Decentralization was a key component of the original cryptocurrency vision. To do so, a method of confirming transactions without the involvement of financial institutions was required. The first solution to this problem was known as proof of work.

What is it?

Proof of work (PoW) is a method of adding new blocks of transactions to the blockchain of a cryptocurrency. In this case, the work consists of creating a hash (a long string of characters) that matches the target hash for the current block. The cryptocurrency miner, who accomplishes this, gains the right to add that block to the blockchain and receive rewards.

Because it is the consensus mechanism used by the first cryptocurrency, Bitcoin, the cryptocurrency began with proof of work (CRYPTO: BTC). It is well-known for its security, but it is also known for inefficiency and a significant environmental impact.

Do you know about its goal?

The goal of proof-of-work is to lengthen the chain. Because it has undergone the most computational work, the longest chain is the most credible as the legitimate one. It is nearly impossible to produce new blocks in Ethereum's PoW algorithm that erase transactions, create fraudulent ones, or maintain a second chain. This is because a malicious miner must always solve the block nonce faster than everyone else.

To continuously generate fraudulent yet valid blocks, you'd need more than 51% of the network mining power to outperform everyone else. This quantity of "work" would necessitate a significant amount of processing power. And the energy expended may even outweigh the profits made in an attack.

How about some advantages? 

•    High level of security.

Proof-of-work is a time-tested consensus mechanism that has kept Bitcoin and Ethereum secure and decentralized for years.

•    Provides a decentralized method of verifying transactions.

Because miners operate in a decentralized manner, two valid blocks can be mined concurrently. This results in the formation of a temporary fork.

•    Allows miners to earn crypto rewards.

Miners who successfully create a block get rewarded with two freshly minted ETH and all the transaction fees within the block.

And some disadvantages! 

•    Inefficient with slow transaction speeds and expensive fees. 

The amount of energy required to keep the network safe is a major criticism of proof-of-work. To maintain security and decentralization, Ethereum uses 73.2 TWh of energy per year, which is equivalent to the energy consumption of a medium-sized country like Austria.

•    High energy usage.

Proof-of-work uses up so much energy that it's bad for the environment.

•    Mining often requires expensive equipment.

If you want to mine, you need such specialized equipment that it's a big investment to start.