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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) January 16, 2015 5 Intended status: Standards Track 6 Expires: July 20, 2015 8 The 'Basic' HTTP Authentication Scheme 9 draft-ietf-httpauth-basicauth-update-05 11 Abstract 13 This document defines the "Basic" Hypertext Transfer Protocol (HTTP) 14 Authentication Scheme, which transmits credentials as userid/password 15 pairs, obfuscated by the use of Base64 encoding. 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.6. 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 July 20, 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 . . . . . . . . . . . . . . . . . . . . . . 12 91 B.1. User Agents . . . . . . . . . . . . . . . . . . . . . . . 12 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 . . . . . . . . . . . . . . . . . . . . . . 13 97 C.2. Since draft-ietf-httpauth-basicauth-update-00 . . . . . . 13 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 . . . . . . 14 103 1. Introduction 105 This document defines the "Basic" Hypertext Transfer Protocol (HTTP) 106 Authentication Scheme, which transmits credentials as userid/password 107 pairs, obfuscated by the use of Base64 encoding (HTTP authentication 108 schemes are defined in [RFC7235]). 110 This scheme is not considered to be a secure method of user 111 authentication unless used in conjunction with some external secure 112 system such as TLS (Transport Layer Security, [RFC5246]), as the user 113 name and password are passed over the network as cleartext. 115 The "Basic" scheme previously was defined in Section 2 of [RFC2617]. 116 This document updates the definition, and also addresses 117 internationalization issues by introducing the "charset" 118 authentication parameter (Section 2.1). 120 Other documents updating RFC 2617 are "Hypertext Transfer Protocol 121 (HTTP/1.1): Authentication" ([RFC7235], defining the authentication 122 framework) and "HTTP Digest Access Authentication" ([DIGEST], 123 updating the definition of the '"Digest" authentication scheme). 124 Taken together, these three documents obsolete RFC 2617. 126 1.1. Notational Conventions 128 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 129 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 130 document are to be interpreted as described in [RFC2119]. 132 1.1.1. Syntax Notation 134 This specification uses the Augmented Backus-Naur Form (ABNF) 135 notation of [RFC5234]. 137 The terms protection space and realm are defined in Section 2.2 of 138 [RFC7235]. 140 The terms (character) repertoire and character encoding scheme are 141 defined in Section 2 of [RFC6365]. 143 2. The 'Basic' Authentication Scheme 145 The "Basic" authentication scheme is based on the model that the 146 client needs to authenticate itself with a user-ID and a password for 147 each protection space ("realm"). The realm value is an opaque string 148 which can only be compared for equality with other realms on that 149 server. The server will service the request only if it can validate 150 the user-ID and password for the protection space applying to the 151 requested resource. 153 The "Basic" authentication scheme utilizes the Authentication 154 Framework as follows: 156 In challenges: 158 o the scheme name is "Basic" 160 o the authentication parameter "realm" is REQUIRED ([RFC7235], 161 Section 2.2) 163 o the authentication parameter "charset" is OPTIONAL (see 164 Section 2.1) 166 o no other authentication parameters are defined -- unknown 167 parameters MUST be ignored by recipients, and new parameters can 168 only be defined by revising this specification 170 Note that both scheme and parameter names are matched case- 171 insensitively. 173 For credentials, the "token68" syntax defined in Section 2.1 of 174 [RFC7235] is used. The value is computed based on user-id and 175 password as defined below. 177 Upon receipt of a request for a URI within the protection space that 178 lacks credentials, the server can reply with a challenge using the 179 401 (Unauthorized) status code ([RFC7235], Section 3.1) and the WWW- 180 Authenticate header field ([RFC7235], Section 4.1). 182 For instance: 184 HTTP/1.1 401 Unauthorized 185 Date: Mon, 04 Feb 2014 16:50:53 GMT 186 WWW-Authenticate: Basic realm="WallyWorld" 188 ...where "WallyWorld" is the string assigned by the server to 189 identify the protection space. 191 A proxy can respond with a similar challenge using the 407 (Proxy 192 Authentication Required) status code ([RFC7235], Section 3.2) and the 193 Proxy-Authenticate header field ([RFC7235], Section 4.3). 