Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1527
  1. Why is it important that the blocks are cryptographically linked together?
    So that changes made to earlier blocks will necessarily create changes to subsequent blocks , allowing the network to detect blocks that have been fraudulently altered.
  2. What does the block structure look like in bitcoin? The transactions on the current block create a hash. The hash of the previous block needs to be hashed with this hash and this has to be hashed with a random number such that the resulting hash is below a specific target that is determined by the difficulty of the network. At some point something has to be done with the cube root of prime numbers or something or perhaps that is just considered part of one of the above aforementioned hashing processes, but I donā€™t really know the exact details.
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#1528

1- Why is it important that the blocks are cryptographically linked together?
Because it ensures that any changes made in previous blocks by bad actors will ripple through the chain and not only invalidate the block that was altered but also all subsequent blocks / links between blocks up to the currently mined block.

2- What does the block structure look like in bitcoin?
Each mined block contains the hash of the previously mined block, a transaction list and the correctly-guessed nonce value that could be hashed to a lower value than the targeted hash threshold.

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#1529
  1. By hashing the end of one block and using that for the next block ensures only one true blockchain. It removes the opportunity amendments to a finished block.

2.it comprises mostly of transactions/data, the previous hash and the nonce. The next block is comprised of all of these factors to ensure a single correct chain.

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#1530

  1. Why is it important that the blocks are cryptographically linked together?
    Each new block is partially made up from the previous blockā€™s hash.

  2. What does the block structure look like in bitcoin?
    The block is made of the previous blockā€™s hash plus all the transaction confirmed within the block.

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#1531
  1. To secure blockchain network, that way no previous transaction can eased and change, no double spent etc.
  2. The block structure in bitcoin is consisting of the hash of the previous, miners are guessing nonce to establish next block, more miners are guessing, the increased in difficulty.
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#1532
  1. Why is it important that the blocks are cryptographically linked together?

Answer: It is important that the blocks are linked together in a cryptographic manner as it secures the blockchain. This security is accomplished by making every block dependent on a previous block via incorporating the HASH from the immediate prior block. Changing the data on one block invalidates all blocks appended afterwards to that block.

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

A.) Prior Hash
B.) Transactions
C.) Nonce

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#1533

  1. Why is it important that the blocks are cryptographically linked together? - because when a microchange happens anywhere in the previous blocks, it will affect all the other blocks miner after that block in a clearly visible way. This way you can always verify the truth in the blocks

  2. What does the block structure look like in bitcoin?- you have the hash, transaction list in the Black and the nounce

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#1534

  1. To ensure the integrity of all blocks and transactions. If transactions or blocks (at any point of the blockchainā€™s history) are modified by a dishonest user, the hash of that block and hashes of blocks followed by the invalid block will be different than the original. Blocks with valid transaction information will have the correct hash - This allows miners to decide which blocks are valid and which arenā€™t.

  2. Block index, header (version, prev block hash, timestamp, nonce), TX hash list, inputs, outputs.

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#1535
  1. It is important because this way it is not possible to change a previous hash, block, transaction.
  2. In a bitcoin block is a hash, which is generated with the transaction list, the previous hash, and the nonce.
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#1536

  1. It is important that the blocks are cryptographically linked together, because it ensures security. Each manipulation f.e. double spent will interrupt the connections between the blocks.

  2. In the block structure are the transactions, the previous hash and the nonce.

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#1537

  1. Why is it important that the blocks are cryptographically linked together?
    This makes it impossible to change a block, because if you change one block all the other hashes will change and also the hashes of other miners that are added change - so you can never catchup

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

Nonce
Previous Hash
New Hash
all linked together in all the following blocks

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#1538
  1. immutability
  2. interlocked links of a chain
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#1539
  1. Why is it important that the blocks are cryptographically linked together?
  • This makes it difficult for a machine, let alone a human, to change the data and get away with it because the processing power needed to re-link the changed data will cost more than it was worth to change the block.
  1. What does the block structure look like in bitcoin?
  • A block has the Block Number, Nonce, Data (Transactions compiled in the block), Previous Hash, and the current Blockā€™s Hash. The current Blockā€™s Hash is obtained by running the Nonce and the Blockā€™s Data through a Hash Function.
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#1540

1-Blocks are cryptographically linked to ensure that previous transactions can not be modified
2-the hash of the Block is based on 3 things: the list of TX,the hash of previous Block and of the Nonce ( random number guessed by the miners using brute force method)

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#1541

  1. Why is it important that the blocks are cryptographically linked together?
    To ensure that previous blocks canā€™t be altered (they are required for the hash of the new block)

  2. What does the block structure look like in bitcoin?
    It has the hash of the previous blockā€™, the list of transactions and the nonce (which is a number). All these three things are required to generate the hash for the block. The miner who generates the new hash that is lower than the target will be able to append the new block to the blockchain and get incentivised.

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#1542

  1. Why is it important that the blocks are cryptographically linked together?
    Because that is what makes Blockchain trustable and secure. Any change in any block, would break the link for forward blocks. Data immutability

  2. What does the block structure look like in bitcoin?
    Previous hash, transactions and nonce.

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#1543

1- Blocks that are cryptographically linked are nearly impossible to manipulate.
2- In bitcoin blocks are hashed from the current blocks content and the previous blocks hash any letter changed will require a complete blockchain makeover.

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#1544

This is the whole point of a blockchain - to ensure that there can be no tampering with blocks, once they are confirmed in the ledger. The best way to do this is to include a hash of the previous block in the next block.

BTC block = Previous block hash + Transaction list + Nonce.

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#1545

  1. It is important so a previous block can not be changed without effecting the next blocks in the series. This enhances security and helps create a trustless system.

  2. Hash > Target = Nonce
    Previous Hash | Hash | Transaction List

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#1546

  1. because transactions are recorded forever. This makes it so all blocks have to match previous blocks, which also makes the blockchain so hard to hack.

  2. [transactions]-[transactions]-[transactions]-[transactions]-[transactions]

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