Homework on Blockchain and Mining Visually - Questions

[myrm]

1. It protects the information in the block and it makes it immutable.
   It makes the blockchain secure.
2. Block Structure:
   • Hash from previous block
   • Transaction list
   • nonce (create the new hash)

[Fabrice]

@Nusterik

transaction data, mining difficulty and nonce

Most importantly, hash of the previous block. To ensure the blocks are cryptographical linked together.

[youri]

1- it is really important for the security of the blockchain, no previous transactions can be changed because it would break the link in between blocks.

2- the hash of the block is based on the hash of the previous block, plus the transaction list and the nonce that has to be guessed.

[KryptoDr]

The cryptographically linked blocks make the blockchain secure and unique. It is nearly impossible to change some previous blocks (theoretically possible) because the link of the current block is based on all previous blocks (and also the puzzle which were solved by the miners). When you want to change one previous block you have to remine every following block. This is very time consuming and expensive. In practical, this is impossible to do.

2. A block consists of the transactions (TX), the hash of the previous block and the nonce.

[mr_e]

1. To ensure that data has not been altered in previous blocks, all blocks are linked together. If any block is altered, the hashes of all proceeding blocks will be changed, requiring them to be re-mined.

2. Blocks are structured by hashing the previous block’s hash, the current block’s transaction list, and a nonce that provides a hash below the target, set by the network difficulty

[Rainer]

1. The blocks cannot be changed as any change in a previous block changes the ongoing next
   created block. So it is a matter of security and immutability.
2. The block header, the transactions, the nonce for the target and the previous blocks hash
   together with the link or output to the succeeding block.

[Wargor]

HI,
1, It provides security against double-spending, changing values of accounts, etc. Without it we would be able to mess with blockchain in any way we want because is public.
2, header, size, transactions, nounce, previous block hash

[DanEvils]

1. Why is it important that the blocks are cryptographically linked together?
   it provides security in the blockchain it prevents someone from changing a previous transaction,

2. What does the block structure look like in bitcoin?
   it consist of: Block header,HASH of previous block, transactions and block size…

[Svetoslav_Mandichev]

1 because it makes it very difficult ( next to impossible) to tamper with the transactions ,because if you want to go back and change information in a older block you will have to remine all the block after that block because of the changing hash
2 the hash , the previous block hash , the transactions data and the random number ( nonce)

[Ross_Mathews]

1. Why is it important that the blocks are cryptographically linked together?/ It is important because it because previous transactions can’t be altered this ensures no funds can be double spent.
2. What does the block structure look like in bitcoin?/ Current block transactions and previous hash data

[Kakurat]

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

• This ensures that any changes that are made to a part will affect the whole of the blockchain. This would require all the blocks to be re-mined or the chain would be invalid.

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

• Hash (Previous hash, tx list, nonce)

[Crypto2revo]

1. It creates data immutability as no one can alter the data from the past because they will have to re-mine all the blocks coming after it which becomes exponentially harder and practically impossible.
2. The structure consists of previous hashes, list of transactions and nonce.

[Web2Hotel]

1
To secure the network: The proof of work ensures it’s not easy someone cause double-spendings or 51% attacks.

2
Like a chain of blocks containing the block number, the nonce string, the list of the UTXOs, the hash of the previous block, and the the hash of the current block
as the working model in https://andersbrownworth.com/blockchain/blockchain

[dpopp1]

1. Why is it important that the blocks are cryptographically linked together?
   To increase the integrity & security of the blockchain.
2. What does the block structure look like in bitcoin?
   It will have hash of previous block with tx data, nonce, block size.

[Mrbryce]

1. This is important as this ensures honesty within the block. Going back and changing anything will brake the link between blocks.
   2.The block structure is a Merkle Tree
   .

[medo_nz]

1. This ensures security and immutability of the network as in by this design, changing data in a single block would change the hash of all proceeding block. This would require someone acting maliciously to not only re-mine the block in which the data was changed, but all the proceeding blocks.
2. Contains the hash from the previous block, the hash of the transaction data in the block (via merkle tree root) and the nonce (random number).

[Bananoid]

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?

1-So if something changes in a block it also change on every other block, making the system trust worthy, immutability.

2-The block number, the Nonce, the actual transactions, the previous Hash and the actual hash of the block

Tarea sobre la Cadena de Bloques y Minado visualmente - Preguntas

1. Porqué es importante que los bloques esten criptográficamente vinculados?
2. Como está compuesta la estructura de un bloque de bitcoin?

1- Si algo cambia en un bloque también cambia en todos los demás, esto hace confiable al sistema, inmutable.

2-En orden, el número de bloque, el “nonce” (número a encontrar), las transaccciones actuales, el hash anterior y el hash del bloque actual.

[cme]

@ivan

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?

1. to assure the immutability of the blockchain to the past blocks, so that it becomes almost impossible to change previously confirmed blocks.

Block[

1. • Magic,
2. • Blocksize,
3. • Blockheader[
     1. Version,
     2. hashPrevBlock,
     3. hashMerkleRoot,
     4. timestamp,
     5. difficultyMask,
     6. Nonce],
4. • NumTransactions,
5. • {transaction_list}]

[Aaron_Lyndon]

1. Why is it important that the blocks are cryptographically linked together?
   one slight change to the data within the blocks changes the cryptographic link and breaks the network link. So having blocks cryptographically linked together creates the highest security within the network. Nothing can be tampered with once transactions are confirmed within the network.

2. What does the block structure look like in bitcoin?
   Block 1:
   a)previous block hash
   b) transactions (Data) within new block
   c) nonce
   Steps a, b & c are used to calculate the new hash number for block 1.

[jpc]

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

1. so that if any changes are added to any block in the blockchain it will break the links from that block onwards.

What does the block structure look like in bitcoin?
2. The hash of a block is determined by the hash of the previous block plus TX’s in existing block and a random number (nonce) such that the resulting hash is less than the ‘target’ number (which is determined by the current difficulty level).