source: draft-ietf-httpbis/latest/p7-auth.xml @ 1692

Last change on this file since 1692 was 1692, checked in by julian.reschke@…, 8 years ago

Simplify use of "Note:", make upper/lowercase of sentence start consistent; use "—" where appropriate

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  • Property svn:mime-type set to text/xml
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1<?xml version="1.0" encoding="utf-8"?>
2<?xml-stylesheet type='text/xsl' href='../myxml2rfc.xslt'?>
3<!DOCTYPE rfc [
4  <!ENTITY MAY "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MAY</bcp14>">
5  <!ENTITY MUST "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST</bcp14>">
6  <!ENTITY MUST-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST NOT</bcp14>">
7  <!ENTITY OPTIONAL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>OPTIONAL</bcp14>">
8  <!ENTITY RECOMMENDED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>RECOMMENDED</bcp14>">
9  <!ENTITY REQUIRED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>REQUIRED</bcp14>">
10  <!ENTITY SHALL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL</bcp14>">
11  <!ENTITY SHALL-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL NOT</bcp14>">
12  <!ENTITY SHOULD "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD</bcp14>">
13  <!ENTITY SHOULD-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD NOT</bcp14>">
14  <!ENTITY ID-VERSION "latest">
15  <!ENTITY ID-MONTH "June">
16  <!ENTITY ID-YEAR "2012">
17  <!ENTITY mdash "&#8212;">
18  <!ENTITY Note "<x:h xmlns:x='http://purl.org/net/xml2rfc/ext'>Note:</x:h>">
19  <!ENTITY architecture                 "<xref target='Part1' x:rel='#architecture' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
20  <!ENTITY notation                     "<xref target='Part1' x:rel='#notation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
21  <!ENTITY abnf-extension               "<xref target='Part1' x:rel='#abnf.extension' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
22  <!ENTITY acks                         "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY whitespace                   "<xref target='Part1' x:rel='#whitespace' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY field-components             "<xref target='Part1' x:rel='#field.components' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY effective-request-uri        "<xref target='Part1' x:rel='#effective.request.uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY msg-orient-and-buffering     "<xref target='Part1' x:rel='#intermediaries' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY end-to-end.and-hop-by-hop    "<xref target='Part1' x:rel='#end-to-end.and.hop-by-hop.header-fields' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY shared-and-non-shared-caches "<xref target='Part6' x:rel='#shared.and.non-shared.caches' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29]>
30<?rfc toc="yes" ?>
31<?rfc symrefs="yes" ?>
32<?rfc sortrefs="yes" ?>
33<?rfc compact="yes"?>
34<?rfc subcompact="no" ?>
35<?rfc linkmailto="no" ?>
36<?rfc editing="no" ?>
37<?rfc comments="yes"?>
38<?rfc inline="yes"?>
39<?rfc rfcedstyle="yes"?>
40<?rfc-ext allow-markup-in-artwork="yes" ?>
41<?rfc-ext include-references-in-index="yes" ?>
42<rfc obsoletes="2616" updates="2617" category="std" x:maturity-level="proposed"
43     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p7-auth-&ID-VERSION;"
44     xmlns:x='http://purl.org/net/xml2rfc/ext'>
45<x:link rel="prev" basename="p6-cache"/>
46<x:feedback template="mailto:ietf-http-wg@w3.org?subject={docname},%20%22{section}%22&amp;body=&lt;{ref}&gt;:"/>
47<front>
48
49  <title abbrev="HTTP/1.1, Part 7">HTTP/1.1, part 7: Authentication</title>
50
51  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
52    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
53    <address>
54      <postal>
55        <street>345 Park Ave</street>
56        <city>San Jose</city>
57        <region>CA</region>
58        <code>95110</code>
59        <country>USA</country>
60      </postal>
61      <email>fielding@gbiv.com</email>
62      <uri>http://roy.gbiv.com/</uri>
63    </address>
64  </author>
65
66  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
67    <organization abbrev="W3C">World Wide Web Consortium</organization>
68    <address>
69      <postal>
70        <street>W3C / ERCIM</street>
71        <street>2004, rte des Lucioles</street>
72        <city>Sophia-Antipolis</city>
73        <region>AM</region>
74        <code>06902</code>
75        <country>France</country>
76      </postal>
77      <email>ylafon@w3.org</email>
78      <uri>http://www.raubacapeu.net/people/yves/</uri>
79    </address>
80  </author>
81
82  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
83    <organization abbrev="greenbytes">greenbytes GmbH</organization>
84    <address>
85      <postal>
86        <street>Hafenweg 16</street>
87        <city>Muenster</city><region>NW</region><code>48155</code>
88        <country>Germany</country>
89      </postal>
90      <email>julian.reschke@greenbytes.de</email>
91      <uri>http://greenbytes.de/tech/webdav/</uri>
92    </address>
93  </author>
94
95  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
96  <workgroup>HTTPbis Working Group</workgroup>
97
98<abstract>
99<t>
100   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
101   distributed, collaborative, hypermedia information systems. HTTP has been in
102   use by the World Wide Web global information initiative since 1990. This
103   document is Part 7 of the seven-part specification that defines the protocol
104   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
105</t>
106<t>
107   Part 7 defines the HTTP Authentication framework.
108</t>
109</abstract>
110
111<note title="Editorial Note (To be removed by RFC Editor)">
112  <t>
113    Discussion of this draft ought to take place on the HTTPBIS working group
114    mailing list (ietf-http-wg@w3.org), which is archived at
115    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
116  </t>
117  <t>
118    The current issues list is at
119    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
120    documents (including fancy diffs) can be found at
121    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
122  </t>
123  <t>
124    The changes in this draft are summarized in <xref target="changes.since.19"/>.
125  </t>
126</note>
127</front>
128<middle>
129<section title="Introduction" anchor="introduction">
130<t>
131   This document defines HTTP/1.1 access control and authentication. It
132   includes the relevant parts of <xref target="RFC2616" x:fmt="none">RFC 2616</xref>
133   with only minor changes (<xref target="RFC2616"/>), plus the general framework for HTTP authentication,
134   as previously defined in "HTTP Authentication: Basic and Digest Access
135   Authentication" (<xref target="RFC2617"/>).
136</t>
137<t>
138   HTTP provides several &OPTIONAL; challenge-response authentication
139   mechanisms which can be used by a server to challenge a client request and
140   by a client to provide authentication information. The "basic" and "digest"
141   authentication schemes continue to be specified in
142   <xref target="RFC2617" x:fmt="none">RFC 2617</xref>.
