Nameprep and NFKC

Abdulrahman I. ALGhadir aghadir at
Sun Oct 17 06:53:28 CEST 2010

Well I got it now I guess the behavior of the demo was a bit confusing
as you mentioned already so it supposed to rise an error or at least
show a notice of wrong input rather than showing the punycode without a
single notice.


-----Original Message-----
From: John C Klensin [mailto:klensin at] 
Sent: 16/Oct/2010 5:04 PM
To: Abdulrahman I. ALGhadir; idna-update at
Subject: RE: Nameprep and NFKC

--On Saturday, October 16, 2010 12:55 +0300 "Abdulrahman I.
ALGhadir" <aghadir at> wrote:

> So basically is that a flaw on the idna2008 demo or is it
> common behavior of the IDNA2008 or is it normalization problem
> (NFC) ? 

Vint's answer is the correct one -- it is deliberate behavior of
IDNA2008 and incorrect input into the demo.  I tried to say that
in an earlier note.   I do think that it would be useful to
alter the demo so that it makes a test for the input strings
being in NFC form (as required in Sections 4.1 and 5.2 of RFC
5891) and generates a clear error message if the test fails
rather than continuing to process the string.  I think that is
more a matter of taste rather than a "flaw" in the demo, but
your experience suggests to me that the demo would be more
useful if these strings were rejected with an explanation.


This message and its attachment, if any, are confidential and may contain legally
privileged information. If you are not the intended recipient, please contact the
sender immediately and delete this message and its attachment, if any, from your
system. You should not copy this message or disclose its contents to any other
person or use it for any purpose. Statements and opinions expressed in this e-mail
are those of the sender, and do not necessarily reflect those of the Communications
and Information Technology Commission (CITC). CITC accepts no liability for damage
caused by this email.

More information about the Idna-update mailing list