source: draft-ietf-httpbis/latest/p7-auth.xml @ 2586

Last change on this file since 2586 was 2576, checked in by fielding@…, 7 years ago

(editorial) fix the introduction to be like other parts and less redundant

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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 "January">
16  <!ENTITY ID-YEAR "2014">
17  <!ENTITY mdash "&#8212;">
18  <!ENTITY Note "<x:h xmlns:x='http://purl.org/net/xml2rfc/ext'>Note:</x:h>">
19  <!ENTITY messaging                    "<xref target='Part1' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
20  <!ENTITY semantics                    "<xref target='Part2' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
21  <!ENTITY architecture                 "<xref target='Part1' x:rel='#architecture' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
22  <!ENTITY conformance                  "<xref target='Part1' x:rel='#conformance' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY notation                     "<xref target='Part1' x:rel='#notation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY abnf-extension               "<xref target='Part1' x:rel='#abnf.extension' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY acks                         "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY whitespace                   "<xref target='Part1' x:rel='#whitespace' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY field-components             "<xref target='Part1' x:rel='#field.components' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY effective-request-uri        "<xref target='Part1' x:rel='#effective.request.uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29  <!ENTITY msg-orient-and-buffering     "<xref target='Part1' x:rel='#intermediaries' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
30  <!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'/>">
31  <!ENTITY status.403                   "<xref target='Part2' x:rel='#status.403' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
32  <!ENTITY caching-authenticated-responses "<xref target='Part6' x:rel='#caching.authenticated.responses' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
33  <!ENTITY caching-rqd-no-store         "<xref target='Part6' x:rel='#cache-request-directive.no-store' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
34  <!ENTITY caching-rsd-private          "<xref target='Part6' x:rel='#cache-response-directive.private' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
35]>
36<?rfc toc="yes" ?>
37<?rfc symrefs="yes" ?>
38<?rfc sortrefs="yes" ?>
39<?rfc compact="yes"?>
40<?rfc subcompact="no" ?>
41<?rfc linkmailto="no" ?>
42<?rfc editing="no" ?>
43<?rfc comments="yes"?>
44<?rfc inline="yes"?>
45<?rfc rfcedstyle="yes"?>
46<?rfc-ext allow-markup-in-artwork="yes" ?>
47<?rfc-ext include-references-in-index="yes" ?>
48<rfc obsoletes="2616" updates="2617" category="std" x:maturity-level="proposed"
49     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p7-auth-&ID-VERSION;"
50     xmlns:x='http://purl.org/net/xml2rfc/ext'>
51<x:link rel="prev" basename="p6-cache"/>
52<x:feedback template="mailto:ietf-http-wg@w3.org?subject={docname},%20%22{section}%22&amp;body=&lt;{ref}&gt;:"/>
53<front>
54
55  <title abbrev="HTTP/1.1 Authentication">Hypertext Transfer Protocol (HTTP/1.1): Authentication</title>
56
57  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
58    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
59    <address>
60      <postal>
61        <street>345 Park Ave</street>
62        <city>San Jose</city>
63        <region>CA</region>
64        <code>95110</code>
65        <country>USA</country>
66      </postal>
67      <email>fielding@gbiv.com</email>
68      <uri>http://roy.gbiv.com/</uri>
69    </address>
70  </author>
71
72  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
73    <organization abbrev="greenbytes">greenbytes GmbH</organization>
74    <address>
75      <postal>
76        <street>Hafenweg 16</street>
77        <city>Muenster</city><region>NW</region><code>48155</code>
78        <country>Germany</country>
79      </postal>
80      <email>julian.reschke@greenbytes.de</email>
81      <uri>http://greenbytes.de/tech/webdav/</uri>
82    </address>
83  </author>
84
85  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
86  <workgroup>HTTPbis Working Group</workgroup>
87
88<abstract>
89<t>
90   The Hypertext Transfer Protocol (HTTP) is a stateless application-level
91   protocol for distributed, collaborative, hypermedia information systems.
92   This document defines the HTTP Authentication framework.
93</t>
94</abstract>
95
96<note title="Editorial Note (To be removed by RFC Editor)">
97  <t>
98    Discussion of this draft takes place on the HTTPBIS working group
99    mailing list (ietf-http-wg@w3.org), which is archived at
100    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
101  </t>
102  <t>
103    The current issues list is at
104    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
105    documents (including fancy diffs) can be found at
106    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
107  </t>
108  <t>
109    The changes in this draft are summarized in <xref target="changes.since.25"/>.
110  </t>
111</note>
112</front>
113<middle>
114<section title="Introduction" anchor="introduction">
115<t>
116   HTTP provides a general framework for access control and authentication,
117   via an extensible set of challenge-response authentication schemes, which
118   can be used by a server to challenge a client request and by a client to
119   provide authentication information. This document defines HTTP/1.1
120   authentication in terms of the architecture defined in
121   <xref target="Part1"/>, including the general framework previously
122   described in <xref target="RFC2617" x:fmt="none">RFC 2617</xref> and
123   the related fields and status codes previously defined in
124   <xref target="RFC2616" x:fmt="none">RFC 2616</xref>.
125</t>
126<t>
127   The IANA Authentication Scheme Registry
128   (<xref target="authentication.scheme.registry"/>) lists registered
129   authentication schemes and their corresponding specifications, including
130   the "basic" and "digest" authentication schemes previously defined by
131   <xref target="RFC2617" x:fmt="none">RFC 2617</xref>.
132</t>
133
134<section title="Conformance and Error Handling" anchor="conformance">
135<t>
136   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
137   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
138   document are to be interpreted as described in <xref target="RFC2119"/>.
139</t>
140<t>
141   Conformance criteria and considerations regarding error handling
142   are defined in &conformance;.
143</t>
144</section>
145
146<section title="Syntax Notation" anchor="notation">
147<t>
148   This specification uses the Augmented Backus-Naur Form (ABNF) notation of
149   <xref target="RFC5234"/> with a list extension, defined in
150   &abnf-extension;, that allows for compact definition of
151   comma-separated lists using a '#' operator (similar to how the '*' operator
152   indicates repetition).
153   <xref target="imported.abnf"/> describes rules imported from
154   other documents.
