Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2633

  1. Why is it important that the blocks are cryptographically linked together?
    To ensure the security of the network, blocks are linked together cryptographically. Making it impossible for the attackers to tamper the transactions.

  2. What does the block structure look like in bitcoin?
    Structure of a block -

  • Block Header - Block number, nonce, previous hash value, current hash value, timestamp, difficulty
  • List of transactions.
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#2634

  1. the cryptographic linking requires that a bad actor that changes a transaction in an existing block remines the entire chain after the manipulated block

  2. block = prev hash, transaction list, nonce (variable guess)

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#2635
  1. Why is it important that the blocks are cryptographically linked together?
    Its important for the security of the blockchain. This structure makes it almost impossible for anyone to change something that’s already been added earlier int the blockchain.

What does the block structure look like in bitcoin?
The hash of a bitcoin is based on the TX in the block plus the hash from the block before and also the nonce that is a random number the miner need to guess.

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#2636

1:Its important that the blocks be linked together so that there can be no change in the previous, it all has to move forward block by block.
2: The block structure has the hash of the block based on the transactions in the block plus the previous hash and the nonce that the miner has guess.

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#2637

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

The link increases the security of the network. Chanigin a previous transaction would also require to re-hash all links.

What does the block structure look like in bitcoin?

New block = hash of previous block + hash of transactions of current block + random number (nonce)

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#2638
  1. to ensure security, integrity, immutability.
  2. each block based on previous block hash, transactions hash and a nounce number mined.
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#2639
  1. It is important for the reason that it is not possible the change the structure of the block
    without changing all the blocks after it. It is for secutity reasons
  2. It has a list of transactions inside. It has it’s own hash and on both sides it has links that ar
    connected with other blocks.
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#2640

1.immutability will be guaranteed if you have them crypto linked it will be nearly impossible
2.a block contains hashes that connect information about transactions

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#2641

  1. It insures that changing one transaction in a block also changes data in the following blocks. Therefore it is almost impossible to change a transaction and be dishonest.

  2. Hash of a block is based on the transaction in that block, and the hash of previous block, and the nonce.

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#2642
  1. Why is it important that the blocks are cryptographically linked together?
    It makes manipulating any block in the change difficult due to it change every block that follows. The network will choose the longest chain when accepting a new block.
  2. What does the block structure look like in bitcoin?
    Previous hash, transaction data -> hash, nonce that is under the target.
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#2643
  1. Why is it important that the blocks are cryptographically linked together?

If a block in the blockchain is changed every other block after that will also change. This makes the blockchain secure.

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

-hash of current block
-transaction list
-nonce (random number)
-hash from previous block

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#2644
  1. Keeping the blockchain cryptographically linked together secures the network through Proof of Work (PoW). Therefore, if the protocol is followed, a trustless environment can be maintained for transactions, which no one would jeopardize by manipulating blocks.
  2. A ledger of transactions, hash from previous blocks, a guessed nonce, with a hash that represents its target rate.
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#2645
  1. It prevents the block to be altered

2)Block, nonce, data , hash of previos block and hash of the currrent block

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#2646

  1. to insure that there is no double spending, and that each block has immutability

  2. Transactions, a hash that is connected to the previous block and a Nonce

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#2647
  1. To create a secure network by ensuring that blocks remain immutable
  2. All transactions in the block, the previous hash, and the nonce
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#2648
  1. Why is it important that the blocks are cryptographically linked together?

Blocks remain immutable which means the cant be altered without the blockchain realising that it is an invalid transaction, which in turn keeps the blockchain secure and keeps the ledger intact.

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

The bitcoin block structure looks like this - The previous hash plus the list of new data plus the nonce (random number less than the target). Once the random number (nonce) is guessed a new block is created.

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#2649

Miners are trying to find a block hash that is below the target, nonce is just a number miners use to help them find the right hash. :slight_smile:

#2650

  1. It prevents double spending, it ensures integrity and the data immutability. This makes the network trustworthy and secured.

  2. Bitcoin block structure contains the below elements:

    1. Previous Block Hash.
    2. The list of all tx's from previous block.
    3. nonce that is below the target.
    4. The new hash.
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#2651
  1. It is important because every block contains hash of the previous one which means we can’t change anything in the block due to lost connection with the next one.
  2. The block structure contains hash from previous block, transactions and nonce which all of this is being then hashed and ready for the next block.
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#2652

Ok thanks :slight_smile: Bit of information overload for me sometimes lol. But after watching the virtual mining this makes sense. Thanks for the feedback :+1: