Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1869
  1. If the blocks are not cryptographically linked. then its not a block chain
  2. Block number, nonce, previous block hash, list of tx, hash of current block.
1 Like
#1870

  1. So no one can create false transactions.

  2. Inside each block is a hash which is made up of information from that block along with information from the previous hash in the chain. It also includes a nonce which needs to be correctly guessed by miners in order to add their block to the chain.

1 Like
#1871
  1. Why is it important that the blocks are cryptographically linked together? this link is very important and represents an important role of PoW, each Link is based on the previous transactions and link it is what allows the protocol to keep a trustless system whereby nothing can be changed only added.
  2. What does the block structure look like in bitcoin?
    (Previous hash, current tx, nonce) = Current Hash that must be less than Target
1 Like
#1872

1.for the safety and integrity of the chain
2.blocknr.
nonce
transactions
hash of block
hash of previous block

1 Like
#1873
  1. Because change in one block destroys connection to all blocks after it.
  2. Each block contains transactions, hash from previous block, nonce and some more data.
1 Like
#1874

Homework - Mining Part 2

The link is important to ensure the blockchain is immutable and users can trust previously confirmed transactions are not modified.

Each block contains a hash of the previous block, a nonce (random number used to solve the “puzzle”), and the transactions to include in the current block. Some additional information is included in the block header as well, difficulty target, timestamp, hash of transactions in block.

2 Likes
#1875

  1. The cryptographic link secures that no one cane change the data in any block without need to recalculate the hashes of the changed block, as well as all subsequent blocks. It preserves the consistency of the blockchain.

  2. The block itself consists of the reference to the date and time of its creation, block header, transaction counter, transaction data added from a mempool, as well hash number. The hash number is the Sha256 algorithmic function of the three inputs: hash number of the preceding block, the data of the current block and a random number called nonce.

1 Like
#1876

  1. This is what allows for data to only be added to the blockchain and never removed or changed

  2. The structure of a bitcoin block is the transactions, the previous block’s hash, and the nonce

1 Like
#1877

  1. It links all the blocks together so that no transaction can be changed/modified/deleted in the previous blocks. it secures the blockchain network.

  2. The block contains of block nr., data(Txs), previous hash and nonce.

1 Like
#1878

  1. To increase security. Difficulty increases if you try to change blocks deeper in the chain. More confirmations (blocks added after your block) more computation power is needed to change things;

  2. Magic no, Blocksize, Blockheader (Version, hash of prev. block, merkle root, current time, current difficulty target, Nonce), Transaction counter, transactions.

1 Like
#1879

  1. It is important because that’s the only way to keep it honest, inmutable, trust less. Linking past blocks with future ones.

  2. Previous hash, TX list, nonce

1 Like
#1880
  1. Why is it important that the blocks are cryptographically linked together?

this makes it so no one could change information (transaction info) in a previous block - makes the blockchain immutable

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

blocks include the previous blocks hash + current block’s transaction data + nonce

1 Like
#1881
  1. Creates a network that can’t be altered due to each link connects information of previous blocks.
  2. previous hash, transaction, nonce
1 Like
#1882
  1. It is important that blocks are cryptographically linked together because it makes the blockchain immutable. No one can go back and change a historic block because it would invalidate all following blocks, because they are based off the previous block’s hash which used inputs containing transactions, timestamp, nonce, and it’s own previous block’s hash.
  2. Transactional data, Timestamp, Nonce, and Previous Block Hash
1 Like
#1883
  1. Why is it important that the blocks are cryptographically linked together?

Previous blocks data cannot be altered without disrupting all blocks afterwards. This makes the network secure and immutable. The difficulty of solving the encryption puzzle discourages users from altering previous blocks and breaking from the rest of the network.

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

A bitcoin block records the time of its inception, records of recent transactions, the hash of the previous block, a unique hash unto itself based off of the data it includes (tx, nonce, previous hash).

1 Like
#1884
  1. So that it is, practically speaking, impossible to change transaction information inside of a block without then needing to change all of the information and hashes of other blocks. It removes the possibility of fraud.
  2. hash of previous block + transaction information + nonce are combined to create the new hash/ digital fingerprint
1 Like
#1885

  1. Is it important that the blocks are cryptographically linked together because then it can make a strong chain of information. If you go back and try to change an old block it will invalidate all of the newer ones that have since been made, meaning that you would have to go back, rehash all of the newer blocks and current blocks faster than all of the miners that are validating on the true chain.

  2. Bitcoins block structure looks like: Hash of previous block, Merkle tree, nonce, and time stamp.

1 Like
#1886

  1. Why is it important that the blocks are cryptographically linked together?
    So that you cannot change the previously added blocks.

  2. What does the block structure look like in bitcoin?
    Hash from the previous block + transaction + Hash for this block

1 Like
#1887

  1. It is crucial for the blocks to be cryptographically linked together so that the blockchain can achieve immutability. This is due to the fact that, with that feature, changes in a previous block affect all subsequent blocks, forcing all of those to be remined by the miner who tries to introduce that change. Without that cryptographic link between blocks, the history of transactions that is recorded in the Blockchain would not be practically and financially impossible to manipulate

  2. In a simplified way, a Bitcoin block includes the following parts in its structure:
    Block number, Nonce, Transaction data, Hash of the previous block, Hash of the block

1 Like
#1888
  1. It is important that the blocks are cryptographically linked togather to have absolute security of the network. This will prevent any change in the data in past blocks or it will be a false chain and will not continue to move on.
  2. Block structure is like a chain of blocks and each blocks are filled with number of transactions hash and blocks are linked with previous and next block in the chain via the algorithm.
    Its main contents are transaction Id, inputs and output transactions having different addresses.
1 Like