idnits 2.17.1 draft-ietf-httpauth-basicauth-update-06.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- -- The draft header indicates that this document obsoletes RFC2617, but the abstract doesn't seem to mention this, which it should. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document seems to contain a disclaimer for pre-RFC5378 work, but was first submitted on or after 10 November 2008. The disclaimer is usually necessary only for documents that revise or obsolete older RFCs, and that take significant amounts of text from those RFCs. If you can contact all authors of the source material and they are willing to grant the BCP78 rights to the IETF Trust, you can and should remove the disclaimer. Otherwise, the disclaimer is needed and you can ignore this comment. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (February 12, 2015) is 3354 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-18) exists of draft-ietf-precis-saslprepbis-13 ** Obsolete normative reference: RFC 7235 (Obsoleted by RFC 9110) == Outdated reference: A later version (-05) exists of draft-ietf-httpbis-auth-info-02 == Outdated reference: A later version (-19) exists of draft-ietf-httpauth-digest-13 -- Obsolete informational reference (is this intentional?): RFC 2617 (Obsoleted by RFC 7235, RFC 7615, RFC 7616, RFC 7617) -- Obsolete informational reference (is this intentional?): RFC 2818 (Obsoleted by RFC 9110) -- Obsolete informational reference (is this intentional?): RFC 2831 (Obsoleted by RFC 6331) -- Obsolete informational reference (is this intentional?): RFC 5246 (Obsoleted by RFC 8446) -- Obsolete informational reference (is this intentional?): RFC 7231 (Obsoleted by RFC 9110) Summary: 1 error (**), 0 flaws (~~), 5 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 HTTPAuth Working Group J. Reschke 3 Internet-Draft greenbytes 4 Obsoletes: 2617 (if approved) February 12, 2015 5 Intended status: Standards Track 6 Expires: August 16, 2015 8 The 'Basic' HTTP Authentication Scheme 9 draft-ietf-httpauth-basicauth-update-06 11 Abstract 13 This document defines the "Basic" Hypertext Transfer Protocol (HTTP) 14 Authentication Scheme, which transmits credentials as user-id/ 15 password pairs, encoded using Base64. 17 Editorial Note (To be removed by RFC Editor before publication) 19 Discussion of this draft takes place on the HTTPAuth working group 20 mailing list (http-auth@ietf.org), which is archived at . 23 XML versions, latest edits and the issues list for this document are 24 available from . 27 The changes in this draft are summarized in Appendix C.7. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at http://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on August 16, 2015. 46 Copyright Notice 48 Copyright (c) 2015 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 This document may contain material from IETF Documents or IETF 62 Contributions published or made publicly available before November 63 10, 2008. The person(s) controlling the copyright in some of this 64 material may not have granted the IETF Trust the right to allow 65 modifications of such material outside the IETF Standards Process. 66 Without obtaining an adequate license from the person(s) controlling 67 the copyright in such materials, this document may not be modified 68 outside the IETF Standards Process, and derivative works of it may 69 not be created outside the IETF Standards Process, except to format 70 it for publication as an RFC or to translate it into languages other 71 than English. 73 Table of Contents 75 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 76 1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 4 77 1.1.1. Syntax Notation . . . . . . . . . . . . . . . . . . . 4 78 2. The 'Basic' Authentication Scheme . . . . . . . . . . . . . . 4 79 2.1. The 'charset' auth-param . . . . . . . . . . . . . . . . . 6 80 2.2. Re-using Credentials . . . . . . . . . . . . . . . . . . . 8 81 3. Internationalization Considerations . . . . . . . . . . . . . 8 82 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 83 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 84 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 85 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 86 7.1. Normative References . . . . . . . . . . . . . . . . . . . 11 87 7.2. Informative References . . . . . . . . . . . . . . . . . . 11 88 Appendix A. Changes from RFC 2617 . . . . . . . . . . . . . . . . 12 89 Appendix B. Deployment Considerations for the 'charset' 90 Parameter . . . . . . . . . . . . . . . . . . . . . . 13 91 B.1. User Agents . . . . . . . . . . . . . . . . . . . . . . . 