Re: [idn] Alpha Online

["D. J. Bernstein" <djb@cr.yp.to>]

McDonald, Ira writes:
> It's likely that the attempt to retroactively introduce case sensitive
> domain names will simply break almost all deployed Internet software.

You are misreading the proposal.

Software will treat uppercase ASCII and lowercase ASCII as equivalent,
for interoperability with existing configurations. However, software
will not adopt the new insensitivity rules for non-ASCII characters.
Uppercase Beta, for example, won't be automatically converted into
lowercase beta.

Registries will prohibit uppercase non-ASCII characters. Users will
stick to lowercase characters. Consequently we'll have the flexibility
to add case-insensitivity later _if_ that turns out to be a good idea.

Case insensitivity is quite a bit of added work for implementors, and it
dramatically expands the number of opportunities for visual confusion,
as well as the severity of the confusion. The only counterargument is
the unjustified speculation that users are too stupid to handle a world
of case-sensitive names---even though URLs are already case-sensitive,
specifically in path names.

Do you think that the unjustified speculation outweighs the big
problems? Are you so sure about this that you support making an
irreversible decision right now?

The careful approach is to start with lowercase IDNs. Registries will
allow a carefully selected set of characters. It will be possible to
expand the set later, when we have more experience, but for the moment
we'll stick to something safe. Similar comments apply to Chinese.

---Dan