From the limited information, it's rather impossible to tell for sure. But considering you need 9 different admins in different countries, I'm presuming they ar

From the limited information, it's rather impossible to tell for sure. But considering you need 9 different admins in different countries, I'm presuming they are basically using a kind of DHT with a bit of extra brains controlling where the various bits and pieces are hashed. So, that said, I would presume it's at least somewhat fault tolerant. However, it's Chaum we're talking about, so we likely won't know until the patent is filed.