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Miners need to spend money while mining as an added part of the incentive, they have to have investment in the mining process and money to loose in order to motivate them to follow the rules so that they are not wasting their electricity money if it does not work out for them. The system needs to punish incorrect mining and reward mining correctly in order to be secure.
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They would have to change that block and then re-mine every block after that to find the right nonces to re-complete the whole chain and they would have to do that all while maintaining 51% hashpower in the world.
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the network regulates mining difficulty by lowering the target for the new hash as more miners compete to complete the puzzle, this decreases the chances of miners guessing a viable nonce.
Why is it important to make sure that miners spend money (on electricity) while mining?
Because the miners have to pay upfront for the electricity to mine there is an incentive only to play by the rules and be honest. As any attempt to change a transaction or try to double spend will be rejected by the network miners need to recoup thier costs by focusing on winning a block.
Why would it be very difficult for someone to go back change a previously added block?
As all blocks are linked any changes made to previos block would change the hash of all blocks before and all blocks after which would again just be rejected by the network.
How does the network regulate mining difficulty
Mining difficulty is determined by either current hashrate or checked after every 2016 block (roughly every 2 weeks) if there are more miners on the network and hashrate is high. The difficulty increases. If there are less miners on the network the difficulty drops.
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Gives incentive to get reward so follow the rules to get the block.
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A change in a previous block would change everything in front of it making a person re-mine everything again which would be pretty much impossible.
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Lowers the target with more miners in turn making it more difficult to guess.
- Why is it important to make sure that miners spend money (on electricity) while mining?
To make them work hard to solve the cryptographic puzzle and win an award while being honest and playing by the rules.
- Why would it be very difficult for someone to go back change a previously added block?
It would break the link to all other blocks because of a change. Then have to re-mine previous blocks and catch up to other new blocks that were created. Since the network wants the longest link since it shows the most pow, it would take a really long time to catch up.
- How does the network regulate mining difficulty?
Because the more miners, the harder the puzzle gets and the lower the target number. With a lower target, it is harder to get a hash that is in between 0 and the target versus the target being higher making it easier to get a hash between the target and 0. When the target is lower you have a better chance of getting a hash above the target and getting rejected.
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To create proof of work. By spending money on electricity to solve a cryptographic puzzle.
Miners intern get rewarded for carrying out the proof of work -
Because the hash of the next block is linked to the hash or the previous block (the block that is changed). This means that the proof of work needs to be done for all blocks. However as new blocks get added the proof of work needs to do done for those blocks too.
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By adjusting the target value. The lower the target value the greater the difficulty
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Why is it important to make sure that miners spend money (on electricity) while mining?
If they try to cheat and create an invalid block, it wonāt be accepted by the other nodes and eventually it will be rejected. But they will have wasted money on electricity so they will lose money if they try to cheat. -
Why would it be very difficult for someone to go back and change a previously added block?
All the blocks are connected by the hash output. If you change one block, it will change the hash of every block higher up the chain and thus break the chain. -
How does the network regulate mining difficulty?
The more hashing power thatās running then the greater the mining difficulty.
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Having them investing money will assure their compromise to follow the rules.
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Because if he is changing the previous block with intention to put it in the real blockchain he will need to āmineā or find the blocks that follow the tampered one and at the same time the blockchain still growing so in practical terms it is impossible.
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By increasing or decreasing the limit (number) whose value must be higher than the hash of the new block
Homework on Mining and Proof of Work - Questions
- Why is it important to make sure that miners spend money (on electricity) while mining?
- Because like this it is more profitable for them to play by the rules than to break the rules.
- Why would it be very difficult for someone to go back change a previously added block?
- Because all of the blocks are specially linked with all the data inside this blocks, once one block changes the data inside, link recognizes this change and all of the links behind it fail in some way, which means that in order to change a previously added block you would need to change all of the next blocks added.
- How does the network regulate mining difficulty?
- If we have alot of miners mining, the target number becomes lower and like this it is more difficult for miners to get the hash number below the target number.
