcardline"><span class="locality">Cambridge</span>, <span class="region">MA</span>&nbsp;<span class="postal-code">02139</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:timbl@w3.org"><span class="email">timbl@w3.org</span></a></span><span class="vcardline">URI: <a href="http://www.w3.org/People/Berners-Lee/" class="url">http://www.w3.org/People/Berners-Lee/</a></span></address>
1019         <address class="vcard"><span class="vcardline"><span class="fn">Yves Lafon</span>
1020               (editor)
1021               <span class="n hidden"><span class="family-name">Lafon</span><span class="given-name">Yves</span></span></span><span class="org vcardline">World Wide Web Consortium</span><span class="adr"><span class="street-address vcardline">W3C / ERCIM</span><span class="street-address vcardline">2004, rte des Lucioles</span><span class="vcardline"><span class="locality">Sophia-Antipolis</span>, <span class="region">AM</span>&nbsp;<span class="postal-code">06902</span></span><span class="country-name vcardline">France</span></span><span class="vcardline">Email: <a href="mailto:ylafon@w3.org"><span class="email">ylafon@w3.org</span></a></span><span class="vcardline">URI: <a href="http://www.raubacapeu.net/people/yves/" class="url">http://www.raubacapeu.net/people/yves/</a></span></address>
1022         <address class="vcard"><span class="vcardline"><span class="fn">Julian F. Reschke</span>
1023               (editor)
1024               <span class="n hidden"><span class="family-name">Reschke</span><span class="given-name">Julian F.</span></span></span><span class="org vcardline">greenbytes GmbH</span><span class="adr"><span class="street-address vcardline">Hafenweg 16</span><span class="vcardline"><span class="locality">Muenster</span>, <span class="region">NW</span>&nbsp;<span class="postal-code">48155</span></span><span class="country-name vcardline">Germany</span></span><span class="vcardline tel">Phone: <a href="tel:+492512807760"><span class="value">+49 251 2807760</span></a></span><span class="vcardline tel"><span class="type">Fax</span>: <a href="fax:+492512807761"><span class="value">+49 251 2807761</span></a></span><span class="vcardline">Email: <a href="mailto:julian.reschke@greenbytes.de"><span class="email">julian.reschke@greenbytes.de</span></a></span><span class="vcardline">URI: <a href="http://greenbytes.de/tech/webdav/" class="url">http://greenbytes.de/tech/webdav/</a></span></address>
1025      </div>
1026      <h1 id="rfc.section.A" class="np"><a href="#rfc.section.A">A.</a>&nbsp;<a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFCs 2616 and 2617</a></h1>
1027      <p id="rfc.section.A.p.1">The "realm" parameter isn't required anymore in general; consequently, the ABNF allows challenges without any auth parameters.
1028         (<a href="#access.authentication.framework" title="Access Authentication Framework">Section&nbsp;2</a>)
1029      </p>
1030      <p id="rfc.section.A.p.2">The "b64token" alternative to auth-param lists has been added for consistency with legacy authentication schemes such as "Basic".
