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/rfc1947.txt | 395 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 395 insertions(+) create mode 100644 doc/rfc/rfc1947.txt (limited to 'doc/rfc/rfc1947.txt') diff --git a/doc/rfc/rfc1947.txt b/doc/rfc/rfc1947.txt new file mode 100644 index 0000000..63ba448 --- /dev/null +++ b/doc/rfc/rfc1947.txt @@ -0,0 +1,395 @@ + + + + + + +Network Working Group D. Spinellis +Request for Comments: 1947 SENA S.A. +Category: Informational May 1996 + + + Greek Character Encoding for Electronic Mail 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. + +Overview and Rational + + This document describes a standard encoding for electronic mail + [RFC822] containing Greek text and provides implementation guide- + lines. The standard is based on MIME [RFC1521] and the ISO 8859-7 + character encoding. Although the implementation of this standard is + straightforward several non-standard but "functional" - though + unlikely to inter-operate - alternatives are in common use. For this + reason we highlight common implementation and mail user agent setup + errors. + + Description + + In order to transfer Greek text via electronic mail the text is first + translated into the ISO 8859-7 character set, and then encoded using + either the Base64 (preferable for text that is mainly Greek) or the + Quoted-Printable (justifiable in cases where some Greek words appear + inside predominately Latin text) method, as defined in MIME. + + The following table provides most common Greek encodings (see also + [RFC1345]): + + 0646 37 M7 51 MC 23 69 LG L1 G7 GO GC 28 97 Description + ---- -- -- -- -- -- -- -- -- -- -- -- -- -- ----------- + 0386 ea a2 86 cd 71 86 b6 Capital alpha with acute + 0388 eb b8 8d ce 72 8d b8 Capital epsilon with + acute + 0389 ec b9 8f d7 73 8f b9 Capital eta with acute + 038a ed ba 90 d8 75 90 ba Capital iota with acute + 038c ee bc 92 d9 76 92 bc Capital omicron with + acute + 038e ef be 95 da 77 95 be Capital upsilon with + acute + 038f f0 bf 98 df 78 98 bf Capital omega with acute + 0390 c0 a1 fd a1 c0 Small iota with acute and + + + +Spinellis Informational [Page 1] + +RFC 1947 Greek Encoding for E-mail Messages May 1996 + + + diaeresis + 0391 80 c1 a4 b0 41 a4 61 41 61 41 41 c1 Capital alpha + 0392 81 c2 a5 b5 42 a5 62 42 62 42 42 c2 Capital beta + 0393 82 c3 a6 a1 43 a6 67 23 43 67 43 44 c3 Capital gamma + 0394 83 c4 a7 a2 44 a7 64 40 44 64 44 45 c4 Capital delta + 0395 84 c5 a8 b6 45 a8 65 45 65 45 46 c5 Capital epsilon + 0396 85 c6 a9 b7 46 a9 7a 46 7a 46 49 c6 Capital zeta + 0397 86 c7 aa b8 47 aa 68 47 68 47 4a c7 Capital eta + 0398 87 c8 ac a3 48 ac 75 5c 48 75 48 4b c8 Capital theta + 0399 88 c9 ad b9 49 ad 69 49 69 49 4c c9 Capital iota + 039a 89 ca b5 ba 51 b5 6b 4b 6b 4a 4d ca Capital kappa + 039b 8a cb b6 a4 52 b6 6c 5e 4c 6c 4b 4e cb Capital lamda + 039c 8b cc b8 bb 53 b7 6d 4d 6d 4c 4f cc Capital mu + 039d 8c cd b7 c1 54 b8 6e 4e 6e 4d 50 cd Capital nu + 039e 8d ce bd a5 55 bd 6a 21 4f 6a 4e 51 ce Capital xi + 039f 8e cf be c3 56 be 6f 50 6f 4f 52 cf Capital omicron + 03a0 8f d0 c6 a6 57 c6 70 3f 51 70 50 53 d0 Capital pi + 03a1 90 d1 c7 c4 58 c7 72 52 72 51 55 d1 Capital rho + 03a3 91 d3 cf aa 59 cf 73 5f 53 73 53 56 d3 Capital sigma + 03a4 92 d4 d0 c6 62 d0 74 54 74 54 58 d4 Capital tau + 03a5 93 d5 d1 cb 63 d1 79 55 79 55 59 d5 Capital upsilon + 03a6 94 d6 d2 bc 64 d2 66 5d 56 66 56 5a d6 Capital phi + 03a7 95 d7 d3 cc 65 d3 78 58 78 57 5b d7 Capital chi + 03a8 96 d8 d4 be 66 d4 63 3a 59 63 58 5c d8 Capital psi + 03a9 97 d9 d5 bf 67 d5 76 5b 5a 76 59 5d d9 Capital omega + 03aa da ab 91 da Capital iota with + diaeresis + 03ab db bd 96 db Capital upsilon with + diaeresis + 03ac e1 dc 9b c0 b1 9b dc Small alpha with acute + 03ad e2 dd 9d db b2 9d dd Small epsilon with acute + 03ae e3 de 9e dc b3 9e de Small eta with acute + 03af e5 df 9f dd b5 9f df Small iota