Re: [idn] Debunking the ACE myth

[David Hopwood <david.hopwood@zetnet.co.uk>]

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Patrik Fältström wrote:
> --On 01-07-18 06.46 +0000 "D. J. Bernstein" <djb@cr.yp.to> wrote:
> 
> > What went wrong is that the browser displayed the address as Unicode
> > characters. The address then passed through the (CTEXT UTF-8, although
> > UTF8_STRING would be better) copy-and-paste mechanism, the UTF-8 xterm,
> > the mail client, and the 8-bit-clean MTA, none of which converted back
> > to ACE. The resulting UTF-8 DNS lookup produced NXDOMAIN.
> 
> In the IDNA proposal we have specified that an application which handle
> IDNA (like you seem to say that the browser is) only support IDNA if also
> the content of the clipboard is converted to ACE before the domainname is
> passed to other applications (which doesn't handle IDNA/ACE solution).

That is practical in *some* situations: when the application uses a widget
that is specifically designed to display a domain name (or email address
or URI). In fact I've partially implemented a name entry widget in Java that
does exactly that. It is *not* practical for domain names appearing in free
text. Therefore, in order for cut and paste to work properly, ACE names must
be restricted as far as possible to a minimal set of well-defined contexts -
which is what IDN-8 does.

- -- 
David Hopwood <david.hopwood@zetnet.co.uk>

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