What is Proof of Work(PoW)?

• Proof of Work, PoW exposes a computer system that can be used to mislead or maliciously use a high amount of effort, such as: spam e-mailing or service attacks, without the need for effort. The PoW concept was first adapted in 2004 by Hal Finney to use the monetary area.

In general approach; POW is the name given to the act of proving the sacrifice demanded by them in order to understand how enthusiastic they are. Let me explain this definition in terms of crypto mining.

"Proof of Work", shortly PoW, is a concept introduced by Cynthia Dwork and Moni Naor before the discovery of bitcoin. In 2008, Nakamoto used this concept in the infrastructure of BitCoin he invented. Thus the concept of PoW becomes more known. Nakamoto needed a rule to protect itself because it was aimed at building a structure without a central authority. For example, it might be easier for a bank rumor to sign the "approve sending money" but it is not so easy in an environment where no authority exists (that is, no one knows anyone). Here PoW allows this.

The goal of Bitcoin mining is to create a block that contains "as many operations as possible". However, the generated block must fit some rules. There is also a need for a considerable computing power to generate a block that is appropriate to the rules. The first system that finds the appropriate block is rewarded with the transaction fee and bitcoin. Here is the work to find the appropriate block in this "proof of work" or "business is proprietary". It was a "value" that would not come out if anyone who wanted to create blocks simply. That is why the business prospect who is required to make trial and error very fast is wanted from those who want to produce blocks.

SHA-256

There are various algorithms for PoW. The algorithm used in Bitcoin is SHA-256. The calculation is difficult, but the easy to prove, "prove" is made by the SHA-256 hash algorithm. I will not touch the details of SHA-256. The SHA-256 structure is a detailed issue in itself. In summary; we can say that we get another string that is scrambled from a sequence of characters. But this output should not be produced with any other input. Also, we should not be able to reach the entrance by acting on the printout.

On the other hand, in Bitcoin, miners attempts to create an SHA-256 value based on the previous block's hash value information. But the difficulty here is that a certain character at the beginning of the value must start with "zero" and the value obtained should be smaller than a certain number. A mathematical formula for achieving this is not possible. Therefore, they try to find appropriate value by random experiment with CPU power.

Mining difficulty

This difficulty is one of the cleverly designed aspects of bitcoin. We said there is try and solve mechanism. but, Can not many people come together and do mining much faster? There is a "difficulty" coefficient that is calculated every two weeks to avoid this and to reduce the difficulty. Thus, each block is targeted to be done in the same time. If there are many miners, this coefficient will increase. If the miner declines, this coefficient also decreases.