Re: [idn] case preservation

["Soobok Lee" <lsb@postel.co.kr>]

----- Original Message ----- 
From: "D. J. Bernstein" <djb@cr.yp.to>
To: <idn@ops.ietf.org>
Sent: Tuesday, October 09, 2001 3:51 PM
Subject: Re: [idn] case preservation


> Patrik writes:
> > characters which look "similar" like 'o' and 0, or '1' and 'l'
> 
> I am not talking about the momentary confusion between ao1.com and
> aol.com. I am not talking about characters that merely look ``similar.'' 
> I am talking about characters whose standard glyphs are IDENTICAL.
> 
> A properly typeset uppercase Alpha is IDENTICAL to a properly typeset
> uppercase A, just as a properly typeset tab is IDENTICAL to a properly
> typeset sequence of spaces. It is simply NOT POSSIBLE to tell the
> difference between AOL.com and AOL.com.
> 
> This does not mean that Alpha and A are the same character, or that tab
> and space are the same character. It does mean, however, that you've
> done a half-assed job with the current version of nameprep.
> 
> If you're not going to do a thorough job of nameprep, then you shouldn't
> be trying to deceive users into believing that IDNs can be safely typed
> from textual printouts. 

Recent Nameprep revision already contains one statement for caution
wrt similarly-looking characters it don't solve.

>It would be better to omit nameprep entirely;

nameprep is not mature but _useful_ for input convenience even with its inability to solve look-alike problems. 


> then users will stick to mechanisms that work, such as clicking on URLs.
> (Bad characters should still be avoided in registrations, of course.)
> 
> ---Dan
>