What is Proof of Work [PoW]? Details of how it works


What is proof-of-wook

What is proof-of-work?

Proof of work Po (PoW) is the first consensus algorithm created in the network Blockchain. Used to confirm transactions and produce new blocks in the chain.

Also known as proof of work. The Pow algorithm is an essential part of the cryptocurrency mining process. This is a basic consensus model of Bitcoin and Bitcoin is the pioneer in using PoW. Accordingly, it is designed by approval Satoshi Nakamoto.

PoW requires that people who own computers on the network have to solve a complex problem in order to add a block to the chain, but it's not easy to get an answer to the math problem.

A decentralized ledger gathers all transactions into blocks in a network. Solving this problem is known as minning and "miners", which are participating nodes competing with each other to validate transactions and receive rewards in cryptocurrencies.

What is a complex problem in blockchain?

How to solve the problem

Proof-of-Work works like a complicated problem. It requires a lot of computational effort to solve. There are several factors that can help solve this problem:

  • Hash Function (hash function): The term you hear a lot, right? In the hash the output value is already known and you need to determine the input value.
  • Integer Factorization (Integer Factorization): Split a number into a product of smaller integers. Used to make public-key encryption system more secure.
  • Guided tour puzzle protocol: In the case the server suspects a DoS attack. It requires recalculation of hashes, for a number of nodes in a particular order. In this case, it can be called "How to find the equivalent string of hash value string".

With the growth of the chain, a myriad of obstacles emerged and algorithms required additional hash power to solve these problems. So the answer to this PoW problem is a "hash function" or "hash".

The reason for the complexity

Hard-to-solve problems take a lot of time to form a block. So the difficulty should not be too complicated. This problem causes transactions to be stuck without being performed and lead to work being stopped in a process.

Fast or slow settling time will affect block creation. And it would be pointless to not do it for a certain time. However, you can question the reverse of this: If the problem is too easy. It makes the network easily accessible with DoS and spam attacks.

Answers to these issues should also be easy to verify and check. Because not all nodes in the network can analyze if the calculation is correct. And the last but not least is trust. You will have to trust other nodes and this is the point where blockchain proves its transparency.

How to deploy PoW in Blockchain

PoW in Blockchain is deployed as follows: The "miners" seek to solve a computational challenge to create new blocks and initiate transaction confirmation.

The nodes must first find the solution to the problem through computing power. This means that the nodes with the highest computing power are most likely to find solutions to math problems.

Then the process of verifying the transactions in the block will be added. Organize these transactions in chronological order in the block and notify the newly exploited block for the entire network (this process does not take much energy and time). The energy consumption part is solving a difficult math problem to link the new block to the last block in the blockchain.

You will see that the hash of the following block contains the hash of the previous block. This increases the security as well as building a valid block.

Integrating proof-of-work into blockchain

For new "miners" (miners) after solving the problem set by the server (network server). Nodes on the network will confirm the submission and finally receive the reward:

reward for successful block mining

Why is Proof-of-work successful on blockchain

PoW is quite successful at the moment for the following reasons:

  • Firstly, the solution to the mathematical problem is quite difficult. Therefore, nodes need to spend time in complex calculations. The power supply for computing power is quite tight and this means that very few people can access it, which is also the reason behind the inability of nodes to cheat in transactions.
  • Secondly, PoW is successful because when one node creates a block, the other nodes can easily verify the process leading to the solution to the problem.

PoW for Bitcoin and other cryptocurrencies

As introduced in the concept section, Bitcoin pioneered the use of PoW. And also the most outstanding. The proof-of-work system on the bitcoin network is called hashcash. It allows changing the complexity of a problem, increasing security.

When a miner finally finds the right solution. The node will broadcast it all over the network at once. They then receive the cryptocurrency (reward) provided by PoW.

At the time of writing this article, mining a block takes 10 minutes. The bitcoin network gives miners a winner of 12,5 bitcoin. The number of bitcoins has been won by half every 4 years or so (this concept should be read by everyone What is halving? easy to understand).

Similar platforms use: Etherum (ETH), Litecoin (LTC), Monero (XMR), Dogecoin (DOGE). With Bitcoin, at the end of a process, new Bitcoin will be distributed by the network to miners (miners) with each block rewarded.

Pow in bitcoin is called hashcash

Why use PoW?

In the process, Proof-of-work helps to protect the network against malicious attacks. Ensure that the "miner" cannot add fake blocks to the blockchain. If a miner tries to attack the network. They will need to use a lot of resources as well as computing force. But they won't get the rewards (Bitcoin newly released) that true miners did.

This is not the only consensus mechanism. Some cryptocurrencies use a different mechanism, each with their own advantages and disadvantages, albeit having the same purpose: Providing a way to process and verify transactions, while keeping the network secure.

The purpose of Proof-of-work is to provide operators with an incentive to support and secure the network by making a profit to do so and making the network hacking attempt unfavorable.

Evaluate the pros and cons of Proof-of-work


  • PoW can ensure the safety of the whole network. This is the main purpose of why many cryptocurrencies use PoW. If multiple nodes are competing to determine the resolution of the problem, then the computational power needed will become so high that the chain will become unattainable for one or even a small group of hackers.
  • Spammers are detected.


  • Waste of time : The miner must check many nonce values ​​to find a suitable solution for the problem to solve for block mining, this is a time-consuming process.
  • Resource consumption : It takes high computational energy consumption to find a solution to a difficult and complex problem. It leads to the waste of precious resources (money, energy, space, hardware).
  • It is not an instant transaction. Because it takes a while to mine, transact and add it to the blockchain to make the transaction.

51% attack

Can be called a bulk attack. This is where the user or a group of users control the majority of the exploiting power. The attacker has enough power to control most events in the network.

They can exclusively create new blocks and receive rewards because they can prevent other miners from completing blocks. And there's a chance to reverse all transactions. A good example of this type of attack is the Bitcoin Gold network hacked at $ 18 million in 2018. And there are many more known as "51% attack".


So I introduced the Proof-of-work brothers and details how it works. As with all PoW related issues. Everyone read to know more about how it works in blockchain. As well as being able to question what I am a miner, what will I do in this case.

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