Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#565
  1. it is so important to make sure no one can go back and change the data
  2. block number - nonce - transaction data - previous hash - target - hash -
#566

Homework on Blockchain and Mining Visually - Questions

Why is it important that the blocks are cryptographically linked together?
So that if someone wants to make a change to the blockchain, all the links will be destroyed.
All blocks are connected by a hash generated by the previous block also, so if a change is made the entire chain of hashes and targets will not match anymore.
This makes it impossible to do any sort of permanent tempering with the chain.

What does the block structure look like in bitcoin?
The block number
The nonce
All transactions in the block
the hash generated by the previous block
the hash generated by this block

#567
  1. This increases security of the blockchain.
  2. It looks like a chain of blocks linked together.
#568
  1. Why is it important that the blocks are cryptographically linked together?
    Because this shows that no alteration has occurred and makes the blockchain trustless. The links of the blocks can be thought as the integrity and security. If any alteration occurred on a previous block, it would break the links between the blocks.
  2. What does the block structure look like in bitcoin?
    The block is made up of the following:
    Block Number
    Nonce Number
    Data (all Transactions)
    Previous Hash (link)
    Current Hash
#569
  1. Why is it important that the blocks are cryptographically linked together?
    Since each block contains the previous block hash, they have to be linked together, otherwise the chain will not be valid. This promotes integrity and security of the data.
  2. What does the block structure look like in bitcoin?
    • Version: The block version number.
    • Time: the current timestamp.
    • The current difficulty target. The lower the target the higher the difficulty.
    The following three area hashed into the block hash, this will be compared to the target (difficulty), if below it will be accepted. Target is low when difficulty (Hash rate is high).
    • Hash of the previous block.
    • Nonce (random number guessed by the miners)
    • Hash of the Merkle Root (transactions).
#570

  1. So that they are immutable

  2. A block contains data of a transaction list, the hash from the previous block and a nonce.

#571

1 . It is important so that if one block is altered, it breaks all of the links to the following blocks.

2 - The block has the hash of the previous block and the new transactions. Then the nonce is guessed and included to create the new hash.

#572

  1. If they were NOT linked together CRYPTOGRAPHICALLY, the netork would be not as secure and hackable. It is in effect another layer of security.

  2. It comprises a number of data and elements, inc:
    Transaction data, Timestamp, Previous block hash, current block hash (based on prev block hash and current block data), Nonce

#573

Because each block has a consensus algorithm called POW which is based on the previous hash in the block (among tx:s in the actual block plus the nonce) and it is to make sure you can’t alter or remove the data in the previous block. If that happends, every following link will be destroyed and you’d have to solve the algorithms again which is next to impossible due to higher difficulty for every link. So it is for security reasons.

  1. Each block consists of previous hashes, transactions in the actual block and then you have to guess the nonce to be able to get the block added in the blockchain.
#574

  • Why is it important that the blocks are cryptographically linked together?
    So that one cannot go back in time and make changes to previous transaction and basically double spend

  • What does the block structure look like in bitcoin?
    Each block is built on previous one + current data + nonce all to come below target and then get accepted by the network, get linked and new block then starts being built

#575

1 so it is impossible to change something in te blockchain

2 each block has a hash, previous block hash a none an tx, in between the block is a link!

#576

1. Why is it important that the blocks are cryptographically linked together?
The idea is the transaction was the transaction. This is to prevent changes to previous transactions to avoid malicious activity. This is a method to increase security and validation, but also promote ownership over ones actions.

2. What does the block structure look like in bitcoin?
The block structure looks like a bunch of blocks linked together. It contains the transactions, previous hash, nonce, and new hash.

#577

  1. It is important because it makes the chain immutable. the fact that they are cryptographically linked means that in order to change the data on one block you would need to resolve the cryptographic puzzle in all of the blocks ahead of it.

  2. a block consists of a Block number, hash ( previous hash + current block data) a nonce, time stamp, merkle root, difficulty target.

#578
  1. So that no one can make modifications to the previously mined blocks and to ensure data integrity.
  2. It is a linked list with Hash of previous block, Tx in current block and nonce value collectively hashed and then appended to the block chain.
#579

1.-Then it is really hard to change a block.
2.-Hash based on Txs previous hash Nonce

#580
  1. Why is it important that the blocks are cryptographically linked together?

This ensures the validity and security of the network as each block is baked in. Any alteration to one block will invalidate subsequent blocks.

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

Data structures linked together.

#581

  1. It is important because of how secure it is. Because of the link it is impossible, or at least extremely hard to go back and alter a transaction made.

  2. The block is based upon the previous hash, the transaction, a nounce and the new hash.

#582
  1. It makes it difficult to amend the transactions in the blockchain.
  2. Hash, Transactions, Nonce more precisely here:

Hash
Confirmations
Timestamp
Height
Miner
Number of Transactions
Difficulty
Merkle root
Version
Bits
Weight
Size
Nonce
Transaction Volume in BTC
Block Reward in BTC
Fee Reward in BTC

#583

1- It’s important that the blocks are cryptographically linked together to keep everything secure because once you change one block all the other blocks would also change.

2- Previous Block Hash, A list one TX, Nonce

#584
  1. It is important that the blocks are cryptographically linked together because it ensures security, and immutability.
  2. The block structure in bitcoin consists of 1) the previous hash 2) the transaction list of the block 3) the mined/guessed nonse