The idea of having a distributed certificate mechanism over a peer to peer net seems like it might be a good starting point. Essentially, you'd self-sign and serve out your certificate on your ports; possibly connecting to some sort of super-node. You get connections from other members of the net, and they'd send you some certificates; you'd cache the certs and their IP addresses. Then after a timeout, you'd broadcast your certificates to all the interested IPs.

Part of the intrinsic concept is that there's no authoritative identity service. Without an authority, you can't crack the authority.

Of course, this is just a sketch of an idea; it has the usual issues with peer to peer nets such as "evil majority wins". Plus, it has the potential to eat a good deal of bandwidth.

Regardless, I think it'd be a good idea to explore, probably in an academic setting first.