The protocol isn't public and Mojang has always refused to say anything about it. The protocol is RE'd by http://mcdevs.org/ http://mcdevs.org/ which runs http:

The protocol isn't public and Mojang has always refused to say anything about it. The protocol is RE'd by http://mcdevs.org/ http://mcdevs.org/ which runs http://wiki.vg http://wiki.vg. There is no technical or otherwise limitation on authorization, they just haven't implemented it yet.