155   <xref target="collected.abnf"/> shows the collected grammar with all list
156   operators expanded to standard ABNF notation.
157</t>
158</section>
159</section>
160
161<section title="Access Authentication Framework" anchor="access.authentication.framework">
162
163<section title="Challenge and Response" anchor="challenge.and.response">
164  <x:anchor-alias value="auth-scheme"/>
165  <x:anchor-alias value="auth-param"/>
166  <x:anchor-alias value="token68"/>
167  <x:anchor-alias value="challenge"/>
168  <x:anchor-alias value="credentials"/>
169<t>
170   HTTP provides a simple challenge-response authentication framework
171   that can be used by a server to challenge a client request and by a
172   client to provide authentication information. It uses a case-insensitive
173   token as a means to identify the authentication scheme, followed
174   by additional information necessary for achieving authentication via that
175   scheme. The latter can either be a comma-separated list of parameters or a
176   single sequence of characters capable of holding base64-encoded
177   information.
178</t>
179<t>
180   Authentication parameters are name=value pairs, where the name token is
181   matched case-insensitively,
182   and each parameter name &MUST; only occur once per challenge.
183</t>
184<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="auth-scheme"/><iref primary="true" item="Grammar" subitem="auth-param"/><iref primary="true" item="Grammar" subitem="token68"/>
185  auth-scheme    = <x:ref>token</x:ref>
186 
187  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> )
188
189  token68        = 1*( <x:ref>ALPHA</x:ref> / <x:ref>DIGIT</x:ref> /
190                       "-" / "." / "_" / "~" / "+" / "/" ) *"="
191</artwork></figure>
192<t>
193   The "token68" syntax allows the 66 unreserved URI characters
194   (<xref target="RFC3986"/>), plus a few others, so that it can hold a
195   base64, base64url (URL and filename safe alphabet), base32, or base16 (hex)
196   encoding, with or without padding, but excluding whitespace
197   (<xref target="RFC4648"/>).
198</t>
199<t>
200   A <x:ref>401 (Unauthorized)</x:ref> response message is used by an origin
201   server to challenge the authorization of a user agent, including a
202   <x:ref>WWW-Authenticate</x:ref> header field containing at least one
203   challenge applicable to the requested resource.
204</t>
205<t>  
206   A <x:ref>407 (Proxy Authentication Required)</x:ref> response message is
207   used by a proxy to challenge the authorization of a client, including a
208   <x:ref>Proxy-Authenticate</x:ref> header field containing at least one
209   challenge applicable to the proxy for the requested resource.
210</t>
211<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="challenge"/>
212  <x:ref>challenge</x:ref>   = <x:ref>auth-scheme</x:ref> [ 1*<x:ref>SP</x:ref> ( <x:ref>token68</x:ref> / #<x:ref>auth-param</x:ref> ) ]
213</artwork></figure>
214<x:note>
215  <t>
216     &Note; Many clients fail to parse a challenge that contains an unknown
217     scheme. A workaround for this problem is to list well-supported schemes
218     (such as "basic") first.<!-- see http://greenbytes.de/tech/tc/httpauth/#multibasicunknown2 -->
219  </t>
220</x:note>
221<t>
222   A user agent that wishes to authenticate itself with an origin server
223   &mdash; usually, but not necessarily, after receiving a
224   <x:ref>401 (Unauthorized)</x:ref> &mdash; can do so by including an
225   <x:ref>Authorization</x:ref> header field with the request.
226</t>
227<t>  
228   A client that wishes to authenticate itself with a proxy &mdash; usually,
229   but not necessarily, after receiving a
230   <x:ref>407 (Proxy Authentication Required)</x:ref> &mdash; can do so by
231   including a <x:ref>Proxy-Authorization</x:ref> header field with the
232   request.
233</t>
234<t>
235   Both the <x:ref>Authorization</x:ref> field value and the
236   <x:ref>Proxy-Authorization</x:ref> field value contain the client's
237   credentials for the realm of the resource being requested, based upon a
238   challenge received in a response (possibly at some point in the past).
239   When creating their values, the user agent ought to do so by selecting the
240   challenge with what it considers to be the most secure auth-scheme that it
241   understands, obtaining credentials from the user as appropriate.
242   Transmission of credentials within header field values implies significant
243   security considerations regarding the confidentiality of the underlying
244   connection, as described in
245   <xref target="confidentiality.of.credentials"/>.
246</t>
247<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="credentials"/>
248  <x:ref>credentials</x:ref> = <x:ref>auth-scheme</x:ref> [ 1*<x:ref>SP</x:ref> ( <x:ref>token68</x:ref> / #<x:ref>auth-param</x:ref> ) ]
249</artwork></figure>
250<t>
251   Upon receipt of a request for a protected resource that omits credentials,
252   contains invalid credentials (e.g., a bad password) or partial credentials
253   (e.g., when the authentication scheme requires more than one round trip),
254   an origin server &SHOULD; send a <x:ref>401 (Unauthorized)</x:ref> response
255   that contains a <x:ref>WWW-Authenticate</x:ref> header field with at least
256   one (possibly new) challenge applicable to the requested resource.
257</t>
258<t>
259   Likewise, upon receipt of a request that omits proxy credentials or
260   contains invalid or partial proxy credentials, a proxy that requires
261   authentication &SHOULD; generate a
262   <x:ref>407 (Proxy Authentication Required)</x:ref> response that contains
263   a <x:ref>Proxy-Authenticate</x:ref> header field with at least one
264   (possibly new) challenge applicable to the proxy.
265</t>
266<t>
267   A server that receives valid credentials which are not adequate to gain
268   access ought to respond with the <x:ref>403 (Forbidden)</x:ref> status
269   code (&status.403;).
270</t>
271<t>
272   HTTP does not restrict applications to this simple challenge-response
273   framework for access authentication. Additional mechanisms can be used,
274   such as authentication at the transport level or via message encapsulation,
275   and with additional header fields specifying authentication information.
276   However, such additional mechanisms are not defined by this specification.
277</t>
278</section>
279
280<section title="Protection Space (Realm)" anchor="protection.space">
281  <iref item="Protection Space"/>
282  <iref item="Realm"/>
283  <iref item="Canonical Root URI"/>
284<t>
285   The "<x:dfn>realm</x:dfn>" authentication parameter is reserved for use by
286   authentication schemes that wish to indicate a scope of protection.