195 To receive authorization, the client 196 1. obtains the userid and password from the user, 198 2. constructs the user-pass by concatenating userid, a single colon 199 (":") character, and the password, 201 3. encodes the user-pass into an octet sequence (see below for a 202 discussion of character encoding schemes), 204 4. and obtains the basic-credentials by encoding this octet sequence 205 using base64 ([RFC4648], Section 4) into a sequence of US-ASCII 206 characters ([RFC0020]). 208 The original definition of this authentication scheme failed to 209 specify the character encoding scheme used to convert the user-pass 210 into an octet sequence. In practice, most implementations chose 211 either a local-specific encoding such as ISO-8859-1 ([ISO-8859-1]), 212 or UTF-8 ([RFC3629]). For backwards compatibility reasons, this 213 specification continues to leave the default encoding undefined, as 214 long as it is compatible with US-ASCII (mapping any US-ASCII 215 character to a single octet matching the US-ASCII character code). 217 The userid and password MUST NOT contain any control characters (see 218 "CTL" in Appendix B.1 of [RFC5234]). 220 Furthermore, a userid containing a colon character is invalid, as 221 recipients will split the user-pass at the first occurence of a colon 222 character. Note that many user agents however will accept a colon in 223 userid, thereby producing a user-pass string that recipients will 224 likely treat in a way not intended by the user. 226 If the user agent wishes to send the userid "Aladdin" and password 227 "open sesame", it would use the following header field: 229 Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ== 231 2.1. The 'charset' auth-param 233 In challenges, servers can use the "charset" authentication parameter 234 to indicate the character encoding scheme they expect the user agent 235 to use when generating "user-pass" (a sequence of octets). This 236 information is purely advisory. 238 The only allowed value is "UTF-8", to be matched case-insensitively 239 (see [RFC2978], Section 2.3). It indicates that the server expects 240 character data to be converted to Unicode Normalization Form C 241 ("NFC", see Section 3 of [RFC5198]) and to be encoded into octets 242 using the UTF-8 character encoding scheme ([RFC3629]). 244 For the userid, recipients MUST support all characters defined in the 245 "UsernameCasePreserved" profile defined in in Section 3.3 of 246 [PRECIS], with the exception of the colon (":") character. 248 For the password, recipients MUST support all characters defined in 249 the "OpaqueString" profile defined in in Section 4.2 of [PRECIS]. 251 Other values are reserved for future use. 253 Note: The 'charset' is only defined on challenges, as "Basic" uses 254 a single token for credentials ('token68' syntax), thus the 255 credentials syntax isn't extensible. 257 Note: The name 'charset' has been chosen for consistency with 258 Section 2.1.1 of [RFC2831]. A better name would have been 259 'accept-charset', as it is not about the message it appears in, 260 but the server's expectation. 262 In the example below, the server prompts for authentication in the 263 "foo" realm, using Basic authentication, with a preference for the 264 UTF-8 character encoding scheme: 266 WWW-Authenticate: Basic realm="foo", charset="UTF-8" 268 Note that the parameter value can be either a token or a quoted 269 string; in this case the server chose to use the quoted-string 270 notation. 272 The user's name is "test", and the password is the string "123" 273 followed by the Unicode character U+00A3 (POUND SIGN). Using the 274 character encoding scheme UTF-8, the user-pass becomes: 276 't' 'e' 's' 't' ':' '1' '2' '3' pound 277 74 65 73 74 3A 31 32 33 C2 A3 279 Encoding this octet sequence in Base64 ([RFC4648], Section 4) yields: 281 dGVzdDoxMjPCow== 283 Thus the Authorization header field would be: 285 Authorization: Basic dGVzdDoxMjPCow== 287 Or, for proxy authentication: 289 Proxy-Authorization: Basic dGVzdDoxMjPCow== 291 2.2. Re-using Credentials 293 Given the absolute URI ([RFC3986], Section 4.3) of an authenticated 294 request, the authentication scope of that request is obtained by 295 removing all characters after the last slash ("/") character of the 296 path component ("hier_part", see [RFC3986], Section 3). A client 297 SHOULD assume that resources identified by URIs with a prefix-match 298 of the authentication scope are also within the protection space 299 specified by the realm value of the that authenticated request. 