Re: [idn] Prohibit CDN code points

["Edmon" <edmon@neteka.com>]

----- Original Message -----
From: <DougEwell2@cs.com>
> If everything is 1-to-1 between TC and SC, the algorithm is trivial.  I
was
> talking about the algorithm that would be necessary to do TC/SC conversion
in
> the case of 1-to-many or many-to-1 conversions.  But, since you say there
are
> none, I guess we can proceed with implementing the tables.
>
It is possible to implement a 1-to-many or many-to-1 conversion.
All it is required is that all "equivalent" characters be matched as
"equivalent" in the authoritative DNS.
For example, a simple rule that says:
A = a = A' = a'  (note that there need not be a "primary" character)
This represents a 1-to-many or many-to-1 situation.
So, if a domain comes in:
aA'.example
it will be matched the same is if a domain:
Aa'.example
comes in.
This is just the matching rule within the DNS server and does not have to
affect any of the IDNA process.
That is, the user wil still see and know and react to whatever they typed in
and believed to be accessing.
It does not take anything away from being able to use multilingual
characters in the DNS.

Edmon