Re: [idn] homograph attacks

[Martin Duerst <duerst@w3.org>]

At 06:40 05/02/17, Martin v. L‹Řis wrote:
>JFC (Jefsey) Morfin wrote:
>> 1. When you register a IANA tag, you are to register it by language, 
script and ccTLD. This is clear.
>
>I don't see how this is relevant for this discussion. If the .com
>registrar decides to use a subset of 639 only, I consider this a valid
>choice. No need to register any language tag with IANA; all tags
>you ever want to use are already there.

Not exactly correct. For cases like Serbian, Azerbaijani, Tajik,
which can be written with different scripts, you need more than
ISO 639. Serbian and Azerbaijani have script variant tags registered
at IANA (see http://www.iana.org/assignments/language-tags); Tajik
doesn't (yet). There is a draft
(see http://www.ietf.org/internet-drafts/draft-phillips-langtags-10.txt)
that makes script codes generative, i.e. they don't have to be
registered anymore.

>> 2. W3C discovered that a language tag by ISO 639 was not enough to 
describe an XML document.

[incorrect; extending ISO 639 with country codes was done by RFC 1766,
with the main input comming from email]

Regards,    Martin.