13 92 B.2. Origin Servers . . . . . . . . . . . . . . . . . . . . . . 13 93 B.3. Why not simply switch the default encoding to UTF-8? . . . 13 94 Appendix C. Change Log (to be removed by RFC Editor before 95 publication) . . . . . . . . . . . . . . . . . . . . 13 96 C.1. Since RFC 2617 . . . . . . . . . . . . . . . . . . . . . . 14 97 C.2. Since draft-ietf-httpauth-basicauth-update-00 . . . . . . 14 98 C.3. Since draft-ietf-httpauth-basicauth-update-01 . . . . . . 14 99 C.4. Since draft-ietf-httpauth-basicauth-update-02 . . . . . . 14 100 C.5. Since draft-ietf-httpauth-basicauth-update-03 . . . . . . 14 101 C.6. Since draft-ietf-httpauth-basicauth-update-04 . . . . . . 15 102 C.7. Since draft-ietf-httpauth-basicauth-update-05 . . . . . . 15 104 1. Introduction 106 This document defines the "Basic" Hypertext Transfer Protocol (HTTP) 107 Authentication Scheme, which transmits credentials as user-id/ 108 password pairs, encoded using Base64 (HTTP authentication schemes are 109 defined in [RFC7235]). 111 This scheme is not considered to be a secure method of user 112 authentication unless used in conjunction with some external secure 113 system such as TLS (Transport Layer Security, [RFC5246]), as the 114 user-id and password are passed over the network as cleartext. 116 The "Basic" scheme previously was defined in Section 2 of [RFC2617]. 117 This document updates the definition, and also addresses 118 internationalization issues by introducing the "charset" 119 authentication parameter (Section 2.1). 121 Other documents updating RFC 2617 are "Hypertext Transfer Protocol 122 (HTTP/1.1): Authentication" ([RFC7235], defining the authentication 123 framework), "HTTP Digest Access Authentication" ([DIGEST], updating 124 the definition of the '"Digest" authentication scheme), and "The 125 Hypertext Transfer Protocol (HTTP) Authentication-Info and Proxy- 126 Authentication-Info Response Header Fields" ([AUTHINFO]). Taken 127 together, these four documents obsolete RFC 2617. 129 1.1. Notational Conventions 131 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 132 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 133 document are to be interpreted as described in [RFC2119]. 135 1.1.1. Syntax Notation 137 This specification uses the Augmented Backus-Naur Form (ABNF) 138 notation of [RFC5234]. 140 The terms protection space and realm are defined in Section 2.2 of 141 [RFC7235]. 143 The terms (character) repertoire and character encoding scheme are 144 defined in Section 2 of [RFC6365]. 146 2. The 'Basic' Authentication Scheme 148 The "Basic" authentication scheme is based on the model that the 149 client needs to authenticate itself with a user-id and a password for 150 each protection space ("realm"). The realm value is a free-form 151 string which can only be compared for equality with other realms on 152 that server. The server will service the request only if it can 153 validate the user-id and password for the protection space applying 154 to the requested resource. 156 The "Basic" authentication scheme utilizes the Authentication 157 Framework as follows: 159 In challenges: 161 o the scheme name is "Basic" 163 o the authentication parameter "realm" is REQUIRED ([RFC7235], 164 Section 2.2) 166 o the authentication parameter "charset" is OPTIONAL (see 167 Section 2.1) 169 o no other authentication parameters are defined -- unknown 170 parameters MUST be ignored by recipients, and new parameters can 171 only be defined by revising this specification 173 See also Section 4.1 of [RFC7235] which discusses the complexity of 174 parsing challenges properly. 176 Note that both scheme and parameter names are matched case- 177 insensitively. 179 For credentials, the "token68" syntax defined in Section 2.1 of 180 [RFC7235] is used. The value is computed based on user-id and 181 password as defined below. 183 Upon receipt of a request for a URI within the protection space that 184 lacks credentials, the server can reply with a challenge using the 185 401 (Unauthorized) status code ([RFC7235], Section 3.1) and the WWW- 186 Authenticate header field ([RFC7235], Section 4.1). 188 For instance: 190 HTTP/1.1 401 Unauthorized 191 Date: Mon, 04 Feb 2014 16:50:53 GMT 192 WWW-Authenticate: Basic realm="WallyWorld" 194 ...where "WallyWorld" is the string assigned by the server to 195 identify the protection space. 197 A proxy can respond with a similar challenge using the 407 (Proxy 198 Authentication Required) status code ([RFC7235], Section 3.2) and the 199 Proxy-Authenticate header field ([RFC7235], Section 4.3). 