143</t>
144
145<section title="Conformance and Error Handling" anchor="intro.conformance.and.error.handling">
146<t>
147   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
148   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
149   document are to be interpreted as described in <xref target="RFC2119"/>.
150</t>
151<t>
152   This document defines conformance criteria for several roles in HTTP
153   communication, including Senders, Recipients, Clients, Servers, User-Agents,
154   Origin Servers, Intermediaries, Proxies and Gateways. See &architecture;
155   for definitions of these terms.
156</t>
157<t>
158   An implementation is considered conformant if it complies with all of the
159   requirements associated with its role(s). Note that SHOULD-level requirements
160   are relevant here, unless one of the documented exceptions is applicable.
161</t>
162<t>
163   This document also uses ABNF to define valid protocol elements
164   (<xref target="notation"/>). In addition to the prose requirements placed
165   upon them, Senders &MUST-NOT; generate protocol elements that are invalid.
166</t>
167<t>
168   Unless noted otherwise, Recipients &MUST; be able to parse all protocol
169   elements matching the ABNF rules defined for them and &MAY; take steps to
170   recover a usable protocol element from an invalid construct. However, HTTP does not define
171   specific error handling mechanisms, except in cases where it has direct
172   impact on security. This is because different uses of the protocol require
173   different error handling strategies; for example, a Web browser might wish to
174   transparently recover from a response where the Location header field
175   doesn't parse according to the ABNF, whereby in a systems control protocol
176   using HTTP, this type of error recovery could lead to dangerous consequences.
177</t>
178</section>
179
180<section title="Syntax Notation" anchor="notation">
181  <x:anchor-alias value="ALPHA"/>
182  <x:anchor-alias value="CR"/>
183  <x:anchor-alias value="DIGIT"/>
184  <x:anchor-alias value="LF"/>
185  <x:anchor-alias value="OCTET"/>
186  <x:anchor-alias value="VCHAR"/>
187  <x:anchor-alias value="SP"/>
188<t>
189   This specification uses the Augmented Backus-Naur Form (ABNF) notation
190   of <xref target="RFC5234"/> with the list rule extension defined in
191   &notation;.  <xref target="collected.abnf"/> shows the collected ABNF
192   with the list rule expanded.
193</t>
194<t>
195  The following core rules are included by
196  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
197  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
198  DIGIT (decimal 0-9), DQUOTE (double quote),
199  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
200  OCTET (any 8-bit sequence of data), SP (space), and
201  VCHAR (any visible US-ASCII character).
202</t>
203
204<section title="Core Rules" anchor="core.rules">
205   <x:anchor-alias value="quoted-string"/>
206   <x:anchor-alias value="token"/>
207   <x:anchor-alias value="BWS"/>
208   <x:anchor-alias value="OWS"/>
209<t>
210   The core rules below are defined in <xref target="Part1"/>:
211</t>
212<figure><artwork type="abnf2616">
213  <x:ref>BWS</x:ref>           = &lt;BWS, defined in &whitespace;&gt;
214  <x:ref>OWS</x:ref>           = &lt;OWS, defined in &whitespace;&gt;
215  <x:ref>quoted-string</x:ref> = &lt;quoted-string, defined in &field-components;&gt;
216  <x:ref>token</x:ref>         = &lt;token, defined in &field-components;&gt;
217</artwork></figure>
218</section>
219</section>
220</section>
221
222<section title="Access Authentication Framework" anchor="access.authentication.framework">
223
224<section title="Challenge and Response" anchor="challenge.and.response">
225  <x:anchor-alias value="auth-scheme"/>
226  <x:anchor-alias value="auth-param"/>
227  <x:anchor-alias value="b64token"/>
228  <x:anchor-alias value="challenge"/>
229  <x:anchor-alias value="credentials"/>
230<t>
231   HTTP provides a simple challenge-response authentication mechanism
232   that can be used by a server to challenge a client request and by a
233   client to provide authentication information. It uses an extensible,
234   case-insensitive token to identify the authentication scheme, followed
235   by additional information necessary for achieving authentication via that
236   scheme. The latter can either be a comma-separated list of parameters or a
237   single sequence of characters capable of holding base64-encoded
238   information.
239</t>
240<t>
241   Parameters are name-value pairs where the name is matched case-insensitively,
242   and each parameter name &MUST; only occur once per challenge.
243</t>
244<figure><artwork type="abnf2616"><iref item="auth-scheme" primary="true"/><iref item="auth-param" primary="true"/><iref primary="true" item="Grammar" subitem="auth-scheme"/><iref primary="true" item="Grammar" subitem="auth-param"/><iref item="b64token" primary="true"/><iref primary="true" item="Grammar" subitem="b64token"/>
245  auth-scheme    = <x:ref>token</x:ref>
246 
247  auth-param     = <x:ref>token</x:ref> <x:ref>BWS</x:ref> "=" <x:ref>BWS</x:ref> ( <x:ref>token</x:ref> / <x:ref>quoted-string</x:ref> )
248
249  b64token       = 1*( <x:ref>ALPHA</x:ref> / <x:ref>DIGIT</x:ref> /
250                       "-" / "." / "_" / "~" / "+" / "/" ) *"="
251</artwork></figure>
252<t>
253   The "b64token" syntax allows the 66 unreserved URI characters (<xref target="RFC3986"/>),
254   plus a few others, so that it can hold a base64, base64url (URL and filename
255   safe alphabet), base32, or base16 (hex) encoding, with or without padding, but
256   excluding whitespace (<xref target="RFC4648"/>).
