Network Working Group HF. Zhu Internet Draft: Chinese Character Encoding Tsinghua U Document: internet-drafts/draft-apng-cc-encoding-03.8.txt DY. Hu Tsinghua U ZG. Wang CITS TC. Kao III WC. Chang III M. Crispin U Washington July 1995 Chinese Character Encoding for Internet Messages Status of this Memo This document is an Internet-Draft. 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." To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). This is a draft document of APNG-CC, the Chinese Character sub-working group of the I18N/L10N (Internationalization and Localization) working group of APNG (Asia-Pacific Networking Group). A revised version of this draft document will be submitted to the RFC editor as an Informational RFC for the Internet Community. Discussion and suggestions for improvement are requested, and should be sent to apng-cc@apng.org or zhf@net.edu.cn (the coordinator). This document will expire before February 30, 1996. Distribution of this memo is unlimited. Abstract This memo provides methods for transporting Chinese characters through, but not limited to, electronic mail [RFC-822] and network news [RFC-1036] in the Internet community. Introduction As the use of Internet covers more and more Chinese people in the world, the need has increased for the ability to send documents containing Chinese characters on the Internet. The methods described in this document provide means of transporting existing Chinese character sets as well as leaving sufficient space for future extension. This document describes three groups of encodings: 1. ISO-2022-CN and ISO-2022-CN-EXT 2. CN-GB and CN-Big5 3. ISO/IEC 10646/Unicode The first group of encodings are designed with interoperability in mind and are encouraged in this document; they are 7-bit, support both simplified and traditional characters using both GB and CNS/Big5, and do not impose any unusual quoting requirements on ASCII characters The second group of encodings describes current common domestic usage. The third group of encodings refers to the universal multilingual character set defined by ISO. Note: ISO/IEC 10646 [ISO-10646] defines a 32bit character space with the intent to encode all characters in the world. Currently, only the lowest 16bit plane of ISO 10646, the Basic Multilingual Plane (BMP), is defined. The BMP is code-by-code identical to Unicode [Unicode 1.1]. Specification 1. 7bit Chinese encodings: ISO-2022-CN and ISO-2022-CN-EXT 1.1 Description ISO-2022-CN is based upon ISO 2022 [ISO-2022], similar to earlier work on ISO-2022-JP [RFC-1468] and ISO-2022-KR [RFC-1557] for Japanese and Korean languages. It is 7-bit, and supports both simplified Chinese characters using GB 2312-80 [GB-2312] and traditional Chinese characters using the first two planes of CNS 11643 [CNS-11643], as well as ASCII [ASCII] characters. ISO-2022-CN-EXT is a superset of ISO-2022-CN that additionally supports other GB character sets and planes of CNS 11643. Since ISO-2022-CN and ISO-2022-CN-EXT are 7-bit encodings, they do not require the 8-bit SMTP extensions. ISO-2022-CN supports almost all the characters which appear in Big5 [BIG5] except for two duplicate characters which were mistakes in defining Big5. 1.2 ISO-2022-CN The starting code of ISO-2022-CN is ASCII. ASCII and Chinese characters are distinguished by the use of designations (ESC sequences) and shift functions. Designations define the Chinese character sets used in the text. There are three kinds of designations: SOdesignation, SS2designation and SS3designation. The SOdesignation is in the form ESC $ ) , where is the "final character" assigned to the character set by ISO (refer to the ISO registry [ISOREG] for more details). The SS2designation is in the form ESC $ * , and the SS3designation is in the form ESC $ + . A designation overrides any previous designation for subsequent bytes in the text. There are four kinds of shifts: SI, SO, SS2 and SS3. The shift SI (one byte with hexadecimal value 0F) declares that subsequent bytes are interpreted in ASCII. The shift SO (one byte with hexadecimal value 0E) declares that subsequent bytes are interpreted in the character set defined by SOdesignation. The shift SS2 (two bytes with hexadecimal values 1B 