Ethereum, led by its founder Vitalik Buterin, has been promoting proof of stake (PoS) over proof of work (PoW) for quite some time. Finally Buterin claims today on twitter: “I don’t believe in proof of work!” Following which he explains：“PoW is in [his] opinion just a phase, social consensus upgrades have their issues but are less bad than on-chain gov or stagnation.”
PoW system is not only used by Ethereum, bitcoin but also many other blockchain based cryptocurrencies. It is the basic computer calculation as known as mining that is required for creating blocks on a distributed ledger as blockchain.
Reasons Buterin favors PoS are one, energy efficiency and two, safer network with the invention of Casper protocol. Casper protocol, according to Buterin’s sharing during 10 Questions with Fred with Mars Finance, requires “the blockchain to ensure that absolutely 100% of the data is valid and available.” This would guarantee any publishing blockchain is actually available. Although skepticism remains due to the PoS system lacks penalties upon attack, where PoW attack requires serious input of programming and energy.
There are voices against PoS saying it is rich get richer for the mechanism behind the protocol. Proof of stake, to put in simple terms, is a miner with more coins has more mining power, thus get more reward as a result. However, Buterin speaks otherwise: “Proof of Work is the rich get richer squared, so if we can get to the rich get richer to the power of one, that’s already a substantial improvement.”
During his interview at 10 Questions with Fred, Buterin explains: “under Casper’s design principle, small miners will not be able to verify a block. I would say not true anymore. First of all, 32 ETH is about 100,000 CNY; I don't think it's practical to be a PoW miner with less than that in any case, since PoW mining requires economies of scale. And even with less than that amount, you can always join a pool.”
Whether Ethereum will choose a PoS hard fork from the current PoW protocol is yet to be determined, although Buterin’s attitude toward PoS is firm.