257</t>
258<t>
259   The 401 (Unauthorized) response message is used by an origin server
260   to challenge the authorization of a user agent. This response &MUST;
261   include a WWW-Authenticate header field containing at least one
262   challenge applicable to the requested resource.
263</t>
264<t>  
265   The 407 (Proxy Authentication Required) response message is used by a proxy to
266   challenge the authorization of a client and &MUST; include a Proxy-Authenticate
267   header field containing at least one challenge
268   applicable to the proxy for the requested resource.
269</t>
270<figure><artwork type="abnf2616"><iref item="challenge" primary="true"/><iref primary="true" item="Grammar" subitem="challenge"/>
271  <x:ref>challenge</x:ref>   = <x:ref>auth-scheme</x:ref> [ 1*<x:ref>SP</x:ref> ( <x:ref>b64token</x:ref> / #<x:ref>auth-param</x:ref> ) ]
272</artwork></figure>
273<x:note>
274  <t>
275     &Note; User agents will need to take special care in parsing the
276     WWW-Authenticate and Proxy-Authenticate header field values because they
277     can contain more than one challenge, or if more than one of each is
278     provided, since the contents of a challenge can itself contain a
279     comma-separated list of authentication parameters.
280  </t>
281</x:note>
282<x:note>
283  <t>
284     &Note; Many clients fail to parse challenges containing unknown
285     schemes. A workaround for this problem is to list well-supported schemes
286     (such as "basic") first.<!-- see http://greenbytes.de/tech/tc/httpauth/#multibasicunknown2 -->
287  </t>
288</x:note>
289<t>
290   A user agent that wishes to authenticate itself with an origin server
291   &mdash; usually, but not necessarily, after receiving a 401 (Unauthorized)
292   &mdash; can do so by including an Authorization header field with the
293   request.
294</t>
295<t>  
296   A client that wishes to authenticate itself with a proxy &mdash; usually,
297   but not necessarily, after receiving a 407 (Proxy Authentication Required)
298   &mdash; can do so by including a Proxy-Authorization header field with the
299   request.
300</t>
301<t>
302   Both the Authorization field value and the Proxy-Authorization field value
303   contain the client's credentials for the realm of the resource being
304   requested, based upon a challenge received from the server (possibly at
305   some point in the past). When creating their values, the user agent ought to
306   do so by selecting the challenge with what it considers to be the most
307   secure auth-scheme that it understands, obtaining credentials from the user
308   as appropriate.
309</t>
310<figure><artwork type="abnf2616"><iref item="credentials" primary="true"/><iref primary="true" item="Grammar" subitem="credentials"/>
311  <x:ref>credentials</x:ref> = <x:ref>auth-scheme</x:ref> [ 1*<x:ref>SP</x:ref> ( <x:ref>b64token</x:ref> / #<x:ref>auth-param</x:ref> ) ]
312</artwork></figure>
313<t>
314   Requests for protected resources that omit credentials, contain invalid
315   credentials (e.g., a bad password), or partial credentials (e.g., when the
316   authentication scheme requires more than one round trip) &SHOULD; return a
317   401 (Unauthorized) response. Such responses &MUST; include a
318   WWW-Authenticate header field containing at least one (possibly new)
319   challenge applicable to the requested resource.
320</t>
321<t>
322   Likewise, requests that require authentication by proxies that omit
323   credentials, or contain invalid or partial credentials &SHOULD; return a
324   407 (Proxy Authentication Required) response. Such responses &MUST;
325   include a Proxy-Authenticate header field containing a (possibly new)
326   challenge applicable to the proxy.
327</t>
328<t>
329   A server receiving credentials that are valid, but not adequate to gain
330   access, ought to respond with the 403 (Forbidden) status code.
331</t>
332<t>
333   The HTTP protocol does not restrict applications to this simple
334   challenge-response mechanism for access authentication. Additional
335   mechanisms &MAY; be used, such as encryption at the transport level or
336   via message encapsulation, and with additional header fields
337   specifying authentication information. However, such additional
338   mechanisms are not defined by this specification.
339</t>
340<t>
341   Proxies &MUST; forward the WWW-Authenticate and Authorization headers
342   unmodified and follow the rules found in <xref target="header.authorization"/>.
343</t>
344</section>
345
346<section title="Protection Space (Realm)" anchor="protection.space">
347  <iref item="Protection Space"/>
348  <iref item="Realm"/>
349  <iref item="Canonical Root URI"/>
350<t>
351   The authentication parameter realm is reserved for use by authentication
352   schemes that wish to indicate the scope of protection.
353</t>
354<t>
355   A <x:dfn>protection space</x:dfn> is defined by the canonical root URI (the
356   scheme and authority components of the effective request URI; see
357   <xref target="Part1" x:fmt="of" x:rel="#effective.request.uri"/>) of the
358   server being accessed, in combination with the realm value if present.
359   These realms allow the protected resources on a server to be
360   partitioned into a set of protection spaces, each with its own
361   authentication scheme and/or authorization database. The realm value
362   is a string, generally assigned by the origin server, which can have
363   additional semantics specific to the authentication scheme. Note that
364   there can be multiple challenges with the same auth-scheme but
365   different realms.
366</t>
367<t>
368   The protection space determines the domain over which credentials can
369   be automatically applied. If a prior request has been authorized, the
370   same credentials &MAY; be reused for all other requests within that
371   protection space for a period of time determined by the
372   authentication scheme, parameters, and/or user preference. Unless
373   otherwise defined by the authentication scheme, a single protection
374   space cannot extend outside the scope of its server.
375</t>
376<t>
377   For historical reasons, senders &MUST; only use the quoted-string syntax.
378   Recipients might have to support both token and quoted-string syntax for
379   maximum interoperability with existing clients that have been accepting both
380   notations for a long time.
381</t>
382</section>
383
384<section title="Authentication Scheme Registry" anchor="authentication.scheme.registry">
385<t>
386  The HTTP Authentication Scheme Registry defines the name space for the
387  authentication schemes in challenges and credentials.