4E) declares that the subsequent TWO bytes are interpreted in the character set defined by SS2designation, after which the previous interpretation (from SI or SO) is restored. The shift SS3 (two bytes with hexadecimal values 1B 4F) declares that the subsequent TWO bytes are interpreted in the character set defined by SS3designation, after which the previous interpretation (from SI or SO) is restored. For example, the sequence: ESC $ ) A SO c_char1 ... c_char1 ESC $ ) G c_char2 ... c_char2 SI transfers mixed simplified Chinese and traditional Chinese text, in which c_char1s are simplified Chinese characters from GB-2312 and c_char2s are traditional Chinese characters from CNS-11643-plane 1. The escape sequence, shift function and character set used in an ISO-2022-CN text are as follows: Character sets Shift in with -------------------------------------------------------------------- ASCII SI GB 2312, CNS 11643-plane-1 SO CNS 11643-plane-2 SS2 ESC $ ) A Indicates the bytes following SO are Chinese characters as defined in GB 2312-80, until another SOdesignation appears ESC $ ) G Indicates the bytes following SO are as defined in CNS 11643-plane-1, until another SOdesignation appears ESC $ * H Indicates the two bytes immediately following SS2 is a Chinese character as defined in CNS 11643-plane-2, until another SS2designation appears If there are any GB or CNS characters on a line, a designation for the corresponding character set should be used so that each line has its own character set information and the text can be displayed correctly when scroll back in a window. Also, there must be a shift to ASCII (SI) before the end of the line (i.e., before the CRLF). In other words, each line starts in ASCII, and ends in ASCII. The name given to this character encoding is "ISO-2022-CN". This name is intended to be used as the "charset" parameter in MIME [MIME-1, MIME-2] messages. Content-Type: text/plain; charset=iso-2022-cn The ISO-2022-CN encoding is already in 7-bit form, so it is not necessary to use a Content-Transfer-Encoding header. Other restrictions are given in the "Formal Syntax of ISO-2022-CN and ISO-2022-CN-EXT" part at the end of this document. 1.3 ISO-2022-CN-EXT ISO-2022-CN-EXT supports all characters in existing GB, Big5 and CNS 11643 character sets. The escape sequence, shift function and character set used in an ISO-2022-CN-EXT text are as follows: Character sets Shift in with -------------------------------------------------------------------- ASCII SI GB 2312, GB 12345, CNS 11643-plane-1, GB 2312+GB 8565 SO GB 7589, GB 13131, CNS 11643-plane-2 SS2 GB 7590, GB 13132 or other new GBs,CNS 11643-plane-3 or SS3 higher planes of CNS 11643 Note: Currently, there are some GB sets that have not been registered in ISO. Here , , , and represent the final character that will be assigned by ISO for those sets. ESC $ ) A Indicates the bytes following SO are Chinese characters as defined in GB 2312-80, until another SOdesignation appears ESC $ * Indicates the two bytes immediately following SS2 is a Chinese character as defined in GB 7589-87 [GB-7589], until another SS2designation appears ESC $ + Indicates the two bytes immediately following SS3 is a Chinese character as defined in GB 7590-87 [GB-7590], until another SS3designation appears ESC $ ) Indicates the bytes following SO are as defined in GB 12345-90 [GB-12345], until another SOdesignation appears ESC $ * Indicates the two bytes immediately following SS2 is a Chinese character as defined in GB 13131-91 [GB-13131], until another SS2designation appears ESC $ + Indicates the two bytes immediately following SS3 is a Chinese character as defined in GB 13132-91 [GB-13131], until another SS3designation appears ESC $ ) E Indicates the bytes following SO are as defined in GB 2312+ GB 8565 [GB-8565], until another SOdesignation appears ESC $ ) G Indicates the bytes following SO are as defined in CNS 11643-plane-1, until another SOdesignation appears ESC $ * H Indicates the two bytes immediately following SS2 is a Chinese character as defined in CNS 11643-plane-2, until another SS2designation appears ESC $ + I Indicates the immediate two bytes following SS3 is a Chinese character as defined in CNS 11643-plane-3, until