Proof-of-Work (PoW) is the first consensus mechanism to appear, and is used by Bitcoin, Ethereum and others Used by many public chains.

Currently, Ethereum is transitioning to PoS. Please refer to the "What is Ethereum" chapter for more information.

In the PoW mechanism, miners compete with each other and use computers to solve complex calculation problems to become block verifiers. The first miner to solve the puzzle becomes the validator of the new block and is rewarded with a certain number of Coin, known as the "block reward."

What is a miner? What is a validator? What does this process mean for blockchain? Please refer to "What is Mining" and "What is a Node/Validator".

Although PoW's scalability has been questioned, under normal circumstances it is still considered the most reliable and secure of all consensus mechanisms.

However, in general, since it requires a large amount of computing power and energy to generate new blocks, PoW's operational cost is very high (for example, the PoW mechanism in the Bitcoin ecosystem applications in the system). This makes it more difficult for new miners to participate, while creating centralization-related risks and limitations on scalability.

In addition, the most common criticism of PoW is its negative impact on the environment due to its large consumption of electricity. This has led many to seek more sustainable and energy-efficient consensus protocols such as Proof of Stake (PoS).

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• What is a block?
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