原文：《Ethereum moved to proof of stake. Why can’t Bitcoin?》by Amy Castorarchive

Compiled by: Block unicorn

Last year, Ethereum went green. The world’s second-most popular crypto blockchain transitions to proof-of-stake (POS), an energy-efficient framework for adding new transaction blocks, NFTs, and other information to the blockchain. When Ethereum completed its upgrade in September last year, known as the "merger," it directly reduced energy consumption by 99%. At the same time, Bitcoin, which continues to grow, consumes as much energy as the entire country of the Philippines.

Bitcoin mining is a computationally intensive process through which new Bitcoins are created and calculated, and has become a global concern. After China cracked down on the process in mid-2021, miners began looking for other cheap, but not necessarily environmentally friendly, sources of energy around the world. In places like Kazakhstan, miners have stressed a grid that relies heavily on carbon-intensive coal-fired power stations, causing localized blackouts and sparking civil unrest. In upstate New York, where miners have taken over shuttered factories and vacant warehouses, locals complain about rising energy bills and the high-pitched hum of data center fans and worry about the environmental damage caused by mining, which now owns more than 38% of the U.S. Bitcoin mining business.

One Bitcoin transaction consumes as much energy as an American household for nearly a month. But does it have to be this way? The Bitcoin community has historically fiercely resisted change, but pressure from regulators and environmentalists fed up with Bitcoin's massive carbon footprint may force them to rethink that stance.

Various other countries, including Kazakhstan, Iran, and Singapore, have also placed restrictions on cryptocurrency mining. In April 2023, the European Parliament will pass a landmark cryptocurrency bill called the "Market in Crypto Assets" (MiCA), which requires cryptocurrency companies to disclose environmental information. The bill is expected to be released sometime in 2024. effective at this time.

This may be just the beginning for the EU: the European Central Bank has previously said it cannot imagine governments banning gasoline-powered cars in favor of electric vehicles but taking no action against Bitcoin's continued CO2 emissions. Alex de Vries, the data scientist behind Digiconomist, a website that tracks cryptocurrency energy use, told MIT Technology Review: "Some members of the European Parliament are already wondering why Bitcoin has not followed Ethereum."

Efforts to combat Bitcoin's wasteful energy are also growing in the United States. In November, New York became the first state to enact a temporary ban on the issuance of new cryptocurrency mining licenses at fossil fuel plants. The new law also requires the state to study the impact of cryptocurrency mining in an effort to reduce greenhouse gas emissions.

So, what can be done to change the status quo?

Proof of Work (POW) and Proof of Stake (POS)

Cryptocurrencies do not have a central guardian like a bank that oversees its public ledger – every transaction data on the blockchain is shared on-chain. Instead, they rely on a consensus mechanism to agree on updates.

In the proof-of-work method that Bitcoin relies on, a global network of computers called "miners" consume electricity in order to be rewarded with Bitcoins. Whoever solves the cryptographic puzzle first gets to add the next block. And collect new Bitcoins in the process. The probability of obtaining Bitcoin is directly proportional to the miner's computing power (the more computing power, the greater the chance of receiving rewards, that is, the more mining machines, the greater the chance of obtaining Bitcoin rewards). Therefore, there are a large number of Bitcoin network nodes around the world, and they are vying to get Bitcoin rewards.

The proof-of-stake approach now used by Ethereum eliminates the massive energy consumption of proof-of-work. The pledge verification system does not use miners, but a large number of "validators". To become a validator, you must deposit or “stake” a certain number of tokens – 32 Ethereum, in the case of Ethereum. The stake verification system gives validators the opportunity to check new blocks of transactions and add them to the blockchain so they can earn rewards on their staked tokens. The more tokens you stake, the better your chances of being selected to add the next block of transactions to the chain.

Both systems are trying to achieve the same goal, with one system (Bitcoin) using a country’s electricity, while the other (Ethereum) only requires participants to stake tokens. Both are decentralized in theory, but not in practice. The vast majority of Bitcoin mining today is done by five major mining pools; in proof-of-stake (POS), the person who owns the majority of the tokens controls the blockchain.

Ethereum faces different pressures

Bitcoin is just a cryptocurrency. It has a team of developers and a team of miners. But Ethereum is a smart contract platform for decentralized applications, with many projects, cryptocurrencies, NFTs, and NFT platforms running on top of it.

Vitalik Buterin, the creator of Ethereum, has always wanted Ethereum to use proof-of-stake. But when Buterin realized that developing a proof-of-stake algorithm to implement a meaningful decentralized system was “so important” — so much so, he once wrote, that some said it was impossible — that he decided to make Ethereum Using Proof of Work while he gradually solved the problem, Proof of Stake ultimately took 7 years.