201 To receive authorization, the client 203 1. obtains the user-id and password from the user, 205 2. constructs the user-pass by concatenating user-id, a single colon 206 (":") character, and the password, 208 3. encodes the user-pass into an octet sequence (see below for a 209 discussion of character encoding schemes), 211 4. and obtains the basic-credentials by encoding this octet sequence 212 using base64 ([RFC4648], Section 4) into a sequence of US-ASCII 213 characters ([RFC0020]). 215 The original definition of this authentication scheme failed to 216 specify the character encoding scheme used to convert the user-pass 217 into an octet sequence. In practice, most implementations chose 218 either a locale-specific encoding such as ISO-8859-1 ([ISO-8859-1]), 219 or UTF-8 ([RFC3629]). For backwards compatibility reasons, this 220 specification continues to leave the default encoding undefined, as 221 long as it is compatible with US-ASCII (mapping any US-ASCII 222 character to a single octet matching the US-ASCII character code). 224 The user-id and password MUST NOT contain any control characters (see 225 "CTL" in Appendix B.1 of [RFC5234]). 227 Furthermore, a user-id containing a colon character is invalid, as 228 recipients will split the user-pass at the first occurrence of a 229 colon character. Note that many user agents however will accept a 230 colon in user-id, thereby producing a user-pass string that 231 recipients will likely treat in a way not intended by the user. 233 If the user agent wishes to send the user-id "Aladdin" and password 234 "open sesame", it would use the following header field: 236 Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ== 238 2.1. The 'charset' auth-param 240 In challenges, servers can use the "charset" authentication parameter 241 to indicate the character encoding scheme they expect the user agent 242 to use when generating "user-pass" (a sequence of octets). This 243 information is purely advisory. 245 The only allowed value is "UTF-8", to be matched case-insensitively 246 (see [RFC2978], Section 2.3). It indicates that the server expects 247 character data to be converted to Unicode Normalization Form C 248 ("NFC", see Section 3 of [RFC5198]) and to be encoded into octets 249 using the UTF-8 character encoding scheme ([RFC3629]). 251 For the user-id, recipients MUST support all characters defined in 252 the "UsernameCasePreserved" profile defined in in Section 3.3 of 253 [PRECIS], with the exception of the colon (":") character. 255 For the password, recipients MUST support all characters defined in 256 the "OpaqueString" profile defined in in Section 4.2 of [PRECIS]. 258 Other values are reserved for future use. 260 Note: The 'charset' is only defined on challenges, as "Basic" uses 261 a single token for credentials ('token68' syntax), thus the 262 credentials syntax isn't extensible. 264 Note: The name 'charset' has been chosen for consistency with 265 Section 2.1.1 of [RFC2831]. A better name would have been 266 'accept-charset', as it is not about the message it appears in, 267 but the server's expectation. 269 In the example below, the server prompts for authentication in the 270 "foo" realm, using Basic authentication, with a preference for the 271 UTF-8 character encoding scheme: 273 WWW-Authenticate: Basic realm="foo", charset="UTF-8" 275 Note that the parameter value can be either a token or a quoted 276 string; in this case the server chose to use the quoted-string 277 notation. 279 The user's name is "test", and the password is the string "123" 280 followed by the Unicode character U+00A3 (POUND SIGN). Using the 281 character encoding scheme UTF-8, the user-pass becomes: 283 't' 'e' 's' 't' ':' '1' '2' '3' pound 284 74 65 73 74 3A 31 32 33 C2 A3 286 Encoding this octet sequence in Base64 ([RFC4648], Section 4) yields: 288 dGVzdDoxMjPCow== 290 Thus the Authorization header field would be: 292 Authorization: Basic dGVzdDoxMjPCow== 294 Or, for proxy authentication: 296 Proxy-Authorization: Basic dGVzdDoxMjPCow== 298 2.2. Re-using Credentials 300 Given the absolute URI ([RFC3986], Section 4.3) of an authenticated 301 request, the authentication scope of that request is obtained by 302 removing all characters after the last slash ("/") character of the 303 path component ("hier_part", see [RFC3986], Section 3). A client 304 SHOULD assume that resources identified by URIs with a prefix-match 305 of the authentication scope are also within the protection space 306 specified by the realm value of the that authenticated request. 