For the login procedure, the server needs a database of uniquenick -> profileid assignment.

The Wii sends its unique nick name, and out of this information, the server returns the profile id (= friend code) to the wii.

This algorithmus must be somewhere in the game, because when you create a new profile, the server sends the profileID and the Wii returns the unique nick name.
So, MKWii knows the algorithmus how to calculate the unique nick name out of the profile ID.

Maybe someone who is good in ASM can find out, how this works and can make an algorithmus for the other way (uniquenick to profile-ID)?

Leseratte

If the player already has a friend code, the connection will fail. The Wii immediately logs off and you get the error code "60000"
If the player doesn't have one, he'll get one.

But when the Wii sends the uniquenick to the server while registering - maybe there is an algorithm to guess this nickname?

@Wiimm: The authtoken contains the "gsbrcd" (the second unique nick name part), the "userid" (the decoded first part), the "ingamesn" (mii name), the "gamecd" (ID4) and the SSL-challenge "challenge".

This data:

gsbrcd\RMCJ17t59gk|userid\5963277895312|ingamesn\.W.i.i.m.m|gamecd\RMCP|challenge\YW8LJMAa
is base64-decoded and prefixed by a "NDS".

So the login server does not need to communicate with naswii, because it gets the SLL-challenge out of the authtoken.
EDIT: This is only true for the server of Nagato. The official ones use another string.

Also, if somebody logs in whose nick name we don't know - the unique nick, the wii serial and some other information are sent to us, so maybe those people can tell us their friend code and we can put it into the database manually after 20th May.