Browser IDN display policy: opinions sought

Gervase Markham gerv at
Wed Dec 14 11:59:02 CET 2011

On 13/12/11 18:16, John Levine wrote:
> Having been reading this discussion with great interest, I don't
> understand what problem is being solved.  Is it:
> A) Only display names that are not deceptive?
> B) Don't display names that might be deceptive?
> C) Don't display names that fail to meet some policy that
> doesn't really have anything to do with deception?
> D) Only display names that meet some policy?
> E) Something else?
> It clearly can't be A, since there's plenty of room for deception in
> plain ASCII, and people can put random names at the Nth level, e.g.,
> FDIC.GOV.FOO.BAR.SOMETHING.TLD.  Beyond that, I'm baffled.

Hence the highlighting of the "Public Suffix + 1" in recent versions of
Firefox and Chrome, and the blacklisting (even before IDNA2008) of
homographs of "." and "/".

The aim is some reasonable approximation of A, given that deceptiveness
is subjective.

(The logic "deceptiveness is subjective -> one should not attempt to do
anything about deceptiveness" is not considered reasonable.)


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