287</t>
288<t>
289   A <x:dfn>protection space</x:dfn> is defined by the canonical root URI (the
290   scheme and authority components of the effective request URI; see
291   <xref target="Part1" x:fmt="of" x:rel="#effective.request.uri"/>) of the
292   server being accessed, in combination with the realm value if present.
293   These realms allow the protected resources on a server to be
294   partitioned into a set of protection spaces, each with its own
295   authentication scheme and/or authorization database. The realm value
296   is a string, generally assigned by the origin server, which can have
297   additional semantics specific to the authentication scheme. Note that a
298   response can have multiple challenges with the same auth-scheme but
299   different realms.
300</t>
301<t>
302   The protection space determines the domain over which credentials can
303   be automatically applied. If a prior request has been authorized, the
304   user agent &MAY; reuse the same credentials for all other requests within
305   that protection space for a period of time determined by the authentication
306   scheme, parameters, and/or user preferences (such as a configurable
307   inactivity timeout). Unless specifically allowed by the authentication
308   scheme, a single protection space cannot extend outside the scope of its
309   server.
310</t>
311<t>
312   For historical reasons, a sender &MUST; only generate the quoted-string syntax.
313   Recipients might have to support both token and quoted-string syntax for
314   maximum interoperability with existing clients that have been accepting both
315   notations for a long time.
316</t>
317</section>
318
319</section>
320
321<section title="Status Code Definitions" anchor="status.code.definitions">
322<section title="401 Unauthorized" anchor="status.401">
323  <iref primary="true" item="401 Unauthorized (status code)" x:for-anchor=""/>
324  <x:anchor-alias value="401 (Unauthorized)"/>
325<t>
326   The <x:dfn>401 (Unauthorized)</x:dfn> status code indicates that the
327   request has not been applied because it lacks valid authentication
328   credentials for the target resource.
329   The server generating a 401 response &MUST; send a
330   <x:ref>WWW-Authenticate</x:ref> header field
331   (<xref target="header.www-authenticate"/>)
332   containing at least one challenge applicable to the target resource.
333</t>
334<t>
335   If the request included authentication credentials, then the 401 response
336   indicates that authorization has been refused for those credentials.
337   The user agent &MAY; repeat the request with a new or replaced
338   <x:ref>Authorization</x:ref> header field (<xref target="header.authorization"/>).
339   If the 401 response contains the same challenge as the prior response, and
340   the user agent has already attempted authentication at least once, then the
341   user agent &SHOULD; present the enclosed representation to the user, since
342   it usually contains relevant diagnostic information.
343</t>
344</section>
345
346<section title="407 Proxy Authentication Required" anchor="status.407">
347  <iref primary="true" item="407 Proxy Authentication Required (status code)" x:for-anchor=""/>
348  <x:anchor-alias value="407 (Proxy Authentication Required)"/>
349<t>
350   The <x:dfn>407 (Proxy Authentication Required)</x:dfn> status code is
351   similar to <x:ref>401 (Unauthorized)</x:ref>, but indicates that the client
352   needs to authenticate itself in order to use a proxy.
353   The proxy &MUST; send a <x:ref>Proxy-Authenticate</x:ref> header field
354   (<xref target="header.proxy-authenticate"/>) containing a challenge
355   applicable to that proxy for the target resource. The client &MAY; repeat
356   the request with a new or replaced <x:ref>Proxy-Authorization</x:ref>
357   header field (<xref target="header.proxy-authorization"/>).
358</t>
359</section>
360</section>
361
362<section title="Header Field Definitions" anchor="header.field.definitions">
363<t>
364   This section defines the syntax and semantics of header fields related to
365   the HTTP authentication framework.
366</t>
367
368<section title="WWW-Authenticate" anchor="header.www-authenticate">
369  <iref primary="true" item="WWW-Authenticate header field" x:for-anchor=""/>
370  <x:anchor-alias value="WWW-Authenticate"/>
371<t>
372   The "WWW-Authenticate" header field indicates the authentication scheme(s)
373   and parameters applicable to the target resource.
374</t>
375<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="WWW-Authenticate"/>
376  <x:ref>WWW-Authenticate</x:ref> = 1#<x:ref>challenge</x:ref>
377</artwork></figure>
378<t>
379   A server generating a <x:ref>401 (Unauthorized)</x:ref> response
380   &MUST; send a WWW-Authenticate header field containing at least one
381   challenge.  A server &MAY; generate a WWW-Authenticate header field
382   in other response messages to indicate that supplying credentials
383   (or different credentials) might affect the response.
384</t>
385<t>
386   A proxy forwarding a response &MUST-NOT; modify any
387   <x:ref>WWW-Authenticate</x:ref> fields in that response.
388</t>
389<t>
390   User agents are advised to take special care in parsing the field value, as
391   it might contain more than one challenge, and each challenge can contain a
392   comma-separated list of authentication parameters. Furthermore, the header
393   field itself can occur multiple times.
394</t>
395<figure>
396  <preamble>For instance:</preamble>
397  <artwork type="example">
398  WWW-Authenticate: Newauth realm="apps", type=1,
399                    title="Login to \"apps\"", Basic realm="simple"
400</artwork>
401  <postamble>
402  This header field contains two challenges; one for the "Newauth" scheme
403  with a realm value of "apps", and two additional parameters "type" and
404  "title", and another one for the "Basic" scheme with a realm value of
405  "simple".
406</postamble></figure>
407<x:note>
408  <t>
409    &Note; The challenge grammar production uses the list syntax as
410    well. Therefore, a sequence of comma, whitespace, and comma can be
411    considered either as applying to the preceding challenge, or to be an
412    empty entry in the list of challenges. In practice, this ambiguity
413    does not affect the semantics of the header field value and thus is
414    harmless.
415  </t>
416</x:note>
417</section>
418
419<section title="Authorization" anchor="header.authorization">
420  <iref primary="true" item="Authorization header field" x:for-anchor=""/>
421  <x:anchor-alias value="Authorization"/>
422<t>
423   The "Authorization" header field allows a user agent to authenticate itself
424   with an origin server &mdash; usually, but not necessarily, after receiving
425   a <x:ref>401 (Unauthorized)</x:ref> response. Its value consists of
426   credentials containing the authentication information of the user agent for
427   the realm of the resource being requested.
