Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3416

1. Why is it important that the blocks are cryptographically linked together?
to ensure the security of a blockchain

2. What does the block structure look like in bitcoin?
previous block hash
Tx’s
nonce

1 Like
#3417

  1. For the integrity and and security of the blockchain.

  2. It has the hash of the previous block, the block size, the nuance, transaction data and hash of the current block.

1 Like
#3418

  1. Why is it important that the blocks are cryptographically linked together?
    If one block changes, all the hashing for the following blocks would have to change. The cryptographical connection of the blocks makes them unique and depended on the previous blocks.

  2. What does the block structure look like in bitcoin?
    A block is made up of the previous blocks hash, current transactions in the block, and a random nonce. All three of these data are hashed and compared to the target difficulty.

2 Likes
#3419

  1. To prevent data from being modified. If you want to change one block you have to remine all the following blocks which is almost impossible.

  2. Magic no, Blocksize, Blockheader, Transaction counter, transactions

1 Like
#3420
  1. To ensure that the block are not changed or modified
  2. The block structure is made as follow:

-nonce

-tx’s

-previous hash

-hash

1 Like
#3421

  1. The blockchain gains its immutability from the fact that each block contains a hash of the previous block. This means that making any changes to a block which is not the most recent, would break the link to subsequent blocks. The result is that the only way to tamper with a past block is to then also re-mine all subsequent blocks fast enough to catch up with and overtake the authentic chain - this is, for all intents and purposes, impossible.

  2. Each block contains the transactions to be verified, the nonce which the miners must guess, the hash of the previous block, and a timestamp.

1 Like
#3422
  1. Why is it important that the blocks are cryptographically linked together?

To keep integrity and immutability securing the network and avoiding double spending

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

Previous hash
Transactions
Nonce

1 Like
#3423

1. Why is it important that the blocks are cryptographically linked together?
To ensure that the chain becomes invalid when one previous block will be changed.
2. What does the block structure look like in bitcoin?
The block structure consists of the previous block hash, the transaction list and the nonce (random number guessed by the miners).

1 Like
#3424
  1. Why is it important that the blocks are cryptographically linked together?

It is important for the security of the blockchain. That way no transactions can be changed in previous blocks. Otherwise it would break the link to the next and all the following blocks.

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

It consists the list of transaction data, hash of previous block and nounce.

1 Like
#3425
  1. Embedding the hash of a previous block in the current block is the feature that “chains” the blocks. Without it, we wouldn’t be using “blockchain” technology.
  2. There are a few key elements to a block in bitcoin: the previous block’s hash, the tx data from the current block, and a nonce, which are hashed together to produce the current block’s hash.
1 Like
#3426
  1. Why is it important that the blocks are cryptographically linked together?
    it makes sure that if someone tries to change something in an older block, every hash of the blocks after them get changed. wich makes them invalid and have to be all mined all over again.
  2. What does the block structure look like in bitcoin?
    Blocks are appended together by a nonce. The hash of each block and transactions within are connected cryptographically to each block. Changing the slightest piece of data in any block throws the whole chain out of sync and consensus for the change is rejected
1 Like
#3427
  1. It will make network secure, so no one can cheat on it
  2. It will has transcation and input and prev hash
1 Like
#3428

  1. To protect the blockchain and the data from being changed.

  2. It contains a list of transactions, the hash of the previous mined block, the nonce, the data, and the current hash.

1 Like
#3429

  1. Because otherwise it is no longer a one way mechanism and you could basically delete or reverse transactions on previous blocks without the network being notified of it happening and even if they did find out something was wrong with the network it would make it very difficult to identify where exactly the breach had occured.

  2. Block are connected to eachother in a linear way where each block contains txs of that block plus the hash of the previous block and a nonce which is guessed by the miner who mined that block.

1 Like
#3430
  1. It is important that all blocks are cryptographically linked so that information is perpetuated through time which also increases the blockchain’s security as a whole. This prevents double spends / and other fraudulent activity from occurring because if the information is changed in one block, it changes the information in all the successive blocks.
  2. Blocks contain information about Txs / previous hash / current block’s hash / and the nounce.
1 Like
#3431

1 To secure the network. So any change in an old block need to update all the next ones.
2 current block transactions, nonce, previous block hash and hash of all that info.

1 Like
#3432
  1. It is to secure the network. If one is changed, the link to the others will break. This prevents changing

2 Each block contains the hash of the previous block, the transfer data and the nonce

1 Like
#3433

  1. To ensure validity within the whole blockchain making it impossible to alter one section without disrupting everything that follows.

  2. Previous block’s hash, Transaction data, Nonce

1 Like
#3434
  1. Integrity, security, and more difficult to change.
  2. Previous hash, tx list and nonce.
1 Like
#3435

  1. This ensures the integrity of the blockchain requiring all valid transactions to be linked together based on the hash of each previous block. This makes manipulating the network is only possible by remining all blocks after a fraudulent + all new blocks.

  2. This structure looks like a chain that links each set of previous transactions to the next… a blockchain,

1 Like