So that they are given an incentive to try and win the block to make up for their losses in electric costs.
because then all blocks that come after the block that was changed would be invalidated and then this person would have to re mine all of them and then catch up on all the other miners.
If allot of people are trying to mine they increase difficulty by making the target number for the hash lower. “Target is low when difficulty is high”
It is important that the miners spend money on electricity to give them the incentive to mine a new block and recuperate the money that they spent.
It is difficult to go back and change a previously added block because all of the blocks depend on previous one. If you change a previously mined block all the blocks following it become invalid.
Difficulty is automatically updated every 2016 blocks to adjust the difficulty of the target taking into account the number of miners and the number of blocks mined. The difficulty adjustment makes sure that mining new blocks always takes about 10 minutes. 10 minutes is required to propagate the new block information to all nodes in the network before a new block is added.
1. Why is it important to make sure that miners spend money (on electricity) while mining?
Because they need to prove that they have worked by mining new blocks and if they are doing things correctly, following the rules, they will be rewarded.
2. Why would it be very difficult for someone to go back change a previously added block?
Because it will brake the whole chain of blocks that were mined af ter the change. Besides it will requiere a lot of computational energy to do so.
3. How does the network regulate mining difficulty?
By increasing the difficulty on the puzzle by lowering the target. Besides that mining difficulty gets regulated every halving by reducing the block reward and increasing the fees.
It is important for miners to spend money on electricity while mining because they will be subjected to losing it when they do not follow the rules of the blockchain.
This process incentivises miners to be honest in creating new blocks and profit from the transactional fees.
Every block contains the transaction data, the nonce which is a random number, as well as the hash from the previous block. Hence, a change in data from the previous block will change its hash, causing subsequent blocks to have a different hash as before.
As this may invalidate the blockchain, the subsequent blocks must now be mined again to pick a new nonce and generate a valid hash in order to continue the blockchain.
In mining, the hash generated from the block has to be lower than the target for it to be valid. The network regulates mining difficulty by setting the target level.
Because when they spend money, they are incentivized to contribute for the bitcoin network and get payd in the process
Because every block has a hash that is linked to a previos block. When changing a hash of a given block, all hashes of blocks after that will also have to be remined. Thus very difficult process.
When there is more computing power (hash rate) in the network, the difficulty becomes higher and the opposite with less hash rate.
Why is it important to make sure that miners spend money (on electricity) while mining?
By spending money miners are incentivised to follow the rules.
Why would it be very difficult for someone to go back change a previously added block?
Because changing a block would change the link to the following blocks. The hashes of all the following blocks would also change, so the miner that changes a previous block would have to re-mine all the following blocks. Mind you, all the other miners keep adding a new block every 10 minutes or so. Successfully changing a previous block is technically possible, but financially it isn’t a reasonable thing to do.
How does the network regulate mining difficulty?
If the hash rate is increasing, the difficulty of guessing the nonce is increased by lowering the target. If the hash rate is decreasing, the difficulty is adjusted downwards.
1.It is important miners spend money (on electricity) while mining so that they play by the rules because of the assoiciated cost in not playing by the rules.
it is very difficult for someone to go back and change a previously added block because it would chain all previous blocks hash.
The network regulate mining difficulty by introducing tolerance. The hash should be below the tolerance.
1.it is important to make sure that miners spend money (on electricity) while mining because the cost of mining ensures that thet play by the rules making it costly to cheat.
It is difficult for someone to go back change a previously added block because the hash of all the blocks in the chain will change.
The network regulate mining difficulty by introducing tolerance where the hash calculated should be below the tolerance.
So they “invest” in mining and they will be incentivized to follow the rules
because it would change all the blockchain and it would take a lot of computing power to re-mining all the changed blocks
if there is more hashing power (more miner or computer more powerful) the difficulty will be greater
So that they are incentivised to achieve block rewards and transaction fees by playing by the rules and sticking to the protocol.
They would have to re-mine that block and then all other blocks that came after. A near impossible task which would cost a lot of money in electricity.
The more miners there are, the lower the target number which means a high difficulty. The higher the target number the lower the difficulty.