301 A client MAY preemptively send the corresponding Authorization header 302 field with requests for resources in that space without receipt of 303 another challenge from the server. Similarly, when a client sends a 304 request to a proxy, it may reuse a userid and password in the Proxy- 305 Authorization header field without receiving another challenge from 306 the proxy server. 308 For example, given an authenticated request to: 310 http://example.com/docs/index.html 312 ...requests to the URIs below could use the known credentials: 314 http://example.com/docs/ 315 http://example.com/docs/test.doc 316 http://example.com/docs/?page=1 318 ...while the URIs 320 http://example.com/other/ 321 https://example.com/docs/ 323 would be considered to be outside the authentication scope. 325 Note that a URI can be part of multiple authentication scopes (such 326 as "http://example.com/" and "http://example.com/docs/"). This 327 specification does not define which of these should be treated with 328 higher priority. 330 3. Internationalization Considerations 332 User names or passwords containing characters outside the US-ASCII 333 character repertoire will cause interoperability issues, unless both 334 communication partners agree on what character encoding scheme is to 335 be used. Servers can use the new 'charset' parameter (Section 2.1) 336 to indicate a preference of "UTF-8", increasing the probability that 337 clients will switch to that encoding. 339 The "realm" parameter carries data that can be considered textual, 340 however [RFC7235] does not define a way to reliably transport non-US- 341 ASCII characters. This is a known issue that would need to be 342 addressed in that specification. 344 4. Security Considerations 346 The Basic authentication scheme is not a secure method of user 347 authentication, nor does it in any way protect the entity, which is 348 transmitted in cleartext across the physical network used as the 349 carrier. HTTP does not prevent the addition of enhancements (such as 350 schemes to use one-time passwords) to Basic authentication. 352 The most serious flaw in Basic authentication is that it results in 353 the cleartext transmission of the user's password over the physical 354 network. Many other authentication schemes address this problem. 356 Because Basic authentication involves the cleartext transmission of 357 passwords it SHOULD NOT be used (without enhancements such as HTTPS 358 [RFC2818]) to protect sensitive or valuable information. 360 A common use of Basic authentication is for identification purposes 361 -- requiring the user to provide a user name and password as a means 362 of identification, for example, for purposes of gathering accurate 363 usage statistics on a server. When used in this way it is tempting 364 to think that there is no danger in its use if illicit access to the 365 protected documents is not a major concern. This is only correct if 366 the server issues both user name and password to the users and in 367 particular does not allow the user to choose his or her own password. 368 The danger arises because naive users frequently reuse a single 369 password to avoid the task of maintaining multiple passwords. 371 If a server permits users to select their own passwords, then the 372 threat is not only unauthorized access to documents on the server but 373 also unauthorized access to any other resources on other systems that 374 the user protects with the same password. Furthermore, in the 375 server's password database, many of the passwords may also be users' 376 passwords for other sites. The owner or administrator of such a 377 system could therefore expose all users of the system to the risk of 378 unauthorized access to all those sites if this information is not 379 maintained in a secure fashion. This raises both security and 380 privacy concerns ([RFC6973]). If the same username and password 381 combination is in use to access other accounts, such as an email or 382 health portal account, personal information could be exposed. 