Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#965
  1. It is important because the transaction in the block is based on the previous hash and so the network is secure.
  2. Previous blocks, transaction data, and nonce.
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#966
  1. Why is it important that the blocks are cryptographically linked together?

As each block hash contains transactions, previous block hash and nonce there is a strong element of security in each block. If someone were to try and interfere with earlier blocks the cryptographic linking would be lost
2. What does the block structure look like in bitcoin?

There are three components, the transactions selected for the block, the previous block hash and a nonce which is a random number calculated to fall below the target. The ease of guessing the nonce will depend on the difficulty level of the system which depends on how much mining capacity is running

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#967
  1. Because it makes it very hard to change a block because you would need to re-mine all block after the one you want to change therefore giving the blockchain immutability.
    2.1. A block contains: Block number, A list of transactions, Hash of previously mined block, Hash of current block and nonce
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#968
  1. So that the hashes are dependent on the previous hashes and prevent data to be changed.
  2. transaction lists + nonce + previous hash which gives the block its own unique hash
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#969

  1. It is super important that the blocks are cryptographically linked together because then it is mathematically and physically impossible to change previous blocks and alter the blockchain. Once you change one you need to change them all by rehashing. Maintaining a secure network.

  2. The block structure of bitcoin looks like Block hash, Nonce, Data (transactions), Previous block hash, final hash based on the factors involved.

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#970
  1. For chain security / integrity reasons.
  2. SHA256 hash function. Based on previous block hash functions + new transaction functions + nonce on block creates new hash input for new bitcoin nodes to be mined by bitcoin miners via POW.
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#971
  1. Why is it important that the blocks are cryptographically linked together?
    For security and immutability of the blockchain
  2. What does the block structure look like in bitcoin?
    previous blokcs hash, Nonce, Transactions, dificulty target.
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#972

Because the hash of the next block is based on the last block, which means no alterations can be made making the system immutable.

Previous Block Hash
Transaction List
Nonce
Less Than Target
Current Hash

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#973

to see in the last block if something has been changed in the previous mind blocks

hash (previous hash + nonce + transactions)

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#974

1.why is it important the blocks are cryptographically linked together? - because if a block’s hash in the middle of the chain is changed then that block and all the blocks linked after that block are discarded including.
2. What does the block structure look like in bitcoin? - It has all of the following:
Version
Previous Block hash
Tx data
Difficulty target
Nonce
Block Size
Block header

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#975

it is important so that an alteration to a prior block will cause a new hash that would in turn fail the forward blocks

Prior hash, tx data, nonce

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#976
  1. This secures the network and prevents transactions from being reversed.
    2)Hash Current Block, Previous Block Hash, Transaction List, nonce, cryptographically link.
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#977

  1. Why is it important that the blocks are cryptographically linked together?
    to ensure the integrity of the blocks / the chain

  2. What does the block structure look like in bitcoin?
    the blocks contain the current hash and the previous hash of the TX - this makes it possible to trace back

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#978

  1. By linking them together is impossible to change just some block without changing block that comes after.

  2. Block structure is [previous hash + transactions + nonce (random number)] all of this makes new hash which is lower that a target.

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#979

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

The hash of each block is generated in relation to the hash of the previous block, and that is what creates a chain of linked blocks. … These hash pointers (identifiers), play a major role in ensuring blockchain security and immutability. Any attempt to change a data in one block, makes all blocks chained invalid.

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

Each block is built (contains), - cryptographic hash of the previous block, - a timestamp, - transaction data and - nonce.

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#980
  1. Why is it important that the blocks are cryptographically linked together?
    Because if one link breaks then all of the next links will break too -> Security of network and transactions in blocks in this network.
  2. What does the block structure look like in bitcoin?
    Hash of the current block is based on previous hash, transactions of the current block and nounce.
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#981

  1. It makes the chain practically immutable.

  2. Previous hash, nonce, txs, version, merkle root hash, time stamp, bits

2 Likes
#982

I’m catching up to you @Lane11!! Lol

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#983

1.information that was agreed on is seccure previous hash and nonce are old block and new block.
2.Hash link, time stamp, nonce, utxo,

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#984
  1. This method keeps every blocks integrity reliant on the integrity of all the chain.
  2. Block is made from; previous blocks hash + transactions + nonce.
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