----- Original Message ----- From: "D. J. Bernstein" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> 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 >
