Ethereum: proof-of-work (POW)

Proof-of-work (POW): is the mechanism that allows the decentralized Ethereum network to come to consensus and ensure Ethereum difficult to attack. 

Example about Consensus:

• Account balances.
• Order of transactions.

💧 The work in proof-of-work

👉 Step 1:  miner will repeatedly put a dataset which get from downloading and running the full chain through a mathematical 

(--> what in fact behavior to get dataset??)

👉 Step 2: dataset gets used to generate a mixHash below a target nonce, as dictated by the block difficulty.

(--> How to generate mixhash and nonce from dataset)

👉 Step 3: other miners and clients to verify 

(--> how to verify that nonce and mixhash are correct?)

Note: explain detail how POW works: https://youtu.be/9V1bipPkCTU

💧 Proof-of-work and security

Because a malicious miner can not solve the block nonce faster than everyone else, so it's nearly impossible to:

• Create new blocks that erase transactions, 
• Create fake ones, 
• Or maintain a second chain.

💧 Proof-of-work economics

• Miner can receive tip and block reward but no longer transaction fee.
• Miner may also get 1.75 ETH for an uncle block (which created same time another miner mined the successful block, happen due to network latency.)

💧 Finality

• Time you should wait to ensure a transaction irreversible (usually six blocks or just over 1 minute)
• This timing doesn't include the wait times for having a transaction picked up by a miner.

💧 Pros and cons

Pros	Cons
Proof-of-work is neutral. You don't need ETH to get started and block rewards allow you to go from 0 ETH to a positive balance. With proof-of-stake you need ETH to start with.	Proof-of-work uses up so much energy that it's bad for the environment.
Proof-of-work is a tried and tested consensus mechanism that has kept Bitcoin and Ethereum secure and decentralized for many years.	If you want to mine, you need such specialized equipment that it's a big investment to start.
Compared to proof-of-stake it's relatively easy to implement.	Due to increasing computation needed, mining pools could potentially dominate the mining game, leading to centralization and security risks.