388</t>
389<t>
390  Registrations &MUST; include the following fields:
391  <list style="symbols">
392    <t>Authentication Scheme Name</t>
393    <t>Pointer to specification text</t>
394    <t>Notes (optional)</t>
395  </list>
396</t>
397<t>
398  Values to be added to this name space require IETF Review
399  (see <xref target="RFC5226" x:fmt="," x:sec="4.1"/>).
400</t>
401<t>
402  The registry itself is maintained at <eref target="http://www.iana.org/assignments/http-authschemes"/>.
403</t>
404
405<section title="Considerations for New Authentication Schemes" anchor="considerations.for.new.authentication.schemes">
406<t>
407  There are certain aspects of the HTTP Authentication Framework that put
408  constraints on how new authentication schemes can work:
409</t>
410<t>
411  <list style="symbols">
412    <x:lt>
413    <t>
414      HTTP authentication is presumed to be stateless: all of the information
415      necessary to authenticate a request &MUST; be provided in the request,
416      rather than be dependent on the server remembering prior requests.
417      Authentication based on, or bound to, the underlying connection is
418      outside the scope of this specification and inherently flawed unless
419      steps are taken to ensure that the connection cannot be used by any
420      party other than the authenticated user
421      (see &msg-orient-and-buffering;).
422    </t>
423    </x:lt>
424    <x:lt>
425    <t>
426      The authentication parameter "realm" is reserved for defining Protection
427      Spaces as defined in <xref target="protection.space"/>. New schemes
428      &MUST-NOT; use it in a way incompatible with that definition.
429    </t>
430    </x:lt>
431    <x:lt>
432    <t>
433      The "b64token" notation was introduced for compatibility with existing
434      authentication schemes and can only be used once per challenge/credentials.
435      New schemes thus ought to use the "auth-param" syntax instead, because
436      otherwise future extensions will be impossible.
437    </t>
438    </x:lt>
439    <x:lt>
440    <t>
441      The parsing of challenges and credentials is defined by this specification,
442      and cannot be modified by new authentication schemes. When the auth-param
443      syntax is used, all parameters ought to support both token and
444      quoted-string syntax, and syntactical constraints ought to be defined on
445      the field value after parsing (i.e., quoted-string processing). This is
446      necessary so that recipients can use a generic parser that applies to
447      all authentication schemes.
448    </t>
449    <t>
450      &Note; The fact that the value syntax for the "realm" parameter
451      is restricted to quoted-string was a bad design choice not to be repeated
452      for new parameters.
453    </t>
454    </x:lt>
455    <x:lt>
456    <t>
457      Definitions of new schemes ought to define the treatment of unknown
458      extension parameters. In general, a "must-ignore" rule is preferable
459      over "must-understand", because otherwise it will be hard to introduce
460      new parameters in the presence of legacy recipients. Furthermore,
461      it's good to describe the policy for defining new parameters (such
462      as "update the specification", or "use this registry").
463    </t>
464    </x:lt>
465    <x:lt>
466    <t>
467      Authentication schemes need to document whether they are usable in
468      origin-server authentication (i.e., using WWW-Authenticate), and/or
469      proxy authentication (i.e., using Proxy-Authenticate).
470    </t>
471    </x:lt>
472    <x:lt>
473    <t>
474      The credentials carried in an Authorization header field are specific to
475      the User Agent, and therefore have the same effect on HTTP caches as the
476      "private" Cache-Control response directive, within the scope of the
477      request they appear in.
478    </t>
479    <t>
480      Therefore, new authentication schemes which choose not to carry
481      credentials in the Authorization header (e.g., using a newly defined
482      header) will need to explicitly disallow caching, by mandating the use of
483      either Cache-Control request directives (e.g., "no-store") or response
484      directives (e.g., "private").
485    </t>
486    </x:lt>
487  </list>
488</t>
489</section>
490
491</section>
492
493</section>
494
495<section title="Status Code Definitions" anchor="status.code.definitions">
496<section title="401 Unauthorized" anchor="status.401">
497  <iref primary="true" item="401 Unauthorized (status code)" x:for-anchor=""/>
498  <iref primary="true" item="Status Codes" subitem="401 Unauthorized" x:for-anchor=""/>
499<t>
500   The request requires user authentication. The response &MUST; include a
501   WWW-Authenticate header field (<xref target="header.www-authenticate"/>) containing a challenge
502   applicable to the target resource. The client &MAY; repeat the
503   request with a suitable Authorization header field (<xref target="header.authorization"/>). If
504   the request already included Authorization credentials, then the 401
505   response indicates that authorization has been refused for those
506   credentials. If the 401 response contains the same challenge as the
507   prior response, and the user agent has already attempted
508   authentication at least once, then the user &SHOULD; be presented the
509   representation that was given in the response, since that representation might
510   include relevant diagnostic information.
511</t>
512</section>
513<section title="407 Proxy Authentication Required" anchor="status.407">
514  <iref primary="true" item="407 Proxy Authentication Required (status code)" x:for-anchor=""/>
515  <iref primary="true" item="Status Codes" subitem="407 Proxy Authentication Required" x:for-anchor=""/>
516<t>
517   This code is similar to 401 (Unauthorized), but indicates that the
518   client ought to first authenticate itself with the proxy. The proxy &MUST;
519   return a Proxy-Authenticate header field (<xref target="header.proxy-authenticate"/>) containing a
520   challenge applicable to the proxy for the target resource. The
521   client &MAY; repeat the request with a suitable Proxy-Authorization
522   header field (<xref target="header.proxy-authorization"/>).
523</t>
524</section>
525</section>
526
527<section title="Header Field Definitions" anchor="header.field.definitions">
528<t>
529   This section defines the syntax and semantics of HTTP/1.1 header fields
530   related to authentication.
531</t>
532
533<section title="Authorization" anchor="header.authorization">
534  <iref primary="true" item="Authorization header field" x:for-anchor=""/>
535  <iref primary="true" item="Header Fields" subitem="Authorization" x:for-anchor=""/>
536  <x:anchor-alias value="Authorization"/>
537<t>
538   The "Authorization" header field allows a user agent to authenticate
539   itself with a server &mdash; usually, but not necessarily, after receiving a 401
540   (Unauthorized) response. Its value consists of credentials containing
541   information of the user agent for the realm of the resource being
542   requested.