with acute + 03b0 e0 fc fe fc e0 Small upsilon with acute + and diaeresis + 03b1 98 e1 d6 e1 8a d6 61 41 61 61 e1 Small alpha + 03b2 99 e2 d7 e2 8b d7 62 42 62 62 e2 Small beta + 03b3 9a e3 d8 e7 8c d8 63 47 63 64 e3 Small gamma + 03b4 9b e4 dd e4 8d dd 64 44 64 65 e4 Small delta + 03b5 9c e5 de e5 8e de 65 45 65 66 e5 Small epsilon + 03b6 9d e6 e0 fa 8f e0 66 5a 66 69 e6 Small zeta + 03b7 9e e7 e1 e8 9a e1 67 48 67 6a e7 Small eta + 03b8 9f e8 e2 f5 9b e2 68 55 68 6b e8 Small theta + 03b9 a0 e9 e3 e9 9c e3 69 49 69 6c e9 Small iota + 03ba a1 ea e4 eb 9d e4 6b 4b 6a 6d ea Small kappa + 03bb a2 eb e5 ec 9e e5 6c 4c 6b 6e eb Small lamda + 03bc a3 ec e6 ed 9f e6 6d 4d 6c 6f ec Small mu + 03bd a4 ed e7 ee aa e7 6e 4e 6d 70 ed Small nu + + + +Spinellis Informational [Page 2] + +RFC 1947 Greek Encoding for E-mail Messages May 1996 + + + 03be a5 ee e8 ea ab e8 6f 4a 6e 71 ee Small xi + 03bf a6 ef e9 ef ac e9 70 4f 6f 72 ef Small omicron + 03c0 a7 f0 ea f0 ad ea 71 50 70 73 f0 Small pi + 03c1 a8 f1 eb f2 ae eb 72 52 71 75 f1 Small rho + 03c2 aa f2 ed f7 af ed 77 57 72 77 f2 Small final sigma + 03c3 a9 f3 ec f3 ba ec 73 53 73 76 f3 Small sigma + 03c4 ab f4 ee f4 bb ee 74 54 74 78 f4 Small tau + 03c5 ac f5 f2 f9 bc f2 75 59 75 79 f5 Small upsilon + 03c6 ad f6 f3 e6 bd f3 76 46 76 7a f6 Small phi + 03c7 ae f7 f4 f8 be f4 78 58 77 7b f7 Small chi + 03c8 af f8 f6 e3 bf f6 79 43 78 7c f8 Small psi + 03c9 e0 f9 fa f6 db fa 7a 56 79 7d f9 Small omega + 03ca e4 fa a0 fb b4 a0 fa Small iota with diaeresis + 03cb e8 fb fb fc b8 fb fb Small upsilon with + diaeresis + 03cc e6 fc a2 de b6 a2 fc Small omicron with acute + 03cd e7 fd a3 e0 b7 a3 fd Small upsilon with acute + 03ce e9 fe fd f1 b9 fd fe Small omega with acute + + Note: All values are in hexadecimal. + + The column headers refer to the following character sets: + +0646 The ISO 2DIS 10646 code. + +37 PC code page 737 also known as 437G. Note that some implementa- + tions of this code page do not include capital letters with acute. + +M7 Character set 8859-7 as implemented in Microsoft Windows 3.1, + Microsoft Windows 3.11, and Microsoft Windows 95. + +51 IBM code page 851. + +MC The Greek code page implemented on the Apple Macintosh computers. + +23 IBM code page 423 (EBCDIC-CP-GR). + +69 IBM code page 869. + +LG Latin Greek (iso-ir-19). + +L1 Latin Greek 1 (iso-ir-27). This page only contains the Greek cap- + ital letters whose glyphs do not exist in the Latin alphabet. The + other capital letters are rendered using the equivalent Latin let- + ter (e.g. "Greek capital letter alpha" is rendered as "Latin capi- + tal letter A"). When mapping "Latin Greek 1" text to ISO 8859-7 + the Latin capital letters should only be transcribed to the + equivalent Greek ones if a suitable heuristic determines that the + + + +Spinellis Informational [Page 3] + +RFC 1947 Greek Encoding for E-mail Messages May 1996 + + + specific Latin letters are used to represent Greek glyphs. + +G7 7 bit Greek (iso-ir-88). + +GO Old 7 bit Greek (iso-ir-18). + +GC Greek CCITT (iso-ir-150). + +28 Character set ISO 5428:1980 (iso-ir-55). + +97 The target character set ISO 8859-7:1987 (ELOT-928) (iso-ir-126). + +MIME Headers + + A mail message that contains Greek text must contain at least the + following MIME headers: + + MIME-Version: 1.0 + Content-type: text/plain; charset=ISO-8859-7 + Content-transfer-encoding: BASE64 | Quoted-Printable + + In the future, when all email systems implement fully transparent + 8-bit e-mail as defined in RFC 1425 and RFC 1426 the message body + encoding phase described in this standard will be no longer + needed. In this case the requisite MIME headers are modified as + follows: + MIME-Version: 1.0 + Content-type: text/plain; charset=ISO-8859-7 + Content-transfer-encoding: 8BIT + Even when RFC 1425 is used, Q or B encoding will continue to apply + to message headers as detailed in the