Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#182

ivanLeader

Jun '19

Homework on Blockchain and Mining Visually - Questions

1. Why is it important that the blocks are cryptographically linked together? - Because the crucial ledger Integrety and POW are created from the contents of existing blocks. If a transaction is altered or removed from a block, the link will be broken and the block rejected.
2. What does the block structure look like in bitcoin? - A block consists of a previous hash, a Tx List and a Nonce. When successfully mined, it is linked to the previous block and the new block.

#183
  1. Why is it important that the blocks are cryptographically linked together?

On the one hand, it makes it difficult to alter history, and on the other hand, it raises the security by including the hash of the previous block in the calculation of the mathematical puzzle of the current block.

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

It has the block number, the nonce, the transactions,the previous block’s hash and then the current hash.

#184
  1. so no entity could ever rewrite history of the ledger.
  2. block header, block size, transactions + transaction counter, nonce, prev blocks hash
#185

because any attempt to change a transaction in a block means all blocks in front have to be remined. A block linked by hashes

#186
  1. Why is it important that the blocks are cryptographically linked together?
    Because of the security of the whole blockchain. So every node have the same blockchain.
  2. What does the block structure look like in bitcoin?
    It consists the list of transactions, the hash of previous mined block and the nonce, with is a random number.
#187

Its important that blocks are cyptographically linked together in order to secure the ledger. It ensures that no one can change the ledger without having to re mine the hashes of the changed block and every block that followed it. Nearly impossible without have 51% of the collective hash rate of the network.

The block structure is a combination of the previous blocks hash, the current new transactions and the correct guessed nonce number. all these parameters need to be under the target hash number set up by the chain to be accepted by other nodes before the block can be linked to the chain.

#188

1.why is it important that the blocks are cryptographically linked together?
because it secures the whole chain with every new block added to the chain

  1. What does the block structure look like in bitcoin?
    each block starts with the hash of the previous block then the transactions in the block and a pointer to the next block
#189

1. Why is it important that the blocks are cryptographically linked together?
For the security of the blockchain, preventing data from being altered. If a block is changed the link is destroyed and needs to be remined.
2. What does the block structure look like in bitcoin?
hash, previous hash, tx, nonce

#190

  1. It is important that the blocks are cryptographically ilinked together because it makes it impossible to change previous already approved transactions. In other words it makes sure the integrity and level of security in the network is very high.

  2. The block in bitcoin consists of data (current block transactions), previous block hash and nonce.

#191

  1. It also makes it impossible to change previous blocks. If you change a previous block, then it breaks the link because it creates a new hash. Then, you would have to create new hashes for all of the broken links. Since it would take thousands of years to recreate the links with new hashes, it disincentivises anyone from altering history.

  2. Block number, Nonce, Data, Hash (from previous block), Hash (from current block)

#192

Homework on Blockchain and Mining Visually - Questions

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

This way security is guaranteed because everything is connected. If something is changed in the previous blocks, the links of the following blocks will be broken.

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

Version
Timestamp
Nonce
Difficulty
Root hash of the merkle tree of all the transactions
Previous block header hash
Block header hash

#193
  1. Why is it important that the blocks are cryptographically linked together?
  • verifies the state of the complete chain is correct
  • makes it impossible changing data in previous blocks without breaking the the consistency of the chain
  1. What does the block structure look like in bitcoin?
  • hash of ancestor block
  • transaction list
  • nonce
  • time stamp
  • version
#194

  1. Why is it important that the blocks are cryptographically linked together? - this is important so information in previous blocks cannot be changed without breaking the hash link to the next block. This ensures the blocks remain immutable.

  2. What does the block structure look like in bitcoin? - block number, Nonce, Transaction Data, Hash of the Previous Block, Hash of the Current Block.

#195
  1. so any change to a previous block invalidates the future blocks.
  2. previous block hash, transactions hash, nonce
#196

cryptographic linkage preserve the finality of the data
previous hash, transactions and nonce compose the structure of the the btc block

#197
  1. becuse then it becomes tamper proven
  2. like a string of blocks or rather a chain that cant be broken
    every block contains a =
    timestamp
    nonce
    previosly hash
    transactions
    current new hash
#198
  1. For network safety
  2. Current transactions block
    Previous hash
    nonce
#199

1- In order to ensure non-reversibility of transactions as well as immutability of data

2- The block includes the hash of the previous block, the transactions list and the nonce. These are hashed together until they reach the target hash.

#200

  1. To keep the pow and keep the Network safe, cause all links are based on the previous Block hash

  2. Block number, nonce, tx data, hash of prev. Block = Hash of current block

#201
  1. It is important as any changes to a block will effect the hash of the other blocks that follow where the change was made, therefore links will be broken.
  2. You have the hash of the previous block, the transactions, nonce and the hash of the current block.