Many major projects on Ethereum, including cryptocurrency exchange Coinbase, stablecoin companies Circle and Tether, and NFT projects Yuga Labs and OpenSea, have publicly supported Ethereum's move to proof-of-stake. It has attractive advantages over proof of work. In addition to the advantage of being more environmentally friendly, network transaction fees will also be reduced. When Ethereum finally migrates, these projects lead the way. Until the Ethereum Foundation, the non-profit organization that helps oversee the platform, hits the red button, the battle is already won.

There is always a risk with Ethereum miners creating competing chains and maintaining proof-of-work versions. All smart contracts, tokens, and NFTs currently existing on the chain will automatically "fork" or copy to the original chain. But while there have been some efforts to create competing versions of Ethereum, none of these efforts have gained traction, with the proof-of-stake version winning out.

There is a political problem

In principle, a small group of people could take control and convert Bitcoin to proof-of-stake. Since it is an open source project, Bitcoin's development relies on decisions made by the community, which theoretically includes anyone who wants to participate. But updates to the Bitcoin code are actually controlled by a small core team of developers called "maintainers," whose salaries are privately funded by influential groups such as Bitcoin startup Blockstream; Coinbase is The largest cryptocurrency exchange in the United States; and the "MIT Digital Currency Initiative", a research project hosted by the MIT Media Lab.

These maintainers can switch like Ethereum, but they are a conservative bunch. Bitcoin is the original proof-of-work cryptocurrency. Although Bitcoin's code is constantly being tweaked and updated, it remains virtually unchanged from its original vision in 2009.

Emin Gün Sirer, founder of Ethereum rival Avalanche, told MIT Technology Review that among Bitcoin purists there are concerns about fundamental changes. “Part of this fear comes from not wanting to take any risks, and part of it comes from fear that this change may ultimately erode confidence in other algorithmic limits,” he said. These limits also include other basic characteristics, such as the maximum number of Bitcoins that can be mined. The quantity was initially fixed at 21 million pieces.

Jorge Stolfi, a computer science professor at Brazil’s State University of Campinas who has followed Bitcoin closely since its early days, explained to MIT Technology Review: “There are no technical barriers to converting Bitcoin to proof-of-stake.”

But Stolfi said the core maintainers can't make the switch alone. They need the support of miners, who currently collect 900 new Bitcoins per day (worth over $20 million), plus transaction fees for the new blocks they mine. Stolfi said: “Faced with the possibility of abandoning this business model, miners may try to keep the proof-of-work fork of Bitcoin and insist that they are the real Bitcoin and the proof-of-stake fork is just another piece of garbage. currency."

Stolfi said: “Ultimately, the battle between the new proof-of-stake branches and the ‘traditional’ proof-of-work branches will be determined by how the price of Bitcoin is divided between the two currencies, which all depends on marketing. "

Bitcoin Cash (BCH): A Lesson from History

The last time anyone tried to make a major change to Bitcoin was Bitcoin Cash, an effort to increase the block size so that Bitcoin could scale and become a more useful real currency.

Since 2015, Bitcoin’s one-terabyte blocks have been filled with transactions. The network is becoming congested, and as a result, transactions are taking longer to process and transaction fees are increasing. A group of developers and miners have come up with a simple solution: increase the size of transaction blocks to 2 or 8 megabytes so that Bitcoin can process more transactions per second.

But this is easier said than done. As David Gerrard, author of “Blockchain’s 51% Attack,” writes, “Even this simple suggestion has led to community divisions, code forks, retaliatory DDOS attacks, death threats, Chinese miners, and The schism among U.S. core programmers, and other evidence, suggests that this and other problems in the Bitcoin protocol will never be resolved through the consensus process."

In August 2017, Bitcoin Cash was launched as a fork of the Bitcoin software. But most miners and developers stuck with the traditional Bitcoin blockchain, leaving Bitcoin Cash as another derivative of Bitcoin. Even today, Bitcoin’s OGs refer to Bitcoin Cash as a “rebellion” and a “corporate takeover” rather than a sincere effort to increase the usability of Bitcoin.

Proof-of-stake will represent a bigger change, and on the surface, there seems to be little reason to expect Bitcoin to adopt it. Nicholas Weaver, a researcher at the University of California, Berkeley, and an outspoken critic of cryptocurrencies, believes this will never happen. Weaver said that as long as Bitcoin miners can profit from proof of work, they will choose proof of work: "The only way to reduce the criminal energy consumption of Bitcoin is to destroy the value of Bitcoin itself. If Bitcoin becomes worthless value, then Bitcoin mining will stop."

Bitcoin may not want to change, but if it doesn't, governments and communities may become increasingly intolerant of its energy waste, and it may be forced into irrelevance.

“Those who will never change Bitcoin are fighting a losing battle, and the sooner they realize this, the sooner we all benefit,” Digiconomist’s DeVries said.