384 Basic Authentication is also vulnerable to spoofing by counterfeit 385 servers. If a user can be led to believe that he is connecting to a 386 host containing information protected by Basic authentication when, 387 in fact, he is connecting to a hostile server or gateway, then the 388 attacker can request a password, store it for later use, and feign an 389 error. This type of attack is not possible with Digest 390 Authentication. Server implementers SHOULD guard against the 391 possibility of this sort of counterfeiting by gateways or CGI 392 scripts. In particular it is very dangerous for a server to simply 393 turn over a connection to a gateway. That gateway can then use the 394 persistent connection mechanism to engage in multiple transactions 395 with the client while impersonating the original server in a way that 396 is not detectable by the client. 398 The use of the UTF-8 character encoding scheme introduces additional 399 security considerations; see Section 10 of [RFC3629] for more 400 information. 402 5. IANA Considerations 404 IANA maintains the registry of HTTP Authentication Schemes 405 ([RFC7235]) at . 407 The entry for the "Basic" Authentication Scheme shall be updated with 408 a pointer to this specification. 410 6. Acknowledgements 412 This specification takes over the definition of the "Basic" HTTP 413 Authentication Scheme, previously defined in RFC 2617. We thank John 414 Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. 415 Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for 416 their work on that specification, from which significant amounts of 417 text were borrowed. See Section 6 of [RFC2617] for further 418 acknowledgements. 420 The internationalization problem with respect to the character 421 encoding scheme used for user-pass has been reported as a Mozilla bug 422 back in the year 2000 (see 423 and also the 424 more recent ). 425 It was Andrew Clover's idea to address it using a new auth-param. 427 We also thank the members of the HTTPAuth Working Group and other 428 reviewers, namely Stephen Farrell, Bjoern Hoehrmann, Kari Hurtta, 429 Amos Jeffries, Benjamin Kaduk, Michael Koeller, James Manger, 430 Kathleen Moriarty, Yaron Sheffer, Michael Sweet, and Martin Thomson 431 for feedback on this revision. 433 7. References 434 7.1. Normative References 436 [PRECIS] Saint-Andre, P. and A. Melnikov, "Preparation, 437 Enforcement, and Comparison of Internationalized 438 Strings Representing Usernames and Passwords", 439 draft-ietf-precis-saslprepbis-12 (work in progress), 440 December 2014. 442 [RFC0020] Cerf, V., "ASCII format for network interchange", 443 RFC 20, October 1969. 445 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 446 Requirement Levels", BCP 14, RFC 2119, March 1997. 448 [RFC2978] Freed, N. and J. Postel, "IANA Charset Registration 449 Procedures", BCP 19, RFC 2978, October 2000. 451 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 452 10646", STD 63, RFC 3629, November 2003. 454 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, 455 "Uniform Resource Identifier (URI): Generic Syntax", 456 STD 66, RFC 3986, January 2005. 458 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data 459 Encodings", RFC 4648, October 2006. 461 [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for 462 Network Interchange", RFC 5198, March 2008. 464 [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for 465 Syntax Specifications: ABNF", STD 68, RFC 5234, 466 January 2008. 468 [RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in 469 Internationalization in the IETF", BCP 166, RFC 6365, 470 September 2011. 472 [RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext 473 Transfer Protocol (HTTP/1.1): Authentication", 474 RFC 7235, June 2014. 476 7.2. Informative References 478 [DIGEST] Shekh-Yusef, R., Ed., Ahrens, D., and S. Bremer, "HTTP 479 Digest Access Authentication", 480 draft-ietf-httpauth-digest-10 (work in progress), 481 January 2015. 483 [ISO-8859-1] International Organization for Standardization, 484 "Information technology -- 8-bit single-byte coded 485 graphic character sets -- Part 1: Latin alphabet No. 486 1", ISO/IEC 8859-1:1998, 1998. 488 [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, 489 S., Leach, P., Luotonen, A., and L. Stewart, "HTTP 490 Authentication: Basic and Digest Access 491 Authentication", RFC 2617, June 1999. 493 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. 495 [RFC2831] Leach, P. and C. Newman, "Using Digest Authentication 496 as a SASL Mechanism", RFC 2831, May 2000. 498 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer 499 Security (TLS) Protocol Version 1.2", RFC 5246, 500 August 2008. 502 [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., 503 Morris, J., Hansen, M., and R. Smith, "Privacy 504 Considerations for Internet Protocols", RFC 6973, 505 July 2013. 