Homework on Mining and Proof of Work - Questions

[Jamie_Frame]

Why is it important to make sure that miners spend money (on electricity) while mining?
This ensures that work is being done to secure the network and that the miners would lose money if they tried to defraud the network.

Why would it be very difficult for someone to go back change a previously added block?
This would require all subsequent blocks and associated hash solutions to be recalculated. This would be prohibitively expensive and time consuming.

How does the network regulate mining difficulty?
A block is created every 10 minutes, so if miners become more efficient and mine the block too quickly then the difficulty of the mining calculation is increased so as to keep the newly mined blocks 10 minutes apart.

[XyzjynX]

[Captaincrypto]

Why is it important to make sure that miners spend money (on electricity) while mining?
They have to have money so that they can earn enough from mining to cover their electricity expenses plus make a profit. It incentivises them to mine.

Why would it be very difficult for someone to go back change a previously added block?
Because it would change the hash of not only that previous block but also the hash of all of the blocks added after it.

How does the network regulate mining difficulty?
The higher the hash rate (number of miners) the lower the nonce/puzzle target, and therefore the higher the mining difficulty. And vice versa.

[Antonastrm]

1. That means that the network is forced to play by the rules. It’s expensive to try to do something else since the electricity is already spent.

2. Because he who mines have to crack all the previous blocks before anyone else puts another block on the chain. This occurs since the blocks are tied together with previous hash.

3. The difficulty increases for the miners. The nonce is harder to guess. The target is decreased.

[AF90]

1. It is important as it gives miners an incentive to construct a hash honestly and stick to the rules, otherwise they come out at a loss.
2. It would be difficult because all blocks contain the previous hash, meaning that every future hash would also need to be corrected before a miner can solve a new hash, meaning they will catch up.
3. The higher the hash-rate, the higher the hash difficulty, the higher security. The higher the hash difficulty, the lower the hash target.

[WesBit]

It is important to make sure that miners spend money while mining so that it holds up the integrity of the network. Changing any previous block would destroy the links between all the blocks. The network regulates mining difficulty by adjusting it according to the miners on the network.

[Hectorgato]

1. By spending the money on electricity to mine, they have skin in the game so they are incentivized with BC reward.

2. Because the blocks contain of all the previous blocks in the chain. It would corrupt and break the links in the chain going forward and you would have to re-mine that chain all over again becoming economically unfeasible including playing catchup to the other miners.

3. The more miners trying to solve the puzzle/puzzles makes the puzzle/puzzles harder to solve by making the target lower on the 0 to infinity line. The nonce, Tx list and previous hash being hashed has to below set target hash/fingerprint.

[Timo_Kussmaul]

1. Why is it important to make sure that miners spend money (on electricity) while mining?
   This is to secure the network, since the miners have to spend much money in advance, they will probably not cheat on the network (fake transactions or sth.) to get the incentives from mining.

2. Why would it be very difficult for someone to go back change a previously added block?
   Since the blocks are connected by hashes (new block contains also the hash of the previous block), manipulations of former blocks would change the hashes of everything after the changed one. Re-mining of all of these is practically impossible for one party.

3. How does the network regulate mining difficulty?
   The higher the hashrate is, the higher the difficulty will get to remain the block creation constant at around 10 minutes.

[Filippo]

1. Because if they spend their money, they have an incentive to respect the rules, otherwise they would lose it.
2. Because all the blocks after what has been changed would be invalidated and this person would have to mine again all the blocks created up to that moment plus those that will be created in the future.
3. There is a target that decreases inversely proportional to the difficulty (how many miners are there). The lower this target, the lower the chance to guess the Hash within the target range.

[Jaap_NL]

• Why is it important to make sure that miners spend money (on electricity) while mining?
  This will increase the safety of the blockchain. The miner that succesfully adds the next block receives a large incentive. (block reward + transaction fees) but any failure will result in zero money. But you have to pay for your equipment and electricity.

• Why would it be very difficult for someone to go back change a previously added block?
  You have to mine the block you want to change but also the next ones and the ones that are being produced. It’s impossible to do this quickly enough.

• How does the network regulate mining difficulty?
  The more hash power the higher the difficulty. The target of the target is being lowered to increase the difficulty.