428</t>
429<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Authorization"/>
430  <x:ref>Authorization</x:ref> = <x:ref>credentials</x:ref>
431</artwork></figure>
432<t>
433   If a request is authenticated and a realm specified, the same credentials
434   are presumed to be valid for all other requests within this realm (assuming
435   that the authentication scheme itself does not require otherwise, such as
436   credentials that vary according to a challenge value or using synchronized
437   clocks).
438</t>
439<t>
440   A proxy forwarding a request &MUST-NOT; modify any
441   <x:ref>Authorization</x:ref> fields in that request.
442   See &caching-authenticated-responses; for details of and requirements
443   pertaining to handling of the Authorization field by HTTP caches.
444</t>
445</section>
446
447<section title="Proxy-Authenticate" anchor="header.proxy-authenticate">
448  <iref primary="true" item="Proxy-Authenticate header field" x:for-anchor=""/>
449  <x:anchor-alias value="Proxy-Authenticate"/>
450<t>
451   The "Proxy-Authenticate" header field consists of at least one
452   challenge that indicates the authentication scheme(s) and parameters
453   applicable to the proxy for this effective request URI
454   (&effective-request-uri;).
455   A proxy &MUST; send at least one Proxy-Authenticate header field in
456   each <x:ref>407 (Proxy Authentication Required)</x:ref> response that it
457   generates.
458</t>
459<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Proxy-Authenticate"/>
460  <x:ref>Proxy-Authenticate</x:ref> = 1#<x:ref>challenge</x:ref>
461</artwork></figure>
462<t>
463   Unlike <x:ref>WWW-Authenticate</x:ref>, the Proxy-Authenticate header field
464   applies only to the next outbound client on the response chain.
465   This is because only the client that chose a given proxy is likely to have
466   the credentials necessary for authentication.  However, when multiple
467   proxies are used within the same administrative domain, such as office and
468   regional caching proxies within a large corporate network, it is common
469   for credentials to be generated by the user agent and passed through the
470   hierarchy until consumed.  Hence, in such a configuration, it will appear
471   as if Proxy-Authenticate is being forwarded because each proxy will send
472   the same challenge set.
473</t>
474<t>
475   Note that the parsing considerations for <x:ref>WWW-Authenticate</x:ref>
476   apply to this header field as well; see <xref target="header.www-authenticate"/>
477   for details.
478</t>
479</section>
480
481<section title="Proxy-Authorization" anchor="header.proxy-authorization">
482  <iref primary="true" item="Proxy-Authorization header field" x:for-anchor=""/>
483  <x:anchor-alias value="Proxy-Authorization"/>
484<t>
485   The "Proxy-Authorization" header field allows the client to
486   identify itself (or its user) to a proxy that requires
487   authentication. Its value consists of credentials containing the
488   authentication information of the client for the proxy and/or realm of the
489   resource being requested.
490</t>
491<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Proxy-Authorization"/>
492  <x:ref>Proxy-Authorization</x:ref> = <x:ref>credentials</x:ref>
493</artwork></figure>
494<t>
495   Unlike <x:ref>Authorization</x:ref>, the Proxy-Authorization header field
496   applies only to the next inbound proxy that demanded authentication using
497   the <x:ref>Proxy-Authenticate</x:ref> field. When multiple proxies are used
498   in a chain, the Proxy-Authorization header field is consumed by the first
499   inbound proxy that was expecting to receive credentials. A proxy &MAY;
500   relay the credentials from the client request to the next proxy if that is
501   the mechanism by which the proxies cooperatively authenticate a given
502   request.
503</t>
504</section>
505
506</section>
507
508<section title="IANA Considerations" anchor="IANA.considerations">
509
510<section title="Authentication Scheme Registry" anchor="authentication.scheme.registry">
511<t>
512   The HTTP Authentication Scheme Registry defines the name space for the
513   authentication schemes in challenges and credentials. It will be created and
514   maintained at (the suggested URI) <eref target="http://www.iana.org/assignments/http-authschemes"/>.
515</t>
516
517<section title="Procedure" anchor="authentication.scheme.registry.procedure">
518<t>
519  Registrations &MUST; include the following fields:
520  <list style="symbols">
521    <t>Authentication Scheme Name</t>
522    <t>Pointer to specification text</t>
523    <t>Notes (optional)</t>
524  </list>
525</t>
526<t>
527  Values to be added to this name space require IETF Review
528  (see <xref target="RFC5226" x:fmt="," x:sec="4.1"/>).
529</t>
530</section>
531
532<section title="Considerations for New Authentication Schemes" anchor="considerations.for.new.authentication.schemes">
533<t>
534  There are certain aspects of the HTTP Authentication Framework that put
535  constraints on how new authentication schemes can work:
536</t>
537<t>
538  <list style="symbols">
539    <x:lt>
540    <t>
541      HTTP authentication is presumed to be stateless: all of the information
542      necessary to authenticate a request &MUST; be provided in the request,
543      rather than be dependent on the server remembering prior requests.
544      Authentication based on, or bound to, the underlying connection is
545      outside the scope of this specification and inherently flawed unless
546      steps are taken to ensure that the connection cannot be used by any
547      party other than the authenticated user
548      (see &msg-orient-and-buffering;).
549    </t>
550    </x:lt>
551    <x:lt>
552    <t>
553      The authentication parameter "realm" is reserved for defining Protection
554      Spaces as defined in <xref target="protection.space"/>. New schemes
555      &MUST-NOT; use it in a way incompatible with that definition.
556    </t>
557    </x:lt>
558    <x:lt>
559    <t>
560      The "token68" notation was introduced for compatibility with existing
561      authentication schemes and can only be used once per challenge or credential.
562      New schemes thus ought to use the "auth-param" syntax instead, because
563      otherwise future extensions will be impossible.
564    </t>
565    </x:lt>
566    <x:lt>
567    <t>
568      The parsing of challenges and credentials is defined by this specification,
569      and cannot be modified by new authentication schemes. When the auth-param
570      syntax is used, all parameters ought to support both token and
571      quoted-string syntax, and syntactical constraints ought to be defined on
572      the field value after parsing (i.e., quoted-string processing). This is
573      necessary so that recipients can use a generic parser that applies to
574      all authentication schemes.