1031         (<a href="#access.authentication.framework" title="Access Authentication Framework">Section&nbsp;2</a>)
1032      </p>
1033      <p id="rfc.section.A.p.3">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;4</a>)
1034      </p>
1035      <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a>&nbsp;<a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1>
1036      <div id="rfc.figure.u.10"></div> <pre class="inline"><a href="#header.authorization" class="smpl">Authorization</a> = credentials
1037
1038<a href="#core.rules" class="smpl">BWS</a> = &lt;BWS, defined in [Part1], Section 1.2.2&gt;
1039
1040<a href="#core.rules" class="smpl">OWS</a> = &lt;OWS, defined in [Part1], Section 1.2.2&gt;
1041
1042<a href="#header.proxy-authenticate" class="smpl">Proxy-Authenticate</a> = *( "," OWS ) challenge *( OWS "," [ OWS
1043 challenge ] )
1044<a href="#header.proxy-authorization" class="smpl">Proxy-Authorization</a> = credentials
1045
1046<a href="#header.www-authenticate" class="smpl">WWW-Authenticate</a> = *( "," OWS ) challenge *( OWS "," [ OWS challenge
1047 ] )
1048
1049<a href="#challenge.and.response" class="smpl">auth-param</a> = token BWS "=" BWS ( token / quoted-string )
1050<a href="#challenge.and.response" class="smpl">auth-scheme</a> = token
1051
1052<a href="#challenge.and.response" class="smpl">b64token</a> = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" )
1053 *"="
1054
1055<a href="#challenge.and.response" class="smpl">challenge</a> = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) *(
1056 OWS "," [ OWS auth-param ] ) ] ) ]
1057<a href="#challenge.and.response" class="smpl">credentials</a> = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param )
1058 *( OWS "," [ OWS auth-param ] ) ] ) ]
1059
1060<a href="#core.rules" class="smpl">quoted-string</a> = &lt;quoted-string, defined in [Part1], Section 3.2.3&gt;
1061
1062realm = "realm" BWS "=" BWS realm-value
1063realm-value = quoted-string
1064
1065<a href="#core.rules" class="smpl">token</a> = &lt;token, defined in [Part1], Section 3.2.3&gt;
1066</pre> <div id="rfc.figure.u.11"></div>
1067      <p>ABNF diagnostics:</p><pre class="inline">; Authorization defined but not used
1068; Proxy-Authenticate defined but not used
1069; Proxy-Authorization defined but not used
1070; WWW-Authenticate defined but not used
1071; realm defined but not used
1072</pre><h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a>&nbsp;<a id="change.log" href="#change.log">Change Log (to be removed by RFC Editor before publication)</a></h1>
1073      <h2 id="rfc.section.C.1"><a href="#rfc.section.C.1">C.1</a>&nbsp;Since RFC 2616
1074      </h2>
1075      <p id="rfc.section.C.1.p.1">Extracted relevant partitions from <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
1076      </p>
1077      <h2 id="rfc.section.C.2"><a href="#rfc.section.C.2">C.2</a>&nbsp;Since draft-ietf-httpbis-p7-auth-00
1078      </h2>
1079      <p id="rfc.section.C.2.p.1">Closed issues: </p>
1080      <ul>
1081         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/35">http://tools.ietf.org/wg/httpbis/trac/ticket/35</a>&gt;: "Normative and Informative references"
1082         </li>
1083      </ul>
1084      <h2 id="rfc.section.C.3"><a href="#rfc.section.C.3">C.3</a>&nbsp;Since draft-ietf-httpbis-p7-auth-01
1085      </h2>
1086      <p id="rfc.section.C.3.p.1">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1087      </p>
1088      <ul>
1089         <li>Explicitly import BNF rules for "challenge" and "credentials" from RFC2617.</li>
1090         <li>Add explicit references to BNF syntax and rules imported from other parts of the specification.</li>
1091      </ul>
1092      <h2 id="rfc.section.C.4"><a href="#rfc.section.C.4">C.4</a>&nbsp;<a id="changes.since.02" href="#changes.since.02">Since draft-ietf-httpbis-p7-auth-02</a></h2>
1093      <p id="rfc.section.C.4.p.1">Ongoing work on IANA Message Header Field Registration (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/40">http://tools.ietf.org/wg/httpbis/trac/ticket/40</a>&gt;):
1094      </p>
1095      <ul>
1096         <li>Reference RFC 3984, and update header field registrations for header fields defined in this document.</li>