Why is it important to make sure that miners spend money (on electricity) while mining?
To give incentives for them to make back the money they spent to mine a block.
Why would it be very difficult for someone to go back change a previously added block?
It would change the hash of that block and the other blocks forward causing them to mine all of those blocks and the blocks other miners are adding onto the blockchain. And then spending money to mine all those blocks. Also the rule of the longest chain wins.
How does the network regulate mining difficulty?
Depends on the amount of miners. If its alot of miners, the target will be very low causing a higher difficulty. Less miners higher target causing lower difficulty.
2.it is very difficult to change the previously added block, because first of all, the change in the past will change all the hash since the change till the current block. It would be necessary to change and find the different node for each blocks. That requires much electricity and time.
3.Net work regulates mining diffuclty by lowering the hash target. More miners network has, lower the target would be.
This is the incentive structure that ensures they will try to get their block added to the blockchain in order to get the block reward. They make an up front investment in electricity costs.
Changing anything in any previous block will invalidate every block following that altered block. In order to make the chain valid, ALL blocks after the altered block would have to be remined by the person who tried to change something. This is practically impossible to accomplish, and renders tampering with the blockchain useless, especially in comparison to just following the rules and earning money the proper way.
The network sets a target #. This target # is the number below which the hash of a newly formed block needs to be in order for the block to be added to the chain. The lower the target #, the harder it is for the nonce being guessed by the miner to yield a hash # lower than the target #.
Mining and PoW Homework
To deter people from trying to be fraudulent. If people want to double-spend or in general manipulate and temper with the blockchain, they have extreme upfront costs that they have to spend on electricity.
Since a change in an earlier part of the blockchain makes re-mining of all following parts necessary, a manipulating party is facing a constantly growing work-load against all the rest of the network. Because everyone else is “mining forward” so to speak, documenting the most recent and new transactions. This happens in an environment whrere the longest (most recent, actual, updated) blockchain is considered the correct and important one.
When more people mine, the difficulty is adjusted, to become more difficult. Miners then have to solve a more difficult “cryptographic puzzle” - finding nonces that lead to hashes that are inside a smaller mathematical range.
Why is it important to make sure that miners spend money (on electricity) while mining?
They are incentivised to mine via the blockchain protocol.
By not following the protocol they can lose their investment as a miner as mining against the protocol will not work within the blockchain protocol.
Why would it be very difficult for someone to go back change a previously added block?
Due to the blockchain hashing algorithm , to re-mine a previous block will break the chain in the blockchain for which then you would have to re-mine blocks whilst other miners have already mined those blocks making your version of the blockchain invalid as the longest chain wins. It would also be very costly and most likely impossible as the current blockchain algorithm is extremely secure.
How does the network regulate mining difficulty?
Difficultly rate is adjusted every 2016 blocks.
Blocks need to be mined within a 10-minute interval.
If the hash rate increases (more miners) so does the difficulty. (nonce target lowers)
If the hash rate decreases (less miners) so does the difficulty. (nonce target higher)
The protocol will adjust the difficulty rate to make sure blocks are mined every 10 minutes.
It is important because it shows that the miners are going through some process to be able to mine new blocks (they have an expense). This shows Proof of Work and it ensures the security of the network because miners are incentivized to make money to cover the cost of mining, so they will play by the rules in order to claim the rewards (block reward and transaction fees).
If someone were to change one bit of data in a previous block, it would completely change the hash of that block and that would also change the hash of the previous block because the hash of any block is based on the hash of the previous block, the transaction list of the current block and the nonce. This is how blocks are linked, so by changing anything in this linking process, it would mean that the links are broken and the blockchain is no longer valid. So if somebody changed any bit of data in a previous block, it would disrupt all the links of subsequent blocks and they would have to remine the next blocks in the sequence and by the time they have done that, the network has already appended new blocks to the chain so it is practically impossible to do so.
The mining difficulty is proportional to the hash rate of the network. A high hash rate means that there is lots of mining activity going on and so therefore the difficulty target to mine new blocks will be very low (this is difficult for miners to solve the hash because the probability of them computing a hash lower than the target is much lower when the target is lower).