This has been a central problem for decentralized or any 'P2P' protocol since day one. When the more popular music sharing sites like Napster and Morpheus were

This has been a central problem for decentralized or any 'P2P' protocol since day one. When the more popular music sharing sites like Napster and Morpheus were taken down due to their reliance upon 'hub servers', more distributed networks like Gnutella attempted to get rid of their need for points of failure. But even they needed a concept of a bootstrap index to obtain a list of hubs from which to get on the network. And sure enough, it turned into a game of whack-a-mole between the industry and these servers. Torrenting has the same problem. If I remember right, the only protocols that work in the long run are those that can broadcast and discover each other, but they're limited to local LANs. Once you need to go outside of your own network, you need some way to discover where nodes are located, and without an initial point of reference(s) (which becomes the point of failure), you're screwed. Same problem with trusting users - either you use a centralized authority or pre-trusted root certs, or you have to know in advance the other users (e.g. physically exchanging PGP certs).