> This setup assumes there’s already consensus on a certain set of validators, but the challenge is arriving at this consensus in the first place. The validato

> This setup assumes there’s already consensus on a certain set of validators, but the challenge is arriving at this consensus in the first place. The validator set changes as people bond or unbond coins in exchange for stake. Running a fair and secure initial distribution is a somewhat orthogonal problem; perhaps you can run an open auction. Any Proof-of-Work or Proof-of-Stake systems has issues with low security in the beginning. Consider that until late ~2012 the total hashrate of the Bitcoin network was less than the hashrate of a single Antminer S9. > This is the general problem of proof-of-stake: it assumes the presence of consensus in order to arrive at consensus. This is because consensus is reached by utilizing the scarce resource that is the chain’s token, but without consensus in the first place this token isn’t scarce at all. Consensus and scarcity are tightly related. The consensus process and protocol spec are what make the token scarce, since by definition the majority agree on the token's inflation rate, supply, block reward, etc.... What happens when validators try to fork and change these parameters? They are directly incentivized to do so, yet similarly, what happens when Bitcoin miners try to change the block reward? Of course, they don't hold all the power; with sufficient cause and collaboration, users can signal a user-activated soft fork, or simply choose to follow the original unmodified fork. > Proof-of-work uses something external to its chain as the scarce resource that determines consensus (energy), while proof-of-stake uses something internal to its chain (the chain’s token). This means that when a PoW chain forks, the two chains have to share the external resource, while the resource is copied for PoS chain forks. Yes, this is called the "nothing-at-stake" problem, and it is solved by punishing validators who equivocate. This enforces scarcity of voting power across forks. The point is they can't exercise their voting power on both chains. As soon as they vote on one fork, they are committed. The validators on the other fork are incentivized to delete their stake if they vote on the other fork simultaneously.