RFC 3629 (rfc3629) - Page 1 of 14


UTF-8, a transformation format of ISO 10646



Alternative Format: Original Text Document



Network Working Group                                         F. Yergeau
Request for Comments: 3629                             Alis Technologies
STD: 63                                                    November 2003
Obsoletes: 2279
Category: Standards Track


              UTF-8, a transformation format of ISO 10646

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   ISO/IEC 10646-1 defines a large character set called the Universal
   Character Set (UCS) which encompasses most of the world's writing
   systems.  The originally proposed encodings of the UCS, however, were
   not compatible with many current applications and protocols, and this
   has led to the development of UTF-8, the object of this memo.  UTF-8
   has the characteristic of preserving the full US-ASCII range,
   providing compatibility with file systems, parsers and other software
   that rely on US-ASCII values but are transparent to other values.
   This memo obsoletes and replaces RFC 2279.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Notational conventions . . . . . . . . . . . . . . . . . . . .  3
   3.  UTF-8 definition . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Syntax of UTF-8 Byte Sequences . . . . . . . . . . . . . . . .  5
   5.  Versions of the standards  . . . . . . . . . . . . . . . . . .  6
   6.  Byte order mark (BOM)  . . . . . . . . . . . . . . . . . . . .  6
   7.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
   8.  MIME registration  . . . . . . . . . . . . . . . . . . . . . .  9
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   10. Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   12. Changes from RFC 2279  . . . . . . . . . . . . . . . . . . . . 11
   13. Normative References . . . . . . . . . . . . . . . . . . . . . 12



Yergeau                     Standards Track