Hello friends,How are you ??

I hope you are all fine by grace of Almighty.

Today I am @Kawser199 Discusse about 51% Attack.

So let's Start...........

51% Attack What?

51% Attack is one of the various attacks on blockchain networks. However, for those who are new to cryptocurrency, it is not known what 51% attack is.

Today we will try to understand in 51% non-technical language what is 51% Attack and how it can happen.

How are blocks made?

We Johnny have 3 data in a block, of which 1st is data, 2nd is hash and third is hash of previous block The opinion of the minors is taken on more than 50% to create a valid block.

Now skip all this. Let's go to non-technical discussions.

Suppose 10 workers work in a ball making factory. The job of 10 people is to make the ball and then check the balls to see if they are right. And everyone has their own machine to make this ball, according to their ability. That means they were not given the machine from the factory. Although this is not supposed to happen in a real factory.

However, this is our discussion but we will not give any machine to the workers.

Since 10 people will make the ball using the machine according to their ability. So it can be said that not everyone will have a machine according to the same ability.

Now suppose that the 5th person out of these ten made a ball and the ball that made it first informed all the other workers that he made a ball. Now since one in 10 made the ball first; So the opinion will be taken from the remaining 9 people whether the ball has been made properly or not?

Now, out of these 9, 6 have announced that his ball has been made correctly. Then that ball will be eligible to be accepted. In other words, more than 50% means 51% of the employees will be considered eligible only if they declare. And this ball; The one who made it first will get some money in return.

One thing here is that everyone tried to make the ball, everyone had an electricity consumption according to their machine. But the one who made the ball will only get the money to make the ball. The rest who tried but got no money.

This way again everyone will stick to making the next ball. To be in it again the ball that will make the ball first will be verified. This will continue. One thing here is that the stronger the machine, the faster it will be able to make balls.

Technically this method is called POW (Proof of Work).

Now consider the staff here as minor. Think of ball making machines as mining machines. And take the balls as blocks. I hope you can easily understand the method of making blocks.

Now let's talk about hash power.

You may be wondering what is 51% Attack? Brother came to know the world palalamare! What started teaching geography?

Actually I'm not teaching geography. There were no good results in geography. So I'm not teaching that geography, rest assured.

What is hash power?

We know that mining requires a lot of equipment. At the same time electricity is required. Suppose I want to do bitcoin mining. I need CPU, GPU or ASIC for this. All of these have different abilities. For example, GPU is more powerful than CPU. ASIC is more powerful than GPU.

For now, I started mining with some equipment and electricity. Now everyone must know that I am not just mining alone. Millions of people like me are mining.

I was the only person who started mining with a little bit of equipment. Now a company bigger than me has started mining at a higher cost than me. So, of course, my equipment is very insignificant compared to the big companies. In other words, the machines of the mining companies bigger than my mining machine are many times more powerful.

Just think of those ball making machines.

The power of this mining machine is called hashing power.

Now the point is that the more hassling power one has, the higher the priority of block mining. Now I am sitting and consuming electricity for mining but I am not getting any opportunity for mining. So why would I just spend electricity?

Suppose I found 10 more people like me who had little equipment. So we all decided together that we will do mining together with 10 people. For this we built a pool. And at the same time for the public like us to join there. So what's going on, we're creating a strong hash power by adding 10 or 15 hash power. As a result, our priority for building blocks is also increasing.

We must have heard the names Poolin, F2pool etc. If you haven't heard, check out the picture below.

Here you can see several mining pools. And it also shows how much hass power the car has. For example, Poolin has 17.7%, BTC.com has 14.2%.

Now suppose there are some new transactions, now it takes all the minors to create a block with these transactions. Now the more hassle you get, the more chances you have to make the next block.

To give an example with the picture above, the chance of Poolin is 17.7%, the chance of F2Pool is 17%, the chance of BTC.com is 14.2%.

Again you can buy hash power without increasing the equipment. One site that sells hash power is https://www.nicehash.com/

Not to mention a word. And that is the threat to the decentralization of such mining pools. Because everyone is working together to create a pool and create centralization. Which increases the chances of a 51% attack.

We have finished teaching geography. Now let's read geography and apply what we know a little bit.

What is 51% Attack and how can it happen?

We already know that if more than 50% of the users or minors declare a block as correct, it will be considered valid and that block will be added to the blockchain.

Now if someone wants to attack 51% of the bitcoin network, they need to have 51% of the total hash power.

And these pools are such a threat. For example, if Poolin, F2Pool, BTC.com and AntPoo want to attack 51% together, they can. Because if these 4 pools are combined, the hash power above 51% will be combined.

This will allow them to create problems in the Bitcoin network.

Now the question is if someone to attack 51%, what changes can be made in the network?

If somehow a hacker gains 51% hash power, that hacker can change the blockchain of the bitcoin network.

Since hackers have got 51% hash power, they will be able to validate or invalidate any block.

Can reverse the transaction by double spending.

May increase block confirmation time.

But yes you can't change anything in the previous block.

And he will have control over the next block as long as he can hold 51% hash power.

As ETC had three times 51% Attack. The last time this problem occurred was on August 29, 2020. As a result, the hacker double-spent and stole 5.6 million.

@TheRandomRewarder Thank you for your Upvoting.......