1097      </ul>
1098      <h2 id="rfc.section.C.5"><a href="#rfc.section.C.5">C.5</a>&nbsp;<a id="changes.since.03" href="#changes.since.03">Since draft-ietf-httpbis-p7-auth-03</a></h2>
1099      <p id="rfc.section.C.5.p.1">None.</p>
1100      <h2 id="rfc.section.C.6"><a href="#rfc.section.C.6">C.6</a>&nbsp;<a id="changes.since.04" href="#changes.since.04">Since draft-ietf-httpbis-p7-auth-04</a></h2>
1101      <p id="rfc.section.C.6.p.1">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1102      </p>
1103      <ul>
1104         <li>Use "/" instead of "|" for alternatives.</li>
1105         <li>Introduce new ABNF rules for "bad" whitespace ("BWS"), optional whitespace ("OWS") and required whitespace ("RWS").</li>
1106         <li>Rewrite ABNFs to spell out whitespace rules, factor out header field value format definitions.</li>
1107      </ul>
1108      <h2 id="rfc.section.C.7"><a href="#rfc.section.C.7">C.7</a>&nbsp;<a id="changes.since.05" href="#changes.since.05">Since draft-ietf-httpbis-p7-auth-05</a></h2>
1109      <p id="rfc.section.C.7.p.1">Final work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1110      </p>
1111      <ul>
1112         <li>Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.</li>
1113      </ul>
1114      <h2 id="rfc.section.C.8"><a href="#rfc.section.C.8">C.8</a>&nbsp;<a id="changes.since.06" href="#changes.since.06">Since draft-ietf-httpbis-p7-auth-06</a></h2>
1115      <p id="rfc.section.C.8.p.1">None.</p>
1116      <h2 id="rfc.section.C.9"><a href="#rfc.section.C.9">C.9</a>&nbsp;<a id="changes.since.07" href="#changes.since.07">Since draft-ietf-httpbis-p7-auth-07</a></h2>
1117      <p id="rfc.section.C.9.p.1">Closed issues: </p>
1118      <ul>
1119         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/198">http://tools.ietf.org/wg/httpbis/trac/ticket/198</a>&gt;: "move IANA registrations for optional status codes"
1120         </li>
1121      </ul>
1122      <h2 id="rfc.section.C.10"><a href="#rfc.section.C.10">C.10</a>&nbsp;<a id="changes.since.08" href="#changes.since.08">Since draft-ietf-httpbis-p7-auth-08</a></h2>
1123      <p id="rfc.section.C.10.p.1">No significant changes.</p>
1124      <h2 id="rfc.section.C.11"><a href="#rfc.section.C.11">C.11</a>&nbsp;<a id="changes.since.09" href="#changes.since.09">Since draft-ietf-httpbis-p7-auth-09</a></h2>
1125      <p id="rfc.section.C.11.p.1">Partly resolved issues: </p>
1126      <ul>
1127         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/196">http://tools.ietf.org/wg/httpbis/trac/ticket/196</a>&gt;: "Term for the requested resource's URI"
1128         </li>
1129      </ul>
1130      <h2 id="rfc.section.C.12"><a href="#rfc.section.C.12">C.12</a>&nbsp;<a id="changes.since.10" href="#changes.since.10">Since draft-ietf-httpbis-p7-auth-10</a></h2>
1131      <p id="rfc.section.C.12.p.1">None.</p>
1132      <h2 id="rfc.section.C.13"><a href="#rfc.section.C.13">C.13</a>&nbsp;<a id="changes.since.11" href="#changes.since.11">Since draft-ietf-httpbis-p7-auth-11</a></h2>
1133      <p id="rfc.section.C.13.p.1">Closed issues: </p>
1134      <ul>
1135         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/130">http://tools.ietf.org/wg/httpbis/trac/ticket/130</a>&gt;: "introduction to part 7 is work-in-progress"
1136         </li>
1137         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/195">http://tools.ietf.org/wg/httpbis/trac/ticket/195</a>&gt;: "auth-param syntax"
1138         </li>
1139         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/224">http://tools.ietf.org/wg/httpbis/trac/ticket/224</a>&gt;: "Header Classification"
1140         </li>
1141         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/237">http://tools.ietf.org/wg/httpbis/trac/ticket/237</a>&gt;: "absorbing the auth framework from 2617"
1142         </li>
1143      </ul>
1144      <p id="rfc.section.C.13.p.2">Partly resolved issues: </p>
1145      <ul>
1146         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/141">http://tools.ietf.org/wg/httpbis/trac/ticket/141</a>&gt;: "should we have an auth scheme registry"
1147         </li>
1148      </ul>