308 A client MAY preemptively send the corresponding Authorization header 309 field with requests for resources in that space without receipt of 310 another challenge from the server. Similarly, when a client sends a 311 request to a proxy, it may reuse a user-id and password in the Proxy- 312 Authorization header field without receiving another challenge from 313 the proxy server. 315 For example, given an authenticated request to: 317 http://example.com/docs/index.html 319 ...requests to the URIs below could use the known credentials: 321 http://example.com/docs/ 322 http://example.com/docs/test.doc 323 http://example.com/docs/?page=1 325 ...while the URIs 327 http://example.com/other/ 328 https://example.com/docs/ 330 would be considered to be outside the authentication scope. 332 Note that a URI can be part of multiple authentication scopes (such 333 as "http://example.com/" and "http://example.com/docs/"). This 334 specification does not define which of these should be treated with 335 higher priority. 337 3. Internationalization Considerations 339 User-ids or passwords containing characters outside the US-ASCII 340 character repertoire will cause interoperability issues, unless both 341 communication partners agree on what character encoding scheme is to 342 be used. Servers can use the new 'charset' parameter (Section 2.1) 343 to indicate a preference of "UTF-8", increasing the probability that 344 clients will switch to that encoding. 346 The "realm" parameter carries data that can be considered textual, 347 however [RFC7235] does not define a way to reliably transport non-US- 348 ASCII characters. This is a known issue that would need to be 349 addressed in that specification. 351 4. Security Considerations 353 The Basic authentication scheme is not a secure method of user 354 authentication, nor does it in any way protect the entity, which is 355 transmitted in cleartext across the physical network used as the 356 carrier. HTTP does not prevent the addition of enhancements (such as 357 schemes to use one-time passwords) to Basic authentication. 359 The most serious flaw in Basic authentication is that it results in 360 the cleartext transmission of the user's password over the physical 361 network. Many other authentication schemes address this problem. 363 Because Basic authentication involves the cleartext transmission of 364 passwords it SHOULD NOT be used (without enhancements such as HTTPS 365 [RFC2818]) to protect sensitive or valuable information. 367 A common use of Basic authentication is for identification purposes 368 -- requiring the user to provide a user-id and password as a means of 369 identification, for example, for purposes of gathering accurate usage 370 statistics on a server. When used in this way it is tempting to 371 think that there is no danger in its use if illicit access to the 372 protected documents is not a major concern. This is only correct if 373 the server issues both user-id and password to the users and in 374 particular does not allow the user to choose his or her own password. 375 The danger arises because naive users frequently reuse a single 376 password to avoid the task of maintaining multiple passwords. 378 If a server permits users to select their own passwords, then the 379 threat is not only unauthorized access to documents on the server but 380 also unauthorized access to any other resources on other systems that 381 the user protects with the same password. Furthermore, in the 382 server's password database, many of the passwords may also be users' 383 passwords for other sites. The owner or administrator of such a 384 system could therefore expose all users of the system to the risk of 385 unauthorized access to all those sites if this information is not 386 maintained in a secure fashion. This raises both security and 387 privacy concerns ([RFC6973]). If the same user-id and password 388 combination is in use to access other accounts, such as an email or 389 health portal account, personal information could be exposed. 391 Basic Authentication is also vulnerable to spoofing by counterfeit 392 servers. If a user can be led to believe that he is connecting to a 393 host containing information protected by Basic authentication when, 394 in fact, he is connecting to a hostile server or gateway, then the 395 attacker can request a password, store it for later use, and feign an 396 error. This type of attack is not possible with Digest 397 Authentication. Server implementers SHOULD guard against the 398 possibility of this sort of counterfeiting by gateways or CGI 399 scripts. In particular it is very dangerous for a server to simply 400 turn over a connection to a gateway. That gateway can then use the 401 persistent connection mechanism to engage in multiple transactions 402 with the client while impersonating the original server in a way that 403 is not detectable by the client. 