507 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext 508 Transfer Protocol (HTTP/1.1): Semantics and Content", 509 RFC 7231, June 2014. 511 Appendix A. Changes from RFC 2617 513 The scheme definition has been rewritten to be consistent with newer 514 specifications such as [RFC7235]. 516 The new authentication parameter "charset" has been added. It is 517 purely advisory, so existing implementations do not need to change, 518 unless they want to take advantage of the additional information 519 which previously wasn't available. 521 Appendix B. Deployment Considerations for the 'charset' Parameter 523 B.1. User Agents 525 User agents not implementing 'charset' will continue to work as 526 before, ignoring the new parameter. 528 User agents which already default to the UTF-8 encoding implement 529 'charset' by definition. 531 Other user agents can keep their default behavior, and switch to 532 UTF-8 when seeing the new parameter. 534 B.2. Origin Servers 536 Origin servers that do not support non-US-ASCII characters in 537 credentials do not require any changes to support 'charset'. 539 Origin servers that need to support non-US-ASCII characters, but 540 cannot use the UTF-8 character encoding scheme will not be affected; 541 they will continue to function as well or as badly as before. 543 Finally, origin servers that need to support non-US-ASCII characters 544 and can use the UTF-8 character encoding scheme can opt in as 545 described above. In the worst case, they'll continue to see either 546 broken credentials or no credentials at all (depending on how legacy 547 clients handle characters they can not encode). 549 B.3. Why not simply switch the default encoding to UTF-8? 551 There are sites in use today that default to a local character 552 encoding scheme, such as ISO-8859-1 ([ISO-8859-1]), and expect user 553 agents to use that encoding. Authentication on these sites will stop 554 to work if the user agent switches to a different encoding, such as 555 UTF-8. 557 Note that sites might even inspect the User-Agent header field 558 ([RFC7231], Section 5.5.3) to decide what character encoding scheme 559 to expect from the client. Therefore they might support UTF-8 for 560 some user agents, but default to something else for others. User 561 agents in the latter group will have to continue to do what they do 562 today until the majority of these servers have been upgraded to 563 always use UTF-8. 565 Appendix C. Change Log (to be removed by RFC Editor before publication) 567 C.1. Since RFC 2617 569 This draft acts as a baseline for tracking subsequent changes to the 570 specification. As such, it extracts the definition of "Basic", plus 571 the related Security Considerations, and also adds the IANA 572 registration of the scheme. Changes to the actual definition will be 573 made in subsequent drafts. 575 C.2. Since draft-ietf-httpauth-basicauth-update-00 577 Fixed Base64 reference to point to an actual definition of Base64. 579 Update HTTPbis and Digest references. 581 Note that this spec, together with HTTPbis P7 and the Digest update, 582 obsoletes RFC 2617. 584 Rewrote text about authentication parameters and their extensibility. 586 Pulled in the definition of the "charset" parameter. 588 Removed a misleading statement about userids potentially being case- 589 sensitive, as the same is true for passwords. 591 Added TODOs with respect to path matching, and colons in userids. 593 C.3. Since draft-ietf-httpauth-basicauth-update-01 595 Minor improvements on Security Considerations. 597 Update Digest reference. 599 Rewrite scheme definition as algorithm rather than pseudo-ABNF. 601 Add a note about colons in userid. 603 Attempt to explain authentication scopes. 605 C.4. Since draft-ietf-httpauth-basicauth-update-02 607 Reference draft-ietf-precis-saslprepbis for the set of characters 608 that need to be supported in userids and passwords. 610 C.5. Since draft-ietf-httpauth-basicauth-update-03 612 Update reference for draft-ietf-precis-saslprepbis (which renames 613 "Password" to "OpaqueString"). 615 Mention HTTPS as enhancement for securing the transmission of 616 credentials. 618 Update DIGEST reference and change it to informative. 620 Use RFC 20 as reference for ASCII. 622 C.6. Since draft-ietf-httpauth-basicauth-update-04 624 Fixed definition of authentication scope. Updated DIGEST reference. 626 Author's Address 628 Julian F. Reschke 629 greenbytes GmbH 630 Hafenweg 16 631 Muenster, NW 48155 632 Germany 634 EMail: julian.reschke@greenbytes.de 635 URI: http://greenbytes.de/tech/webdav/