another SS3designation appears ESC $ + J Indicates the immediate two bytes following SS3 is a Chinese character as defined in CNS 11643-plane-4, until another SS3designation appears ESC $ + K Indicates the immediate two bytes following SS3 is a Chinese character as defined in CNS 11643-plane-5, until another SS3designation appears ESC $ + L Indicates the immediate two bytes following SS3 is a Chinese character as defined in CNS 11643-plane-6, until another SS3designation appears ESC $ + M Indicates the immediate two bytes following SS3 is a Chinese character as defined in CNS 11643-plane-7, until another SS3designation appears As in ISO-2022-CN, each line should start in ASCII, and end in ASCII, and should have its own designation information before any Chinese characters appear. The name given to this character encoding is "ISO-2022-CN-EXT". This name is intended to be used as the "charset" parameter in MIME messages. Content-Type: text/plain; charset=ISO-2022-CN-EXT The ISO-2022-CN-EXT encoding is also in 7-bit form, so it is not necessary to use a Content-Transfer-Encoding header. Other restrictions are given in the "Formal Syntax of ISO-2022-CN and ISO-2022-CN-EXT" part at the end of this document. 1.4 How to Support Big5 or other internal codesets with ISO-2022-CN and ISO-2022-CN-EXT Since there are many different Chinese internal coding systems [CJK], such as Big5, GB internal code, CCCII (an encoding for library systems in Taiwan), XGB (the codepage for Microsoft simplified Chinese Windows 95) etc. ISO-2022-CN and ISO-2022-CN-EXT, which are 7bit and will not lose information during communication among different codesets and thus increase interoperability, are ideal interchange encodings for various internal Chinese codesets in international communication. For instance, ISO-2022-CN and ISO-2022-CN-EXT can be used to support Big5, because CNS-11643-plane 1 and 2 incorporate all Chinese characters in Big5 except two duplicate characters which was a mistake when defining Big5. Since the code sequence of Big5 and CNS-11643 is different, it needs a conversion table for converting Big5 to and from CNS-11643. The conversion table is attached as an appendix in this document. Public domain software (either binary or source in C) is provided in many places in the Internet too: 1) Beijing: ftp://ftp.net.tsinghua.edu.cn/pub/Chinese/ (IP address: 166.111.1.11) 2) Taiwan: ftp://tpdns.seed.net.tw/Pub/Chinese/DOS/code-convert/chcode.zip (IP address: 139.175.1.12) 3) US: ftp://ftp.ifcss.org/pub/software/unix/convert/BeTTY-1.534.tar.gz (IP address: 128.123.1.55) 4) Japan: ftp://etlport.etl.go.jp/pub/iso-2022-cn/ (IP address: 192.31.197.99) 2. 8bit Chinese encodings: CN-GB and CN-Big5 The CN-GB and CN-Big5 charset names are given below. Among other things, these support current practice; specifically, CN-GB reflects the current usage for simplified Chinese e-mail, and CN-Big5 reflects the current usage for traditional Chinese e-mail. Note: the use of 8-bit character sets requires the use of either an 8-to-7 Content-Transfer-Encoding mechanism such as "BASE64" or "QUOTED-PRINTABLE" if the network is not 8-bit clean, or the 8-bit SMTP extensions [SMTPEXT] with the "8BIT" Content-Transfer-Encoding on 8-bit clean networks. Otherwise, an 8-bit message which passes through a 7-bit mailer is likely to have the 8th bit truncated, resulting in an unreadable message. Although "just send 8-bit data" has been common practice in the past, it is incorrect according to the Internet standards and causes interoperability problems. 2.1 CN-GB E-mail using GB characters is sent in this way: GB 2312-80 characters are used with ASCII characters, not GB 1988-80 [GB-1988]. GB 2312-80 is also 7-bit, to avoid conflicting with ASCII. If the character is from GB 2312-80, the MSB (bit-8) of each byte is set to 1, and therefore becomes a 8-bit character. Otherwise, the byte is interpreted as ASCII. This constructs a character set named "GB Internal Code". This method is also adopted in the .gb files in the Internet. To use this character scheme with MIME, CN-GB is used as the value for the charset parameter: Content-Type: text/plain; charset=cn-gb GB-12345 is the traditional form of GB-2312, the charset