1149      <h2 id="rfc.section.C.14"><a href="#rfc.section.C.14">C.14</a>&nbsp;<a id="changes.since.12" href="#changes.since.12">Since draft-ietf-httpbis-p7-auth-12</a></h2>
1150      <p id="rfc.section.C.14.p.1">None.</p>
1151      <h2 id="rfc.section.C.15"><a href="#rfc.section.C.15">C.15</a>&nbsp;<a id="changes.since.13" href="#changes.since.13">Since draft-ietf-httpbis-p7-auth-13</a></h2>
1152      <p id="rfc.section.C.15.p.1">Closed issues: </p>
1153      <ul>
1154         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/276">http://tools.ietf.org/wg/httpbis/trac/ticket/276</a>&gt;: "untangle ABNFs for header fields"
1155         </li>
1156      </ul>
1157      <h2 id="rfc.section.C.16"><a href="#rfc.section.C.16">C.16</a>&nbsp;<a id="changes.since.14" href="#changes.since.14">Since draft-ietf-httpbis-p7-auth-14</a></h2>
1158      <p id="rfc.section.C.16.p.1">None.</p>
1159      <h2 id="rfc.section.C.17"><a href="#rfc.section.C.17">C.17</a>&nbsp;<a id="changes.since.15" href="#changes.since.15">Since draft-ietf-httpbis-p7-auth-15</a></h2>
1160      <p id="rfc.section.C.17.p.1">Closed issues: </p>
1161      <ul>
1162         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/78">http://tools.ietf.org/wg/httpbis/trac/ticket/78</a>&gt;: "Relationship between 401, Authorization and WWW-Authenticate"
1163         </li>
1164         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/177">http://tools.ietf.org/wg/httpbis/trac/ticket/177</a>&gt;: "Realm required on challenges"
1165         </li>
1166         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/195">http://tools.ietf.org/wg/httpbis/trac/ticket/195</a>&gt;: "auth-param syntax"
1167         </li>
1168         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/257">http://tools.ietf.org/wg/httpbis/trac/ticket/257</a>&gt;: "Considerations for new authentications schemes"
1169         </li>
1170         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/287">http://tools.ietf.org/wg/httpbis/trac/ticket/287</a>&gt;: "LWS in auth-param ABNF"
1171         </li>
1172         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/309">http://tools.ietf.org/wg/httpbis/trac/ticket/309</a>&gt;: "credentials ABNF missing SP (still using implied LWS?)"
1173         </li>
1174      </ul>
1175      <h2 id="rfc.section.C.18"><a href="#rfc.section.C.18">C.18</a>&nbsp;<a id="changes.since.16" href="#changes.since.16">Since draft-ietf-httpbis-p7-auth-16</a></h2>
1176      <p id="rfc.section.C.18.p.1">None yet.</p>
1177      <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1>
1178      <p class="noprint"><a href="#rfc.index.4">4</a> <a href="#rfc.index.A">A</a> <a href="#rfc.index.B">B</a> <a href="#rfc.index.C">C</a> <a href="#rfc.index.G">G</a> <a href="#rfc.index.H">H</a> <a href="#rfc.index.P">P</a> <a href="#rfc.index.R">R</a> <a href="#rfc.index.S">S</a> <a href="#rfc.index.W">W</a>
1179      </p>
1180      <div class="print2col">
1181         <ul class="ind">
1182            <li><a id="rfc.index.4" href="#rfc.index.4"><b>4</b></a><ul>
1183                  <li>401 Unauthorized (status code)&nbsp;&nbsp;<a href="#rfc.iref.15"><b>3.1</b></a>, <a href="#rfc.xref.status.401.1">5.2</a></li>
1184                  <li>407 Proxy Authentication Required (status code)&nbsp;&nbsp;<a href="#rfc.iref.16"><b>3.2</b></a>, <a href="#rfc.xref.status.407.1">5.2</a></li>
1185               </ul>
1186            </li>
1187            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
1188                  <li><tt>auth-param</tt>&nbsp;&nbsp;<a href="#rfc.iref.a.2"><b>2.1</b></a></li>
1189                  <li><tt>auth-scheme</tt>&nbsp;&nbsp;<a href="#rfc.iref.a.1"><b>2.1</b></a></li>
1190                  <li>Authorization header field&nbsp;&nbsp;<a href="#rfc.xref.header.authorization.1">2.1</a>, <a href="#rfc.xref.header.authorization.2">3.1</a>, <a href="#rfc.iref.a.3"><b>4.1</b></a>, <a href="#rfc.xref.header.authorization.3">5.3</a></li>
1191               </ul>
1192            </li>
1193            <li><a id="rfc.index.B" href="#rfc.index.B"><b>B</b></a><ul>
1194                  <li><tt>b64token</tt>&nbsp;&nbsp;<a href="#rfc.iref.b.1"><b>2.1</b></a></li>
1195               </ul>
1196            </li>
1197            <li><a id="rfc.index.C" href="#rfc.index.C"><b>C</b></a><ul>
