A Mail-Safe Transformation Format of Unicode

and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months. Internet-Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet-Drafts as reference material or to cite them other than as a "working draft" or "work in progress". To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net Abstract The Unicode Standard, version 2.0, and ISO/IEC 10646-1:1993(E) (as amended) jointly define a character set (hereafter referred to as Unicode) which encompasses most of the world's writing systems. However, Internet mail (STD 11, RFC 822) currently supports only 7-bit US ASCII as a character set. MIME (RFC 1521 and RFC 1522) extends Internet mail to support different media types and character sets, and thus could support Unicode in mail messages. MIME neither defines Unicode as a permitted character set nor specifies how it would be encoded, although it does provide for the registration of additional character sets over time. This document describes a transformation format of Unicode that contains only 7-bit ASCII characters and is intended to be readable by humans in the limiting case that the document consists of characters from the US-ASCII repertoire. It also specifies how this transformation format is used in the context of MIME and RFC 1641, "Using Unicode with MIME".