405 The use of the UTF-8 character encoding scheme introduces additional 406 security considerations; see Section 10 of [RFC3629] for more 407 information. 409 5. IANA Considerations 411 IANA maintains the registry of HTTP Authentication Schemes 412 ([RFC7235]) at . 414 The entry for the "Basic" Authentication Scheme shall be updated with 415 a pointer to this specification. 417 6. Acknowledgements 419 This specification takes over the definition of the "Basic" HTTP 420 Authentication Scheme, previously defined in RFC 2617. We thank John 421 Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. 422 Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for 423 their work on that specification, from which significant amounts of 424 text were borrowed. See Section 6 of [RFC2617] for further 425 acknowledgements. 427 The internationalization problem with respect to the character 428 encoding scheme used for user-pass has been reported as a Mozilla bug 429 back in the year 2000 (see 430 and also the 431 more recent ). 432 It was Andrew Clover's idea to address it using a new auth-param. 434 We also thank the members of the HTTPAuth Working Group and other 435 reviewers, namely Stephen Farrell, Bjoern Hoehrmann, Kari Hurtta, 436 Amos Jeffries, Benjamin Kaduk, Michael Koeller, Eric Lawrence, James 437 Manger, Alexey Melnikov, Kathleen Moriarty, Yaron Sheffer, Michael 438 Sweet, and Martin Thomson for feedback on this revision. 440 7. References 442 7.1. Normative References 444 [PRECIS] Saint-Andre, P. and A. Melnikov, "Preparation, 445 Enforcement, and Comparison of Internationalized 446 Strings Representing Usernames and Passwords", 447 draft-ietf-precis-saslprepbis-13 (work in progress), 448 December 2014. 450 [RFC0020] Cerf, V., "ASCII format for network interchange", 451 RFC 20, October 1969. 453 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 454 Requirement Levels", BCP 14, RFC 2119, March 1997. 456 [RFC2978] Freed, N. and J. Postel, "IANA Charset Registration 457 Procedures", BCP 19, RFC 2978, October 2000. 459 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 460 10646", STD 63, RFC 3629, November 2003. 462 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, 463 "Uniform Resource Identifier (URI): Generic Syntax", 464 STD 66, RFC 3986, January 2005. 466 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data 467 Encodings", RFC 4648, October 2006. 469 [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for 470 Network Interchange", RFC 5198, March 2008. 472 [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for 473 Syntax Specifications: ABNF", STD 68, RFC 5234, 474 January 2008. 476 [RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in 477 Internationalization in the IETF", BCP 166, RFC 6365, 478 September 2011. 480 [RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext 481 Transfer Protocol (HTTP/1.1): Authentication", 482 RFC 7235, June 2014. 484 7.2. Informative References 486 [AUTHINFO] Reschke, J., "The Hypertext Transfer Protocol (HTTP) 487 Authentication-Info and Proxy-Authentication-Info 488 Response Header Fields", 489 draft-ietf-httpbis-auth-info-02 (work in progress), 490 February 2015. 492 [DIGEST] Shekh-Yusef, R., Ed., Ahrens, D., and S. Bremer, "HTTP 493 Digest Access Authentication", 494 draft-ietf-httpauth-digest-13 (work in progress), 495 February 2015. 497 [ISO-8859-1] International Organization for Standardization, 498 "Information technology -- 8-bit single-byte coded 499 graphic character sets -- Part 1: Latin alphabet No. 500 1", ISO/IEC 8859-1:1998, 1998. 502 [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, 503 S., Leach, P., Luotonen, A., and L. Stewart, "HTTP 504 Authentication: Basic and Digest Access 505 Authentication", RFC 2617, June 1999. 507 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. 509 [RFC2831] Leach, P. and C. Newman, "Using Digest Authentication 510 as a SASL Mechanism", RFC 2831, May 2000. 512 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer 513 Security (TLS) Protocol Version 1.2", RFC 5246, 514 August 2008. 516 [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., 517 Morris, J., Hansen, M., and R. Smith, "Privacy 518 Considerations for Internet Protocols", RFC 6973, 519 July 2013. 521 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext 522 Transfer Protocol (HTTP/1.1): Semantics and Content", 523 RFC 7231, June 2014. 525 Appendix A. Changes from RFC 2617 527 The scheme definition has been rewritten to be consistent with newer 528 specifications such as [RFC7235]. 