Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#525
  1. This will improve the security of the blockchain by invalidating all the blocks after an altered block.
  2. The block structure contains the hash of the previous block, the hash of all transactions in the block, and a nonce value.
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#526

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    Because that ensures that the mined blocks cannot be changed or removed later since that would change ever hash of the chain.

  2. What does the block structure look like in bitcoin?
    A block contains the hash of the previous block, all new transactions and a nonce.

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#527
  1. It increases security of the network by making it almost impossible to modify a block in the chain.
  2. header (nonce + previous hash) + data.
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#528
  1. Blocks are linked to insure data cannot be altered once mined.
  2. Once the initial block has been set, the next block will contain the hash of the previous block and the nonce that the hash function has been solved for.
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#529

  1. By linking blocks cryptographically together, you ensure that no block in the chain can be altered, without having to re-mine all subsequent blocks in the chain , hence making it next to impossible for a hacker to do this, because he would need to have more hashpower than the entire chain to be able to remine and overtake the original chain, to make his fraudulant chain the new longest chain ie. the “truth”.

  2. Overall a block contains a header and a detail area: The header contains the info that links this block to the previous block (hash of previous block), and the hash of current block. The detail area consists of a list of transactions

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#530

  1. So it guarantees the integrity of the blockchain. Changing a block means destroying the links between the following blocks in a domino effect, which makes the chain shorter and thus not chosen a true by the network.

  2. A block includes the transactions of the block, the hash of the previous block and finally a nonce. If the right nonce is found, the block can be “closed” by a final hash lower than the target number imposed by the PoW process.

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#531

Homework on Blockchain and Mining Visually

Why is it important that the blocks are cryptographically linked together?

This is required for security of the blockchain and to avoid easy manipulation of transaction data. If a tiny amount of change is made in any part of the blockchain, solving the subsequent corrections in this interlinked cryptographic network would take astronomically large amounts of power to the point where it’s either impossible or they would profit a lot more from being a miner that followed the rules.

What does the block structure look like in bitcoin?

[-----------------]
[Header-------]
[Nonce--------]
[Data----------]
[Prev.Hash—]
[Hash----------]
[----------------]

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#532

  1. Why is it important that the blocks are cryptographically linked together?
    Blocks are linked cryptographically with hashes to ensure their immutability. By linking them with a hash from a previous block, and then hashing that hash with a hash of the data in the currant block, you ensure that changing even a single bit of data will invalidate the entire chain.

  2. What does the block structure look like in bitcoin?
    A block in bitcoin contains the block number, a timestamp, the transactions included in the block, the coinbase reward, the the fees rewarded, the nonce for the new block, the size, the merkele root, and the hash from the previous block, and new hash made by combining all data in the new block with the hash from the previous block.

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#533

  1. The cryptographic linkage of blocks makes it impossible for data on the blockchain to be changed once a block has been mined and broadcasted to the network. If changing a transaction is attempted it will be obvious that it is invalid and will be rejected, since subsequent blocks will no longer be linked to it cryptographically.

  2. Each block contains the hash of the previous block, the nonce, block hash, and the latest transactions. Blocks are connected to one another sequentially in a structure that is chain-like, hence the expression “blockchain”.

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#534

  1. By being cryptographically linked the blocks form an unchangeable record of data. Thus forming the most secure network yet, the Blockchain.

  2. like beautiful poetry.

#535
  1. It maintains the immutability of the system.
  2. Hash of the previous block, the transaction list, and the nonce.
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#536

1: Cryptographically linking blocks ensures the security and immutability of the blockchain and the transactions within.

2: The block structure contains the following:

  • Timestamp
  • The hash
  • Record of all transactions in the block
  • Reference to the previous block’s hash
  • The nonce
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#537

  1. So that the chain can be easily traced, it is more secure, and remain immutable.

  2. The block structure consists of the previous hash, the transaction fee, and the nonce. all together this creates the new hash for the next block in the chain.

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#538
  1. Why is it important that the blocks are cryptographically linked together?
    • Prevents a malicious user from being able to amend the previous blocks. It forces the malicious user to re-mine all future blocks which is practically impossible.
  2. What does the block structure look like in bitcoin?
    • Previous block hash, transaction list and nonce
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#539

Why is it important that the blocks are cryptographically linked together?
This adds security to the blockchain as it prevents previous blocks from being altered by prohibitively increasing the resources required to change the blocks further down the chain. This means that the current blockchain is up to date and maintains its immutability and source of provenance.

What does the block structure look like in bitcoin?
Each block includes the hash of the previous block, a transaction hash, the nonce (cyrptographic mining puzzle) and the details of the current transaction.

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#540

Screenshot 2020-05-01 at 15.40.53
Screenshot 2020-05-01 at 15.40.531352×1274 256 KB

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#541

  1. Blocks are linked together and if someone tries to compromise the blockchain going back to another block they are linked and all follows. So this prevents altering data on previous blocks.

  2. Each block has Transaction Data ( UTXO’s). Block # , Nonce, Previous and current block hash.

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#542

Why is it important that the blocks are cryptographically linked together?
To prevent manipulation and to ensure security and immutability.

What does the block structure look like in bitcoin?
Hash header, hash previous transactions and current transactions list

#543

  1. This makes the network as strong as it is. By having them linked, it is extremely difficult for a someone to change the previous block, since all other blocks will change as well. Removes any chance of double spending as well.

  2. The current block is based on the hash of the previous block. The upcoming block is based on current block hash. If the data in any block is changed, they also change.

#544
  1. It is important for blocks to be cryptographically linked as it prevents people from altering the transactional information on blocks, thus increasing security and maintaining its integrity.
  2. (Previous Hash + List of Transactions + Nonce) < Target
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