543</t>
544<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Authorization"/>
545  <x:ref>Authorization</x:ref> = <x:ref>credentials</x:ref>
546</artwork></figure>
547<t>
548   If a request is
549   authenticated and a realm specified, the same credentials &SHOULD;
550   be valid for all other requests within this realm (assuming that
551   the authentication scheme itself does not require otherwise, such
552   as credentials that vary according to a challenge value or using
553   synchronized clocks).
554</t>
555<t>
556      When a shared cache (see &shared-and-non-shared-caches;) receives a request
557      containing an Authorization field, it &MUST-NOT; return the
558      corresponding response as a reply to any other request, unless one
559      of the following specific exceptions holds:
560</t>
561<t>
562  <list style="numbers">
563      <t>If the response includes the "s-maxage" cache-control
564         directive, the cache &MAY; use that response in replying to a
565         subsequent request. But (if the specified maximum age has
566         passed) a proxy cache &MUST; first revalidate it with the origin
567         server, using the header fields from the new request to allow
568         the origin server to authenticate the new request. (This is the
569         defined behavior for s-maxage.) If the response includes "s-maxage=0",
570         the proxy &MUST; always revalidate it before re-using
571         it.</t>
572
573      <t>If the response includes the "must-revalidate" cache-control
574         directive, the cache &MAY; use that response in replying to a
575         subsequent request. But if the response is stale, all caches
576         &MUST; first revalidate it with the origin server, using the
577         header fields from the new request to allow the origin server
578         to authenticate the new request.</t>
579
580      <t>If the response includes the "public" cache-control directive,
581         it &MAY; be returned in reply to any subsequent request.</t>
582  </list>
583</t>
584</section>
585
586<section title="Proxy-Authenticate" anchor="header.proxy-authenticate">
587  <iref primary="true" item="Proxy-Authenticate header field" x:for-anchor=""/>
588  <iref primary="true" item="Header Fields" subitem="Proxy-Authenticate" x:for-anchor=""/>
589  <x:anchor-alias value="Proxy-Authenticate"/>
590<t>
591   The "Proxy-Authenticate" header field consists of at least one
592   challenge that indicates the authentication scheme(s) and parameters
593   applicable to the proxy for this effective request URI (&effective-request-uri;).
594   It &MUST; be included as part of a 407 (Proxy Authentication Required) response.
595</t>
596<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Proxy-Authenticate"/>
597  <x:ref>Proxy-Authenticate</x:ref> = 1#<x:ref>challenge</x:ref>
598</artwork></figure>
599<t>
600   Unlike WWW-Authenticate, the Proxy-Authenticate header field applies only to
601   the current connection and &SHOULD-NOT;  be passed on to downstream
602   clients. However, an intermediate proxy might need to obtain its own
603   credentials by requesting them from the downstream client, which in
604   some circumstances will appear as if the proxy is forwarding the
605   Proxy-Authenticate header field.
606</t>
607<t>
608   Note that the parsing considerations for WWW-Authenticate apply to this
609   header field as well; see <xref target="header.www-authenticate"/> for
610   details.
611</t>
612</section>
613
614<section title="Proxy-Authorization" anchor="header.proxy-authorization">
615  <iref primary="true" item="Proxy-Authorization header field" x:for-anchor=""/>
616  <iref primary="true" item="Header Fields" subitem="Proxy-Authorization" x:for-anchor=""/>
617  <x:anchor-alias value="Proxy-Authorization"/>
618<t>
619   The "Proxy-Authorization" header field allows the client to
620   identify itself (or its user) to a proxy which requires
621   authentication. Its value consists of
622   credentials containing the authentication information of the user
623   agent for the proxy and/or realm of the resource being requested.
624</t>
625<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Proxy-Authorization"/>
626  <x:ref>Proxy-Authorization</x:ref> = <x:ref>credentials</x:ref>
627</artwork></figure>
628<t>
629   Unlike Authorization, the Proxy-Authorization header field applies only to
630   the next outbound proxy that demanded authentication using the Proxy-Authenticate
631   field. When multiple proxies are used in a chain, the
632   Proxy-Authorization header field is consumed by the first outbound
633   proxy that was expecting to receive credentials. A proxy &MAY; relay
634   the credentials from the client request to the next proxy if that is
635   the mechanism by which the proxies cooperatively authenticate a given
636   request.
637</t>
638</section>
639
640<section title="WWW-Authenticate" anchor="header.www-authenticate">
641  <iref primary="true" item="WWW-Authenticate header field" x:for-anchor=""/>
642  <iref primary="true" item="Header Fields" subitem="WWW-Authenticate" x:for-anchor=""/>
643  <x:anchor-alias value="WWW-Authenticate"/>
644<t>
645   The "WWW-Authenticate" header field consists of at least one
646   challenge that indicates the authentication scheme(s) and parameters
647   applicable to the effective request URI (&effective-request-uri;).
648</t>
649<t>  
650   It &MUST; be included in 401 (Unauthorized) response messages and &MAY; be
651   included in other response messages to indicate that supplying credentials
652   (or different credentials) might affect the response.
653</t>
654<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="WWW-Authenticate"/>
655  <x:ref>WWW-Authenticate</x:ref> = 1#<x:ref>challenge</x:ref>
656</artwork></figure>
657<t>
658   User agents are advised to take special care in parsing the WWW-Authenticate
659   field value as it might contain more than one challenge,
660   or if more than one WWW-Authenticate header field is provided, the
661   contents of a challenge itself can contain a comma-separated list of
662   authentication parameters.
663</t>
664<figure>
665  <preamble>For instance:</preamble>
666  <artwork type="example">
667  WWW-Authenticate: Newauth realm="apps", type=1,
668                    title="Login to \"apps\"", Basic realm="simple"
669</artwork>
670  <postamble>
671  This header field contains two challenges; one for the "Newauth" scheme
672  with a realm value of "apps", and two additional parameters "type" and
673  "title", and another one for the "Basic" scheme with a realm value of
674  "simple".
