Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1809
  1. to maintain the security of blockchain so no data in prv blocks can be changed cus it would change all the next blocks.
  2. Target > SHA256 (current block [prv hash+ data+nonce] )
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#1810

  1. It’s important that the blocks are cryptographically linked together because with every variation of data in the block a different hash is created. When the data changes, the hash changes. When one hash changes, all the hashes change. This creates immutability.

  2. Bitcoin’s Block structure:

| Tx list. |
| Previous hash. | ---- hash
| Nounce. |

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#1811
  1. It is important that blocks are cryptographically linked together for the security of the blockchain. That way no transactions can be changed in previous blocks because it would break the link to the next block and all that follow.
  2. Target > SHA256 (current block [prv hash+ data+nonce] ).
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#1812

  1. It is important that the blocks are crypto-graphically linked together because this is a large part of ensuring the security of the network. Not even one transaction in any block can be changed without the hashes in every single block following the altered tx because it will not match what everyone else’s copy of the blockchain and will automatically be rejected by the network. It ensures the blockchain is immutable and to try to change every other full nodes copy of the blockchain would be so financially expensive that it would not be worth it.

  2. Block structure of 1 Block in Chain which are All Linked to All Previous Blocks in Chain

  1. current block hash
  1. based on hash of prev_block
  2. based on hash of transactions in the block
  3. based on hash of random(NONCE)
  1. Difficulty or Target is determined by the amount of the Hashing Power of the Miners which is constantly changing
    • Finally, after guessing and guessing many, many random NONCES, the Miners Hash must be less than of the Current Blocks Hash aka Target/Difficulty - THIS IS KNOWN AS THE PUZZLE

All of the above info is connected to the Hash of the Previous Block which will change All of the Data/Hashes in the blocks prior to it if attempt to change any of the hashes in this previous blocks. To do any of these changes will require massive amount of electricity and there would not be no economic incentive to do so.

  1. curr-block-hash
  2. prev-block-hash
  3. transactions
  4. random_NONCE
  5. miner must guess a NONCE that gives you a hash that must be less than the target difficulty of the Current Block Hash
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#1813
  1. Why is it important that the blocks are cryptographically linked together?
    To prevent previous blocks from being manipulated.
  2. What does the block structure look like in bitcoin?
    The nonce, the data of transaction and the previous hash building together the hash of the block.
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#1814

to keep the network safe, impossible to change something in single block

hash of previous block + transactions + nonce

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#1815

1- Its important for the security of the blockchain, because if any previous transaction is changed the following links will break.
2- The block is made with data (transactions), also is made with the previous hash, and the nonce, wich is a number that have to be guessed.

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#1816

  1. It prevents double spending.

  2. previous hash
    transaction list
    nonce
    repeat

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#1817
  1. Why is it important that the blocks are cryptographically linked together?

Because that assures that nothing can be changed in the previous blocks. Blockchain is a distributed ledger technology and every node has a copy of the ledger, and they will realise if there is a miner that is trying to be dishonest and create a different blockchain.

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

There is the hash rate that has to be calculated, the nonce -the random number that is guessed-, the list of transactions, and the previous hash.

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#1818
  1. The importance of blocks being cryptographically linked ensures the integrity of data.
  2. The block signiture in bitcoin = TXs + previous hash + nonce
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#1819
  1. To make it difficult to do any changes in the block
    2.Unique hash, Prev Hash, nonce
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#1820

Homework on Blockchain and Mining Visually - Questions

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

Because the hash of a new block exists partly of the hash of the previous block.

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

The structure is hash of the previous block, tx list plus nonce

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#1821

Brilliant visuals! :ok_hand:

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#1822

1.To ensure inmutability of the blockchain.

2.The hash of a block is based on previous block transactions and hashes. A block could be seen as a train wagon linked to the wagons that follow, each holding the forementioned variables the present block needs to operate. On top of this, a random number - nonce - needs to be guessed in order for the valid hash to be created.

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#1823

You can just use the hash of the previous block. :slight_smile:

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#1824
  • Why is it important that the blocks are cryptographically linked together? This way blockchain secures itself.
  • What does the block structure look like in bitcoin? Hash is based on previous hash, data , nonce
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#1825

[quote=“ivan, post:1, topic:8433, full:true”]
Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    , it adds a layer of security as each block references the previous blocks hash. by doing this it makes it extremely difficult to amend transactions in a previous block as you would invalidate all blocks thereafter
  2. What does the block structure look like in bitcoin?
    The hash of the previous block
    The list of transactions
    The nonce
1 Like
#1826
  1. To ensure no double spend and secure the network.
    2.Block structure look like a linked blocks list with hash of each block transaction , hash of previous block and nonce.
2 Likes
#1827

  1. So that each block secures the network. If anything changes in the previous block it invalidate blocks that come after.

  2. The structure is hash of the previous block, tx list of current block plus nonce

1 Like
#1828

  1. Gaurantees immutability

  2. image
    image950×578 75.4 KB

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