1- They get rewarded if they can attach their block to the blockchain
2- It practically Impossible as they would have to guess all the hashes of the forward blocks by themselves, at the same time others miners would be producing more blocks one miner could never catch up
3- More miners mining more difficult to guess the nonce
Because the miners are spending money on electricity and are incentivised to play by the rules when building there block to be accepted into the blockchain and claim their fees and inflation.
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Becouse when you go back and try to change some information in the blockchain the transactions that happen after the block you changed will get invalidated. This means that itās not feasible to spend the money necessary to change a previous block rather than using the computational power to mine within the rules.
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The target gets lower which in turn makes the puzzle harder to solve because off the increased difficulty for the miners.
- Because they want the reward and the fee to take some profit. If they play by the rules, they can make money, if they donāt, they lose money. They have to demonstrate that they done work.
- Becuse you remine the previous blocks and then link the following blocks. But the rate of creation new blocks is faster than you remine the previous blocks. Itās impossible.
- If there are more miners or the hash-power of their computers is more powerful, the target is lower. The target is low when difficulty is high.
1* By spending their money on electricity theyre investing to get incentives which will only be got by following the rules.
2It would be difficult because they would have to change every block after it and whilst the chain is getting longer they would never be able to catch up.
3Difficulty relates to the networks hash rate the moree miners the more difficult it is so a block is mined every 10 mins on average.
- Its important because in this way they are incentivised to play by the rules so they can make money to pay off the elec. bill.
- It would be difficult because that would change the hash of that block, and the hashes of every next block, and thats impossible
- When many people are mining the difficulty increases because the target is lower and so its harder to guess a nonce, when there is few people mining the target is higher, making easier to find a nonce that will result in a hash lower than the target is currently.
Why is it important to make sure that miners spend money (on electricity) while mining?
So that they are motivated to recoup their upfront costs by playing by the rules ensuring the security and integrity of the blockchain. If they donāt other nodes will ignore their block and they will lose the money they invested into electricity
Why would it be very difficult for someone to go back change a previously added block?
because the block is a hash that uses the previous blockās hash along with the hash of each transaction in the specified block, changing the previous block would therefore change the hash of the new block and every block thereafter. One would need to re-mine the entire block chain plus any new blocks that had been created, it would just not be practical to do so
How does the network regulate mining difficulty?
The target hash will be chosen lower so there is a greater chance to guess over the target effectively making it more difficult
1. Why is it important to make sure that miners spend money (on electricity) while mining?
Because of the upfront cost in the form of electricity you have an incentive to play by the rules so you have a chance to receive a block reward and transaction fees.
2. Why would it be very difficult for someone to go back change a previously added block?
It will cost a lot of energy.
3. How does the network regulate mining difficulty?
If there are more miners the difficulty increases and vice versa.
Correct, but you didnāt answer the question. Its difficult because they would have to mine all of the blocks again from that point on. They would have to spend electricity without any block rewards in the hope they have enough hash power to catch up with the current chain.
Got you! Thanks Mauro.
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Miner need to invest money upfront in form of electricity cost and are therefore incentivized to behave according the rules.
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Because all subsequent blocks would need to be mined again, since the hash of the previous block is an input for the subsequent block. This would take a lot of time and resources. The blockchain would keep growing in the meantime.
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The difficulty increases with the hashrate. The target value will be lowered and hence the miners will need more guesses to find the right nonce.
- its important that the miners spend money because thats the incentive to work correctly to get rewarded .
- because when he chances a block the hash changes and so the hash the previous block and following block chances and they become unvalid . to fix that he must then mine all the blocks again and this is practically not possible!
- the difficulties are regulated by the target. if the hash rate is high the target is low and its more difficult to guess the nonce for the miners and opposite.
- So they are incentivized not to cheat and spend that money en electricity for nothing.
- They would have to remine all the blocks after that and catch up, might be possible with 51%attack but would not make economical sense.
- The more miners, the higher the difficulty, the lower the target.