Homework on Mining and Proof of Work - Questions

Blockchain and Bitcoin 101
#586

1/ Make them financially invested in keep the network secure
2/ Changing a previous block modifies the hash all subsequent block which means they would need to re-mine those as well
3/ The difficulty is adjusted with the hash target. The lower the value the harder it is to find the correct hash thus increasing difficulty

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#587
  1. Making miners sacrifice time and energy in pursuit of mining creates an entry barrier while incentivizing efficiency.
  2. Changing a past block midstream is near impossible because the edit would require solving the hash for all subsequent blocks.
  3. By balancing speed, number of transactions and hash rates.
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#588
  1. Why is it important to make sure that miners spend money (on electricity) while mining?

Because they can lose money if do not play by the rules.

  1. Why would it be very difficult for someone to go back change a previously added block?

The chain will be break and they will have to recreate all subsequent block and spread it to entire network.

  1. How does the network regulate mining difficulty?

By adjusting the hash target. (based on the number of miners trying to solve to puzzle using the nonce).

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#589
  • Why is it important to make sure that miners spend money (on electricity) while mining? >> do give the result in form of the hash a real world value (insentive)
  • Why would it be very difficult for someone to go back change a previously added block? >> to do this he will need the hashing power to change the complete chain to the actual block, because mining happens every time by other miners ant the actual hash always is based on the previous hashes
  • How does the network regulate mining difficulty? >> by adjusting the target, is the hashpower high, the target will be low so that it is more difficult to find the correct hash below the target set
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#590
  1. Miners spend electricity to ensure that they follow the rules to get the reward otherwise, they will be at a loss.
  2. If someone would change the block data all the hashes would change and so that block would be rejected by the system.
  3. Network regulates the difficulty by lowering the TARGET number witch is based on the number of miners on the network.
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#591

  1. to control the number of miners

  2. he would have to change all the other blocks that come after the “changed one”

  3. by have a so called “target” which is a number that gets reduced if more miners start mining which makes all the miners have to guess more numbers in orders to complete the block

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#592
  1. By spending money before getting any reward, miners are incentivized to play by the rule: in fact their BTC reward depends on the correctness of their job.
    2.Because the Hash of one block depends on the hashes of all the previous blocks, to make this change acceptable by the whole network, one should mine from the modified block all the subsequent hashes. This is practically impossible because it would require an enormous amount of time (in which other blocks are probably added to the blockchain) and energy.
  2. By increasing or reducing the Hash’s target level.
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#593
  1. to make them felt a great loss if they went mining by not following the rules
  2. to change the previous block mean they have to also change the other block that has chained, even when they had reach there, all other new block will already build within the longest chain
  3. by setting the target depends on the rate of transaction and miners available who compete to solve the puzzle
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#594

Homework on Mining and Proof of Work - Questions

Why is it important to make sure that miners spend money (on electricity) while mining?
This ensures that miners are incentivized to do the right thing when they make a new block.
If miners temper with the data and their block gets put into the network, the other computer will reject that block.
The miner will have lost a lot of money mining that block, and now he has no compensation for his effort.

Why would it be very difficult for someone to go back change a previously added block?
It would be completely impractical, because the network would have moved on and the change will not exist in the longest blockchain.
In order for that change to be implumented you need to catch up to the blocks, wich is impossible.
The time it would take you to do such a thing would be so high and it would rise exponentially when you would try it.

How does the network regulate mining difficulty?
By lowering the target of that particulair block.
By doing so that block would become way more difficult to mine.
The amount of random guesses would be higher and you would theoreticly need more time to mine that block.
There is also a factor of luck involved, like winning the lottery. If you would have many more tickets the odds would also decrease.

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#595
  1. If miners spend money they become incentivized to get it back. If there were no incentives miners woukd not mine.
  2. If you change a previously added block, all subsequent blocks are also changed. You would then meed to re-mine each of the subsequent blocks and any additional blocks created while you were in the process of re-mining. You would need a faster hashrate than all of the combined nodes on the network to bet your “re-mined” blockchain accepted by the network. This is not currently practical.
  3. A target number is set from 0 to infinity. To increase difficulty, the target is set at a low number. Using random number selection, iy would be more difficult to guess a lower number because there are many more higher numbers.
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#596

  1. Why is it important to make sure that miners spend money (on electricity) while mining?
    The miners have to buy hardware and consume electricity first to be able mine for bitcoin. The miners are incentivised to play by the rules. If they fail to play by the network and protocol rules, they will loose any potential gains by mining and everything spent on mining (including electricity) will come to nothing.

  2. Why would it be very difficult for someone to go back change a previously added block?
    Because once any data from the previous block (Prev Hash, Data, Nonce) has been change, changes the hash number. This would negate any subsequent blocks and use a considerable amount of computing power. Plus it would take a considerable amount of time to re-mine to catch up to the current blocks.

