Network Working Group P. Hoffman Internet-Draft VPN Consortium Expires: June 4, 2006 December 1, 2005 Using non-ASCII Characters in RFCs draft-hoffman-utf8-rfcs-01.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on June 4, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document specifies a change to the IETF process in which RFCs are allowed to have non-ASCII characters. The proposed change is to change the encoding of RFCs to UTF-8. 1. Introduction The purpose of this document is to specify one possible way for the IETF to use non-ASCII characters in RFCs. It does not advocate that Hoffman Expires June 4, 2006 [Page 1] Internet-Draft Non-ASCII in RFCs December 2005 the IETF should actually make such a change; instead, if the IETF decides that it wants to make such a change, this document gives a very simple way to do so. The author believes that the IETF is not going to make such a change any time soon because of the IETF's reflexive tendency to spend huge amounts of time debating process issues that are actually quite simple. Further, the RFC series is extremely important to the IETF and the Internet at large, so any change to the way RFCs are published tends to cause even more concern than "normal" IETF process issues. This document specifies only how to change RFCs to allow non-ASCII characters; it does not talk about changing Internet Drafts in a similar fashion. The reason for doing this on one document series at a time is because the IETF, when it does deal with changing its process, does so better when it tries to change only one part of the process at a time. Because Internet Drafts are handled in a very different process than RFCs, internationalizing Internet Drafts should be done in a separate change to minimize IETF process overload. This document discusses a change to RFCs that does not require a different text format for the RFC series. That is, it does not require a change in the base format to HTML, XML, SVG, or ASN.1. Similarly, this document does not require that there be multiple authoritative versions, or multiple alternative representations, of a particular RFC. This document has absolutely nothing to do with whether or not RFCs should have a different format to allow graphics. 1.1. Reasons to allow non-ASCII characters in RFCs Various guideline documents in the IETF, notably [RFC2223], specify that RFCs must use only the US-ASCII character set. This restriction has historically caused many problems, notably: o Names and addresses of authors of IETF documents are misspelled o Names and document titles in references are misspelled o Protocol examples that show non-ASCII characters cannot be shown directly The first two issues cause real problems for people searching for RFCs for particular authors or references that contain non-ASCII characters. For many languages that use Latin characters outside the ASCII range, there are not absolute mappings between those non-ASCII characters and ASCII equivalents. A common example is that "u-with- Hoffman Expires June 4, 2006 [Page 2] Internet-Draft Non-ASCII in RFCs December 2005 umlaut" may be mapped to "u" or to "ue"; many other mapping difficulties exist. Now that UTF-8 [RFC3629] is nearly universally available in text- editing and display systems, the IETF can eliminate these problems by changing RFCs to use UTF-8, if the IETF wants to change the content of RFCs from being all-ASCII. 2. Use of UTF-8 in RFCs Upon publication of this document as an RFC, all RFCs will be considered to be encoded in UTF-8. The the RFC Editor needs to change their processes to publish documents that are valid UTF-8. Note that the change described in this document only applies to RFCs. Internet Drafts retain their restriction to US-ASCII. This means that, during the RFC preparation phase, document authors can ask the RFC Editor to change the spelling of some parts of the Internet Draft from which the RFC Editor is preparing the final RFC. It is suggested that the RFC Editor limit non-ASCII characters to the following: o Names and addresses of authors, used at the top of RFCs and in the author contact section o Names and document titles used in the References sections o Quotations from non-English languages o Protocol examples that show non-ASCII characters, such as when showing internationalized domain names (IDNs) and internationalized resource identifiers (IRIs) The RFC Editor should determine in an expedient manner which characters are acceptable in RFCs. For example, the RFC Editor might exclude some control characters because they could affect automatic processing of RFCs, but they might also allow them. The RFC Editor should publish one or more RFCs with a variety of non-ASCII characters to help determine which characters, if any, will be problematic for processing. 3. Security considerations A display program that expects only US-ASCII input may fail when it encounters octets outside the US-ASCII range of values. Such a Hoffman Expires June 4, 2006 [Page 3] Internet-Draft Non-ASCII in RFCs December 2005 failure may become a security issue. For example, the program may display incorrect results for the input. More seriously, the program may have an internal error that causes it to fail in a security- compromising fashion. 4. IANA considerations This document does not change or create any IANA-registered values. 5. Informative References [RFC2223] Postel, J. and J. Reynolds, "Instructions to RFC Authors", RFC 2223, October 1997. [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003. Appendix A. Arguments against changing to UTF-8 Over the past decade, the question of changing the encoding of RFCs to UTF-8 has come up repeatedly. Although many people wanted the change, various people had different reasons why they felt it was a bad idea. This appendix is a summary of those arguments and an explanation of why they are no longer as critical as they were a decade ago. A.1. Difficulty in displaying Some text display systems only know how to display US-ASCII. Displaying an RFC that uses non-ASCII characters encoded in UTF-8 will cause those characters to be unreadable. There are, of course, still such display systems, and there always will be. However, the number is dwindling as more software is improved to display non-ASCII characters and, in particular, to read UTF-8 as an encoding. Of the systems that can only render US-ASCII, only a small subset drop non-ASCII characters: the others show an incorrect character in its place. Thus, the person using such a system can often see that there is a problem, and can possibly choose to get better display software. A.2. Difficulty in printing Some printers can only print a limited set of characters due to the fact that they are character-oriented, not graphical. Such printers Hoffman Expires June 4, 2006 [Page 4] Internet-Draft Non-ASCII in RFCs December 2005 inherently cannot print characters they do not understand. Almost all such printers print the ASCII characters just fine. There are, of course, still such printers, and there always will be. However, the number is dwindling as older printers are replaced with ones that can print graphics so that now-common text features like boldface and italics can be printed. A.3. Insufficient fonts Almost no display system that can display text that is encoded with UTF-8 can display every character in the Unicode repertoire. Thus, some non-ASCII characters that are included in RFCs will not display properly. Virtually every system that can display Unicode knows how to substitute a replacement character for ones that cannot be displayed. In fact, most such systems have glyphs for rendering unknown characters and different glyphs for rendering known characters for which the system has no font. A.4. Inability to search for non-ASCII characers If authors start using non-ASCII characters in their names and/or addresses, people who know the characters but are unfamiliar with the user interface on their computers may not be able to enter those characters in the search criteria. For example, some people do not know how to enter "u-with-umlaut" in their operating system, even though the operating system allows such input. This is a valid concern, but one that is orthogonal to whether or not RFCs should use these characters. The alternative (never go to UTF-8) simply shifts the problem to forcing the user to guess which ASCII-only spelling to use when searching. A.5. Normalization Due to the way that Unicode uses combining characters, there are sometimes multiple ways to spell the same character. For example, the character "lowercase-a-with-accent" can be spelled in two ways: as a single character (U+00E1) or as two characters (U+0061 followed by U+0301). Thus, searching for this character can be ambiguous. Although there are multiple ways to spell some characters, almost all such characters have a shortest form that can be found using the Unicode normalization rules. The RFC Editor should use only normalized strings in RFCs. Hoffman Expires June 4, 2006 [Page 5] Internet-Draft Non-ASCII in RFCs December 2005 Author's Address Paul Hoffman VPN Consortium 127 Segre Place Santa Cruz, CA 95060 USA Email: paul.hoffman@vpnc.org Full Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary Hoffman Expires June 4, 2006 [Page 6] Internet-Draft Non-ASCII in RFCs December 2005 rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Hoffman Expires June 4, 2006 [Page 7]