Unicode versions (Re: Criteria for exceptional characters)

[Harald Alvestrand]

Mark Davis wrote:
>
>     If that is accepted as the problem definition, it is reasonable to
>     assume
>     that a solution does NOT lock us again into a fixed set of
>     scripts, but
>     rather allows scripts to be added in an incremental fashion.
>     And if that is accepted, the option of disallowing a script "until
>     we have
>     sorted out the identified issues" becomes far less of an issue
>     than it
>     seems to be regarded by Mark/Ken/Michel today
>     (apologies if I have mischaracterized a position here).
>
>
>
> I think the "until we have sorted out the identified issues" is too 
> vague to be a useful criterion. There is general consensus that there 
> isn't any problem with leaving out the historic scripts (although, as 
> I said, frankly it doesn't buy much in terms of reducing spoofing). 
> But which other scripts did you have in mind omitting, and on what 
> grounds?
Many, including Arabic, Sanskrit and Dhivehi. Possibly Hebrew too. But 
"leaving out" may be an underspecified term here - see next comment.
>
> There is also a big difference between the flexibility in the protocol 
> vs that available to registries and user-agents. Suppose that in the 
> protocol we allow Hebrew, but recommend against (for some reason) 
> final forms of letters. Registries and user-agents can then start by 
> following those recommendations, but if it turns out to be necessary 
> to allow them in (either fully or in limited circumstances), it is 
> relatively easy for them to do so. Baking a prohibition against 
> final-forms of letters into the protocol is a much different matter -- 
> it takes quite a while for everyone to update to a new version. (And 
> during that time, I have no doubt that we will hear charges of 
> discrimination...)
>
You may want to review draft-klensin-idnabis-issues again, and see at 
which steps of the protocol we are thinking of switching to an 
inclusion-based model that starts off with a sharply limited set.

I think we are best served if we install the maximum amount of 
restrictions initially in section 2.1.3 "Registration of IDNs - 
Permitted Character Identification" (and therefore also in section 
2.1.5), while we should install a minmum set of restrictions in section 
2.2.3 "Domain Name Resolution - Pre-Nameprep Validation and Character 
List Testing".
>
>     I think.
>
>
>
> Since you didn't comment on any of the other issues I wrote, does that 
> mean that you agree with them, or that you just hadn't gotten to them. 
> ;-)
It meant that I regarded them as irrelevant until we get this one 
settled, I think.