Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#4442

1. Why is it important that the blocks are cryptographically linked together?
In this way it makes it harder to change any block without affecting the rest.

2.What does the block structure look like in bitcoin?
Previous block hash, List on unconfirmed transactions, Nonce

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#4443
  1. Why is it important that the blocks are cryptographically linked together?
    [Ans] Primarily two reasons, First the validation and verification process becomes impractical to break/modify and second it provides ways to trace-back and maintain history of transactions.
  2. What does the block structure look like in bitcoin?

image

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#4444
  1. Why is it important that the blocks are cryptographically linked together?
    Cryptographically linking every block ensures it is very difficult to change the history of the blockchain.
  2. What does the block structure look like in bitcoin?
    Each block contains a nonce, data, and the hash of the previous block, all three of which are used to generate the hash of that block. Every block thereafter contains the same combination of the nonce, data, and previous hash, thereby creating the ‘links’ in the chain.
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#4445

  1. It is important as the hashes for each block contain the hashed value of all the transaction data in that block + the hash value of the previous block. So, if any digit/character/space or whatever is altered in block X, then blocks Y > Z > A > B > C hash value will alter making all links break and voiding any wrong doers claim of block X.

  2. A chain. Hence the name Block-CHAIN. Example, ▢-▢-▢-▢-▢ - Each square represents a block consisting of the transaction data for that block followed by a linking line representing the hash value of the preceding block making it look like a chain.

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#4446

  1. So that when a block is changed all the subsequent one are invalidated

  2. Block structure has the transactions, hash of the previous block and nonce

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#4447

  1. It creates an unbreakable chain known as the blockchain.

  2. It is composed of sequential groups of data that are put together into blocks strung together.

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#4448

  1. Why is it important that the blocks are cryptographically linked together?
    The linking of blocks creating the chain in blockchain, is what keep the data of past transactions secure and impermeable to alteration (i.e. double spending) in the future.

  2. What does the block structure look like in bitcoin?
    Each block is a unique combination of the previous block’s hash, the transaction data to be included, and a nonce, which has to generate a hash below the current target to be accepted as the next block in the chain.

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#4449
  1. Why is it important that the blocks are cryptographically linked together?

If the blocks were not cryptographically linked together there is no way for miners to accurately verify previous transactions, meaning a person can double-spend and edit the current and previous blocks and there would be no way to find out.

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

Each block is approximately 10mins long. The block has all the verified transactions that happened in that 10min window. Each new block will take data from the last block and data from the current block to process the current block.

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#4450

Homework on Blockchain and Mining Visually - Questions:

  1. Why is it important that the blocks are cryptographically linked together?
    Because it secures the blockchain and makes sure a block is practically impossible to change. Any change to a block invalidates the link to the next block and all sub-sequent blocks and links following.

  2. What does the block structure look like in bitcoin?
    A block is composed of:

  • The transaction data
  • The hash of the previous block in the blockchain
  • The nonce
    The hash of the block is calculated based on those 3 information.
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#4451
  1. For enhanced security, the blocks are cryptographically connected so that any outsider tries to tamper the block in between, then the whole blockchain becomes invalid
  2. The transaction details as data, the “nonce” a magic number and the previous block hash are the elements which forms the block structure.
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#4452

  1. Blocks are cryptographically linked to make it difficult or to deter any changes to previously added blocks

  2. A block consists previous hash, transaction I/O, and the nonce

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#4453
  1. It is for the integrity of the blockchain, all transactions are linked and can be traced.
  2. Transaction hash, inputs and outputs
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#4454
  1. to make the blockchain tamperproof
  2. Hash of previous block, nonce, transactions of current block
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#4455
  1. Why is it important that the blocks are cryptographically linked together?
    In order to ensure the integrity between each block. And because of each puzzle is linked to blocks and, in addition, to the links between each block?
  2. What does the block structure look like in bitcoin?
    In a block structure, we have a hash (based on the following elements), a hash of the previous block, all transaction data in a list and a nonce number.
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#4456

  1. Why is it important that the blocks are cryptographically linked together?
    This creates the difficulty of hacking a block. Each block is dependent on the previous block for it’s hash ID. Therefore, if someone hacks a block and generates a new hash for that block with the edited transactions, that hash would no longer match to the hash of the next block in the chain, which would also require re-solving, and so on and so forth, all the way up the chain to the most current block. The amount of computational power would be staggering.

  2. What does the block structure look like in bitcoin?
    Each block consists of the hash of the previous block, the transactions, the nonce, and it’s own hash.

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#4457
  1. It is important that the blocks are cryptographically linked together so that the previous blocks are used in the new blocks calculation, making it so that if you were to change anything in a previous block it would also change every calculation for each block after it. This is important so people cant go back and change previous blocks
  2. Block structure in bitcoin looks like : The previous blocks hash, Transaction info, Current block hash. and block nonce
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#4458
  1. So that the POW can be trusted to ensure as the blocks are added it is more difficult for someone to go back and change a transaction.
  2. The block hash, previous hash, transactions and the nonce
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#4459

Homework - mining part 2

Why is it important that the blocks are cryptographically linked together?
Because if you change a older block, the new blocks will become invalid. This makes it impossible to alter the blockchain.

What does the block structure look like in bitcoin?
The block is build up with transactions and a header at the top containing the metadata.

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#4460

  1. Why is it important that the blocks are cryptographically linked together?
    It provides security, accuracy and immutability. Incentivizes miners to play by the rules

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

The block structure takes the hash from the previous transaction then adds in the new transaction ID. From there, the miners must guess the nonce based on the previous hash and new transaction ID

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#4461

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

=> Because a change down in the blockchain “bubbles up”, breaking the hashes and links all the way up and causing the whole blockchain to be invalid.

What does the block structure look like in bitcoin?

=> A bitcoin block has transactions, the nonce and a link to the previous block.

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