575    </t>
576    <t>
577      &Note; The fact that the value syntax for the "realm" parameter
578      is restricted to quoted-string was a bad design choice not to be repeated
579      for new parameters.
580    </t>
581    </x:lt>
582    <x:lt>
583    <t>
584      Definitions of new schemes ought to define the treatment of unknown
585      extension parameters. In general, a "must-ignore" rule is preferable
586      over "must-understand", because otherwise it will be hard to introduce
587      new parameters in the presence of legacy recipients. Furthermore,
588      it's good to describe the policy for defining new parameters (such
589      as "update the specification", or "use this registry").
590    </t>
591    </x:lt>
592    <x:lt>
593    <t>
594      Authentication schemes need to document whether they are usable in
595      origin-server authentication (i.e., using <x:ref>WWW-Authenticate</x:ref>),
596      and/or proxy authentication (i.e., using <x:ref>Proxy-Authenticate</x:ref>).
597    </t>
598    </x:lt>
599    <x:lt>
600    <t>
601      The credentials carried in an <x:ref>Authorization</x:ref> header field are specific to
602      the User Agent, and therefore have the same effect on HTTP caches as the
603      "private" Cache-Control response directive (&caching-rsd-private;),
604      within the scope of the request they appear in.
605    </t>
606    <t>
607      Therefore, new authentication schemes that choose not to carry
608      credentials in the <x:ref>Authorization</x:ref> header field (e.g., using a newly defined
609      header field) will need to explicitly disallow caching, by mandating the use of
610      either Cache-Control request directives (e.g., "no-store",
611      &caching-rqd-no-store;) or response directives (e.g., "private").
612    </t>
613    </x:lt>
614  </list>
615</t>
616</section>
617</section>
618
619<section title="Status Code Registration" anchor="status.code.registration">
620<t>
621   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
622   shall be updated with the registrations below:
623</t>
624<?BEGININC p7-auth.iana-status-codes ?>
625<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
626<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
627   <ttcol>Value</ttcol>
628   <ttcol>Description</ttcol>
629   <ttcol>Reference</ttcol>
630   <c>401</c>
631   <c>Unauthorized</c>
632   <c>
633      <xref target="status.401"/>
634   </c>
635   <c>407</c>
636   <c>Proxy Authentication Required</c>
637   <c>
638      <xref target="status.407"/>
639   </c>
640</texttable>
641<!--(END)-->
642<?ENDINC p7-auth.iana-status-codes ?>
643</section>
644
645<section title="Header Field Registration" anchor="header.field.registration">
646<t>
647   HTTP header fields are registered within the Message Header Field Registry
648   maintained at
649   <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/>.
650</t>
651<t>
652   This document defines the following HTTP header fields, so their
653   associated registry entries shall be updated according to the permanent
654   registrations below (see <xref target="BCP90"/>):
655</t>
656<?BEGININC p7-auth.iana-headers ?>
657<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
658<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
659   <ttcol>Header Field Name</ttcol>
660   <ttcol>Protocol</ttcol>
661   <ttcol>Status</ttcol>
662   <ttcol>Reference</ttcol>
663
664   <c>Authorization</c>
665   <c>http</c>
666   <c>standard</c>
667   <c>
668      <xref target="header.authorization"/>
669   </c>
670   <c>Proxy-Authenticate</c>
671   <c>http</c>
672   <c>standard</c>
673   <c>
674      <xref target="header.proxy-authenticate"/>
675   </c>
676   <c>Proxy-Authorization</c>
677   <c>http</c>
678   <c>standard</c>
679   <c>
680      <xref target="header.proxy-authorization"/>
681   </c>
682   <c>WWW-Authenticate</c>
683   <c>http</c>
684   <c>standard</c>
685   <c>
686      <xref target="header.www-authenticate"/>
687   </c>
688</texttable>
689<!--(END)-->
690<?ENDINC p7-auth.iana-headers ?>
691<t>
692   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
693</t>
694</section>
695</section>
696
697<section title="Security Considerations" anchor="security.considerations">
698<t>
699   This section is meant to inform developers, information providers, and
700   users of known security concerns specific to HTTP authentication.
701   More general security considerations are addressed in HTTP messaging
702   &messaging; and semantics &semantics;.
703</t>
704<t>
705   Everything about the topic of HTTP authentication is a security
706   consideration, so the list of considerations below is not exhaustive.
707   Furthermore, it is limited to security considerations regarding the
708   authentication framework, in general, rather than discussing all of the
709   potential considerations for specific authentication schemes (which ought
710   to be documented in the specifications that define those schemes).
711   Various organizations maintain topical information and links to current
712   research on Web application security (e.g., <xref target="OWASP"/>),
713   including common pitfalls for implementing and using the authentication
714   schemes found in practice.
715</t>
716
717<section title="Confidentiality of Credentials" anchor="confidentiality.of.credentials">
718<t>
719   The HTTP authentication framework does not define a single mechanism for
720   maintaining the confidentiality of credentials; instead, each
721   authentication scheme defines how the credentials are encoded prior to
722   transmission. While this provides flexibility for the development of future
723   authentication schemes, it is inadequate for the protection of existing
724   schemes that provide no confidentiality on their own, or that do not
725   sufficiently protect against replay attacks. Furthermore, if the server
726   expects credentials that are specific to each individual user, the exchange
727   of those credentials will have the effect of identifying that user even if
728   the content within credentials remains confidential.
729</t>
730<t>
731   HTTP depends on the security properties of the underlying transport or
732   session-level connection to provide confidential transmission of header
733   fields. In other words, if a server limits access to authenticated users
734   using this framework, the server needs to ensure that the connection is
735   properly secured in accordance with the nature of the authentication
736   scheme used. For example, services that depend on individual user
737   authentication often require a connection to be secured with TLS
738   ("Transport Layer Security", <xref target="RFC5246"/>) prior to exchanging
739   any credentials.
