From 4bfd864f10b68b71482b35c818559068ef8d5797 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Wed, 27 Nov 2024 20:54:24 +0100 Subject: doc: Add RFC documents --- doc/rfc/rfc1555.txt | 283 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 283 insertions(+) create mode 100644 doc/rfc/rfc1555.txt (limited to 'doc/rfc/rfc1555.txt') diff --git a/doc/rfc/rfc1555.txt b/doc/rfc/rfc1555.txt new file mode 100644 index 0000000..1b0ca56 --- /dev/null +++ b/doc/rfc/rfc1555.txt @@ -0,0 +1,283 @@ + + + + + + +Network Working Group H. Nussbacher +Request for Comments: 1555 Israeli Inter-University +Category: Informational 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 IBM PC ISO + Hebrew 8859-8 + letter 8-bit 7-bit 8-bit + Ascii EBCDIC Ascii Ascii + ---------- ----- ------ ----- ------ + alef 128 41 96 224 + bet 129 42 97 225 + gimel 130 43 98 226 + dalet 131 44 99 227 + he 132 45 100 228 + vav 133 46 101 229 + zayin 134 47 102 230 + het 135 48 103 231 + tet 136 49 104 232 + yod 137 51 105 233 + kaf sofit 138 52 106 234 + kaf 139 53 107 235 + lamed 140 54 108 236 + + + +Nussbacher & Bourvine [Page 1] + +RFC 1555 Hebrew Character Encoding December 1993 + + + mem sofit 141 55 109 237 + mem 142 56 110 238 + nun sofit 143 57 111 239 + nun 144 58 112 240 + samekh 145 59 113 241 + ayin 146 62 114 242 + pe sofit 147 63 115 243 + pe 148 64 116 244 + tsadi sofit 149 65 117 245 + tsadi 150 66 118 246 + qof 151 67 119 247 + resh 152 68 120 248 + shin 153 69 121 249 + tav 154 71 122 250 + + 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 ilan- + h@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. + + + +Nussbacher & Bourvine [Page 2] + +RFC 1555 Hebrew Character Encoding December 1993 + + + In the future, when all email systems implement fully transparent 8- + bit 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 "Content- + transfer-encoding" will be altered to use 8BIT rather than Base64 or + Quoted-Printable. + +Optional + + It is recommended, although not required, to support Hebrew encoding + in mail headers as specified in RFC 1522. Specifically, the Q- + encoding format is to be the default method used for encoding Hebrew + in Internet mail headers and not the B-encoding method. + +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 the name of the list which the user wants full, + unabridged headers to appear. This will update their private entry + and all subsequent mail from that list will be with full RFC822 + headers, including MIME headers. + + In addition, Listserv usually maintains automatic archives of all + postings to a list. These archives, contained in the file "listname + LOGyymm", do not contain the MIME headers, so all encoding + information will be lost. This is a limitation of the Listserv + software. + + + + + + + + + + + + +Nussbacher & Bourvine [Page 3] + +RFC 1555 Hebrew Character Encoding December 1993 + + +Example + + Below is a short example of Quoted-Printable encoded Hebrew email: + + Date: Sun, 06 Jun 93 15:25:35 IDT + From: Hank Nussbacher + Subject: Sample Hebrew mail + To: 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 .=EC=E0=F8=F9=E9 =F5= + =F8=E0=EE =ED=E5=EC=F9 + + + Hank Nussbacher =F8=EB=E1=F1=E5= + =F0 =F7=F0=E4 + +Acknowledgements + + 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. + + [RFC1425] 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. + + [RFC1426] 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. + + + + + +Nussbacher & Bourvine [Page 4] + +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. + + [RFC1522] Moore K., "MIME Part Two: Message Header Extensions for + Non-ASCII Text", University of Tennessee, September 1993. + +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 + + + + + + + + + + + + + + + + + +Nussbacher & Bourvine [Page 5] + \ No newline at end of file -- cgit v1.2.3