About this blog…

I am employed by Netnod as head of engineering, research and development and am among other things chair of the Security and Stability Advisory Committee at ICANN. You can find CV and photos of me at this page.

As I wear so many hats, I find it being necessary to somewhere express my personal view on things. This is the location where that happens. Postings on this blog, or at Facebook, Twitter etc, falls under this policy.

The views expressed on this post are mine and do not necessarily reflect the views of Netnod or any other of the organisations I have connections to.

Trademark Clearing House and Internationalized Domain Names

The other day I discussed TMCH and IDN’s with a few people from ICANN Staff. They where very very patient and that gave me the ability to think really hard trying to understand what the issues I feel really are. At the end I think we have the embryo of a problem statement. A statement that you can see illustrated on this picture:

Registration in TMCH and DNS lookups with variant calculation

Maybe this is a bit tricky to understand, so let me explain in a different way.

When dealing with variants, there exists a mapping function that maps any potential variant to a base string. Lets call this function f(x). The definition is such that if the function f(x) is applied to any of the strings sx in the set S={s0, s1, …, sn} the result will be the base string sb. I.e. f(sx) = sb for every x such that 0≤x≤n.

This implies that if one tries to for example register any of the strings in the set S, the other strings can be blocked, allocatable etc.

So far so good. Now lets have a look at TMCH. They also have a registry where strings are to be registered. They do have mapping functions, but not for calculations of variants. Instead it is whoever interacts with the TMCH that is to register every string they want to register, which in the case of variants can be many.

Let’s say a trademark holder registers café in the TMCH. This imply that it would be impossible for someone to later try to register cafe without triggering some TMCH event, because cafe (which happens to be the base string for both cafe and café) is viewed as a variant of café. We have S={cafe, café} and both f(cafe)=cafe and f(café)=cafe.

The problem arises if the original registry does not send both cafe and café to the TMCH at the time of registration café. When a registry later tries to register cafe, no event will be triggered because cafe was never put into the TMCH.

What SSAC talked about in SAC-0601 was the fact such calculations by the registry might be extremely difficult to do, and that it would be better if also the TMCH calculated f(t) for every string t that is sent to it. That way, if one sent café to the TMCH, both café and cafe would be registered.

Or to put it differently, today the registry must have an inverse function f´(sb)=S so that for any domain sx that someone want to register, the registry must first calculate sb (where f(sx)=sb0≤x≤n), then must calculate S using the inverse function, and then for every sx in S register it in the TMCH.

This hopefully explains what SSAC is concerned about, that for some f(x) there is no f'(x) such that the following is true:

  • S = {s0, s1, …, sn}, the variant set
  • sb is the base character in S
  • f(sx) = sb for any 0≤x≤n
  • f'(sb) = S

  1. SAC-060: SSAC Comment on Examining the User Experience Implications of Active Variant TLDs Report (23 July 2013)

Comments are closed.