ned+ietf-822(_at_)mrochek(_dot_)com wrote:
I also note that Dan Kohn's alternative News Article Format draft uses
punycode, which already includes a stringprep profile.
Actually, Punycode does not include a Stringprep profile, or depend on
one in any way. Punycode maps *any* Unicode string to an ASCII string,
reversibly (without loss).
The ASCII-compatible encoding (ACE) defined by IDNA is a combination of
Punycode, Nameprep (a profile of Stringprep), a prefix (xn--), and a few
other checks. Unlike Punycode, ACE deliberately rejects some Unicode
strings and loses some information (to make comparisons behave better).
AMC