675</postamble></figure>
676<x:note>
677  <t>
678    &Note; The challenge grammar production uses the list syntax as
679    well. Therefore, a sequence of comma, whitespace, and comma can be
680    considered both as applying to the preceding challenge, or to be an
681    empty entry in the list of challenges. In practice, this ambiguity
682    does not affect the semantics of the header field value and thus is
683    harmless.
684  </t>
685</x:note>
686</section>
687
688</section>
689
690<section title="IANA Considerations" anchor="IANA.considerations">
691
692<section title="Authenticaton Scheme Registry" anchor="authentication.scheme.registration">
693<t>
694  The registration procedure for HTTP Authentication Schemes is defined by
695  <xref target="authentication.scheme.registry"/> of this document.
696</t>
697<t>
698   The HTTP Method Authentication Scheme shall be created at <eref target="http://www.iana.org/assignments/http-authschemes"/>.
699</t>
700</section>
701
702<section title="Status Code Registration" anchor="status.code.registration">
703<t>
704   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
705   shall be updated with the registrations below:
706</t>
707<?BEGININC p7-auth.iana-status-codes ?>
708<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
709<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
710   <ttcol>Value</ttcol>
711   <ttcol>Description</ttcol>
712   <ttcol>Reference</ttcol>
713   <c>401</c>
714   <c>Unauthorized</c>
715   <c>
716      <xref target="status.401"/>
717   </c>
718   <c>407</c>
719   <c>Proxy Authentication Required</c>
720   <c>
721      <xref target="status.407"/>
722   </c>
723</texttable>
724<!--(END)-->
725<?ENDINC p7-auth.iana-status-codes ?>
726</section>
727
728<section title="Header Field Registration" anchor="header.field.registration">
729<t>
730   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
731   with the permanent registrations below (see <xref target="RFC3864"/>):
732</t>
733<?BEGININC p7-auth.iana-headers ?>
734<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
735<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
736   <ttcol>Header Field Name</ttcol>
737   <ttcol>Protocol</ttcol>
738   <ttcol>Status</ttcol>
739   <ttcol>Reference</ttcol>
740
741   <c>Authorization</c>
742   <c>http</c>
743   <c>standard</c>
744   <c>
745      <xref target="header.authorization"/>
746   </c>
747   <c>Proxy-Authenticate</c>
748   <c>http</c>
749   <c>standard</c>
750   <c>
751      <xref target="header.proxy-authenticate"/>
752   </c>
753   <c>Proxy-Authorization</c>
754   <c>http</c>
755   <c>standard</c>
756   <c>
757      <xref target="header.proxy-authorization"/>
758   </c>
759   <c>WWW-Authenticate</c>
760   <c>http</c>
761   <c>standard</c>
762   <c>
763      <xref target="header.www-authenticate"/>
764   </c>
765</texttable>
766<!--(END)-->
767<?ENDINC p7-auth.iana-headers ?>
768<t>
769   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
770</t>
771</section>
772</section>
773
774<section title="Security Considerations" anchor="security.considerations">
775<t>
776   This section is meant to inform application developers, information
777   providers, and users of the security limitations in HTTP/1.1 as
778   described by this document. The discussion does not include
779   definitive solutions to the problems revealed, though it does make
780   some suggestions for reducing security risks.
781</t>
782
783<section title="Authentication Credentials and Idle Clients" anchor="auth.credentials.and.idle.clients">
784<t>
785   Existing HTTP clients and user agents typically retain authentication
786   information indefinitely. HTTP/1.1 does not provide a method for a
787   server to direct clients to discard these cached credentials. This is
788   a significant defect that requires further extensions to HTTP.
789   Circumstances under which credential caching can interfere with the
790   application's security model include but are not limited to:
791  <list style="symbols">
792     <t>Clients which have been idle for an extended period following
793        which the server might wish to cause the client to reprompt the
794        user for credentials.</t>
795
796     <t>Applications which include a session termination indication
797        (such as a "logout" or "commit" button on a page) after which
798        the server side of the application "knows" that there is no
799        further reason for the client to retain the credentials.</t>
800  </list>
801</t>
802<t>
803   This is currently under separate study. There are a number of work-arounds
804   to parts of this problem, and we encourage the use of
805   password protection in screen savers, idle time-outs, and other
806   methods which mitigate the security problems inherent in this
807   problem. In particular, user agents which cache credentials are
808   encouraged to provide a readily accessible mechanism for discarding
809   cached credentials under user control.
810</t>
811</section>
812
813<section title="Protection Spaces" anchor="protection.spaces">
814<t>
815  Authentication schemes that solely rely on the "realm" mechanism for
816  establishing a protection space will expose credentials to all resources on a
817  server. Clients that have successfully made authenticated requests with a
818  resource can use the same authentication credentials for other resources on
819  the same server. This makes it possible for a different resource to harvest
820  authentication credentials for other resources.
821</t>
822<t>
823  This is of particular concern when a server hosts resources for multiple
824  parties under the same canonical root URI (<xref target="protection.spaces"/>).
825  Possible mitigation strategies include restricting direct access to
826  authentication credentials (i.e., not making the content of the
827  Authorization request header field available), and separating protection
828  spaces by using a different host name for each party.
829</t>
830</section>
831</section>
832
833<section title="Acknowledgments" anchor="acks">
834<t>
835  This specification takes over the definition of the HTTP Authentication
836  Framework, previously defined in <xref target="RFC2617" x:fmt="none">RFC 2617</xref>.
837  We thank John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. Lawrence,
838  Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for their work
839  on that specification. See <xref target="RFC2617" x:fmt="of" x:sec="6"/>
840  for further acknowledgements. 