  3. How does the network regulate mining difficulty?
    This is done by adjusting the mining target. The more miners there are on the network, the lower the target Nonce number and the hard it is to guess the correct Nonce. This is vis-verca when there are less miners mining, the Nonce number target is higher and easier to guess.

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#597
  1. Why is it important to make sure that miners spend money (on electricity) while mining?
    Since the BTC algorithm is based on POW miners are required to spend money (electricity) to have some skin in the game and be incentivized to follow the rules and be rewarded eventually and make up for their investment.
  2. Why would it be very difficult for someone to go back change a previously added block?
    When they do that the block is invalidated and they will have to remine the whole chain that they altered. In the meantime all others miners will be moving on with other blocks and the Blockchain by default chooses the longest chain. Which makes it almost impossible (unless they control more than half the mining) to alter the chain. Even if they did do that, they would make more money mining normally rather than altering chains and remining.
  3. How does the network regulate mining difficulty?
    The mining difficulty is based on the hash rate. The more miners are hashing the higher the difficulty and the lower the target.
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#598

  1. By having them spend money before earning, and the only way to earn is to play by the rules, they are then incentivised to keep the chain intact and by the rules

  2. Because all blocks which have been added after it would be affected which wouldn’t be accepted by all the other nodes. The only way to do that would be to re-mine all those blocks faster than everybody else together is mining new ones, which is practically impossible.

  3. The more miners the lower the target number. Miners have to hit below the target number and their hits are completely random, which means that the lower the target number - the lower are the chances of hitting below it.

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#599

  1. To incentivise the miners to work for a the solution to get a chance to earn the reward. (IE: skin in the game!)

  2. If a block was changed, then the hash function would change (not only for the current block but also for the previous block) because the blocks contain the hash of the block before included in the new hash.These blocks would no0w be rejected by the system as no longer valid.
    THAT would mean each block would have to be re-mined, individually, making almost impossible to do.

  3. The more miners competing, the harder the puzzle becomes to solve and vice versa so this is a self rgulating d\feature to enable the blocks to be mined at around every 10mins

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#600

  1. Because they need to be incentivized to recoup the money spent by keep wanting new blocks and keep the blockchain going.

  2. Because you would have to remine all the following links (new POW) that are broken plus keep up with the new blocks that are added as well. The hash rate increases exponentially for every block so it wil be next to impossible to solve it

  3. If the difficulty is higher the target gets lower which makes it harder for miners to guess the nonces

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#601

  • Why is it important to make sure that miners spend money (on electricity) while mining?
    To have a skin in the game (basically they risk a lot if they don’t play by the rules)

  • Why would it be very difficult for someone to go back change a previously added block?
    Every input change, changes the hash which in return changes the hash of the next block and so on. To do it, computer would have to hash super fast to change all blocks that came afterwards and then catch up to all the new blocks being created in the meantime and have the longest chain that network will accept.

  • How does the network regulate mining difficulty?
    It changes the target number and makes it lower (harder to guess) when there is high competition

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#602

1 than they will be incentived to deliver a good job, follow the rules in order to get paid.

2 than you have to minen alle the blocks again beginning by the block that is changed

3 If there are a lot of miners in the network, there is a high hashspeed, the target is low,

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#603

1. Why is it important to make sure that miners spend money (on electricity) while mining?
By spending money they have incentive to play by the rules, recoup their money, and gain rewards.

2. Why would it be very difficult for someone to go back change a previously added block?
One a change to the hash in the previous blocks invalidates the forward blocks and requires them to be re-mined.

3. How does the network regulate mining difficulty?
The more miners, the harder the puzzle to solve. Less miners, the easier the puzzle. The target goes lower or higher based on the participation.

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#604

  1. It is important because it incentives them to do honest and correct work. Because if they enter in wrong information and their block is rejected they will have spent money on all of that electricity for no reward.

  2. It is highly infeasible because it would take too much time to remine all of the affected blocks. Also by the time you finished remining said block there will already be multiple other blocks that have been produced and the network always favors the longest chain.

  3. when the hash rate changes the network regulates mining difficulty buy lowering or raising the difficulty target .

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#605

  1. Because we need to make them pay upfront for the incentives, they desire. And if they try to go against the rules then lose money.

  2. Because the hashing of new block depends on previous hashed blocked(and in turn previous Tx) so making modification from past de-links entire block chain and even if they previous blocked is hashed, the computer cannot cope up with the speed to mine other blocks as the other chain must have become longest anyway unless the person has 51% hashing power can perform an attack.

  3. If the mining becomes easy, the target that is required to compare with the hash decreases, and difficulty increases.

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