Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3617

The cryptographical links makes it very hard and costly to change a confirmed block
A block contains transaction, previous hash, nonce and the hash

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#3618

  1. The importance of cryptographic linking is to make it more difficult to create fraud, double send, etc… It forces a miner to cover their tracks by having to change the hash of each successive block in the cryptographic link, and also the new blocks being mined after their initial interruption.

  2. like a train of blocks to me.

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#3619
  1. So that nobody can change a previous block without change all the following blocks too
  2. The block is made of the data(transactions), plus the hash of the previous block plus a nonce which should be guessed
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#3620

1 Why is it important that the blocks are cryptographically linked together?
It is important that the blocks are cryptographically connected together in order to prevent any transactions from being altered. It ensures consistency and immutability.

2.What does the block structure look like in bitcoin?
The block is made of a header, containing metadata, followed by a long list of transactions that make up the bulk of its size

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#3621

1. Why is it important that the blocks are cryptographically linked together?
Ensures that the network is secure as it will be not possible to change a block in the past.

2. What does the block structure look like in bitcoin?
A block consists of the previous hash + the transaction list + the nonce.

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#3622
  1. Why is it important that the blocks are cryptographically linked together?
    So if someone wishes to change a transaction in a block, it will unlink all blocks and the person will need to resolve each cryptographic block without knowing the new answer to all following blocks.
  2. What does the block structure look like in bitcoin?
    [hash/previous hash/transactions/nonce)
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#3623

Immutability. The network retains its immutability by using a quality of hash functions in order to create unique outputs which link blocks. This means that transactions cannot be censored, altered, or stopped.

  • Block number
  • Nonce
  • Transaction Data
  • Hash of the Previous Block
  • Hash of current block
    2021-04-16T01:54:00Z
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#3624
  1. Why is it important that the blocks are cryptographically linked together?

So that no one can tamper the blockchain. If some malicious miner even tries to change any block within the chain to double spend then he will need to make huge efforts by trying to change all the blocks after the block which have been changed. Theoretically it’s possible but almost impossible to do so with current set of technologies. Over to that if tries to do so he will need to spend lot of electricity & will further lead to heavy monetary loss in paying electricity bills.

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

Previous Blocks Hash + Current Set of Transaction within That Block + Guessed Nonce
Further their conversion into new hash as per target set by blockchain.

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#3625
  1. This ensures that the blockchain is correct and creates a bond that cannot be altered.
  2. Hashes of the previous and new blocks, transaction details, nonce.
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#3626
  1. For reasons of security and so there is no double spend.
  2. Previous TX Hash Nonce Transactions
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#3627

  1. Why is it important that the blocks are cryptographically linked together?
    So that if some date are changed, deleted or added into one block, all subsequent link to that block will the broken. It makes cheating virtually impossible.

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

  • Hash
  • Previous hash
  • A list of transaction
  • A nonce
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#3628
  1. Because it makes practically impossible to go back in time and change the transactions, as all the subsequent blocks would need to be remined.
  2. The block contains the previous hash, the transactions, the nonce, and the current hash.
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#3629
  1. The blocks are linked like this so that if there is a change to a previous hash the chain will appear incorrect and the new block will not be accepted. Unique hashes/fingerprints to insure integrity of the chain.
  2. Each block: The hash of the previous block, the transaction history from all previous blocks, and a nonce that is less than the Target number.
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#3630

  1. To ensure security, and make sure no transactions or data can be changed in previous blocks without immediately compromising the whole chain.

  2. The hash of the current block is based on its transactions, the nonce, and the hash of the previous block.

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#3631

  1. So then because its in a linear fashion it makes it harder to alter the longer the chain progesses.

  2. One after another in one straight line since inception. Blocks are made up of transactions, the hash from the previous block and a nonce or target number.

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#3632

  1. The blocks are linked together cryptographically in order to make it practically impossible to change the transactions already added to the blockchain.

  2. A block consists of transactions (a list of addresses and bitcoin amounts), a nonce (a random number which make the hash of the block less than the target), the hash of the previous block and the hash of the current block. The blockchain could be visualized as an immutable linked list stored in a network of computers.

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#3633
  1. Why is it important that the blocks are cryptographically linked together?
    • So that it’s exponentially more complicated to change many block in the chain which ensure security that what happen in the past won’t be rewritten by bad actors easily.
  2. What does the block structure look like in bitcoin?
    • There is the header information, the previous block hash, the nonce (random number) and the list of transactions to include in the new block with other technical informations
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#3634
  1. Cryptographically linking the blocks together is what ensures the integrity of a blockchain. This integrity is what nodes use to verify that the blockchain history is correct.
  2. The block structure in Bitcoin consists of the Block hash, which is based on the list of the transactions in the block, the hash of the previous block, and the nonce that needs to be guessed.
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#3635
  1. Why is it important that the blocks are cryptographically linked together?

Cryptographically linked blocks add to the blockchain as long as they are confirmed and legitimate. The longer the links in the blockchain, the more transactions that can be verified.

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

A block in the Bitcoin blockchain is based on a hash which is based on the hashes of transactions inside the block which are based on the hash of a previous. The hash of a previous block along with the hashes of transactions in a current block are used to find a nonce, which is used to find the hash of a current block. Finding the hash of a current block adds the block to the blockchain.

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#3636
  1. Because that incentives miners to be honest and play by the rules. It makes the cost to expensive to go back and change all blocks.
  2. Size, version, previous block hash, merkle root, timestamp, difficulty, nonce, transactions.
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