name given to this set is CN-GB-12345-90. There is also a kind of dependent character set that can only be used with one of the above sets. For example, if GB 8565 is used, it can only be used with GB 2312 or GB 12345, in this case, "+" is permitted to appear in the charset name, i.e. CN-GB-2312-80+GB-8565-88. Similarly as CN-GB, CN-GB-12345-90 and CN-GB-2312-80+GB-8565-88 support ASCII too, the MSB of Chinese characters should be set to 1, in order to be distinguished from ASCII. Note: There are some supplementary character sets in GB, i.e. GB 7589-87, GB 7590-87, GB 13131-91 and GB 13132-91. Normally, they won't be used independently without using GB-2312 or GB-12345, so they are not necessarily be registered. Characters in these standards could be support with ISO-2022-CN and ISO-2022-CN-EXT. If, in the future, they do needed to be used with "charset" names in some cases, it is the responsibility of any interested third party (the standardization organization herself or anybody else) to write the necessary documents and do the IANA registration for them. It is greatly encouraged that their charset names should also take the form of CN-GB-- as CN-GB-12345-90. Here, is the GB standard number, and is the year of edition represented with the last two digits of the year. They should be coded in 8-bit as CN-GB. To avoid hindering interoperability, CN-GB is encouraged to be used whenever possible. 2.2 CN-Big5 Big5 is a character set of traditional Chinese characters, widely used in Taiwan and overseas. E-mail using Big5 characters is sent in this way: Big5 characters are used with ASCII characters. Big5 is a two-byte coding, in which the first byte is 7-bit, and the second byte is 8-bit. If the character is from Big5, the MSB (bit-8) of the first byte is set to 1, and therefore becomes an 8-bit character. Otherwise, the byte is interpreted as ASCII. (Big5 uses the code space: [0xa1-0xfe,0x40-0x7e] and [0xa1-0xfe,0xa1-0xfe], and two other user areas with the first byte in the range of [0x81-0xa0].) To use this character scheme with MIME, CN-Big5 is used as the value for the charset parameter: Content-Type: text/plain; charset=cn-big5 3. Universal Multilingual Character Set: ISO/IEC-10646/Unicode ISO/IEC 10646's BMP (code-to-code identical to Unicode) contains large repertoire of Chinese characters (it currently includes all the characters of GB 2312-80, GB 12345-90, GB 8565-89, CNS 11643's plane 1 and 2, and part of some other standards) and therefore can be used to transporting Chinese characters in the Internet community. This document does not give any details on how to do this, as this has been done elsewhere. For details of using Unicode with MIME, refer to RFC 1641 [RFC-1641], RFC 1642 [RFC-1642]. For assigned names for 10646 sets, refer to STD 2--"Assigned Numbers", which is RFC 1700 [RFC-1700] currently. For more up-to-date assigned numbers, please check: ftp://ftp.isi.edu/in-notes/iana/assignments/character-sets A New MIME parameter -- "charset-variant" Here, a new MIME parameter--"charset-variant" is defined as below: This parameter is used after the MIME "charset" parameter mainly in the form of -, or any extension based on this form, in which is the product name and indicates its version number. It is case-insensetive and optional, and any value of this parameter should be registered in IANA. For example: Content-Type: text/plain; charset=CN-Big5; charset-variant=ETen-2.00.03-DOS This may indicate Eten company's variant of Big5: ETen 2.00.03 for DOS. The reason to define this parameter is that some implementation may want to check the variants in order to deal with them in slightly different methods to gain better operability. Although some features of certain variant may bring problem of interoperability, however, variants will still exist as they will go; moreover, certain variant may be so popular that it becomes de facto industrial standard, therefore indicating its name can improve the ability of communication implementation in handling its messages. Background Information 1. Writing systems and their encodings in Chinese-spoken nations and regions The mainland provinces of China use simplified Chinese character in daily life. GB is the standard electronic