Re: [idn] upstream and downstream

["Adam M. Costello" <idn.amc+0@nicemice.net.RemoveThisWord>]

James Seng <james@seng.cc> wrote:

> We do treat "." specially in IDNA because that's part of domain name.

Yes, but IDNA's special treatment of "." was motivated by user
convenience, not by defense against homographs of ".", so it's not
surprising that IDNA's special treatment of "." is insufficient to
prevent homograph attacks against ".".

For example, someone could register a name that looks like
"foo.bar.com", where the first dot was really U+0702.  This attack
would be equally effective no matter what larger structure (URI, email
address, etc) the domain name appeared in.

AMC