1198                  <li><tt>challenge</tt>&nbsp;&nbsp;<a href="#rfc.iref.c.1"><b>2.1</b></a></li>
1199                  <li><tt>credentials</tt>&nbsp;&nbsp;<a href="#rfc.iref.c.2"><b>2.1</b></a></li>
1200               </ul>
1201            </li>
1202            <li><a id="rfc.index.G" href="#rfc.index.G"><b>G</b></a><ul>
1203                  <li><tt>Grammar</tt>&nbsp;&nbsp;
1204                     <ul>
1205                        <li><tt>auth-param</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.2"><b>2.1</b></a></li>
1206                        <li><tt>auth-scheme</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>2.1</b></a></li>
1207                        <li><tt>Authorization</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>4.1</b></a></li>
1208                        <li><tt>b64token</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>2.1</b></a></li>
1209                        <li><tt>challenge</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>2.1</b></a></li>
1210                        <li><tt>credentials</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>2.1</b></a></li>
1211                        <li><tt>Proxy-Authenticate</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>4.2</b></a></li>
1212                        <li><tt>Proxy-Authorization</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>4.3</b></a></li>
1213                        <li><tt>realm</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>2.2</b></a></li>
1214                        <li><tt>WWW-Authenticate</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>4.4</b></a></li>
1215                     </ul>
1216                  </li>
1217               </ul>
1218            </li>
1219            <li><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul>
1220                  <li>Header Fields&nbsp;&nbsp;
1221                     <ul>
1222                        <li>Authorization&nbsp;&nbsp;<a href="#rfc.xref.header.authorization.1">2.1</a>, <a href="#rfc.xref.header.authorization.2">3.1</a>, <a href="#rfc.iref.h.1"><b>4.1</b></a>, <a href="#rfc.xref.header.authorization.3">5.3</a></li>
1223                        <li>Proxy-Authenticate&nbsp;&nbsp;<a href="#rfc.xref.header.proxy-authenticate.1">3.2</a>, <a href="#rfc.iref.h.2"><b>4.2</b></a>, <a href="#rfc.xref.header.proxy-authenticate.2">5.3</a></li>
1224                        <li>Proxy-Authorization&nbsp;&nbsp;<a href="#rfc.xref.header.proxy-authorization.1">3.2</a>, <a href="#rfc.iref.h.3"><b>4.3</b></a>, <a href="#rfc.xref.header.proxy-authorization.2">5.3</a></li>
1225                        <li>WWW-Authenticate&nbsp;&nbsp;<a href="#rfc.xref.header.www-authenticate.1">3.1</a>, <a href="#rfc.iref.h.4"><b>4.4</b></a>, <a href="#rfc.xref.header.www-authenticate.2">5.3</a></li>
1226                     </ul>
1227                  </li>
1228               </ul>
1229            </li>
1230            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
1231                  <li><em>Part1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1.2</a>, <a href="#rfc.xref.Part1.2">1.2.1</a>, <a href="#rfc.xref.Part1.3">1.2.1</a>, <a href="#rfc.xref.Part1.4">1.2.1</a>, <a href="#rfc.xref.Part1.5">1.2.1</a>, <a href="#rfc.xref.Part1.6">1.2.1</a>, <a href="#rfc.xref.Part1.7">2.2</a>, <a href="#rfc.xref.Part1.8">2.3.1</a>, <a href="#rfc.xref.Part1.9">4.2</a>, <a href="#rfc.xref.Part1.10">4.4</a>, <a href="#rfc.xref.Part1.11">7</a>, <a href="#Part1"><b>8.1</b></a><ul>
1232                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1.2</a></li>
1233                        <li><em>Section 1.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.3">1.2.1</a>, <a href="#rfc.xref.Part1.4">1.2.1</a></li>
1234                        <li><em>Section 2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.8">2.3.1</a></li>
1235                        <li><em>Section 3.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.5">1.2.1</a>, <a href="#rfc.xref.Part1.6">1.2.1</a></li>
1236                        <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.7">2.2</a>, <a href="#rfc.xref.Part1.9">4.2</a>, <a href="#rfc.xref.Part1.10">4.4</a></li>
