# Homework on Blockchain and Mining Visually - Questions

Homework on Blockchain and Mining Visually - Questions

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

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

• Why is it important that the blocks are cryptographically linked together?
to setup a blockchain of integrity, to secure the network to ensure no double spend
• What does the block structure look like in bitcoin?
linked list with hash of each block and hash of previous block in the blockchain. In bitcoin it will have UTXO and a current block reward of approx 12.5 BTC plus any transactions rewarded.
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.
1. This helps prevent the data from being altered. Data immutability

2. TX hash
Inputs
Outputs

1. The link between the blocks is a mathematical puzzle that links all previous blocks together.
2. The block is made out of data, previous block hash and a nounce, which is used to calculate a hash number below a threshold (difficulty).
1. Why is it important that the blocks are cryptographically linked together?
This makes it more difficult to change a block. When you change one block, you have to change all the blocks and create new hashed relations between the blocks, something which is impossible.

2. What does the block structure look like in bitcoin?
Version
Previous Block hash
Merkle root hash
Timestamp
Difficulty target
Nonce
Block Size
Transaction counter
Transactions

1. Cryptographic linkage ensures integrity of the blockchain. It makes network more trustworthy through maths.Cheating is disincentivised as remining is too costly.
2)Blockchain looks like a double linked datastructure where each block contains previous hash along with current transactions value.
1. Why is it important that the blocks are cryptographically linked together?

To ensure the whole system follow the rules, no one could change, modify, delete any history transaction practically.

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

In the block we have previous hash, transactions and nonce. The hash of current block base on all these three factors.

1. It is important that the blocks are cryptographically linked because it ensures the integrity of the data in the blockchain since if you change any previous block in the chain every subsequent block would then need to be re-mined.

2. The structure of a block in bitcoin contains the list of transactions, the hash of the previously mined block and the nonce, which is essentially a random number which is used to try and get the hash low enough to be accepted.

1. The network retains immutability by using a quality of hash functions, to create unique outputs, to link blocks. This means transactions cannot be censored, altered, or stopped by anyone.

2. Block number > Nonce > Transaction Data > Hash of the Previous Block > Hash of current block

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

so a change cannot be pushed onto the network. if a previous block changes, the hash changes and cryptographically link will break

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

A block contains a list of transaction data (UTXO’s), blocknr, nonce, previous block and current block hash.

1. Why is it important that the blocks are cryptographically linked together?
To make sure nothing can be changed because it would be too difficult to recalculate everything again.

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

• block size
• transactions + transaction counter
• nonce
• prev block hash
1. By cryptographically linking the blocks, it becomes impossible to manipulate the previous transaction as it will break the chain.

2. The block has 3 things based on which it calculates the hash of a block

• Hash of the previous block
• Transactions
• nounce which is a number randomely guessed by the miner (the correct one would be the one which makes the hash value lower than the target)
1. This way no block can be manipulated without destroying the chain. If you manipulated one block, you will automatically give a wrong forwarded answer (hash) to the next block.

2. Block–> nounce–>data–> hash of previous block–>hash of the current block

1. For the security and the integrity of the network, so that is more like data on a stone that cant be changed.

2. Previous Block Hash
A list one TX
Nonce

• Why is it important that the blocks are cryptographically linked together?
to make the blockchain more reliable.

• What does the block structure look like in bitcoin?
previous block hash, current block data and nonce.

• Why is it important that the blocks are cryptographically linked together?
The cryptographic link is paramount in the security and immutability of the blockchain.
• What does the block structure look like in bitcoin?
The blockchain comprises the Hash of the previous block, the UTXOs inputs and outputs and the fee and or Blockchain reward

Homework on Blockchain and Mining Visually - Questions

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

Because it makes almost impossible to do any change in the history of blockchain.

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

It consist of the hash of the previous and current block, list of transactions, nonce, amount of transactions, summaries, fee, times, sizes, version and reward.

1- to ensure that network safety and no previous block can be changed
2- a hash number based on random number, previous block hash, current block transactions