[Kalx1]

It is important because they are taking a loss now to gain a reward. This encourages them to play by the rules because it waste of money if they don’t.

2. It would be difficult because a hash contains the hash of a previously added block. If data is changed then all blocks hashes will change which means you will need to re-mine every block.

3. If there is a lot of miners, the difficulty target will be low so there is a smaller gap to guess the puzzle. miners have find the hash that is lower than the target

[SGB]

1. Why is it important to make sure that miners spend money (on electricity) while mining?
   Forcing miners to spend money upfront, to invest in blockchain, before earning money from successful block additions is another incentive to keep all players honest and the network secure.

2. Why would it be very difficult for someone to go back change a previously added block?
   Since all blocks are hashed, and included in block hashes are a reference to the previous block’s hash, changing anything in the blockchain would have a ripple effect of invalidating the current, and all following blocks.

3. How does the network regulate mining difficulty?
   The hash rate of the network determines the mining difficulty. The higher the number of miners and hashing power, the higher the difficulty level is set - and conversely, should the hash rate decline, the difficulty will be reduced also.

[Katoch]

1. Why is it important to make sure that miners spend money (on electricity) while mining?
   Cryptographic puzzles are solved by miners consuming electricity, which is a valuable method to show PoW(Proof Of Work).
2. Why would it be very difficult for someone to go back change a previously added block?
   If you want to change the previously added block, then it will require all other previous blocks to be changed as well. This is because each block has a a hash correlating to the previous block has, so changing one block will change its hash, thus breaking the link to previous blocks.
3. How does the network regulate mining difficulty?
   As the number of miner increase, there will be an increase in the hashing power needed to mine the block, which correlates to an increases in the difficulty of the cryptographic puzzle and electricity needed.

[simplist]

1. Incentivized by the money they spend on electricity
2. They would have to re-mine all following blocks and catch up to length of longest chain
3. Adjusting target as a way to make nonce harder to guess

[tulitea]

1. Doing so allows them to show Proof of Work. Although it is really the computer that is working, LOL! The miners show that the computer is actually working aka “hashing.”

2. It becomes difficult because any change in the blockchain would obliterate previous blocks in the chain, which would then need to be re-mined if you will. In other words, it is a waste of time and money.

3. If too many people are mining, that is if the hash rate is high, the network regulates the difficulty by lowering the target number that needs to be beaten by the hash output.

[FeloniousBaker]

1. Since it costs money to mine, miners are incentivised to follow the rules because it pays more

2. Any single change changes the hash

3. The stronger the hash rate the lower the nonce, making it harder to guess

[Crypto_Mofo]

1. Why is it important to make sure that miners spend money (on electricity) while mining?
   Answer: They’re required to pay upfront with electricity to gain the reward.

2. Why would it be very difficult for someone to go back change a previously added block?
   Answer: They would need to re-mine that block and all the subsequent blocks at much faster rate then the current version of the chain.

3. How does the network regulate mining difficulty?
   Answer: Via the hashrate

[Andre_Niederkofler]

1. So that they are incentivised not to cheat.

2. Because then that person would have to remine every Block after that and convince everyone else that this is the Blockchain (which is practically impossible), while everyone else just carries one mining new blocks. So that guy would have to have at least 51% of all of the hashing power (which would be of better use just mining new blocks).

3. If more people are mining the target is lower, which means that the difficulty is higher. If the number of people mining decreases the target will be higher, so the difficulty is lower.

[Ondrej.S]

1. In order to make sure they mine and add blocks honestly. If they were not to play by the rules, they would be losing money.
2. Any changes in the block would change its hash and thus the whole sequence of the following blocks. The computational power to solve the puzzles created would be virtually endless.
3. If the number of miners increases, the difficulty of guessing the correct nonce by the lowered target.

[JustinP]

1. It is important to make mining a new block expensive so that the network rules will be followed and the blockchain integrity is preserved. Producing a corrupt block would be a waste of lots of money.

2. Changing anything in a previous block changes the hash which then changes the hash of every future block.

3. When there are more miners, the difficulty is increased by lowering the target meaning that guessing the Nonce takes more computer power.