Homework on Blockchain and Mining Visually - Questions

[Lystopher]

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

• The blocks must be linked together as this ensures the integrity & immuatbility of the data being stored on the blockchain. The interlocking gaurantees this and reuires a 51% or + attack to disrupt making it majoritively secure.

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

• The block structure contains data from the previous hash, current data, current hash info and a valid nonce. Together these inputs generate a new hash that is crypticly used in the next hash calculation.

[motond30]

1. Why is it important that the blocks are cryptographically linked together?
   It is important because anyone trying to change a block from the past must re-mine all blocks moving forward. It makes it practically impossible to hack the network.

2. What does the block structure look like in bitcoin?
   a. Previous Hash
   b. List of Txs
   c. Nonce

[Noemi]

1. So one does not have to trust people, authorities, but only math and phsysics.
2. A block consists tx-list, prev. hash, nonce

[Riane_Louise]

1. It is important that blocks are linked together cryptographically so that a miner wouldn’t be able to change or alter a hash. Since the previous hash is need to create the next hash both hashes would need to change for it to be altered and it would also have to be re mined. This creates incentive to follow the protocol.
2. Block
   Hash
   Previous hash
   Transactions list
   Nonce
   Target number

[Cryptocle]

1. This ensures that previous blocks cannot be changed. Changing one block will break the whole blockchain from that point on.
2. The block hash is based on three things: the previous block hash, the transactions in the block and a nounce, which the miner has to guess. Blocks are linked to one another to form the blockchain.

[GarActual]

1. Why is it important that the blocks are cryptographically linked together?
   Keeps the blockchain secure
2. What does the block structure look like in bitcoin?
   Transaction data, nonce, hash form previous and current block

[MarkAlvee]

1. Its important that blocks are cryptographically linked together because it creates a sequence of integrity that can not be broken.

2. The structure of a block in bitcoin contains list of transactions, the hash of the previously mined block and the nonce.

[Blanca.Micu]

1. so the confirmed Txs cannot be altered and so the block would not become invalid
2. Txs, previous hash, nonce

[Rusokovich]

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

This is important to maintain the integrity of the whole networks, so the rules of the network are followed and discourage any transaction

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

block number
transactions
previous block hash
current hash

[Casperc]

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

to prevent anyone from changing data in previous blocks, it will impact the hash of the current block and linked block, which will cause it to be invalid

What does the block structure look like in bitcoin?

It will have the transactions and the previous hash from the previous block in it, with the nonce that’s being guessed.

[DNC]

1. Why is it important that the blocks are cryptographically linked together?
   So that the network will be safe (the blockchain unchanged) and not vulnerable to changes made to previous blocks.
   In order for someone to change something in a block and then have the single version of truth (the blockchain that the whole network accepts), he/she would need to remine the changed block, and all the blocks that follow (including those blocks that the network mined in the meantime).

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

• Block Header - Several fields form the block header
• Transaction Counter - How many transactions follow
• Transactions - The transactions recorded in this block

The structure of the block header:

https://www.oreilly.com/library/view/mastering-bitcoin/9781491902639/ch07.html

[Masterplan]

Why is it important that the blocks are cryptographically linked together?
To prevent the double-spend problem and secure the integrity

• What does the block structure look like in bitcoin?
  Contains the data (input, outputs, etc.) a hash of the previous block, Nonce

[Gry]

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

So that changing the blocks is more difficult.

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

Every block has a hash in it containing the previous block. Each block contains a nounce, block´s header and transactions.

[kiwicrypto1]

it causes a chain of perfect data that is pretty much unchagable

hash of previous block+list of utxo+nonce=current block hash

[Kerok]

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

• A blockchain has to be cryptographically linked together to ensure the integrity of the blockchain. Since the hash of a block is built up of the previous hash + the current block’s data, the whole blockchain is easy to validate and incredibly difficult to tamper with.

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

Bitcoin is structured in

• Identifiers (block hash, block height)
• A block header (previous block hash, nonce, merkle root hash, difficulty target, etc.)
• Transactions

[Jayman]

1. So that there is integrity and security. To prevent fraudulent attacks and data from being changed.
2. There is data of the previous hash of the block and the nonce which calculates the level of difficulty.

[miro049]

1. Since it secures the blockchain and makes all blocks links intra connected. If someone tries to change any transaction complete blockchain will be invalidated as all blocks are intra related.

2. Hash of the previous block + Data (transtactions) + Nonce = Block hash

[Talk2coded]

1. It enhances the security by ensuring that data/transactions aren’t altered.

2. linked list with hash of each blocks and hash of previous block in blockchain.

[Kerux_api]

1. This is very important so the blockchain network is secured and truthful mining integrity and very hard to be manipulated or compromised.

2. Block structure: hash, previous txns hash, transactions list and nonce.

[Spiros_Kaftanis]

1. Because this way it’s impossible to alter the past, which is essential.
2. A list of transactions, with the previous block hash and a nonce.