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Network Working Group Request for Comments: 1555 Category: Informational

H. Nussbacher Israeli Inter-University Computer Center Y. Bourvine Hebrew University December 1993

Hebrew Character Encoding for Internet Messages Status of this Memo This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract This document describes the encoding used in electronic mail [RFC822] for transferring Hebrew. The standard devised makes use of MIME [RFC1521] and ISO-8859-8. Description All Hebrew text when transferred via e-mail must first be translated into ISO-8859-8, and then encoded using either Quoted-Printable (preferable) or Base64, as defined in MIME. The following table provides the four most common Hebrew encodings: PC Hebrew letter 8-bit Ascii ---------- ----alef 128 bet 129 gimel 130 dalet 131 he 132 vav 133 zayin 134 het 135 tet 136 yod 137 kaf sofit 138 kaf 139 lamed 140 IBM PC 7-bit Ascii ----96 97 98 99 100 101 102 103 104 105 106 107 108 ISO 8859-8 8-bit Ascii -----224 225 226 227 228 229 230 231 232 233 234 235 236

EBCDIC -----41 42 43 44 45 46 47 48 49 51 52 53 54

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RFC 1555

Hebrew Character Encoding

December 1993

mem sofit mem nun sofit nun samekh ayin pe sofit pe tsadi sofit tsadi qof resh shin tav

141 142 143 144 145 146 147 148 149 150 151 152 153 154

55 56 57 58 59 62 63 64 65 66 67 68 69 71

109 110 111 112 113 114 115 116 117 118 119 120 121 122

237 238 239 240 241 242 243 244 245 246 247 248 249 250

Note: All values are in decimal ASCII except for the EBCDIC column which is in hexadecimal. ISO 8859-8 8-bit ASCII is also known as IBM Codepage 862. The default directionality of the text is visual. This means that the Hebrew text is encoded from left to right (even though Hebrew text is entered right to left) and is transmitted from left to right via the standard MIME mechanisms. Other methods to control directionality are supported and are covered in the complementary RFC 1556, "Handling of Bi-directional Texts in MIME". All discussion regarding Hebrew in email, as well as discussions of Hebrew in other TCP/IP protocols, is discussed in the ilanh@vm.tau.ac.il list. To subscribe send mail to listserv@vm.tau.ac.il with one line of text as follows: subscribe ilan-h firstname lastname MIME Considerations Mail that is sent that contains Hebrew must contain the following minimum amount of MIME headers: MIME-Version: 1.0 Content-type: text/plain; charset=ISO-8859-8 Content-transfer-encoding: BASE64 | Quoted-Printable Users should keep their text to within 72 columns so as to allow email quoting via the prefixing of each line with a ">". Users should also realize that not all MIME implementations handle email quoting properly, so quoting email that contains Hebrew text may lead to problems.

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RFC 1555

Hebrew Character Encoding

December 1993

In the future, when all email systems implement fully transparent 8bit email as defined in RFC 1425 and RFC 1426 this standard will become partially obsolete. The "Content-type:" field will still be necessary, as well as directionality (which might be implicit for 8BIT, but is something for future discussion), but the "Contenttransfer-encoding" will be altered to use 8BIT rather than Base64 or Quoted-Printable. Optional It is recommended, although in mail headers as specified encoding format is to be the in Internet mail headers and Caveats Within Israel there are in excess of 40 Listserv lists which will now start using Hebrew for part of their conversations. Normally, Listserv will deliver mail from a distribution list with a "shortened" header, one that does not include the extra MIME headers. This will cause the MIME encoding to be left intact and the user agent decoding software will not be able to interpret the mail. Each user is able to customize how Listserv delivers mail. For lists that contain Hebrew, users should send mail to Listserv with the following command: set listname full where listname is unabridged headers and all subsequent headers, including In addition, postings to LOGyymm", do information software. the name of the list which the user wants full, to appear. This will update their private entry mail from that list will be with full RFC822 MIME headers. archives of all the file "listname encoding the Listserv not required, to support Hebrew encoding in RFC 1522. Specifically, the Qdefault method used for encoding Hebrew not the B-encoding method.

Listserv usually maintains automatic a list. These archives, contained in not contain the MIME headers, so all will be lost. This is a limitation of

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RFC 1555

Hebrew Character Encoding

December 1993

Example Below is a short example of Quoted-Printable encoded Hebrew email: Date: From: Subject: To: Sun, 06 Jun 93 15:25:35 IDT Hank Nussbacher Sample Hebrew mail Hank Nussbacher , Yehavi Bourvine MIME-Version: 1.0 Content-Type: Text/plain; charset=ISO-8859-8 Content-Transfer-Encoding: QUOTED-PRINTABLE The end of this line contains Hebrew =F8=E0=EE =ED=E5=EC=F9 .=EC=E0=F8=F9=E9 =F5=

Hank Nussbacher =F0 =F7=F0=E4 Acknowledgements

=F8=EB=E1=F1=E5=

Many thanks to Rafi Sadowsky and Nathaniel Borenstein for all their help. References [ISO-8859] Information Processing -- 8-bit Single-Byte Coded Graphic Character Sets, Part 8: Latin/Hebrew alphabet, ISO 8859-8, 1988. [RFC822] Crocker, D., "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, UDEL, August 1982. Klensin, J., Freed N., Rose M., Stefferud E., and D. Crocker, "SMTP Service Extensions", RFC 1425, United Nations University, Innosoft International, Inc., Dover Beach Consulting, Inc., Network Management Associates, Inc., The Branch Office, February 1993. Klensin, J., Freed N., Rose M., Stefferud E., and D. Crocker, "SMTP Service Extension for 8bit-MIME Transport", RFC 1426, United Nations University, Innosoft International, Inc., Dover Beach Consulting, Inc., Network Management Associates, Inc., The Branch Office, February 1993.

[RFC1425]

[RFC1426]

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RFC 1555

Hebrew Character Encoding

December 1993

[RFC1521]

Borenstein N., and N. Freed, "MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies", Bellcore, Innosoft, September 1993. Moore K., "MIME Part Two: Message Header Extensions for Non-ASCII Text", University of Tennessee, September 1993.

[RFC1522]

Security Considerations Security issues are not discussed in this memo. Authors' Addresses Hank Nussbacher Computer Center Tel Aviv University Ramat Aviv Israel Fax: +972 3 6409118 Phone: +972 3 6408309 EMail: hank@vm.tau.ac.il

Yehavi Bourvine Computer Center Hebrew University Jerusalem Israel Phone: +972 2 585684 Fax: +972 2 527349 EMail: yehavi@vms.huji.ac.il

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