Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#4362

  • To ensure the integrity of the network

  • A chain of blocks linked through a solved puzzle that carry a piece of the previous block

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#4363
  1. Why is it important that the blocks are cryptographically linked together?
    • makes it impossible to change previous blocks n the chain, as sll following blocks need to be re-mined
  2. What does the block structure look like in bitcoin?
    • Block# -> data (transactions) -> nonce -> previous block hash -> this block hash
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#4364

1.- It makes it harder to alter the data in them.
2.-The block is made out of a previous block hash, TX data and a nounce. The latter is a hash number to be calculated by miners that when below the target, they are rewarded.

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#4365

  1. Why is it important that the blocks are cryptographically linked together?
    It is important that blocks are cryptographically linked together, so that miners can’t go in and alter their data for their own gain. If a miner changes anything on a block it breaks the chain to all the blocks that came after it.

  2. What does the block structure look like in bitcoin?
    Block 1( Previous hash, Tx Data, Nonce) -> mash -> Block 2.

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#4366

1)Because the blocks cannot be altered

2)It has transactions and previous hashes inputs

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#4367
  1. Limits the endeavour to change transactions as subsequent links and blocks will also need to be changed. In addition it will be extremely expensive and extremely difficult to catch up to the current block link.
  2. Previous Hash + Transactions + nonce
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#4368

The reason it is important that the blocks are cryptographically linked is to guarantee the integrity of the data in the blockchain. This is because if a previous block in the chain is changed, all subsequent blocks will need to be re-mined.

The structure of a bitcoin block contains a list of transactions, a hash of the previously mined block, and a nonce. nonce is basically a random number that is used to make sure that the hash is low enough to be accepted.

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#4369
  1. Why is it important that the blocks are cryptographically linked together?

To ensure data integrity.

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

The new block is comprised of the current transaction data, the nonce, and the previously added blocks hash.

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#4370

Homework on Blockchain and Mining Visually - Questions

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

It’s important for blocks to be cryptographically linked together because it improves the networks security. It does this by forcing someone wanting to change data on a certain block, to have to change data on all blocks previously mined and the ones following as well.

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

In order for a new block to be created, it needs the hash from the previous block,
the data needed to create a new block (transactions) and for the nonce to be
guessed.

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#4371

  1. Why is it important that the blocks are cryptographically linked together?
    It ensures the immutability of the blockchain, if you change something in a block the subsequences links would be broken and the change wouldn’t work

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

Number of the block in the chain:
Nonce:
Data: (transactions)
previous hash:
Hash of the block

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#4372
  1. Why is it important that the blocks are cryptographically linked together?
    dis incentivizing cheating, because PoW
  2. What does the block structure look like in bitcoin?
    a block created with transactions list/ hash from the previous block, and the hash from a previous link.
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#4373
  1. To secure the network - this link contains information about the hash of the previous block (and so on), from which the next block is created, thus making fraudulent attempts practically impossible, since changing this link would break subsequent blocks in the network.
  2. Each block has its own hash, which is generated from the current block’s transaction data, the previous block’s hash, and a random nonce - a word that the miner must guess while mining.
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#4374
  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.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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#4375

  1. Why is it important that the blocks are cryptographically linked together?
    so that it is very difficult to alter a previous block. It creates integrity so people can’t break the rules.

  2. What does the block structure look like in bitcoin?
    a new block includes the previous’s block hash, the current transactions and a nonce, that has to be less than the target number.

QUESITON
I still don’t understand why computers can’t “guess” the nonce being 1, 2 ,3 or any small number, that would still be less than the target.

#4376

Because SHA256 returns a seemingly random number from the hashed data, you can’t just return any number and have it considered correct.

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#4377
  1. It is important that the block are cryptograhpically linked together because in it keeps the network secure and prevents data from being altered because in doing so, changing one block would break the links between all blocks down that chain.
  2. The block structure in Bitcoin is based on the hash of block plus hash of previous blocks which are all the transactions in the blocks plus tx list and nonce.
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#4378

  1. The blocks need to be cryptographically linked together to ensure that the blocks cannot be tampered with. You would need to change all proceeding blocks since they are cryptographic.

  2. The block contains the hash of the current block previous block as well as the nonce that needs to be guessed.

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#4379
  1. it is important for them to be linked together because of POW, especially when mining.
  2. every block has its own hash number with the previous hash number inside of the block. Along with transactions and the corrected nonce number.
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#4380
  1. Bitcoin that makes the blockchain inmutable in a way that past cant be manipulated withouth remining all the blocks till present and paying a stupidly high cost for it, even been imposible to catch up other miners.
    2.Each blocks takes 3 elements to generate a new hash:
    -Previous hash.
    -Current transaction
    -Nonce
    The miner will be trying different nonces and generated different hashes out of the 3 elements till the hash is lower than the target number.
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#4381
  1. Why is it important that the blocks are cryptographically linked together?
    make it more secure and harder to solve by the miners.
  2. What does the block structure look like in bitcoin?
    is combination of the previous hash and the transactions hashed together
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