Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3677

1.To verify integrity of the network and the system, the system works on a trueth mathematical equation, any input modified from previous block will render the entire chain useless.
2. block number, transaction data, nonce, hash of previous and current block.

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#3678

  1. Why is it important that the blocks are cryptographically linked together?
    This ensures the network is as secure as possible, eliminating the chance of any manipulation of previous blocks.

  2. What does the block structure look like in bitcoin?
    It consists of the previous block hash, current transactions, nonce, current hash, and current block number.

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#3679
  1. Why is it important that the blocks are cryptographically linked together?
  • Immutability is a crucial part of the security and stability of the blockchain. Cryptographically linking blocks implies that if a change occurs on a certain position in the chain then automatically the blocks that follow have to be recalculated.
  1. What does the block structure look like in bitcoin?
  • A block structure it is composed of: The hash of the previous block, data (TX`s) of the current block and the nonce. When the target is met by the hash value of the block then the block will be appended to the blockchain.
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#3680

  1. By linking the blocks together cryptographically it is extremely difficult to change or amend a previous block because all subsequent blocks will be changed. As the network accepts the longest blockchain, attemps to dishonestly change it will result in the links between the blocks breaking down and the blockchain is then in risk of invalidation. This process ensures that blocks remain immutable.

  2. Each block contains the following information:

    1. The previous blockā€™s hash
    2. The blockā€™s transactions (TX)
    3. The nonce number (the cryptographic puzzle)

These components are then hashed together to generate a new, unique hash. This is the hash of ā€˜thisā€™ block. When the next block is generated, this hash is passed to it as ā€˜prevous blockā€™s hashā€™ and so on.

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#3681
  1. With blocks being linked cryptographically, any changes in previous hashes or TXs would invoke next blocks and links concurrently. So, even if previous blocksā€™ hashes are changed successfully, the links will never be changed and prevent the blockchain to be manipulated.
  2. Magic number to be recognized that this is a bitcoin block and is same for all blocks: 4 Bytes
    Block size 4 Bytes
    Block header which is: 80 Bytes
    Transactions counter which tells how many transactions are there: 1 to 9 Bytes
    Transactions list that follows the counter
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#3682
  1. It is important that the blocks are cryptographicly linked togethter so that a miner cant change the content of one block without changing huge parts of the chain. This is never profitable for the miner because it is nearly impossible to get the chain to make sense again, and if they area ble to, it would never be profitable for the miner.
  2. The blockstructure is built up so that the blocks are connected to eachother through the blocks hashes. For example you have 3 blocks a, b and c. Block b will be base don the hash of block a, and block c will be base don the hash of block b. If you change the hash of block a, then block b and c dosnt make sense anymore and nodes wont approve the chain.

A block consists of transactions (who has inputs and outputs), the nonce and the hash of that block

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#3683
  1. The blocks have to be cryptographically linked to ensure the integrity of the data in the blockchain. New blocks are building on top of the old ones. This makes it impossible to change previously mined blocks.
  2. A block in Bitcoin is structured by the previous hash, the data and the nonce. This information is used to mine the hash for this block.
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#3684

  1. so that you can not go back to a previous block and change any transactions, as this would change the hash for all blocks after it

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

each block has the hash of the previous block, the transactions in its own block, and the nonce

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#3685

  1. In order to avoid that someone alters any of the blocks by purpose and profits from fake transactions

  2. A set of grouped transactions, which are linked through the previous hash functions

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#3686
  1. It needs to be cryptographically linked together in order to secure the blocks are held together in the network.
  2. A Bitcoin block has the information of the previous data, the present transaction and a nonce which a target number needed to be solved to create another Block.
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#3687
  1. Both so that miners spend electricity to mine, and so that only playing by the rules makes money
  2. Each individual block is composed of the previous blockā€™s hash, the current blocks sequence of transactions, and the nonce which must be lower than the target.
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#3688

1)Why is it important that the blocks are cryptographically linked together?
They are Cryptographically linked to create a secure network and keep the integrity of the blockchain so their is no cheating.
2)What does the block structure look like in bitcoin?
Each block of the bitcoin blockchain is connected to the previous blocks the hashes that are calculated with the bitcoin algorithm from data collected from all previous blocks added to the chain in succession.

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#3689

  1. Why is it important that the blocks are cryptographically linked together? This feature creates a situation where it is virtually impossible to change data in a block without being detected. A change in the previous block will break the links in all subsequent blocks due to the blocks being cryptographically connected.

  2. What does the block structure look like in bitcoin? Bitcoin blocks contain a nouce, data, previous block hash, and the current hash of the block.

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#3690

  1. So that you canā€™t just change one individual block. All other blocks will have to be re-mined as each block consists of itā€™s content or tx list as well as the hash of the previous block thereby creating another unique hash.

  2. the block consists of the hash of the previous block, the own/current blocks tx list as well as a random number (the nonce) that it must guess to reach an answer which should be below the ā€œtargetā€. A new BTC block is mined every 10 minutes.

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#3691

1.) It is important that the blocks are cryptographically linked because a change in any data to a block causes a chain reaction to the blocks, helping to keep the network immutable

2.) previous hash, transaction list and the nonce makes up the block structure in bitcoin

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#3692

  1. the cryptographic link make the re-mine exponentially difficult

  2. It is a set of input (UTXOs) output and btc values or data

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#3693
  1. Why is it important that the blocks are cryptographically linked together?

For the security of the blockchain and to ensure the whole system follow the rules.

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

The hash of the block is based on the transactions in the block plus the previous hash and the nonce that needs to be guessed

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#3694

  1. Itā€™s important to link the blocks together cryptographically so that no information can be changed in previous trasactions within previous blocks

  2. The structure looks like boxes connected with lines.

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#3695

  1. Why is it important that the blocks are cryptographically linked together?
    To secure the network; to ensure that previous historic data canā€™t be changed; to ensure that there is no double spend.

  2. What does the block structure look like in bitcoin?
    Each block has own hash (own digital fingerprint of the block), and this hash consists of: 1/ Previous hash; 2/ tx list; 3/ Nonce (random number which we have to guess)

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#3696

Whatā€™s in the boxes? :wink: