Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3516

1**. Why is it important that the blocks are cryptographically linked together?**
To ensure that history cannot be changed. It keeps the information (txs) on the blockchain safe from tampering.
2. What does the block structure look like in bitcoin?
It consists of a hash that is made up of previous block’s hash, the transaction list of the block and the nonce.

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#3517

1.)Why is it important that the blocks are cryptographically linked together?
-By cryptographically linking all the blocks it makes it more difficult for anyone to attempt to change data as they would have to re-mine all the data that comes after it. It would take far too much time and money to even attempt this.

2.)What does the block structure look like in bitcoin?
-A block is based on the previous block hash, current transactions for that block, and a none (random number).

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#3518

1: The reason is so that if any old information gets changed, a future block will also have the hash number changed. This would force the person to need 51% computing power and mine the blocks twice as fast.

2: The block structure is, the hash number of the previous block and the transactions you are looking to confirm as well as the nonce that needs to be guessed.

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#3519
  1. So that data can’t be altered.

2.nonce, Tx and hash.

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#3520

Homework on Blockchain and Mining Visually - Questions

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

That warrants the integrity of the blockchain. In that way, no one can change what is in previous blocks because that would break the link between blocks and would change every block rash of subsequent blocks from that point onwards.

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

Each block provides rash information to be used in the next block rash forming a chain.

So in order to solve the rash and get the rewards you need:

Previous block rash, the list of transactions of the current block, and nonce.
It also needs to be below the target.
Which decreases (more difficult) as the number of participants increase.

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#3521

  1. Why is it important that the blocks are cryptographically linked together?
    It is important, to check the previous hash, because if some data is changed in one block, all blocks hashes, after changed block, will change. Then we will be able to see that data was altered.

  2. What does the block structure look like in bitcoin?
    The block structure is made out of 3 parts. The previous block hash number, all transactions that are in the block and the nonce, which is a random number.

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#3522

  1. To secure the integrity of the network. The link means you cannot change any single block without breaking all the following blocks.

  2. Simplified it consists of the previous block hash, the nonce and its transactions. Technically, the structure is as follows:

  • block size
  • block header (version, prev block hash, merkle root, timestamp, difficulty target, nonce)
  • transaction counter
  • transactions
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#3523

1.If the blocks wouldn’t be linked cryptographically you could simply change a previous one.
Therefore blockchain wouldn’t be as secure as it is. I could go to a previous block and change previous tx without breaking the blockchain.
2.a block is made from data from the last block + the not yet confirmed transactions+ the nonce
The nonce would be the solution to solve the puzzle.
It has to be guessed until I undervalues the target

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#3524

  1. Why is it important that the blocks are cryptographically linked together?
    So that changes in one block will affect all other blocks subsequentally

  2. What does the block structure look like in bitcoin?
    It looks like a block chain, one after another

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#3525

What is inside a bitcoin block?

#3526

mmm… candies?
Ah ok, i misunderstood the question.
The block contains all the transactions the miner validate, the nounce and the hash from the previous block.

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#3527

  1. Because it stops any manipulation of data and altering previous blocks.

  2. It contains the hash of the previous block, transactions and the nonce.

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#3528
  1. So that the blocks will not change in the future and we can track back the last transaction.
  2. Block hash, Previous hash, Nonce and Data.
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#3529

  1. It is important for blocks to be cryptographically linked together because that is what make the data immutable and tamper proof.

  2. The structure of a block contains

previous transaction hash
current transactions
nonce

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#3530

Its previous block hash. :slight_smile:

#3531
  1. Why is it important that the blocks are cryptographically linked together?
    This link secures the network by making it necessary to go back and remine all previous blocks if one was to change a single transaction in a given previous block. Because the hash output, nonce and data from all previous blocks are used to create all future hash outputs this makes it impossible to go back and change data in the block without changing all subsequent blocks.
  2. What does the block structure look like in bitcoin?
    Previous hash, data within block and nonce.
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#3532

  1. Because it acts as a level of security and integrity to the blockchain. So it deters miners from changing/removing past transactions.

  2. Its -
    Previous block hash
    Transaction list
    nonce

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#3533

All blocks are not allowed to be changed / mutated. The cryptographic link prevents any mutation.

Block number
Hash of previous block
Hash of current block
Nonce / magic number
transactions

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#3534
  1. Why is it important that the blocks are cryptographically linked together?
  • This particular feature of the blockchain ensures that “the present state depends on the past states”. It makes it practically impossible to change the already established blockchain structure and at the same time make it acceptable for the rest of the network.
  1. What does the block structure look like in bitcoin?

  • Block content:

    1. List of transactions to be confirmed
    2. Nonce
    3. Hash of the previous block

  • Hash of the content

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#3535

  1. Blocks need to be linked together to create security on the blockchain. This way no transactions can be altered in previous blocks because it would break the link to the next block and all that follow.

  2. Bitcoin block structure is based on the fact that hash of the block is based on the transactions in the block plus the previous hash and the nonce that needs to be guessed by the miners.

1 Like