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Network Working Group                                      H. NussbacherRequest for Comments: 1555                      Israeli Inter-UniversityCategory: Informational                                  Computer Center                                                             Y. Bourvine                                                       Hebrew University                                                           December 1993Hebrew Character Encoding for Internet MessagesStatus 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     236Nussbacher & 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 complementaryRFC1556, "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 lastnameMIME 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 inRFC 1425 andRFC 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 inRFC 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 fullRFC822   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 1993Example   Below is a short example of Quoted-Printable encoded Hebrew email:   Date:         Sun, 06 Jun 93 15:25:35 IDT   From:         Hank Nussbacher <HANK@VM.BIU.AC.IL>   Subject:      Sample Hebrew mail   To:           Hank Nussbacher <Hank@BARILVM>,                 Yehavi Bourvine <yehavi@hujivms>   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=E4Acknowledgements   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.ilNussbacher & Bourvine                                           [Page 5]