Ok, there is a terribly wrong framework emerging around consensus protocols. People think that PoW and PoS are consensus protocols, and that they are the only two consensus protocols out there.
This is false. Let me explain.
This is false. Let me explain.
Proof-of-Work and Proof-of-Stake are **sybil control mechanisms**. PoS doesn't achieve consensus by itself. It has to be coupled with a protocol, such as PBFT, or Ben-Or, or Tendermint/Cosmos, or Avalanche, to make decisions.
PoW, by itself, isn't a consensus mechanism. In BTC/BCH, it works with the heaviest/"longest" chain selection rule to achieve consensus. PoW by itself can be used to thwart spam, as originally proposed by Dwork&Naor. PoW doesn't get you agreement, it gets you rate limiting.
There are many consensus protocols (mechanisms), and there are many Sybil control mechanisms. These two kinds of mechanisms are distinct and separate.
A system or coin will end up combining one with the other. Of course, not all combos make sense. But many combos are possible.
A system or coin will end up combining one with the other. Of course, not all combos make sense. But many combos are possible.
One could use Avalanche either with PoW or PoS, if one wanted.
One could use a PoS coin, which had in it a PoW mechanism to make sure that a rogue but staked actor does not flood the network layer.
One could use a PoS coin, which had in it a PoW mechanism to make sure that a rogue but staked actor does not flood the network layer.
The big design decisions in coins aren't between PoW vs. PoS. They are between the consensus protocols themselves, as they determine performance, scale, energy expenditure, and security.
This concludes today's #microlecture. I hope it clarifies the discourse around coins and avoids confounding mechanisms that are independent.
