Homework on Blockchain and Mining Visually - Questions

[Alex22]

Yeahhh it’s a hash, a footprint from the transactions data, the hash of the previous block and the nonce. Thanks for the push !

[redux]

1. Why is it important that the blocks are cryptographically linked together?
   It makes it practically impossible to change a transaction in the blockchain since all the blocks after are depending on the hash of the block that is being changed.

2. What does the block structure look like in bitcoin?
   Hash of the previous block
   Hash of the block data
   Hash of the nonce

[JoseE]

1. It is very important to link the blocks, this for making the blockchain inmmutable. If you change, manipulate or erase any information, the link will be broken, this causing a rejection to the network.
2. Previous Hash / Transaction List / Nounce

[RonJambo]

1. To ensure data integrity, making changing old blocks practically impossible.

2. Blocks consists of the block number, hash of the previous block, the nonce, the target, plus the hash of the current block.

[NickCryptoInvestor]

1. Why is it important that the blocks are cryptographically linked together?
   By linking each block on a chain ensures integrity of the transactions because it makes really difficult to change any thing nearly impossible.

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

• Hash of the block
• Id of the block
• Data (Transactions list) of the block
• Previous hash of the block
• Nonce of the block

[Kenny.7410]

1. Because it means that everyone collectively agrees on previous transactions and on wallet balances, preventing double spending.

2. The block structure is a string of blocks, each relying on the previous block to have the correct output hash. Otherwise the chain would be broken because the previous blocks would not equal the subsequent block hash.
   Consisting of the block number, nonce, data(transactions), input hash and output hash.

[Miguelislegend]

1.The link created makes it harder to change the blocks.
2.The block structure looks like data structure of the previous block hash, a nonce, difficulty target, and transactions.

[Liquidbaker89]

1. Its important that the blocks are linked together so that blocks are extremely difficult to change; immutability and making a double spend impossible.

2. The block structure is composed of: hash from previous block, hash of current transactions to be put into this block and the fees associated.

[Fima]

1. Why is it important that the blocks are cryptographically linked together?
   A: It is important for the security of the blockchain.
2. What does the block structure look like in bitcoin?
   A: data, previous block hash and nounce.

[Lara1mariah]

1. Why is it important that the blocks are cryptographically linked together?
   Having the blocks cryptographically linked together makes it impractical/impossible for a minor to cheat and alter a block. The link will force the minor to have to update every single block created after the change was made which is not possible.

2. What does the block structure look like in bitcoin?
   A block will have the hash from the previous block, the transaction list, and a nonce. That block will then have its own hash that is linked to the new block.

[Leonard_Gohlke]

1. If not, it would be easy to change one block and the network would be secure anymore

2. Block Structure:

Nonce
+Previous hash
+Transactions
=>Hash

[Y2z3H]

1. Since the connection between the blocks is a mathematical puzzle, it makes it practically impossible to alter, thus enforcing the concept of immutability.

2. The block structure of BTC:

• Nonce
• Data
• Previous Hash
• Target Number

[Adrian1980]

1. It is important that the blocks are cryptographically linked together so the network is kept secure , no transaction is changed because it will change all the blocks that follow.
   2.The blockchain looks like this : Inputs , outputs, hash , nonce , blocks.

[hartfield97]

1. It is important for the blocks to be cryptographically linked together because this creates the trustless system that allows all transactions to be tracked
2. The block structure contains the transactions (usually the ones with the highest fees), the previous hash and the nonce

[Mrcrypto1]

1.) It’s important that the blocks are cryptographically linked together because it makes it harder for someone to back change a block.
2.) The block structure of Bitcoin involves the miner’s transactions, previous block’s hash and a nonce.

[joshuamonteiro]

1. Why is it important that the blocks are cryptographically linked together?
   To secure the blockchain
2. What does the block structure look like in bitcoin
   The hash of block is based on transactions in the block plus previous has and the nonce has to be guessed.

[jae_mclean]

1. it is important that blocks are cryptographically linked for the purpose of maintaining a secure trusties society by proving providence.
2. in bitcoin the blocks carry verified data from 1 block to the next, each block contains a nonce, data and previous hash, once mined succesfully to calculate the nonce which will create a new hash. any data change will void all links.
   In next block once linked the current hash will be previous hash in next block.

[MPatrick]

1.Because this link is the result of a lot of work and cannot be easily replaced.

2.The block contains a list of several transactions chosen by the miner from among those that provide the greatest financial return. This block will be represented by a hash that will serve as a unique identification, originated from the transaction data of that block and the hash of the previous block, as well by a random number called ‘nonce’.

[ClaudiaM]

1. The fact the the blocks are cryptographically liked together determine the unbreakable integrity of the network.
   2.Each block is composed by:
   The hash from the previous block
   A transaction list
   when mining a nonce is calculated in order to hash the block and as a result it should give a number smaller than the target.

[tony1999]

1. The nomenclature is very simple. Block. Chain. Chain of blocks. If the chain is broken, all blocks after that point would be invalidated. This way, no one can “double spend” or create fallacious transactions.
2. It’s basically a doubly linked list. The hash of a block is calculated depending on the previous block’s hashes, transactions, and a random nonce. These 3 inputs are passed into the hash function (SHA256). The transaction list can change depending on how many transactions are done on the network, but the blocks previous hash stays static. The value that never stays static is the nonce, which is repeatedly guessed by the miner program until a hash is given that meets a value below the target, which is decided depending on the difficulty.