Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1929

  1. Why is it important that the blocks are cryptographically linked together?
    It gives security, no way to change or cancel or modify anything in the block.

  2. What does the block structure look like in bitcoin?
    A block takes the hash of the previous block, the transaction list of the block, and a nounce (just a random number) to be guessed by the miner.

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#1930

1-to ensure that the system follows the rules maintaining the integrity of the information contained

2- the block has the previous hash, transactions and nonce

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#1931

  1. It’s important that blocks are cryptographically linked together because it provides for a unique connection between blocks that if one is broken then all the subsequent blocks will be broken as well.

  2. The block structure in bitcoin consists of the previous hash, new hash, nonce, block number and list of transactions on the block.

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#1932

  1. It is important because changing the data in a previous block will change the data in all future hash and require a user to decrypt all future nonces as well.

  2. The block has the previous Hash, transactions, and the nonce that creates the correct new Hash.

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#1933

  1. It makes altering any transaction impossible as altering a transaction would break the links of all the blocks

  2. The hash of the current block is based on the hash of the previous block and the hash of all the transactions within the current block. Nonce is a random number that is part of the current blocks hash.

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#1934

  1. It’s important due to security reasons (immutability). Otherwise, it would be easier to change a previous block or transaction.

  2. The block structure contains a list of transactions, hash (based on previous hash/block), and nonce (random number).

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#1935
  1. This helps prevent data inside blocks from being altered, changing one thing in one block would nullify the validity of all blocks in the chain after that block.
  2. The block structure looks like a linked list data structure, with each list containing a block header, the hash of the previous block, the transaction data, the once, and the hash of the current block.
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#1936
  1. To ensure that if you make a change to a passed block, all future blocks will fail.
  2. List of transactions.
    Hash of previous block
    Naunce.(Random number)
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#1937

1-> because this makes it harder to change the data inside the blocks, there for are hashpower needed

2-> A chain of blocks, each block contains data and the links between the blocks are based on hashes and those hashes are based on al previous data ans hashes, you can say Bitcoins block structure is serial so the say in one line

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#1938
  1. Why is it important that the blocks are cryptographically linked together? To ensure security and a trustless environment
  2. What does the block structure look like in bitcoin? Interlinked blocks, whereas each block contains the hash of the previous block, the list of transactions, the once and current hash.
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#1939

Q1. Why is it important that the blocks are cryptographically linked together?

A1. Blocks are cryptographically linked together for the purpose of security - i.e. to prevent existing blocks being tampered with/altered.

Because a block hash is dependent on the previous block’s hash, changing any details of a block would change the hash which would in turn result in the links being broken.

Q2. What does the block structure look like in bitcoin?

A2. The structure of a bitcoin is: a) The Block Hash + b) Transactions/details + c) the Previous Block hash + d) Random Number (the nonce) - bearing in mind that the block hash (a) is dependant on b), c) and d).

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#1940
  1. Why is it important that the blocks are cryptographically linked together? It is important that all blocks are link for the security of the blockchain making it impossible for anyone to change any information within a block because it will break all links between the blocks.
  2. What does the block structure look like in bitcoin? A bitcoin block structure consists of block number, time and date, all the transaction listed which is hashed, the previous hash of the last block and the nonce which is hashed to be lower than the target number.
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#1941

  1. The link tells us all the information is correct. If they were not linked, that would mean there is incorrect data somewhere.

  2. Transactions, previous hash, nonce.

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#1942

  1. It is important that the blocks are cryptographically linked together because it furthers efforts to make it more difficult to alter the confirmed blockchain in any way because you would need to apply new POW to recreate all the hashes in order to succeed… an impossible task.

  2. In bitcoin the block structure is as follows:

  • Version
  • Prev Block
  • Merkle Root
  • Time
  • Bits
  • Nonce
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#1943

  1. Why is it important that the blocks are cryptographically linked together?
    To ensure data integrity and security of the blockchain

  2. What does the block structure look like in bitcoin?
    Block structure = { Nounce, TX, Hash of previous block, Block hash}

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#1944
  1. Why is it important that the blocks are cryptographically linked together?
    For security. Change in the block causes breaking all links to the following blocks. Then is necessary to Re-mine all following blocks as well which is practically impossible to achieve.
  2. What does the block structure look like in bitcoin?
    Hash of the block is created by hashing data of: Previous Hash + TX in block + NONCE
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#1945
  1. Why is it important that the blocks are cryptographically linked together?
  2. What does the block structure look like in bitcoin?

1- It is important to be cryptographically linked, so that it makes it almost impossible to remove a block or change a transaction inside it which means in another word data immutablity.

2- Tx hash and Inputs and outputs, the hash of the block will be based on the hash of the previous block, so any change will change every thing and cut the links between blocks.

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#1946
  1. For security reasons. Iff the blocks would not be linked someone good go back in times and change 1 block without needing to changes the block that come after that one.
  2. The block structure is the previous hash plus the transaction in the new block. And you reach that by guessing the nonce. This also prevents you from changing something in the previous hash because then that hash will change and your new one also. The hash is like a unique fingerprint.
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#1947

1: Having cryptographically linked blocks makes it almost impossible for a block to be
tampered with as the data would have to be changed in all the other blocks almost
simultaneously which would be an incredibly difficult task.

2: The block structure on a bitcoin block has the block hash from the previous block,
transactions , and a nonce and a hash for the block.

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#1948

  1. to make shure the network is safe and following the rules of the protocool. The beautiful part of this is that when you wanna change 1 block you have to change all the blocks after that one and because there is gonna be a vew new blocks mined before you have that one you wanted to change it is almost impossible to tamper with it.

  2. it has a nonce code, utxo’s, previous hash, next hash, the transactioins, when the transaction is done, how big the transactions is in bits, the fees for the miner and also the difficulty target.

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