Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#4462

  1. It ensures consensus. All blocks being linked together ensures that all previous transactions are valid.

  2. Block structure is as follows: a hash based on the hash of the previous block, the data of the current block (transactions) and a nonce(random # that has to be guessed).

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#4463

1.The Cryptographic linkage is a maths puzzle and ensures integrity of the blockchain. It makes the network more trustworthy through maths and physics and retains immutability by hash functions that create unique outputs to solve the puzzle and link the blocks.
2. Block number
Nonce
Transaction Data
Hash of the Previous Block
Hash of current block

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#4464

  1. It is important that blocks are cryptographically linked together, because this format ensures the integrity, security and immutability of the blockchain.

  2. The bitcoin block structure consists of the previous hash, transaction list as well as the nonce.

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#4465

  1. To ensure the integrity and security of the network. So it is very difficult to change the data in the mined blocks.

  2. The block consists of the previous block hash. current block TXNs list and nonce. A nonce is a random number that is guessed by the miner and it must be lower than the target number.

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#4466

1.By changing even the slightest data point the hash changes thus all the rest of the blocks that follow would be incorrect.
2. the current hash of the block is the output of the previous hash + data + nounce which is the output of the previous blocks hash + data + nounce.

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#4467

  1. Why is it important that the blocks are cryptographically linked together?
    So that one block cannot be changed without all the others needing to be changed as well. It makes changing information much more difficult.

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

    • The block number
    • The nonce
    • The current blocks data (transaction list)
    • The previous block’s hash
    • The current blocks hash
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#4468

  1. They need to be cryptographically linked together as this increases the security level of the blockchain - making it hard / very expensive to alter previously mined blocks. Concept of immutability.

  2. Block Header - including timestamp and previous hash and Merkle root and height + list of transactions + nonce.

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#4469

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

In order to add a new block, miners must solve a cryptographic puzzle which is based on the contents of previous blocks. This means changing any previous blocks is massively expensive and time intensive. The system ensures that the blockchain can’t be manipulated or altered - it’s almost impossible. It creates incentive to play fair, while ensuring the network is essentially tamper proof.

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

Block structure contains:

  • Block header
  • Block size
  • UTXOs
  • Previous block hash
  • Nonce
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#4470
  1. So that it keeps the security super high so that you can’t make changes on previous blocks.
  2. As follows:
  • Version: The cryptocurrency version being used.
  • Previous block hash: Contains a hash (encrypted number) of the previous block’s header.
  • Hash Merkle root: Hash of transactions in the Merkle tree of the current block.
  • Time: A timestamp to place the block in the blockchain.
  • Bits: The difficulty rating of the target hash, signifying the difficulty in solving the nonce.
  • Nonce: The encrypted number that a miner must solve to verify the block and close it.
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#4471

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    So that the block history cannot be altered.

  2. What does the block structure look like in bitcoin?
    Block Number (Height)
    Previous Block Hash
    Transaction List
    Nonce
    Current Block Hash
    Difficulty Target

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#4472

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

One block is based on a previous block’s information (the hash) so if you change any information of this block everything else will collapse and it will take too much time to restore everything.

What does the block structure look like in bitcoin?
Previous block hash, all the transactions in the actual block with nonce

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#4473

  1. It’s important for blocks to be linked together to ensure that nothing could be altered and the data maintains its immutability.

  2. Block that has previous hash, txs, and the nonce guessed that is below the target.

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#4474

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

If all blocks are linked together, changing anything, even by a tiny amount, breaks the chain.

What does the block structure look like in bitcoin?

Current block number

Previous block hash

Transaction data from mempool

Nonce (random number used once)

Current block hash (which must be lower than current threshold for the block to be mined)

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#4475

  1. It is important because that link becomes strong security point for the network that links one block to the next block. Changing anything in a previous block will break all “chains” after it.

  2. When a new block is created that block is given a hash which is comprised of all the transactions that took place in that block as well as the hash from the previous block. A Hash is created when miners mine to find the target number or the nonce.

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#4476

  1. Because the previous hash effect the current hash

  2. previous has > transaction data > nonce

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#4477
  1. Because of security reasons, that you cannot just change a block in the chain without affecting other blocks.
  2. One block depends on the hash of the previous blocks and the transactions and the nonce that needs to be guessed.
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#4478
  1. Why is it important that the blocks are cryptographically linked together?

It adds to the stability and integrity of the BTC network by making it extremely hard to reverse or double spend a transaction.

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

The block structure is made of of the Prior Hash + the List of transactions in the present block + the Nonce to make the new Block Hash. So the Blocks are cryptographically chained together.

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#4479

1.it is important for the security and the immutability of the blockchain.
2.-hash from the previous block
-Tx list
-nonce

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#4480

  1. Why is it important that the blocks are cryptographically linked together?
    This ensures that the data in previous blocks can not be changed without breaking the link. This would invalidate the copy of the blockchain of the participant that attempts this, and the new block will be rejected.

  2. What does the block structure look like in bitcoin?
    Each block contains the transaction list, the nonce, and the hash of the previous block.

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#4481

Blockchain and Mining visually-

  1. To secure the network and make sure all transactions are correct in each block. When they are linked, the block before has to be correct before a new block can be formed.

  2. The block structure contains the list of transactions, the hash of the block before it and the nonce the miner uses to guess a hash to get below the current target.

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