character set. It is the main means for communications between people who share simplified Chinese characters in the world. Taiwan uses traditional Chinese characters in daily life. CNS-11643 is the formal character set for information interchange in Taiwan; however, Big5, a widely-used character set of traditional Chinese characters, is the de-facto industrial standard in Taiwan. Hong Kong uses traditional Chinese characters in daily life, but uses both GB and Big5 in electronic form, because Hong Kong people often communicate with people in all of China's provinces. Singapore seldom uses Chinese characters, and uses the simplified form when Chinese characters are used. In electronic form, Unicode is more popular, however GB is also used. 2. Miscellaneouses about Chinese character sets The GB 1988-80 character set is identical to ISO 646 [ISO-646] except for currency symbol and tilde. The currency symbol and the tilde are replaced by the Yuan sign and the over line. This set is GB's variant of ISO 646. This character set and CNS 5205 [CNS-5205] are not encouraged for use in the Internet, since ASCII combined with GB 2312 or CNS 11643-plane 1 and plane 2 comprises all characters in them. The GB 2312-80 character set consists of simplified Chinese characters, digits, Latin, Greek and Russian alphabets, and some other symbols; in all, 7445 characters. Each character is represented with two bytes. GB 13000-95 [GB-13000] is the GB's variant of ISO 10646. However, for interoperability in the Internet, assigned names for ISO 10646 are encouraged to be used. 3. Miscellaneous implementation information For maximum interoperability, implementations SHOULD at least support sending and receiving ISO-2022-CN. Supporting all registered character sets in ISO-2022-CN-EXT is greatly encouraged. It is also essential to be able to support CN-GB (the status quo for simplified Chinese e-mail ) and CN-Big5 (the status quo for traditional Chinese e-mail). But sending ISO-2022-CN message is always encouraged whenever possible. To the maximum extent possible, implementations should be capable of receiving messages in any of the encodings introduced in this document, even if they only transmit messages in one form. Preferably the implementation should display the characters with glyphs appropriate to the typographic tradition that is implied in the encoding of the received text. Implementation may also translate these encodings to the encoding that its platform supports. The human user (not implementor) should try to keep lines within 80 display columns, or, preferably, within 75 (or so) columns, to allow insertion of ">" at the beginning of each line in excerpts. Each Chinese character takes up two columns, and the shift sequences do not take up any columns. The implementor is reminded that Chinese characters take up two bytes and should not be split in the middle to break lines for displaying, etc. Freely available fonts of Chinese characters: Beijing: ftp://ftp.net.tsinghua.edu.cn/pub/Chinese/fonts/ Taiwan: ftp://ftp.edu.tw/Chinese/ifcss/software/fonts/ ftp://ftp.ntu.edu.tw/Chinese/ifcss/software/fonts/ HongKong: ftp://ftp.cuhk.hk/pub/chinese/ifcss/software/fonts/ Singapore: ftp://ftp.technet.sg:/pub/chinese/fonts/ US: ftp://ftp.ifcss.org/pub/software/fonts/ http://ccic.ifcss.org/www/pub/software/fonts/ X.400 Considerations X.400 has the ability of carrying different character sets in a message by using the body part "GeneralText" defined by ISO/IEC-10021-7. [ISO-10021]. The X.400 ASN.1 definition of the GeneralText body part is: general-text-body-part EXTENDED-BODY-PART-TYPE PARAMETERS GeneralTextParameters IDENTIFIED BY id-ep-general-text DATA GeneralTextData ::= id-et-general-text GeneralTextParameters ::= SET OF CharacterSetRegistration CharacterSetRegistration ::= INTEGER (1..32767) GeneralTextData ::= GeneralString Therefore, to use ISO-2022-CN, set the "CharacterSetRegistration" part as { 6 58 171 172 }, and add an ESC sequence of ESC ( B (three bytes, hexadecimal values: 1B 28 42) before the beginning of ISO-2022-CN text. Similarly, to use ISO-2022-CN-EXT, set the registered numbers of all character sets in the "CharacterSetRegistration" part and add ESC ( B at the