1237                        <li><em>Section 12</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.11">7</a></li>
1238                     </ul>
1239                  </li>
1240                  <li><em>Part6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">4.1</a>, <a href="#Part6"><b>8.1</b></a><ul>
1241                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">4.1</a></li>
1242                     </ul>
1243                  </li>
1244                  <li>Protection Space&nbsp;&nbsp;<a href="#rfc.iref.p.1">2.2</a></li>
1245                  <li>Proxy-Authenticate header field&nbsp;&nbsp;<a href="#rfc.xref.header.proxy-authenticate.1">3.2</a>, <a href="#rfc.iref.p.2"><b>4.2</b></a>, <a href="#rfc.xref.header.proxy-authenticate.2">5.3</a></li>
1246                  <li>Proxy-Authorization header field&nbsp;&nbsp;<a href="#rfc.xref.header.proxy-authorization.1">3.2</a>, <a href="#rfc.iref.p.3"><b>4.3</b></a>, <a href="#rfc.xref.header.proxy-authorization.2">5.3</a></li>
1247               </ul>
1248            </li>
1249            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
1250                  <li>Realm&nbsp;&nbsp;<a href="#rfc.iref.r.1">2.2</a></li>
1251                  <li><tt>realm</tt>&nbsp;&nbsp;<a href="#rfc.iref.r.2"><b>2.2</b></a></li>
1252                  <li><tt>realm-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.r.3"><b>2.2</b></a></li>
1253                  <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.1</a>, <a href="#RFC2119"><b>8.1</b></a></li>
1254                  <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.1">1</a>, <a href="#RFC2616"><b>8.2</b></a>, <a href="#rfc.xref.RFC2616.2">C.1</a></li>
1255                  <li><em>RFC2617</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2617.1">1</a>, <a href="#rfc.xref.RFC2617.2">1</a>, <a href="#rfc.xref.RFC2617.3">7</a>, <a href="#rfc.xref.RFC2617.4">7</a>, <a href="#RFC2617"><b>8.2</b></a><ul>
1256                        <li><em>Section 6</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2617.4">7</a></li>
1257                     </ul>
1258                  </li>
1259                  <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">5.3</a>, <a href="#RFC3864"><b>8.2</b></a></li>
1260                  <li><em>RFC3986</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">2.1</a>, <a href="#RFC3986"><b>8.2</b></a></li>
1261                  <li><em>RFC4648</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4648.1">2.1</a>, <a href="#RFC4648"><b>8.2</b></a></li>
1262                  <li><em>RFC5226</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">2.3</a>, <a href="#RFC5226"><b>8.2</b></a><ul>
1263                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">2.3</a></li>
1264                     </ul>
1265                  </li>
1266                  <li><em>RFC5234</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2">1.2</a>, <a href="#RFC5234"><b>8.1</b></a><ul>
1267                        <li><em>Appendix B.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.2">1.2</a></li>
1268                     </ul>
1269                  </li>
1270               </ul>
1271            </li>
1272            <li><a id="rfc.index.S" href="#rfc.index.S"><b>S</b></a><ul>
1273                  <li>Status Codes&nbsp;&nbsp;
1274                     <ul>
1275                        <li>401 Unauthorized&nbsp;&nbsp;<a href="#rfc.iref.s.1"><b>3.1</b></a>, <a href="#rfc.xref.status.401.1">5.2</a></li>
1276                        <li>407 Proxy Authentication Required&nbsp;&nbsp;<a href="#rfc.iref.s.2"><b>3.2</b></a>, <a href="#rfc.xref.status.407.1">5.2</a></li>
1277                     </ul>
1278                  </li>
1279               </ul>
1280            </li>
1281            <li><a id="rfc.index.W" href="#rfc.index.W"><b>W</b></a><ul>
1282                  <li>WWW-Authenticate header field&nbsp;&nbsp;<a href="#rfc.xref.header.www-authenticate.1">3.1</a>, <a href="#rfc.iref.w.1"><b>4.4</b></a>, <a href="#rfc.xref.header.www-authenticate.2">5.3</a></li>
1283               </ul>
1284            </li>
1285         </ul>
1286      </div>
1287   </body>
1288</html>
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