- To make sure they have something to lose by not following the rule.
- Because to do so he will break every chain that will follow (since a data change into a block modifies the hash, which is used as the previous hash for the next block). Therefore he’ll need to rewrite every block that follow and before the validation of every miner in the actual block. It would be very costly and impractical.
- The lower the Target, the higher the Difficulty
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Because they will follow all the rules in mining and make money, if not they lose money.
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if something is changed in previous block than you would have to change all the next blocks which is a waste of power, time and money.
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When there is more miners target is low when difficulty is high. Hash of the new block has to be below the target.
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This is because as they spend money, they follow the rules in order to get the incentives (transaction fees) and (block)rewards due to them.
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It would be difficult because once you change any data in the previous block, it affects changes to the current block and any other block following it or going before it.
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The network regulates mining difficulty by increasing the target when there are few miners in the network and reducing the target when there are many miners in the network (thereby increasing difficulty)
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It is important to make them spend money on electricity, because there needs to be reproductions if you don’t follow the rules. The cost of electricity incentives miners to follow the rules in order to get block rewards and fees. It also limits the amount of people who would want to start mining so that the hash rate isn’t always high.
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If you change a previously added block, then you need to re-mine that block. All of the links after that altered block will be broken, so you will have to remind those as well. After that you must catchup to and surpass the current Blockchain length. The longest blockchain will be the one chosen by the network. This is practically impossible to do.
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The more miners there are the lower the nonce is. This means the target number miners must guess is more difficult to determine. The fewer miners the higher the nonce.
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Homework on Mining and Proof of Work - Questions
- Why is it important to make sure that miners spend money (on electricity) while mining?
- They spent money on a lot of electricity, so it will cost them money if they don’t follow the rules.
- Why would it be very difficult for someone to go back change a previously added block?
- If a previous block is changed, the next blocks will also change. So you would have to re-mine the changed block and the other blocks that are mined after. And every 10min there is a new block being mined, so you also have to catch up with the other miners.
- How does the network regulate mining difficulty?
- The more people are mining, the lower the target will be. Target is low when difficulty is high. this makes it harder.
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Ans.:
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this incentive mechanism secures the blockchain network. when miners fail to follow the rules to generate block, they will get no reward; at the same time, it is impossible to dominate the consensus in practice, which requires the hashrate more than 51% of the entire network
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the altered block itself is very hard to solve to generate the new hash, and all the forward blocks of the altered block need to be re-mined, while there are many new blocks attached to the previous chain as well
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the target number will be reduced if the hashrate of the entire network turns high, such that it is more difficult for miners to guess the nonce number to generate the acceptable hash
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- By spending money the miners have incentives to follow the rules since they are invested in the mining process.
- If anything is changed in the previous block it would break the link to the next and the following blocks.
- As there are more miners the difficulty to guess the nonce is increased by lowering the target.
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1- Incentive, to make sure that the miner will follow the network rules.
2- Because while he is trying to change it too money new blocks will join the blockchain and he has to mine for too many blocks and it’s impossible to do that.
3- 1. The lower the target, the higher the difficulty
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1.So they are invested and abide to the rules to secure the network for incentives, they play fair they earn money, they dont follow the rules then you probably lose money, like the electricity you paid for.
2.This would require so much computing power and would require you to change an immutable block, if you were to change anything in that block,the hash output would change and for all the following blocks also, you would to have to remine all the blocks, virtually impossible.
3.They lower or raise the target to keep it around 10 minutes a new block is found.
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Why is it important to make sure that miners spend money (on electricity) while mining?
It gives them an incentive to follow the rules so they can be rewarded properly by doing so by creating blocks. -
Why would it be very difficult for someone to go back change a previously added block?
You would need 51% of the hash rate to be able to double spend which is incredibly difficult and nearly impossible to do. -
How does the network regulate mining difficulty?
Miners have to guess a random number called a nonce which must be lower then a target number which is adjusted according to difficulty. The target number becomes lower when mining difficulty becomes higher. This makes it more difficult to guess a lower target since there are less possible numbers.
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1.) It’s important to make sure that miners spend money on electricity while mining so that they follow the rules of the protocol (i.e. no double spending) and don’t have their blocks rejected. It’s also important because it proves the amount of electrical energy they’ve used to solve the cryptographic puzzle and then they can receive their block rewards/transaction fee rewards.
2.) It would be very difficult for someone to go back and change a previously added block because any transaction change to that block will break the link/fingerprints of the next blocks too (chain reaction).
3.) The network regulates mining difficulty by lowering the target number with the more miners there are on the network. The lower this target number is, the lower the probability of finding the nonce part of the hash (more difficult for miners to find).
