>For instance, could you have a defined chain of authoritative servers, where the authority passes in a way where it cannot be abused? Ripple and Stellar use a

>For instance, could you have a defined chain of authoritative servers, where the authority passes in a way where it cannot be abused? Ripple and Stellar use a federated network of validating transactions to reach cascading consensus (validators A, B and C said this txn is good, and I "trust" them, so I will say this txn is good too) that while not completely abuse-proof, is significantly cheaper than PoW and possibly PoS (not certain about PoS costs; since the network of validators can be modeled as a graph, the central-most validators in the graph could censor transactions, but if validators "trust" a wide-enough variety of validators, it won't happen).