beginning. For the registered numbers, please refer to ISO registry. In addition to the character sets supported by ISO-2022-CN, currently registered numbers are: GB 2312+GB 8565: 165 CNS 11643-plane 3: 183 CNS 11643-plane 4: 184 CNS 11643-plane 5: 185 CNS 11643-plane 6: 186 CNS 11643-plane 7: 187 176 is the registered number for the BASESET of ISO/IEC 10646-1:1993 UCS-2 with implementation level 3, Escape sequence of ESC % / E (four bytes, hexadecimal values 1B 25 2F 45) indicates starting of this codeset. For CN-GB and CN-Big5 character sets, there currently are no formal methods that could be used in X.400 yet. For detail about X.400 use of character sets, please refer to RFC 1502 [RFC-1502]. Formal Syntax of ISO-2022-CN and ISO-2022-CN-EXT The notational conventions used here are identical to those used in RFC 822. 1. Formal Syntax of ISO-2022-CN body ::= * ( ascii_line / c_line ) ascii_line ::= *char CRLF c_line ::= *char 1*(1*designation 1*(*char 1*c_text *char)) CRLF designation ::= SOdesignation / SS2designation SOdesignation ::= ESC "$" ")" finalchar_for_SO SS2designation ::= ESC "$" "*" finalchar_for_SS2 finalchar_for_SO ::= "A" / "G" finalchar_for_SS2 ::= "H" c_text ::= 1* ( SO-SI-segment / SS2segment ) SO-SI-segment ::= SO 1*c_char *designation *( c_segment / SO-segment ) SI c_segment ::= 1* ( c_char / SS2segment ) SO-segment ::= SO 1*c_char SS2segment ::= SS2 c_char c_char ::= one_of_94 one_of_94 ; ( Octal, Decimal.) ESC ::= ; ( 33, 27.) SI ::= ; ( 17, 15.) SO ::= ; ( 16, 14.) SS2 ::= ; ( 33 116, 27 78.) SS3 ::= ; ( 33 117, 27 79.) one_of_94 ::= ; (41-176, 33-126.) char ::= ; (40-177, 30-127.) 2. Formal Syntax of ISO-2022-CN-EXT body ::= * ( ascii_line / c_line ) ascii_line ::= *char CRLF c_line ::= *char 1*(1*designation 1*(*char 1*c_text *char)) CRLF designation ::= SOdesignation / SS2designation / SS3designation SOdesignation ::= ESC "$" ")" finalchar_for_SO SS2designation ::= ESC "$" "*" finalchar_for_SS2 SS3designation ::= ESC "$" "+" finalchar_for_SS3 finalchar_for_SO ::= "A" / / "G" / "E" finalchar_for_SS2 ::= / / "H" finalchar_for_SS3 ::= / / "I" / "J" / "K" / "L" / "M" c_text ::= 1* ( SO-SI-segment / SS2segment / SS3segment ) SO-SI-segment ::= SO 1*c_char *designation *( c_segment / SO-segment ) SI c_segment ::= 1* ( c_char / SS2segment / SS3segment ) SO-segment ::= SO 1*c_char SS2segment ::= SS2 c_char SS3segment ::= SS3 c_char c_char ::= one_of_94 one_of_94 ; ( Octal, Decimal.) ESC ::= ; ( 33, 27.) SI ::= ; ( 17, 15.) SO ::= ; ( 16, 14.) SS2 ::= ; ( 33 116, 27 78.) SS3 ::= ; ( 33 117, 27 79.) one_of_94 ::= ; (41-176, 33-126.) char ::= ; (40-177, 30-127.) Registration of New "charset"s and New MIME parameter 1. This document defines the following MIME "charset" names for Chinese text: ISO-2022-CN, ISO-2022-CN-EXT CN-GB, CN-Big5 CN-GB-12345-90 CN-GB-2312-80+GB-8565-88 2. This document defines a new MIME parameter: charset-variant Acknowledgments This document is the result of cooperation in the APNG-CC, the Chinese Character sub-working group of the I18N/L10N (Internationalization and Localization) working group of APNG (Asia-Pacific Networking Group), coordinator Zhu Haifeng . The membership of APNG-CC consists of individuals from both sides of the Taiwan Strait, HongKong, and from Singapore and other countries. The authors wish to thank all members of APNG-CC. Prof.Yao Shiquan and Ms.Lin Ning of CITS (China Information Technology Standardization Technical Committee), Prof. Zhao Jingrong, Prof. Li Xing, and Mr.YouYue of Tsinghua University gave many help in the process of the work. Many thanks to Mr. C.J.Cherng and Mr. C.K.Fan of III (Institute for Information Industry), and Mr. Chang JingShin from Tsinghua University in Hsinchu, Taiwan. In particular, Mr.Masataka Ohta, who is the coordinator of APNG-I18N, contributed many efforts towards the work from the beginning of APNG-CC. The authors also wish to thank the following people who contributed in many ways towards this draft. Martin J. Duerst Kenichi Handa Zhang Ling Zhang ZhouCai Zhu Bin Nelson Chin Lu Chin Ding ZyKaan Chen Shuyi Mao Yonggang Mao Yonggang Ken Lunde Lua Kim Teng Victor Cheng Stephen G. Simpson Yuan Jiang Liu HuiFang Harald T. Alvestrand Feng Hui Security Considerations Security