740</t>
741</section>
742
743<section title="Authentication Credentials and Idle Clients" anchor="auth.credentials.and.idle.clients">
744<t>
745   Existing HTTP clients and user agents typically retain authentication
746   information indefinitely. HTTP does not provide a mechanism for the
747   origin server to direct clients to discard these cached credentials, since
748   the protocol has no awareness of how credentials are obtained or managed
749   by the user agent. The mechanisms for expiring or revoking credentials can
750   be specified as part of an authentication scheme definition.
751</t>
752<t>
753   Circumstances under which credential caching can interfere with the
754   application's security model include but are not limited to:
755  <list style="symbols">
756     <t>Clients that have been idle for an extended period, following
757        which the server might wish to cause the client to re-prompt the
758        user for credentials.</t>
759
760     <t>Applications that include a session termination indication
761        (such as a "logout" or "commit" button on a page) after which
762        the server side of the application "knows" that there is no
763        further reason for the client to retain the credentials.</t>
764  </list>
765</t>
766<t>
767   User agents that cache credentials are encouraged to provide a readily
768   accessible mechanism for discarding cached credentials under user control.
769</t>
770</section>
771
772<section title="Protection Spaces" anchor="protection.spaces">
773<t>
774  Authentication schemes that solely rely on the "realm" mechanism for
775  establishing a protection space will expose credentials to all resources on
776  an origin server. Clients that have successfully made authenticated requests
777  with a resource can use the same authentication credentials for other
778  resources on the same origin server. This makes it possible for a different
779  resource to harvest authentication credentials for other resources.
780</t>
781<t>
782  This is of particular concern when an origin server hosts resources for multiple
783  parties under the same canonical root URI (<xref target="protection.space"/>).
784  Possible mitigation strategies include restricting direct access to
785  authentication credentials (i.e., not making the content of the
786  <x:ref>Authorization</x:ref> request header field available), and separating protection
787  spaces by using a different host name (or port number) for each party.
788</t>
789</section>
790</section>
791
792<section title="Acknowledgments" anchor="acks">
793<t>
794  This specification takes over the definition of the HTTP Authentication
795  Framework, previously defined in <xref target="RFC2617" x:fmt="none">RFC 2617</xref>.
796  We thank John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. Lawrence,
797  Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for their work
798  on that specification. See <xref target="RFC2617" x:fmt="of" x:sec="6"/>
799  for further acknowledgements. 
800</t>
801<t>
802  See &acks; for the Acknowledgments related to this document revision.
803</t>
804</section>
805</middle>
806
807<back>
808
809<references title="Normative References">
810
811<reference anchor="Part1">
812  <front>
813    <title>Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing</title>
814    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
815      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
816      <address><email>fielding@gbiv.com</email></address>
817    </author>
818    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
819      <organization abbrev="greenbytes">greenbytes GmbH</organization>
820      <address><email>julian.reschke@greenbytes.de</email></address>
821    </author>
822    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
823  </front>
824  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
825  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
826</reference>
827
828<reference anchor="Part2">
829  <front>
830    <title>Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content</title>
831    <author fullname="Roy T. Fielding" initials="R." role="editor" surname="Fielding">
832      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
833      <address><email>fielding@gbiv.com</email></address>
834    </author>
835    <author fullname="Julian F. Reschke" initials="J. F." role="editor" surname="Reschke">
836      <organization abbrev="greenbytes">greenbytes GmbH</organization>
837      <address><email>julian.reschke@greenbytes.de</email></address>
838    </author>
839    <date month="&ID-MONTH;" year="&ID-YEAR;" />
840  </front>
841  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;" />
842  <x:source basename="p2-semantics" href="p2-semantics.xml">
843    <x:defines>403 (Forbidden)</x:defines>
844    <x:defines>Location</x:defines>
845  </x:source>
846</reference>
847
848<reference anchor="Part6">
849  <front>
850    <title>Hypertext Transfer Protocol (HTTP/1.1): Caching</title>
851    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
852      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
853      <address><email>fielding@gbiv.com</email></address>
854    </author>
855    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
856      <organization>Akamai</organization>
857      <address><email>mnot@mnot.net</email></address>
858    </author>
859    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
860      <organization abbrev="greenbytes">greenbytes GmbH</organization>
861      <address><email>julian.reschke@greenbytes.de</email></address>
862    </author>
863    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
864  </front>
865  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
866  <x:source href="p6-cache.xml" basename="p6-cache"/>
867</reference>
868
869<reference anchor="RFC2119">
870  <front>
871    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
872    <author initials="S." surname="Bradner" fullname="Scott Bradner">
873      <organization>Harvard University</organization>
874      <address><email>sob@harvard.edu</email></address>
875    </author>
876    <date month="March" year="1997"/>
877  </front>
878  <seriesInfo name="BCP" value="14"/>
879  <seriesInfo name="RFC" value="2119"/>
880</reference>
881
882<reference anchor="RFC5234">
883  <front>
884    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
885    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
886      <organization>Brandenburg InternetWorking</organization>
887      <address>
888        <email>dcrocker@bbiw.net</email>
889      </address> 
890    </author>
891    <author initials="P." surname="Overell" fullname="Paul Overell">
892      <organization>THUS plc.</organization>
893      <address>
894        <email>paul.overell@thus.net</email>
895      </address>
896    </author>
897    <date month="January" year="2008"/>
898  </front>
899  <seriesInfo name="STD" value="68"/>
900  <seriesInfo name="RFC" value="5234"/>
901</reference>
902
903</references>
904
905<references title="Informative References">
906
907<reference anchor="RFC2616">
908  <front>
909    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
910    <author initials="R." surname="Fielding" fullname="R. Fielding">
911      <organization>University of California, Irvine</organization>
