Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#383
  1. its important that blocks are linked together to ensure the integrity of the chain. if one block gets altered the links between the blocks break.
  2. block structure takes the previous block hash[input], guesses nonces until below target difficulty, mines data to make new hash for output. sha256 [data] = hash
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#384

  1. Because any change in previous blocks invalidate subsequent blocks.

  2. The block structure of bitcoin is made up of the content of the previous blocks or the previous hash, the current transaction list, plus the nonce which solves the current potential block puzzle which less than a target.

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#385
  1. Why is it important that the blocks are cryptographically linked together?

The hash links between blocks prevents the transactions in previous blocks from being altered, ensuring immutability, which is one of the important features of bitcoin.

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

Each block contains transaction data, a nonce, target, and a hash.

#386
  1. So as to ensure the immutability of the ledger transactions, to ensure the security of the blockchain.
  2. A bitcoin block looks like a list of transactions - to/from public addresses and amounts. It contains the previous block’s hash, the nonce, and the target.
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#387

  1. Is important because it creates a secure TX by independent verification by validating each block that affects the other along with a unique finger print. Its designed if anything is change will create a different result that will break the link affecting the next block which prevents data from being accepted.

  2. TX hash input outputs.

#388

Blocks need to be linked for security and if anything is changed the links are broken.

The block structure comprises previous hash, current hash, transaction details, and nonce

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#389

  1. Why is it important that the blocks are cryptographically linked together?
    Because it adds security to the network, making very difficult (nearly impossible) to change previous blocks.

  2. What does the block structure look like in bitcoin?
    A block contains a hash that is calculated using the following information (contained in the block itself): data (list of transactions), hash of the previous block and nonce (random number guessed by the PoW algorithm).

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#390
  1. Why is it important that the blocks are cryptographically linked together?
  2. What does the block structure look like in bitcoin?

To make sure that any records that have been hashed will remain the same and not duplicated

Data from the 1st hash copied to new hash then nounce to make a new hash

#391

  1. Because any change in the data of a previous block will affect it´s hash and the following block, as it needs the previous blocks hash in order to be created. This makes it so that miners in the network will know if a block is valid or not.

  2. A block contains, the previous block´s hash, block header, transaction data, timestamp and nonce.

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#392

1, If any data is changed in a block this would break the link between blocks, this cryptography ensures the integrity of the blockchain.

2, Consists of, Block number, Previous block Hash, current block Hash and Nonce

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#393

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

  1. Cryptography in digital world offers three core area that protect you and your data from attempt theft, theft or an unauthorize use of your data and possible fraud. Cryptography cover these essential area; authentication, integrity, and confidentiality.

What does the block structure look like in bitcoin?

  1. Blocks are chained together by linking the hash of the previous block to the current block’s hash. previous hash + transactions + nounce = new hash
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#394

• This gives a high level of security to the blockchain, as if data is manipulated in one block it instantly breaks all the other blocks. This is a great way to keep to the thrustless system, as even manipulating a single digit has a crazy effect.
• Nonce, Data, Previous Hash & New Hash.

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#395
  1. The link between block ensures the immutable proporty of the network.
  2. The hash of a block is the hash function of the transactions + the hash of the prev block + the nonce
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#396
  1. links between blocks are the crypogrphic puzzle to be solved by the miner to be rewarded (block reward plus transaction fee) for producing the new block in the chain
  2. block structure = transaction list + hash of previous block + nonce and new hash of the new block is based on that data in the block
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#397

1.) It is important for blocks to be cryptographically linked together because any change in a previous block causes errors in all subsequent blocks. This is the security of the Bitcoin protocol.

2.) A block is made out of the data input from TX’s > a hash is generated > the previous block’s hash is input > and once the nonce is found, a new block can be mined.

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#398

Not the nonce need to be below the target but the blockhash. So you guess a random number (nonce) hash the block and check if the blockhash is below target

#399

  1. To ensure the blockchain immutability as the miners are dis-incentivised from manipulating transactions. Doing so would be very expensive for miners as their blocks would be rejected by node consensus.

  2. Each block is cryptographically linked by a hash of the prevoius block and a hash of the current blocks nonce and transactions. Each hash must be less than a target that varies depending on difficulty.

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#400
  1. The links make it practically impossible to corrupt the data one the block is added. This prevents censorship and double spending.
  2. The block structure in bitcoin consists of nonce, transactions, previous hash and the current hash.
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#401

  1. This is to ensure the finality and security of the network. Having the blocks cryptographically linked together means that if any change happens in one of the already mined blocks, all the other blocks that follow will have to be mined again for each to find a new hash value that again links the blocks.

  2. A block structure in Bitcoin is comprised of the transactions data, the hash of the previous block and a nonce that defines the block’s hash value considering the current target hash of the network.

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#403

What I meant was
“The sha256 hash of (the current block txs plus previous block hash plus a nonce)”

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