841</t>
842<t>
843  See &acks; for the Acknowledgments related to this document revision.
844</t>
845</section>
846</middle>
847
848<back>
849
850<references title="Normative References">
851
852<reference anchor="Part1">
853  <front>
854    <title abbrev="HTTP/1.1">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
855    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
856      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
857      <address><email>fielding@gbiv.com</email></address>
858    </author>
859    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
860      <organization abbrev="W3C">World Wide Web Consortium</organization>
861      <address><email>ylafon@w3.org</email></address>
862    </author>
863    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
864      <organization abbrev="greenbytes">greenbytes GmbH</organization>
865      <address><email>julian.reschke@greenbytes.de</email></address>
866    </author>
867    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
868  </front>
869  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
870  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
871</reference>
872
873<reference anchor="Part6">
874  <front>
875    <title abbrev="HTTP/1.1">HTTP/1.1, part 6: Caching</title>
876    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
877      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
878      <address><email>fielding@gbiv.com</email></address>
879    </author>
880    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
881      <organization abbrev="W3C">World Wide Web Consortium</organization>
882      <address><email>ylafon@w3.org</email></address>
883    </author>
884    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
885      <organization>Rackspace</organization>
886      <address><email>mnot@mnot.net</email></address>
887    </author>
888    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
889      <organization abbrev="greenbytes">greenbytes GmbH</organization>
890      <address><email>julian.reschke@greenbytes.de</email></address>
891    </author>
892    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
893  </front>
894  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
895  <x:source href="p6-cache.xml" basename="p6-cache"/>
896</reference>
897
898<reference anchor="RFC2119">
899  <front>
900    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
901    <author initials="S." surname="Bradner" fullname="Scott Bradner">
902      <organization>Harvard University</organization>
903      <address><email>sob@harvard.edu</email></address>
904    </author>
905    <date month="March" year="1997"/>
906  </front>
907  <seriesInfo name="BCP" value="14"/>
908  <seriesInfo name="RFC" value="2119"/>
909</reference>
910
911<reference anchor="RFC5234">
912  <front>
913    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
914    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
915      <organization>Brandenburg InternetWorking</organization>
916      <address>
917        <email>dcrocker@bbiw.net</email>
918      </address> 
919    </author>
920    <author initials="P." surname="Overell" fullname="Paul Overell">
921      <organization>THUS plc.</organization>
922      <address>
923        <email>paul.overell@thus.net</email>
924      </address>
925    </author>
926    <date month="January" year="2008"/>
927  </front>
928  <seriesInfo name="STD" value="68"/>
929  <seriesInfo name="RFC" value="5234"/>
930</reference>
931
932</references>
933
934<references title="Informative References">
935
936<reference anchor="RFC2616">
937  <front>
938    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
939    <author initials="R." surname="Fielding" fullname="R. Fielding">
940      <organization>University of California, Irvine</organization>
941      <address><email>fielding@ics.uci.edu</email></address>
942    </author>
943    <author initials="J." surname="Gettys" fullname="J. Gettys">
944      <organization>W3C</organization>
945      <address><email>jg@w3.org</email></address>
946    </author>
947    <author initials="J." surname="Mogul" fullname="J. Mogul">
948      <organization>Compaq Computer Corporation</organization>
949      <address><email>mogul@wrl.dec.com</email></address>
950    </author>
951    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
952      <organization>MIT Laboratory for Computer Science</organization>
953      <address><email>frystyk@w3.org</email></address>
954    </author>
955    <author initials="L." surname="Masinter" fullname="L. Masinter">
956      <organization>Xerox Corporation</organization>
957      <address><email>masinter@parc.xerox.com</email></address>
958    </author>
959    <author initials="P." surname="Leach" fullname="P. Leach">
960      <organization>Microsoft Corporation</organization>
961      <address><email>paulle@microsoft.com</email></address>
962    </author>
963    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
964      <organization>W3C</organization>
965      <address><email>timbl@w3.org</email></address>
966    </author>
967    <date month="June" year="1999"/>
968  </front>
969  <seriesInfo name="RFC" value="2616"/>
970</reference>
971
972<reference anchor="RFC2617">
973  <front>
974    <title abbrev="HTTP Authentication">HTTP Authentication: Basic and Digest Access Authentication</title>
975    <author initials="J." surname="Franks" fullname="John Franks">
976      <organization>Northwestern University, Department of Mathematics</organization>
977      <address><email>john@math.nwu.edu</email></address>
978    </author>
979    <author initials="P.M." surname="Hallam-Baker" fullname="Phillip M. Hallam-Baker">
980      <organization>Verisign Inc.</organization>
981      <address><email>pbaker@verisign.com</email></address>
982    </author>
983    <author initials="J.L." surname="Hostetler" fullname="Jeffery L. Hostetler">
984      <organization>AbiSource, Inc.</organization>
985      <address><email>jeff@AbiSource.com</email></address>
986    </author>
987    <author initials="S.D." surname="Lawrence" fullname="Scott D. Lawrence">
988      <organization>Agranat Systems, Inc.</organization>
989      <address><email>lawrence@agranat.com</email></address>
990    </author>
991    <author initials="P.J." surname="Leach" fullname="Paul J. Leach">
992      <organization>Microsoft Corporation</organization>
993      <address><email>paulle@microsoft.com</email></address>
994    </author>
995    <author initials="A." surname="Luotonen" fullname="Ari Luotonen">
996      <organization>Netscape Communications Corporation</organization>
997    </author>
998    <author initials="L." surname="Stewart" fullname="Lawrence C. Stewart">
