Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#725

  1. Why is it important that the blocks are cryptographically linked together?
    Because if linked, changing one block results in changes of all following blocks. This makes the blockchain very secure and practically almost unhackable.

  2. What does the block structure look like in bitcoin?

  • hash of the previous block
  • all transaction in this block
  • the nonce that needs to be guessed
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#726

  1. The cryptography secures the block, giving it immutability and integrity. making sure there is no double spending.

  2. Block number - Nonce - Transaction Data - Hash of the Previous Block - hash of Current Block

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#727

1.so that changing data in any block cannot be possible. if previous block be change, the hash changes and cryptographic link break making sure no alteration is possible.
2. block size > Nonce > Transaction > previous hash > current hash

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#728

  1. It is important to have blocks cryptographically linked together to demonstrate provenance, consensus and integrity within the network

  2. In bitcoin the block structure consists of a hash derived from the hash of the previous block, the list of transactions to move forward into the next block and a nonce to be guessed so that the new block can be created

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#729

  1. It is important that blocks are cryptographically linked together because it makes it almost impossible to change existing blocks (which is one of the main features of the blockchain). If a person were to change some data in a previous block it would cause all following links to break, therefore basically making their manipulated version of the blockchain useless.

  2. The block structure consists of the hash of the previous block, the data of the current block (transactions) and nonce (a random number).

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#730

So that we can see any changes that were made to the past blocks. The blockchain will also pick the longest chain of blocks when selecting which miner gets the Block reward. This increases the PoW of the miner as well.

It consists of three things

  1. The hash of the previous block ( which is linked to all previous block.
  2. The transactions of the current block.
  3. The guess number nonce.
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#731

Thank you Mauro for clearing that up :slight_smile:

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#732

Answer 1:
It makes it impossible to change a block without affecting subsequent blocks.

Answer 2:
It looks like this

  • Blockheader
    • Version
    • Timestamp
    • Hash of previous block
    • Hash of merkle root
    • Target
    • Nonce
  • Transactions
  • Transactions count
  • Blocksize
  • Magic number
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#733

1.to prevent ceating like not follow the code.and security2. new block contain previus block hash +tx +nonce

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#734

  1. Why is it important that the blocks are cryptographically linked together?
    The fact that blocks are cryptographically linked together is what makes the blockchain immutable

  2. What does the block structure look like in bitcoin?
    A block contains the hash of the previous block, the hash of all the transactions included in the block chosen by the miner, the nonce and the timestamp.

#735

1.) It is important for blocks to be cryptographically linked because that link is the source of bitcoin immutability. Nothing can be altered in a previous block without changing all subsequent blocks and thus, breaking the chain.

2.) The block structure is set up with the nonce, transaction data of the current block, and the hash of the previous block.

#736

  1. it is important for blocks to be cryptographically linked together so that if one small thing is changed in any block, all links in blockchain will be broken. Or better yet, that change will be invalid, it will not be accepted.

  2. the block structure in bitcoin is: the transaction list, a nonce, the hash of the previous block, and the hash of the current block based on all of the above (nonce, tx list, and prev. Hash)

#737

in contributes to the feature of immutability. it makes it nearly impossible to change data once the blocks are linked
2. hash of the previous block, txs, nonce

#738

Why is it important that the blocks are cryptographically linked together?
It is important for blocks to be cryptographically linked together because it creates significant barriers to making any changes and preventing theft, fraud, or other behavior that falls outside of established rules. It also forms a function based on mathematics and physics not a central authority which automatically enables high trust in the Blockchain.

What does the block structure look like in bitcoin?
The current block structure has the current hash (which is a combination of the prior block’s hash and a random number for the current block), a list of TXs, and the nounce.

#739
  1. so that they are linked so that if you change something in a previos block all the next blocks are invalid and you need to re guess the nonce for each subsequent block and catch up to the blocks being added
  2. the hash of the current block is based on the transactions in the current block with the hash of the prev block with the nonce.
#740
  1. Its important to link blocks cryptographically together because that prevents anyone from going back and changing info in previous blocks as described earlier, but also it gives trust to the information thats in all previous blocks that it has not been changed, from block1 to current block. Prevents overspending.
  2. The block structure contains block number, confirmed transactions, the hash of previous block, and the correct nonce that the computer guessed correct that resulted in hash of all the above being less than the target.
#741
  1. by linking the blocks together and making them interdependent, it is practically impossible to predict what the next block is going to look like, and as such tamper with the blocks. It also makes it impossible to tamper with previous blocks as it would break the chain of subsequent blocks
    2.The block structure exists of the hash of the previous block, the List of transactions accumulated into the block and the nonce, a randomly generated number which combined with the other two inputs generates the new output/hash
#742

  1. So that you get a basically random hash number when you mine and the difficulty adjustment mechanism work.

  2. The block’s hash is based on previous block’s hash, current block’s transactions and nonce.

#743
  1. It is important for several reason : Any attempt to temper with a block will be invalidated in lack of that cryptographic proof. It is, at each step of processing, the proof that all informations on the blockchain are approved by the consensus mechanism.
  2. It’s based on the Merkel tree structure.
#744
  1. In order to ensure integrity and security of the blockchain. If data elements from a previous transaction would be modified it will break all links and blocks would need to be minded again, which is an impossible and endless task considering that the chain keeps on expanding.
  2. Transactions + hash from previous block + nonce.