530 The new authentication parameter "charset" has been added. It is 531 purely advisory, so existing implementations do not need to change, 532 unless they want to take advantage of the additional information 533 which previously wasn't available. 535 Appendix B. Deployment Considerations for the 'charset' Parameter 537 B.1. User Agents 539 User agents not implementing 'charset' will continue to work as 540 before, ignoring the new parameter. 542 User agents which already default to the UTF-8 encoding implement 543 'charset' by definition. 545 Other user agents can keep their default behavior, and switch to 546 UTF-8 when seeing the new parameter. 548 B.2. Origin Servers 550 Origin servers that do not support non-US-ASCII characters in 551 credentials do not require any changes to support 'charset'. 553 Origin servers that need to support non-US-ASCII characters, but 554 cannot use the UTF-8 character encoding scheme will not be affected; 555 they will continue to function as well or as badly as before. 557 Finally, origin servers that need to support non-US-ASCII characters 558 and can use the UTF-8 character encoding scheme can opt in as 559 described above. In the worst case, they'll continue to see either 560 broken credentials or no credentials at all (depending on how legacy 561 clients handle characters they cannot encode). 563 B.3. Why not simply switch the default encoding to UTF-8? 565 There are sites in use today that default to a local character 566 encoding scheme, such as ISO-8859-1 ([ISO-8859-1]), and expect user 567 agents to use that encoding. Authentication on these sites will stop 568 to work if the user agent switches to a different encoding, such as 569 UTF-8. 571 Note that sites might even inspect the User-Agent header field 572 ([RFC7231], Section 5.5.3) to decide what character encoding scheme 573 to expect from the client. Therefore they might support UTF-8 for 574 some user agents, but default to something else for others. User 575 agents in the latter group will have to continue to do what they do 576 today until the majority of these servers have been upgraded to 577 always use UTF-8. 579 Appendix C. Change Log (to be removed by RFC Editor before publication) 580 C.1. Since RFC 2617 582 This draft acts as a baseline for tracking subsequent changes to the 583 specification. As such, it extracts the definition of "Basic", plus 584 the related Security Considerations, and also adds the IANA 585 registration of the scheme. Changes to the actual definition will be 586 made in subsequent drafts. 588 C.2. Since draft-ietf-httpauth-basicauth-update-00 590 Fixed Base64 reference to point to an actual definition of Base64. 592 Update HTTPbis and Digest references. 594 Note that this spec, together with HTTPbis P7 and the Digest update, 595 obsoletes RFC 2617. 597 Rewrote text about authentication parameters and their extensibility. 599 Pulled in the definition of the "charset" parameter. 601 Removed a misleading statement about user-ids potentially being case- 602 sensitive, as the same is true for passwords. 604 Added TODOs with respect to path matching, and colons in user-ids. 606 C.3. Since draft-ietf-httpauth-basicauth-update-01 608 Minor improvements on Security Considerations. 610 Update Digest reference. 612 Rewrite scheme definition as algorithm rather than pseudo-ABNF. 614 Add a note about colons in user-id. 616 Attempt to explain authentication scopes. 618 C.4. Since draft-ietf-httpauth-basicauth-update-02 620 Reference draft-ietf-precis-saslprepbis for the set of characters 621 that need to be supported in user-ids and passwords. 623 C.5. Since draft-ietf-httpauth-basicauth-update-03 625 Update reference for draft-ietf-precis-saslprepbis (which renames 626 "Password" to "OpaqueString"). 628 Mention HTTPS as enhancement for securing the transmission of 629 credentials. 631 Update DIGEST reference and change it to informative. 633 Use RFC 20 as reference for ASCII. 635 C.6. Since draft-ietf-httpauth-basicauth-update-04 637 Fixed definition of authentication scope. Updated DIGEST reference. 639 C.7. Since draft-ietf-httpauth-basicauth-update-05 641 Updated DIGEST and PRECIS references. 643 Avoid the term "obfuscated". Say "free-form string" instead of 644 "opaque string" in realm description. 646 Mention AUTHINFO as yet another draft that helps obsoleting RFC 2617. 648 Add a note about the complexity of parsing challenges correctly. 650 Author's Address 652 Julian F. Reschke 653 greenbytes GmbH 654 Hafenweg 16 655 Muenster, NW 48155 656 Germany 658 EMail: julian.reschke@greenbytes.de 659 URI: http://greenbytes.de/tech/webdav/