Re: [idn] IDNRA comments

["A. Vine" <avine@eng.sun.com>]

Maynard Kang wrote:
> 
> Dave Crocker wrote:
> 
> > On the other hand, these techniques very much DO preserve the uniqueness
> of
> > a string, including when that string is a domain name, since the MIME
> > content-transfer-encodings must be entirely idempotent and reversible.
> 
> I'm afraid I have to disagree. The transformation itself may be idempotent
> and reversible, but the fact that any arbitrary character set may be used in
> MIME content-transfer-encodings makes the domain name (not the string)
> non-unique.
> 
> For example, the same abstract characters (zhongguo.gongsi in chinese, which
> means china.com), ideographically speaking, can be represented in at least
> three different ASCII-encoded strings using QP:
> 
> =?GB2312?Q?=D6=D0=B9=FA.=B9=AB=CB=BE?=
> =?BIG5?Q?=A4=A4=B0=EA.=A4=BD=A5q?=
> =?UTF8?Q?=E4=B8=AD=E5=9B=BD.=E5=85=AC=E5=8F=B8?=
> 
> Perhaps I should clarify, I agree that the *transformation* results in a
> unique string. But not a unique domain name in the case of multiple CCS
> used. The transformation is fine, but for use in IDNs the CCS should be
> restricted to a single, universal one such as ISO10646, like in the case of
> RACE and UTF-5.

I don't see where RFC 2047 encoded words came into the discussion,
sorry.  QP and base64 are transfer encodings which work with any data,
binary included.  They are used external to RFC 2047.  Dave didn't
mention RFC 2047 format.  It is up to the proposal to specify the CCS or
even CES which is to be transfer encoded using QP, base64, or another
transfer encoding scheme.  It is only because MIME never restricted the
charset that multiple charsets are allowed.  If the proposal restricts
the CCS, then the ambiguity of the CCS is not an issue.

Andrea
-- 
Andrea Vine, avine@eng.sun.com, iPlanet i18n architect
"A bibliophile is a lover of books; a bibliomane, a wildly enthusiastic
collector. An abandoned fanatic, once he succumbs to bibliolatry,
graduates into a bibliomaniac. While a bibliomaniac's spouse might easily
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destroyer
of books." -- Bill Strubbe, A Bibliophile in Britain