The original article [1] referenced is interesting, but I'm not sure if the proposed algorithm is useful in a completely unauthenticated and decentralized netwo

The original article [1] referenced is interesting, but I'm not sure if the proposed algorithm is useful in a completely unauthenticated and decentralized network, since it makes assumptions about identity of nodes and the latency between them. Are these chosen "observer" Nodes doing any PoW? Otherwise I assume this is a nice vector for a sybil attack. PS: Could the link be changed to the original paper [1]? The linked article doesn't add much and shows ads. [1] https://vitalik.ca/general/2018/08/07/99_fault_tolerant.html https://vitalik.ca/general/2018/08/07/99_fault_tolerant.html