> I think Anubis is a good first start, but the fact that it uses a fixed size stamp, a small one, does not have a reputation database, and from what I can tell, does not have a robust detector of good versus bad players. These shortcomings will make it challenging to provide adequate protection without interfering with good players.

That's what it's intended to be right now. I've been thinking out how to do a reputation database; I'm half considering using a DHT like BitTorrent's for a cross-Anubis coordination (haven't filed an issue about this because I'm still noodling it out into a spec). I'm also working on more advanced risk calculation, but this kind of exploded out of nowhere for me.