999      <organization>Open Market, Inc.</organization>
1000      <address><email>stewart@OpenMarket.com</email></address>
1001    </author>
1002    <date month="June" year="1999"/>
1003  </front>
1004  <seriesInfo name="RFC" value="2617"/>
1005</reference>
1006
1007<reference anchor='RFC3864'>
1008  <front>
1009    <title>Registration Procedures for Message Header Fields</title>
1010    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
1011      <organization>Nine by Nine</organization>
1012      <address><email>GK-IETF@ninebynine.org</email></address>
1013    </author>
1014    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
1015      <organization>BEA Systems</organization>
1016      <address><email>mnot@pobox.com</email></address>
1017    </author>
1018    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
1019      <organization>HP Labs</organization>
1020      <address><email>JeffMogul@acm.org</email></address>
1021    </author>
1022    <date year='2004' month='September' />
1023  </front>
1024  <seriesInfo name='BCP' value='90' />
1025  <seriesInfo name='RFC' value='3864' />
1026</reference>
1027
1028<reference anchor="RFC3986">
1029 <front>
1030  <title abbrev='URI Generic Syntax'>Uniform Resource Identifier (URI): Generic Syntax</title>
1031  <author initials='T.' surname='Berners-Lee' fullname='Tim Berners-Lee'>
1032    <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1033    <address>
1034       <email>timbl@w3.org</email>
1035       <uri>http://www.w3.org/People/Berners-Lee/</uri>
1036    </address>
1037  </author>
1038  <author initials='R.' surname='Fielding' fullname='Roy T. Fielding'>
1039    <organization abbrev="Day Software">Day Software</organization>
1040    <address>
1041      <email>fielding@gbiv.com</email>
1042      <uri>http://roy.gbiv.com/</uri>
1043    </address>
1044  </author>
1045  <author initials='L.' surname='Masinter' fullname='Larry Masinter'>
1046    <organization abbrev="Adobe Systems">Adobe Systems Incorporated</organization>
1047    <address>
1048      <email>LMM@acm.org</email>
1049      <uri>http://larry.masinter.net/</uri>
1050    </address>
1051  </author>
1052  <date month='January' year='2005'></date>
1053 </front>
1054 <seriesInfo name="STD" value="66"/>
1055 <seriesInfo name="RFC" value="3986"/>
1056</reference>
1057
1058<reference anchor="RFC4648">
1059  <front>
1060    <title>The Base16, Base32, and Base64 Data Encodings</title>
1061    <author fullname="S. Josefsson" initials="S." surname="Josefsson"/>
1062    <date year="2006" month="October"/>
1063  </front>
1064  <seriesInfo value="4648" name="RFC"/>
1065</reference>
1066
1067<reference anchor='RFC5226'>
1068  <front>
1069    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1070    <author initials='T.' surname='Narten' fullname='T. Narten'>
1071      <organization>IBM</organization>
1072      <address><email>narten@us.ibm.com</email></address>
1073    </author>
1074    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1075      <organization>Google</organization>
1076      <address><email>Harald@Alvestrand.no</email></address>
1077    </author>
1078    <date year='2008' month='May' />
1079  </front>
1080  <seriesInfo name='BCP' value='26' />
1081  <seriesInfo name='RFC' value='5226' />
1082</reference>
1083
1084</references>
1085
1086<section title="Changes from RFCs 2616 and 2617" anchor="changes.from.rfc.2616">
1087<t>
1088  The "realm" parameter isn't required anymore in general; consequently, the
1089  ABNF allows challenges without any auth parameters.
1090  (<xref target="access.authentication.framework"/>)
1091</t>
1092<t>
1093  The "b64token" alternative to auth-param lists has been added for consistency
1094  with legacy authentication schemes such as "Basic".
1095  (<xref target="access.authentication.framework"/>)
1096</t>
1097<t>
1098  Change ABNF productions for header fields to only define the field value.
1099  (<xref target="header.field.definitions"/>)
1100</t>
1101</section>
1102 
1103<?BEGININC p7-auth.abnf-appendix ?>
1104<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1105<figure>
1106<artwork type="abnf" name="p7-auth.parsed-abnf">
1107<x:ref>Authorization</x:ref> = credentials
1108
1109<x:ref>BWS</x:ref> = &lt;BWS, defined in [Part1], Section 3.2.1&gt;
1110
1111<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 3.2.1&gt;
1112
1113<x:ref>Proxy-Authenticate</x:ref> = *( "," OWS ) challenge *( OWS "," [ OWS
1114 challenge ] )
1115<x:ref>Proxy-Authorization</x:ref> = credentials
1116
1117<x:ref>WWW-Authenticate</x:ref> = *( "," OWS ) challenge *( OWS "," [ OWS challenge
1118 ] )
1119
1120<x:ref>auth-param</x:ref> = token BWS "=" BWS ( token / quoted-string )
1121<x:ref>auth-scheme</x:ref> = token
1122
1123<x:ref>b64token</x:ref> = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" )
1124 *"="
1125
1126<x:ref>challenge</x:ref> = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) *(
1127 OWS "," [ OWS auth-param ] ) ] ) ]
1128<x:ref>credentials</x:ref> = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param )
1129 *( OWS "," [ OWS auth-param ] ) ] ) ]
1130
1131<x:ref>quoted-string</x:ref> = &lt;quoted-string, defined in [Part1], Section 3.2.4&gt;
1132
1133<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.4&gt;
1134</artwork>
1135</figure>
1136<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
1137; Authorization defined but not used
1138; Proxy-Authenticate defined but not used
1139; Proxy-Authorization defined but not used
1140; WWW-Authenticate defined but not used
1141</artwork></figure></section>
1142<?ENDINC p7-auth.abnf-appendix ?>
1143
1144<section title="Change Log (to be removed by RFC Editor before publication)"  anchor="change.log">
1145<t>
1146  Changes up to the first Working Group Last Call draft are summarized
1147  in <eref target="http://trac.tools.ietf.org/html/draft-ietf-httpbis-p7-auth-19#appendix-C"/>.
1148</t>
1149
1150<section title="Since draft-ietf-httpbis-p7-auth-19" anchor="changes.since.19">
1151<t>
1152  Closed issues:
1153  <list style="symbols">
1154    <t>
1155      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/348"/>:
1156      "Realms and scope"
1157    </t>
1158    <t>
1159      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/349"/>:
1160      "Strength"
1161    </t>
1162    <t>
1163      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/357"/>:
1164      "Authentication exchanges"
1165    </t>
1166    <t>
1167      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/361"/>:
1168      "ABNF requirements for recipients"
1169    </t>
1170  </list>
1171</t>
1172</section>
1173
1174</section>
1175
1176</back>
1177</rfc>
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