issues are not discussed in this memo. Authors' Addresses Zhu,Hai-feng (HF. Zhu) Dept. of Computer Science & Technology Tsinghua University Beijing, 100084 China Tel: +86-1-2561144 ext. 3492 Fax: +86-1-2564173 Email: zhf@net.edu.cn, zhf@net.tsinghua.edu.cn Hu,Dao-yuan (DY. Hu) Tsinghua Networking Center Tsinghua University Beijing, 100084 China Tel: +86-1-2594016 Fax: +86-1-2564173 Email: hdy@tsinghua.edu.cn Wang,Zhi-guan (ZG. Wang) SubCommitte 2 (SC2) China Information Technology Standardization Technical Committee (CITS) Beijing, 100083 China Tel: +86-1-4012392 Fax: +86-1-4010601 Kao,Tien-cheu (TC. Kao) I.T. Promotion Division Institute for Information Industry(III) Taipei Taiwan Tel: +886-2-5631688 Fax: +886-2-563-4209 Email: tckao@iiidns.iii.org.tw Chang,Wen-chung (WC. Chang) Institute for Information Industry(III) Taipei Taiwan Tel: +886-2-7327771 Fax: +886-2-7370188 Email: chung@iiidns.iii.org.tw Mark R. Crispin Networks and Distributed Computing University of Washington 4545 15th Avenue NE Seattle, WA 98105-4527 USA Tel: +1 (206) 543-5762 Fax: +1 (206) 685-4045 Email: MRC@CAC.Washington.EDU Appendix -- Conversion Table for CNS-11643 and Big5 This is a conversion table for the Chinese characters in Big5 and CNS-11643, including some specific characters in Eten variant of Big5. Noted that this list only contains Chinese characters, symbols are not provided. For more complete table, please refer to [CJK] or the ftp sites listed in section 1.4, where conversion programs are available. 1. Big5 Level 1 correspondence to CNS 11643-1992 Plane 1: 0xA440-0xACFD <-> 0x4421-0x5322 # Level 1 Chinese start 0xACFE <-> 0x5753 0xAD40-0xAFCF <-> 0x5323-0x5752 0xAFD0-0xBBC7 <-> 0x5754-0x6B4F 0xBBC8-0xBE51 <-> 0x6B51-0x6F5B 0xBE52 <-> 0x6B50 0xBE53-0xC1AA <-> 0x6F5C-0x7534 0xC1AB-0xC2CA <-> 0x7536-0x7736 0xC2CB <-> 0x7535 0xC2CC-0xC360 <-> 0x7737-0x782C 0xC361-0xC3B8 <-> 0x782E-0x7863 0xC3B9 <-> 0x7865 0xC3BA <-> 0x7864 0xC3BB-0xC455 <-> 0x7866-0x7961 0xC456 <-> 0x782D 0xC457-0xC67E <-> 0x7962-0x7D4B # Level 1 Chinese end 2. Big5 Level 2 correspondence to CNS 11643-1992 Plane 2: 0xC940-0xC949 <-> 0x2121-0x212A 0xC94A -> 0x4442 # duplicate of 0xA461 0xC94B-0xC96B <-> 0x212B-0x214B 0xC96C-0xC9BD <-> 0x214D-0x217C 0xC9BE <-> 0x214C 0xC9BF-0xC9EC <-> 0x217D-0x224C 0xC9ED-0xCAF6 <-> 0x224E-0x2438 0xCAF7 <-> 0x224D 0xCAF8-0xD6CB <-> 0x2439-0x376E 0xD6CC <-> 0x3E63 0xD6CD-0xD779 <-> 0x3770-0x387D 0xD77A <-> 0x3F6A 0xD77B-0xDADE <-> 0x387E-0x3E62 0xDADF <-> 0x376F 0xDAE0-0xDBA6 <-> 0x3E64-0x3F69 0xDBA7-0xDDFB <-> 0x3F6B-0x4423 0xDDFC -> 0x4176 # duplicate of 0xDCD1 0xDDFD-0xE8A2 <-> 0x4424-0x554A 0xE8A3-0xE975 <-> 0x554C-0x5721 0xE976-0xEB5A <-> 0x5723-0x5A27 0xEB5B-0xEBF0 <-> 0x5A29-0x5B3E 0xEBF1 <-> 0x554B 0xEBF2-0xECDD <-> 0x5B3F-0x5C69 0xECDE <-> 0x5722 0xECDF-0xEDA9 <-> 0x5C6A-0x5D73 0xEDAA-0xEEEA <-> 0x5D75-0x6038 0xEEEB <-> 0x642F 0xEEEC-0xF055 <-> 0x6039-0x6242 0xF056 <-> 0x5D74 0xF057-0xF0CA <-> 0x6243-0x6336 0xF0CB <-> 0x5A28 0xF0CC-0xF162 <-> 0x6337-0x642E 0xF163-0xF16A <-> 0x6430-0x6437 0xF16B <-> 0x6761 0xF16C-0xF267 <-> 0x6438-0x6572 0xF268 <-> 0x6934 0xF269-0xF2C2 <-> 0x6573-0x664C 0xF2C3-0xF374 <-> 0x664E-0x6760 0xF375-0xF465 <-> 0x6762-0x6933 0xF466-0xF4B4 <-> 0x6935-0x6961 0xF4B5 <-> 0x664D 0xF4B6-0xF4FC <-> 0x6962-0x6A4A 0xF4FD-0xF662 <-> 0x6A4C-0x6C51 0xF663 <-> 0x6A4B 0xF664-0xF976 <-> 0x6C52-0x7165 0xF977-0xF9C3 <-> 0x7167-0x7233 0xF9C4 <-> 0x7166 0xF9C5 <-> 0x7234 0xF9C6 <-> 0x7240 0xF9C7-0xF9D1 <-> 0x7235-0x723F 0xF9D2-0xF9D5 <-> 0x7241-0x7244 3. Big5 Level 2 correspondence to CNS 11643-1992 Plane 3: 0xF9D6 <-> 0x4337 # ETen-specific Chinese 0xF9D7 <-> 0x4F50 # ETen-specific Chinese 0xF9D8 <-> 0x444E # ETen-specific Chinese 0xF9D9 <-> 0x504A # ETen-specific Chinese 0xF9DA <-> 0x2C5D # ETen-specific Chinese 0xF9DB <-> 0x3D7E # ETen-specific Chinese 0xF9DC <-> 0x4B5C # ETen-specific Chinese References [ASCII] American National Standards Institute, "Coded character set -- 7-bit American National Standard Code for Information Interchange", ANSI X3.4-1986. [BIG5] Institute for Information Industry, "Chinese Coded Character Set in Computer ", March, 1984 [CJK] Ken Lunde, On-line documentation of Chinese/Japanese/Korean Information Processing, 1995, available at: ftp://ftp.ora.com/pub/examples/nutshell/ujip/doc/cjk.inf [CNS-5205] "Information processing -- 7-Bit Coded Character Set For Information Interchange", CNS-5205. [CNS-11643] "Chinese Standard Interchange Code", CNS-11643 version 1992; "Standard Interchange Code for Generally-Used Chinese Characters", CNS 11643 version 1986. [GB-1988] "7-bit Coding Character Set for Information Interchange", GB 1988-80. [GB-2312] "Coding of Chinese Ideogram Set for Information Interchange Basic Set", GB 2312-80. [GB-7589] "Code of Chinese Ideograms Set for Information Interchange, the 2nd Supplementary Set", UDC 681.3.048, GB 7589-87. [GB-7590] "Code of Chinese Ideogram Set for Information Interchange, the 4th Supplementary Set",UDC 681.3.048, GB 7590-87. [GB-8565] "Information Processing Coded Character Sets for Text Communication", UDC 681.3, GB 8565-88. [GB-12345] "Code of Chinese Ideogram Set for Information Interchange Supplementary Set", GB/T 12345-90. [GB-13000] "Information technology--Universal Multiple-Octet Coded Character Set(UCS)---Part 1: Architecture and Basic Multilingual Plane", GB13000.1 [GB-13131] "Code of Chinese Ideogram Set for Information Interchange, the 3rd Supplementary Set", GB 13131-91. [GB-13132] "Code of Chinese Ideogram Set for Information Interchange, the 5th Supplementary Set", GB 13132-91. [ISO-646] International Organization for Standardization (ISO), "Information technology -- ISO 7-bit coded character set for information interchange", International Standard, Ref. No. ISO/IEC 646:1991. [ISO-2022] International Organization for Standardization (ISO), "Information processing -- ISO 7-bit and 8-bit coded character sets -- Code extension techniques", International Standard, Ref. No. ISO 2022-1986 (E). [ISO-10021] Information Technology - Text communication - Message-Oriented Text Interchange Systems (MOTIS), ISO 10021, October 1988. [ISO-10646] ISO/IEC 10646-1:1993(E) Information Technology--Universal Multiple-octet Coded Character Set (UCS)---Part 1: Architecture and Basic Multilingual Plane" [ISOREG] International Organization for Standardization (ISO), "International Register of Coded Character Sets To Be Used With Escape Sequences". [MIME-1] Borenstein, N., and Freed, N., "MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies", RFC 1521, Bellcore, Innosoft, September 1993. [MIME-2] Moore, K., "MIME (Multipurpose Internet Mail Extensions) Part Two: Message Header Extensions for Non-ASCII Text", RFC 1522, University of Tennessee, September 1993. [RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, University of Delaware, August 1982. [RFC-1036] Horton M., and Adams, R., "Standard for Interchange of USENET Messages", RFC 1036, AT&T Bell Laboratories, Center for Seismic Studies, December 1987. [RFC-1468] Murai J., Crispin M. and E. van der Poel, Japanese Character Encoding for Internet Messages, June 1993. [RFC-1557] Choi U., Chon K. and Park H., Korean Character Encoding for Internet Messages, December 1993. [RFC-1641] Goldsmith D., and Davis M., "Using Unicode with MIME", RFC 1641, Taligent Inc., July 1994 [RFC-1642] Goldsmith D., and Davis M.," UTF-7, A Mail-Safe Transformation Format of Unicode", July 1994 [RFC-1700] Reynolds J., and Postel J., "Assigned Numbers",RFC 1700, STD 2, ISI, October 1994 [SMTP] Postel, Jonathan B. "Simple Mail Transfer Protocol", STD 10, RFC 821, USC/Information Sciences Institute, August 1982. [SMTPEXT] Klensin, J.; Freed, N.; Rose, M.; Stefferud, E.; and Crocker, D., "SMTP Service Extensions", RFC 1651, July 1994. [Unicode 1.1] "The Unicode Standard, Version 1.1", Addison-Wesley, Reading, MA (to be published; the contents of this standard is currently available by combining [Unicode92], [Unicode93], and [Unicode4]). [Unicode92] The Unicode Consortium, "The Unicode Standard - Worldwide Character Encoding - Version 1.0", Volume 1, Addison-Wesley, Reading, MA, 1992 (ISBN 0-201-56788-1). [Unicode93] The Unicode Consortium, "The Unicode Standard - Worldwide Character Encoding - Version 1.0", Volume 2, Addison-Wesley, Reading, MA, 1992 (ISBN 0-201-60845-6). [Unicode4] The Unicode Consortium, "The Unicode Standard - Version 1.1 (Prepublication Edition)", Unicode Technical Report #4 (avaliable from the Unicode Consortium).