912      <address><email>fielding@ics.uci.edu</email></address>
913    </author>
914    <author initials="J." surname="Gettys" fullname="J. Gettys">
915      <organization>W3C</organization>
916      <address><email>jg@w3.org</email></address>
917    </author>
918    <author initials="J." surname="Mogul" fullname="J. Mogul">
919      <organization>Compaq Computer Corporation</organization>
920      <address><email>mogul@wrl.dec.com</email></address>
921    </author>
922    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
923      <organization>MIT Laboratory for Computer Science</organization>
924      <address><email>frystyk@w3.org</email></address>
925    </author>
926    <author initials="L." surname="Masinter" fullname="L. Masinter">
927      <organization>Xerox Corporation</organization>
928      <address><email>masinter@parc.xerox.com</email></address>
929    </author>
930    <author initials="P." surname="Leach" fullname="P. Leach">
931      <organization>Microsoft Corporation</organization>
932      <address><email>paulle@microsoft.com</email></address>
933    </author>
934    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
935      <organization>W3C</organization>
936      <address><email>timbl@w3.org</email></address>
937    </author>
938    <date month="June" year="1999"/>
939  </front>
940  <seriesInfo name="RFC" value="2616"/>
941</reference>
942
943<reference anchor="RFC2617">
944  <front>
945    <title abbrev="HTTP Authentication">HTTP Authentication: Basic and Digest Access Authentication</title>
946    <author initials="J." surname="Franks" fullname="John Franks">
947      <organization>Northwestern University, Department of Mathematics</organization>
948      <address><email>john@math.nwu.edu</email></address>
949    </author>
950    <author initials="P.M." surname="Hallam-Baker" fullname="Phillip M. Hallam-Baker">
951      <organization>Verisign Inc.</organization>
952      <address><email>pbaker@verisign.com</email></address>
953    </author>
954    <author initials="J.L." surname="Hostetler" fullname="Jeffery L. Hostetler">
955      <organization>AbiSource, Inc.</organization>
956      <address><email>jeff@AbiSource.com</email></address>
957    </author>
958    <author initials="S.D." surname="Lawrence" fullname="Scott D. Lawrence">
959      <organization>Agranat Systems, Inc.</organization>
960      <address><email>lawrence@agranat.com</email></address>
961    </author>
962    <author initials="P.J." surname="Leach" fullname="Paul J. Leach">
963      <organization>Microsoft Corporation</organization>
964      <address><email>paulle@microsoft.com</email></address>
965    </author>
966    <author initials="A." surname="Luotonen" fullname="Ari Luotonen">
967      <organization>Netscape Communications Corporation</organization>
968    </author>
969    <author initials="L." surname="Stewart" fullname="Lawrence C. Stewart">
970      <organization>Open Market, Inc.</organization>
971      <address><email>stewart@OpenMarket.com</email></address>
972    </author>
973    <date month="June" year="1999"/>
974  </front>
975  <seriesInfo name="RFC" value="2617"/>
976</reference>
977
978<reference anchor='BCP90'>
979  <front>
980    <title>Registration Procedures for Message Header Fields</title>
981    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
982      <organization>Nine by Nine</organization>
983      <address><email>GK-IETF@ninebynine.org</email></address>
984    </author>
985    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
986      <organization>BEA Systems</organization>
987      <address><email>mnot@pobox.com</email></address>
988    </author>
989    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
990      <organization>HP Labs</organization>
991      <address><email>JeffMogul@acm.org</email></address>
992    </author>
993    <date year='2004' month='September' />
994  </front>
995  <seriesInfo name='BCP' value='90' />
996  <seriesInfo name='RFC' value='3864' />
997</reference>
998
999<reference anchor="RFC3986">
1000 <front>
1001  <title abbrev='URI Generic Syntax'>Uniform Resource Identifier (URI): Generic Syntax</title>
1002  <author initials='T.' surname='Berners-Lee' fullname='Tim Berners-Lee'>
1003    <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1004    <address>
1005       <email>timbl@w3.org</email>
1006       <uri>http://www.w3.org/People/Berners-Lee/</uri>
1007    </address>
1008  </author>
1009  <author initials='R.' surname='Fielding' fullname='Roy T. Fielding'>
1010    <organization abbrev="Day Software">Day Software</organization>
1011    <address>
1012      <email>fielding@gbiv.com</email>
1013      <uri>http://roy.gbiv.com/</uri>
1014    </address>
1015  </author>
1016  <author initials='L.' surname='Masinter' fullname='Larry Masinter'>
1017    <organization abbrev="Adobe Systems">Adobe Systems Incorporated</organization>
1018    <address>
1019      <email>LMM@acm.org</email>
1020      <uri>http://larry.masinter.net/</uri>
1021    </address>
1022  </author>
1023  <date month='January' year='2005'></date>
1024 </front>
1025 <seriesInfo name="STD" value="66"/>
1026 <seriesInfo name="RFC" value="3986"/>
1027</reference>
1028
1029<reference anchor="RFC4648">
1030  <front>
1031    <title>The Base16, Base32, and Base64 Data Encodings</title>
1032    <author fullname="S. Josefsson" initials="S." surname="Josefsson"/>
1033    <date year="2006" month="October"/>
1034  </front>
1035  <seriesInfo value="4648" name="RFC"/>
1036</reference>
1037
1038<reference anchor='RFC5226'>
1039  <front>
1040    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1041    <author initials='T.' surname='Narten' fullname='T. Narten'>
1042      <organization>IBM</organization>
1043      <address><email>narten@us.ibm.com</email></address>
1044    </author>
1045    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1046      <organization>Google</organization>
1047      <address><email>Harald@Alvestrand.no</email></address>
1048    </author>
1049    <date year='2008' month='May' />
1050  </front>
1051  <seriesInfo name='BCP' value='26' />
1052  <seriesInfo name='RFC' value='5226' />
1053</reference>
1054
1055<reference anchor="OWASP" target="https://www.owasp.org/">
1056        <front>
1057    <title abbrev="OWASP">A Guide to Building Secure Web Applications and Web Services</title>
1058    <author role="editor" initials="A." surname="van der Stock"
1059            fullname="Andrew van der Stock"/>
1060    <date month="July" day="27" year="2005"/>
1061  </front>
1062  <seriesInfo name="The Open Web Application Security Project (OWASP)" value="2.0.1"/>
1063</reference>
1064
1065<reference anchor='RFC5246'>
1066   <front>
1067      <title>The Transport Layer Security (TLS) Protocol Version 1.2</title>
1068      <author initials='T.' surname='Dierks' fullname='T. Dierks'/>
1069      <author initials='E.' surname='Rescorla' fullname='E. Rescorla'>
1070         <organization>RTFM, Inc.</organization>
1071      </author>
1072      <date year='2008' month='August' />
1073   </front>
1074   <seriesInfo name='RFC' value='5246' />
1075</reference>
1076
1077</references>
1078
1079<section title="Changes from RFCs 2616 and 2617" anchor="changes.from.rfc.2616">
1080<t>
1081  The framework for HTTP Authentication is now defined by this document,
1082  rather than RFC 2617.
