Homework on Mining and Proof of Work - Questions

Blockchain and Bitcoin 101
#967 
Why is it important to make sure that miners spend money (on electricity) while mining?

Because it incentivises miners to play by the rules, otherwise their block will be rejected and they will lose money.
Why would it be very difficult for someone to go back change a previously added block?
Because they would need to re-mine every block after and in theory would need to become the longest chain.
How does the network regulate mining difficulty?
Difficulty is regulated by the hashrate on the network.

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#968

  1. Investment so as to secure blockchain. Also, to get rewards and to make sure their block gets added.

  2. Bring change to whole blockchain blocks. Remine all further blocks which is practically impossible.

  3. More miners means difficulty increases by lowering the target.

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#969
  1. Because then if they will try to break the rules the miners lost money and did not earn anything by wasting their electricity.
  2. Because re-solving all the previous puzzles and catching up on all the future mined blocks takes a lot of time and requires 51% percent of the hashrate and a lot of electricity.
  3. It will regulate mining difficulty by what the total hashrate is, how many miners there are mining.
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#970

  1. Why is it important to make sure that miners spend money (on electricity) while mining?
    This is to make them want to get the incentive ( basically earn the money back that they spent)

  2. Why would it be very difficult for someone to go back change a previously added block?
    changing a previous block would mean you would need to start mining from scratch to create other blocks. another thing is that if it is noticed that a miner tries to change the previous block, his block will be rejected and he will basically loose money

  3. How does the network regulate mining difficulty?
    the mining difficulty is regulated through the so called target. the more miners on the network, the lower the target will be. and the lower the target, the higher the difficulty

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#971

  1. When miners have to spend electricity, they are incentivised to play by the rules, so they can earn their money back and make some profit.

  2. He would need a lot of mining power and electricity - or time. If successful he would also have to remine all blocks after the block he changed. It gets exponential more difficult to change a block, the further you go back in time.

  3. The more miners there are in the system the higher the “difficulty” gets. Higher difficulty means that the target for the hash of the new block gets lower (more zeros at the beginning of the hash will be required).

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#972

  1. By paying electricity miners are incentivized to follow the rules and stick to there protocol.

  2. A change in a previous transaction would change the output of the hashed block. Since this output is used in the next block it would also change the output of the next block and so on. So to change a transaction you would need to mine the whole chain again. This is impossible to do it on you own, if the network is large enough.

  3. The mining difficulty is adjusted to the number of mining nodes in the network. The more people is mining, the higher the difficulty is.

2 Likes
#973

  1. Why is it important to make sure that miners spend money (on electricity) while mining?
    Spending electricity is stimulating for them to go after the rewards and play by the rules.

  2. Why would it be very difficult for someone to go back change a previously added block?
    Becouse they have to catch up and remin all the blocks ahead.

  3. How does the network regulate mining difficulty?
    By targeting a low nonse, difficulty increases. Difficulty goes up also when the number of miners is high.

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#974
  1. Because it makes less attractive for them trying to cheat.
  2. Because it will change every block since that one, and it will necessary re mine all blocks until the new blockchain is larger than the hones blockchain, and it is practically imposible.
  3. By increasing or decreasing the target for nonces guessing.
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#975

  1. Why is it important to make sure that miners spend money (on electricity) while mining?
    That way they have skin in the game and follow the rules. If they don’t then they waste time and money.

  2. Why would it be very difficult for someone to go back change a previously added block?
    This is difficult because they would have to mine all the blocks after the one that they changed in order to finalize it in the system. For every new block that is added, catching up to the longest blockchain becomes incrementally harder.

  3. How does the network regulate mining difficulty?
    The more miners there are the harder it is to earn a reward. This is so that the blocktime remains around 10 min per block.

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#976

1. Why is it important to make sure that miners spend money (on electricity) while mining?

There has to be some level of difficulty in mining. If mining was free then people could spam the network with nonsense.

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

If you change one thing on a previous block it changes everything that was mined after that block. You would have to mine all the blocks again and it would not be fair to the other participants.

3. How does the network regulate mining difficulty?

Mining difficulty is in relation to the amount of miners on the network actively trying to find a block. When there is less miners mining the nonce is easier to solve.

4 Likes
#977

Homework on Mining and Proof of Work - Questions

  1. To tie the miner into the block reward transaction- if the miner pulls out or tries to cheat the reward is lost, creating a reset.

  2. All data is fused into the hash, all blocks contain part of the previous hash, Therefor any alteration to the block will cause a chain reaction through all consecutive blocks and be rejected.

  3. The more miners there are the lower the hash rate target range will lie, raising the difficulty and visa versa.

1 Like
#978
  1. That’s how they become incentive to follow the rules. Otherwise they will lose money.
  2. Because they will change the whole blockchain and have to re-mine everything again, which is practically impossible.
  3. By lowering the target. The more miners, the higher the difficulty.
1 Like
#979

  1. Why is it important to make sure that miners spend money (on electricity) while mining?
    It is the way Proof of work is provided on the network by the miner and they are given incentives to follow rules and are rewarded.

  2. Why would it be very difficult for someone to go back change a previously added block?
    This create a separation between all the previously mined blocks and would create a need to go back and write to each previous block in the network chain again. It is very difficult as each time another block is mined it still need to catch up and the changes.

  3. How does the network regulate mining difficulty? With regard to mining difficulty it is based on how many miners are on the network. The more miners mining the longer the transaction will take as the new transaction has to be written across the block chain.

#980
  1. Why is it important to make sure that miners spend money (on electricity) while mining?

To make sure they follow the rules and secure the network through proof of work

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

Because they would have to re-mine every other block after the one they have altered as well as solve the latest blocks created at the same time to ensure they have the longest chain.

  1. How does the network regulate mining difficulty?

By raising or lowering the hash target to solve the nonce.

#981
  1. So they’re incentivized.
  2. because they would have to have 51% of the power of the network to catch up with new blocks being created.
  3. by making the target low enough. You don’t have to get the exact target just low enough so its within the range … I think, still a little confused about that.
#982

1 That way they are forced to follow the rules and make the network secure.
2 Because the hash of the new block take the hash of the previous block as an input, so by changing a previously added block it will need to recalculate every block after the change.
3 By the hashpower of the previous block.

#983

  1. This ensures that the miners have incentives to follow the rules. they have to make money to pay for the electrcity they just used.

  2. Because it changes all the blocks after it

  3. As there are more miners the diffculty to guess the nonce is increased by lowering the target

#984
  1. to incentives the miners to get the block reward and transaction fee
  2. when something is changed in the block the hash is changed for that block and every block after it
  3. the mining difficulty is adjusted depending on how many miners combine their hash power
#985
  1. Miners are unable to cheat and be dishonest when spending money on electricity.
  2. Because they would have to change all of the blocks.
  3. By lowering the target, the difficulty of guessing the nonce is increased.
#986
  1. So that if they are dishonest they will lose money this prevents them from doing it
  2. Because if he wanted to change it he would have to re-mine all blocks after up to the present which is practically impossible because people are always adding to the blockchain so he would have to be able to mine very fast which would cost him a fortune for electricity and hardware.
  3. the mining difficulty is regulated by the nonce for example the more miners the higher the difficulty guessing the nonce and the lower the target and if there isn’t many miners the difficulty is low and the target is high