Re: [idn] Debunking the ACE myth

["Adam M. Costello" <amc@cs.berkeley.edu>]

Dan Oscarsson <Dan.Oscarsson@trab.se> wrote:

> For both ACE and UTF-8 there are two ways that it can be done:
>
> 1) All names are transmitted in a form/semantic insensitive format
> (that is what nameprep is for) so that names can be compared using
> binary matching.
>
> 2) Names are transmitted with form retained (that is any form, though
> they should be normalised).
>
> 1) is the IDNA case and also in Microsofts draft-skwan-utf8-dns.  This
> results in that for example upper case characters cannot be used in
> responses from DNS.

For the UTF-8 case, as I've pointed out before, it is not necessary
for DNS queries and DNS responses to use the same rules.  It would
be perfectly reasonable to use nameprep'd UTF-8 in queries and
non-nameprep'd UTF-8 in responses.

For the ACE case, as I've pointed out before, mixed-case ACE can easily
be used to represent mixed-case Unicode.  You would lose things like
circled-digit-one (which becomes a regular digit-one), but mixed case
can be conveyed in ACE.

By the way, it would be pointless to combine ACE with option 2 (no
nameprep).

AMC