SASLprep200x

[Erik van der Poel]

On 1/9/07, Patrik Fältström <patrik at frobbit.se> wrote:
>
>   1 We have a set of theoretical codepoints. 0x0000 and up.
>   2 Unicode Character Set include for each version a subset of those
> codepoints.
>   3 Stringprep allow a subset of the Unicode Character Set.
>   4 A profile of stringprep (like Nameprep) is a subset of stringprep
> allowed "stuff".
>   5 Registry policy talk about a subset of Nameprep.
>   6 Registrar policy talk about a subset of the registry policy.
>   7 User interface issues is a subset of the registrar policy (might
> at least create a subset).
>
> I really wanted it to be "7 layers" ;-)

Interesting idea. I really enjoyed your 7 layers. :-)

There is at least one hitch. How can a user agent
implementor/implementation know which registrar a registrant used for
a particular label in the registry?

Another issue is the one I pointed out earlier: for true end-to-end
interoperability (from human registrant to human user), the user agent
set must not be a subset of the registry set. (They must be the same
set.)

Also, it is my understanding that a profile of stringprep does not
necessarily have to be a subset. It can also create a superset of
stringprep.

Erik