Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3035
  1. Why is it important that the blocks are cryptographically linked together?

This is key to the functioning of Blockchain since linking all the blocks secures the network and makes it very difficult to create invalid transactions.

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

The block structure is a sequence of hashes, where each hash is determined by the previous hash, the transaction data, and the nonce that the miners must guess.

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#3036

  1. It makes it almost impossible to manipulate the blockchain.

  2. transactions, previous hash value, nonce.

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#3037

-To ensure that the everyone follow the rules, no one could change, modify, any history transaction. ( only theoreticly)
-.The hash of the block is based on the transactions in the block and the previous hash, transactions and nonce

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#3038
  1. to secure the network. so that previous transactions canā€™t be modified.
  2. 1: Prev Hash
    2: Transaction List
    3: Nonce.
    4: Hash of the block
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#3039

  1. Because that means that if you change the hash of any previous block, you change the hash of any future block. This makes blocks that are cryptographically linked together, very secure.

  2. The block structure includes previous hash, plus data, plus nonce.

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#3040
  1. Why is it important that the blocks are cryptographically linked together?

That way no transactions can be changed in previous blocks because it would break the link
to the next block and all that follow.
The link between the blocks is a mathematical puzzle that links all previous blocks together.

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

The hash of the block is based on the transactions in the block(data),
plus the previous hash and the nonce that needs to be guessed.

Version
Previous Block hash
Merkle root hash
Timestamp
Difficulty target
Nonce
Block Size
Block header
Transaction counter
Transactions

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#3041
  1. Every new mined block contains the previous hash + link and everything before that in its hash.
  2. The block structure of BTC is: Previous Hash, Transactions, Nonce (random Number to be guessed by the miner)
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#3042

ADD to 1) because of the blocks being linked to each other they are very secure and practically impossible to manipulate or change.

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#3043

  1. Why is it important that the blocks are cryptographically linked together?
    its important because it creates trust within the network.

  2. What does the block structure look like in bitcoin?
    The block structure of bitcoin consist of, Previous hash,TX & Nounce. The hash of the current blocks are also base off all these details which = The current block Hash.

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#3044
  1. It is important to link the blocks so that nobody can go back to a previous block and make a change such as double spending. Any change will break all the links and will be seen by everyoneā€¦
  2. The block structure is a list of transactions. This list has a limited size. The block is linked to the previous block. The list of transactions plus the hash from the previous block plus the nonce must all be combined in one hash that is lower than the target required to allow the block to be appended to the chain.
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#3045

If you change something in the block, all links are broken. Need to solve a new puzzle. Requiring more mining/more difficulty.
Linked chain of blocks with Hash, tx, and noonce

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#3046
  1. To ensure the integrity of the data in the blockchain.
  2. The data contained in each block is: a) list of transactions
    b) hash of previous block
    c) nonce (random number)
    sha256(data) = hash ā€“ of new block needs to be equal to or lower then set target number.
2 Likes
#3047
  1. So noone can just change the information in a previous block.
  2. ItĀ“s made up of the hash of the previous block, transactions and the nonce.
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#3048

1 That makes that the previous txs cannot be changed, it secures the blockchain and makes imposible oracticly to double spend.
2 Data transactions, previous has.new hash, nonce

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#3049
  1. To make the network secure, it impossible to change the data.

A list of data resembling a ā€˜blockā€™ the data includes the transaction data hash, the previous block hash, the nonce

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#3050
  1. Why is it important that the blocks are cryptographically linked together?
    Its practically impossible to change the information in previous blocks because we have broken links between the blocks - remining necessary.
  2. What does the block structure look like in bitcoin?
    We have the hash of the previous block, tx list and the nonce.
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#3051

1. Why is it important that the blocks are cryptographically linked together?
It is important they are linked together to make an immutable link of data that cannot be changed without destroying the entire sequence and having to re-add all the new information within the same hash function. The process of cheating an changing is simply too costly and practically impossible to do.

2. What does the block structure look like in bitcoin?
A block structure looks like:-
PREVIOUS HASH
CURRENT TX LIST
NONCE(random number)

This block is then put into a has function in the hope the nonce is below or on target.

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#3052

1- It is important, so miners do not fix data in their block and to improve security overall.
2- It is linked blocks with data that are all confirmed with each other. Each block has a TX+Hash from the prev. block+ Nonce+ newly generated Hash.

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#3053
  1. It is important that blocks are cryptographically linked together because it ensures that protocols are being followed.
  2. includes previous hash, nonce, and transaction list
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#3054

  1. Because in this way greater security is achieved in case someone wants to modify something

  2. It has, the block number, the transactions, the hash of the previous block and the nonce.

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