1083</t>
1084<t>
1085  The "realm" parameter is no longer always required on challenges;
1086  consequently, the ABNF allows challenges without any auth parameters.
1087  (<xref target="access.authentication.framework"/>)
1088</t>
1089<t>
1090  The "token68" alternative to auth-param lists has been added for consistency
1091  with legacy authentication schemes such as "Basic".
1092  (<xref target="access.authentication.framework"/>)
1093</t>
1094<t>
1095  This specification introduces the Authentication Scheme Registry, along with
1096  considerations for new authentication schemes.
1097  (<xref target="authentication.scheme.registry"/>)
1098</t>
1099</section>
1100 
1101<section title="Imported ABNF" anchor="imported.abnf">
1102  <x:anchor-alias value="ALPHA"/>
1103  <x:anchor-alias value="CR"/>
1104  <x:anchor-alias value="DIGIT"/>
1105  <x:anchor-alias value="LF"/>
1106  <x:anchor-alias value="OCTET"/>
1107  <x:anchor-alias value="VCHAR"/>
1108  <x:anchor-alias value="SP"/>
1109  <x:anchor-alias value="quoted-string"/>
1110  <x:anchor-alias value="token"/>
1111  <x:anchor-alias value="BWS"/>
1112  <x:anchor-alias value="OWS"/>
1113<t>
1114  The following core rules are included by
1115  reference, as defined in <xref target="RFC5234" x:fmt="of" x:sec="B.1"/>:
1116  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
1117  DIGIT (decimal 0-9), DQUOTE (double quote),
1118  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
1119  OCTET (any 8-bit sequence of data), SP (space), and
1120  VCHAR (any visible US-ASCII character).
1121</t>
1122<t>
1123   The rules below are defined in <xref target="Part1"/>:
1124</t>
1125<figure><artwork type="abnf2616">
1126  <x:ref>BWS</x:ref>           = &lt;BWS, defined in &whitespace;&gt;
1127  <x:ref>OWS</x:ref>           = &lt;OWS, defined in &whitespace;&gt;
1128  <x:ref>quoted-string</x:ref> = &lt;quoted-string, defined in &field-components;&gt;
1129  <x:ref>token</x:ref>         = &lt;token, defined in &field-components;&gt;
1130</artwork></figure>
1131</section>
1132
1133<?BEGININC p7-auth.abnf-appendix ?>
1134<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1135<t>
1136  In the collected ABNF below, list rules are expanded as per <xref target="Part1" x:rel="#notation"/>.
1137</t><figure>
1138<artwork type="abnf" name="p7-auth.parsed-abnf">
1139<x:ref>Authorization</x:ref> = credentials
1140
1141<x:ref>BWS</x:ref> = &lt;BWS, defined in [Part1], Section 3.2.3&gt;
1142
1143<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 3.2.3&gt;
1144
1145<x:ref>Proxy-Authenticate</x:ref> = *( "," OWS ) challenge *( OWS "," [ OWS
1146 challenge ] )
1147<x:ref>Proxy-Authorization</x:ref> = credentials
1148
1149<x:ref>WWW-Authenticate</x:ref> = *( "," OWS ) challenge *( OWS "," [ OWS challenge
1150 ] )
1151
1152<x:ref>auth-param</x:ref> = token BWS "=" BWS ( token / quoted-string )
1153<x:ref>auth-scheme</x:ref> = token
1154
1155<x:ref>challenge</x:ref> = auth-scheme [ 1*SP ( token68 / [ ( "," / auth-param ) *(
1156 OWS "," [ OWS auth-param ] ) ] ) ]
1157<x:ref>credentials</x:ref> = auth-scheme [ 1*SP ( token68 / [ ( "," / auth-param )
1158 *( OWS "," [ OWS auth-param ] ) ] ) ]
1159
1160<x:ref>quoted-string</x:ref> = &lt;quoted-string, defined in [Part1], Section 3.2.6&gt;
1161
1162<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.6&gt;
1163<x:ref>token68</x:ref> = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" )
1164 *"="
1165</artwork>
1166</figure>
1167</section>
1168<?ENDINC p7-auth.abnf-appendix ?>
1169
1170<section title="Change Log (to be removed by RFC Editor before publication)"  anchor="change.log">
1171<t>
1172  Changes up to the IETF Last Call draft are summarized
1173  in <eref target="http://trac.tools.ietf.org/html/draft-ietf-httpbis-p7-auth-24#appendix-D"/>.
1174</t>
1175
1176<section title="Since draft-ietf-httpbis-p7-auth-24" anchor="changes.since.24">
1177<t>
1178  Closed issues:
1179  <list style="symbols">
1180    <t>
1181      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/510"/>:
1182      "SECDIR review of draft-ietf-httpbis-p7-auth-24"
1183    </t>
1184    <t>
1185      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/513"/>:
1186      "APPSDIR review of draft-ietf-httpbis-p7-auth-24"
1187    </t>
1188    <t>
1189      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/516"/>:
1190      "note about WWW-A parsing potentially misleading"
1191    </t>
1192  </list>
1193</t>
1194</section>
1195
1196<section title="Since draft-ietf-httpbis-p7-auth-25" anchor="changes.since.25">
1197<t>
1198  Closed issues:
1199  <list style="symbols">
1200    <t>
1201      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/522"/>:
1202      "Gen-art review of draft-ietf-httpbis-p7-auth-25"
1203    </t>
1204    <t>
1205      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/536"/>:
1206      "IESG ballot on draft-ietf-httpbis-p7-auth-25"
1207    </t>
1208    <t>
1209      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/538"/>:
1210      "add 'stateless' to Abstract"
1211    </t>
1212    <t>
1213      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/539"/>:
1214      "mention TLS vs plain text passwords or dict attacks?"
1215    </t>
1216    <t>
1217      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/542"/>:
1218      "improve introduction of list rule"
1219    </t>
1220    <t>
1221      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/549"/>:
1222      "augment security considerations with pointers to current research"
1223    </t>
1224  </list>
1225</t>
1226</section>
1227</section>
1228
1229</back>
1230</rfc>
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