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1. Why is it important to make sure that miners spend money (on electricity) while mining?
It is important that miners spend on energy, so the are incentivised to play by the rules. Since trying to append a block with an invalid transaction = no block-reward. And therefore capital wasted on energy.
2. Why would it be very difficult for someone to go back change a previously added block?
Because not only would the attempting party have to control at least 51% of the hashrate. They would also have to re-mine back in to the past. To the block they wish to alter, and then catch up to the present block.
This gets so exponentially harder for each block that in practice such a attempt could never succeed.
3. How does the network regulate mining difficulty?
By adjusting the “Mining Difficulty”. All the miners are hashing numbers they wish to be the nonce, if the resulting hash of the previous’s block hash + TX list + Nonce is smaller than a certain target. The nonce is accepted, and that miner gets to append a block to the blockchain.
If more Hashing power joins the network, the target is lowered. Making it harder to guess the nonce.
If hashing power is leaving the network the target is raised, making it easier to find the nonce.
The difficulty will always adjust to maintain an average block time of 10 minutes.
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- Why is it important to make sure that miners spend money (on electricity) while mining? If they spend money than they need to earn money. Incentives based principle - to earn money minors need to follow the rules and to secure PoW… If minors follow the rules they earn money and if they do not follow the rule they do not earn money.
- Why would it be very difficult for someone to go back change a previously added block?
Because once the change is done all following blocks are changes as well and the combinations becoming endless, while electricity costs during mining are very high. . - How does the network regulate mining difficulty? Hash rate determines the difficulty of the puzzle, the more people mining the higher the hash rate. Every puzzle has the difficulty level. The lower the target the higher the difficulty.
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Why is it important to make sure that miners spend money (on electricity) while mining?
It’s part of the incentive process. Miners have to have an outgoing cost to make sure they follow the rules, or suffer a financial hit. If they don’t follow the rules and try to game the system, they lose out by wasting their time and money.
Why would it be very difficult for someone to go back change a previously added block?
Changing a previous block in any way will also change the nonce and hashes, meaning the changed block and all following blocks will need to be mined again.
This would be massively expensive, time consuming, and also put any miner that did this in a constant state of catchup with the chain.
How does the network regulate mining difficulty?
The more miners that are active on the network, the harder the nonce becomes to guess. This increases mining difficulty the more miners there are, and decreases it the less miners there are.
This leads to a fairly steady equilibrium, ensuring there are always enough miners to process transactions at a decent speed.
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- So they are incentivised to follow the rules because they will lose money if they don’t
- The longest chain with the most proof of work is always accepted as the blockchain by the network so they would have to remine the previously added block and every subsequent block to catch up and do all of this faster than new blocks are added to the blockchain by other miners which is practically impossible
- It changes the target that the hash needs to be below by making it lower and therefore more difficult to find a nonce that will result in that hash
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- They should prove their work they are doing by spending electricity/resources therefore making money afterwards.
- To go back and change the previous block, you need to change also existing and all other “future” blocks that are already mined. But it requires impossible power right now.
- The more people are mining in the network, the harder it is to get a block hashed - to guess a nonce.
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- It is important for miners to spend money while mining because it ensures them to be less likely to cheat as they will lose the money.
- It would be extremely difficult as the miner would have to change every other existing block to fit with the one they changed.
- The network regulates mining difficulty by creating a low target through the increase of miners.
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Why is it important to make sure that miners spend money (on electricity) while mining? To incentivize them to act honorably, the more they spend, the more inclined they are to secure and uphold the network.
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Why would it be very difficult for someone to go back change a previously added block? The would have to change the hash of all subsequent and previous blocks at a speed it which is entirely impossible.
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How does the network regulate mining difficulty? Difficulty is a measure of how many miners are active on the network, It is regulated by making the solution to the puzzle more difficult to solve the more people are mining.
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1.To incentivize the miners to recoup their losses through block reward and mining.
2. Any change to the previous block will then change any subsequent blocks.
3. the network self regulates by setting a target.
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- Why is it important to make sure that miners spend money (on electricity) while mining?
PoW - prove of work - miners spend lot of money on electricity so they have to play by the rules and be honest (do not double spend etc.), because they will loose more money. - Why would it be very difficult for someone to go back change a previously added block?
If someone will change previously added block, he will have to re-mine again and re-mine all other blocks, plus there are other new blocks, that are constantly added so he will have to catch up and re-mine new blocks etc… it is simply like a chain or domino effect. - How does the network regulate mining difficulty?
If there is high difficulty, lower target will be. If there is low target, it is very difficult for miners to guess nonce.
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