following section. + + Optional + + It is recommended, although not required, to support Greek encod- + ing in mail headers as specified in RFC 1522. Specifically, the + B-encoding format is to be the default method used for encoding + Greek text in RFC-822 mail headers, and the Q-encoding format the + method to use for the exceptional case of encoding a single Greek + word or letter in an otherwise Latin-character-based header. + + + + + + + + + + + +Spinellis Informational [Page 4] + +RFC 1947 Greek Encoding for E-mail Messages May 1996 + + +Example + + Below is a short example of Quoted-Printable encoded Greek + email: + + Date: Wed, 31 Jan 96 20:15:03 EET + From: Diomidis Spinellis + Subject: Sample Greek mail + To: Achilleas Voliotis + MIME-Version: 1.0 + Content-ID: + Content-Type: Text/plain; charset=ISO-8859-7 + Content-Transfer-Encoding: Base64 + +yuHr5+zd8eEsCgrU7yDl6+vn7enq/CDh6/bc4uf07yDh8O/05evl3/Th6SDh8PwgMjYg4/Hc +7Ozh9OEuCg== + +Discussion + + It is possible [RFC1428] (and unfortunately common practice) to + set up an arrangement of mail user and transfer agents that allow + end users to communicate with Greek e-mail messages while + violating a number of standards. Such arrangements are unlikely + to offer wide scale interoperability. + + One common error is to arrange the rendering and composition of + Greek messages by rigging a mail user agent hosted in an ISO + 8859-1 environment to use a presentation font that contains Greek + glyphs and a keyboard input method that generates Greek text using + those glyphs. The resulting messages begin with header items + indicating contents in the ISO 8859-1 character set and include + text in a totally different encoding. Unfortunately this + "solution" appears to "work" across similar systems and is widely + used. + + One other error is to tag Greek text generated on Microsoft + Windows platforms as ISO 8859-7 without an intermediate + translation phase. It is important to note that the character set + used by the Microsoft Windows Greek implementations is NOT the + same as the ISO 8859-7 representation. First of all, the + character set used to represent Greek characters differs slightly + from the ISO 8859-7 encoding (this difference was instrumented in + order to rectify the appearance of an early version of Microsoft + Word for Windows in which the end-of-section symbol clashed with + the "Greek capital alpha with acute" glyph). In addition, a + number of 8-bit characters available on Greek Windows + implementations are not part of the ISO 8859-7 character set. + + + + +Spinellis Informational [Page 5] + +RFC 1947 Greek Encoding for E-mail Messages May 1996 + + + Note that the ISO 8859-7 encoding is equivalent to the Greek + Standards Organisation ELOT-928 encoding. + +References + + [ISO-8859] Information Processing -- 8-bit Single-Byte Coded Graphic + Character Sets, Part 7: Latin/Greek alphabet, ISO 8859-7, + 1987. + + [RFC822] Crocker, D., "Standard for the Format of ARPA Internet + Text Messages", STD 11, RFC 822, UDEL, August 1982. + + [RFC1345] Simonsen, K., "Character Mnemonics & Character Sets" RFC + 1345, Rationel Almen Planlaegning, June 1992. + + [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. + + [RFC1428] Vaudreuil, G., "Transition of Internet Mail from + Just-Send-8 to 8bit-SMTP/MIME", RFC 1428, CNRI, February + 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. + + + + + + + + + + + + +Spinellis Informational [Page 6] + +RFC 1947 Greek Encoding for E-mail Messages May 1996 + + +Security Considerations + + Security issues are not discussed in this memo. + +Author's Address + + Diomidis Spinellis + SENA S.A. + Kyprou 27 + GR-152 47 Filothei + GREECE + + Phone: +30 (1) 6854535 + Fax: +30 (1) 6840631 + EMail: D.Spinellis@senanet.com + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Spinellis Informational [Page 7] + -- cgit v1.2.3