Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3898
  1. This makes it so no one can break the rules and double spend, if one block is changed all the blocks ahead of it are broken
  2. The block structure in bitcoin is the hash of the previous block, the tx list of the current block, and the nonce
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#3899

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

It ensures the integrity of the blockchain. If a transaction is changed it will change the block hash, which will change the subsequent block hash, which will change the link.

What does the block structure look like in bitcoin?

Hash = previous hash + data/transactions + nonce

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#3900

1.Ensure the integrity of the BTC network because blocks can’t be altered.
2.Hash from previous block, tx list + nonce =hash lower than target*

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#3901

  • Why is it important that the blocks are cryptographically linked together?
    Virtually unbreakable. Theoretically impossible to break and impractical in a realistic & financial way.

  • What does the block structure look like in bitcoin?
    A length of agreed on blocks of transactions by a community of nodes who come together and confirm these transactions. These are picked up by miners that have their block hash matched after a nonce is guessed correctly that is then uploaded and chained together in like order.

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#3902
  1. Because the cryptographic link (digital finger print or hash link) references the connected blocks’ data, timestamp, and digital finger print. This adds security to the block chain from someone altering data.
  2. A block with data (transactions) with nuance header, and then followed by a hash link, connected to the current target.
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#3903
  1. so that we stick to keeping the chain secure.
  2. the hashes link each block and previous and nonce.
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#3904
  1. Linking the blocks together cryptographically, increases security as it makes it impossible to make a change to just one block.
  2. A blocks sturcture is made up of the Block header, Nonce, Transaction Data and Previous Blocks Hash.
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#3905

  1. It’s important that the blocks are linked together as this is part of the blockchain integrity. The hash of the previous block is part of the next block, so if someone wants to change something in the previous, confirmed block, he will need to mine again all the following blocks, which is practically impossible.

  2. A block contains the hash of the previous block, its data (which is the confirmed transactions), a nounce that the miners have to guess and its own hash.

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#3906

  1. Why is it important that the blocks are cryptographically linked together?
    To avoid anyone from cheating or breaking the rules (changing a transaction). It also links
    all blocks on the blockchain.

  2. What does the block structure look like in bitcoin?
    1st transaction of the block is always the Block Reward. Followed by transactions added
    by a miner for that particular block. Block contains a hash which contains information from the previous blocks hash, all the transactions of the present block and the nonce.

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#3907

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

It is important to cryptographically link the blocks together so that if someone tries to change the transaction data inside the previous blocks all the links get broken in the next following blocks. It helps to secure the network.

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

Bitcoin block has:

  1. block header consisting of:-
    • Block version number
    • hash of the previous block
    • hash based on all of the transactions in the block
    • time stamp
    • current target
    • nonce
  2. block size
  3. transactions
  4. transaction counter
  5. Magic no - value always 0xD9B4BEF9
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#3908

  1. Why is it important that the blocks are cryptographically linked together?
    So that no one can change a previous transaction. It offers security.

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

  3. Hash of previous block.

  4. List of transactions.

  5. Random Nonce that needs to be guessed.

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#3909

It is important that blocks are cryptographically linked together for the security of the blockchain. That way no transactions can be changed in previous blocks because it would break the link to the next block and all that follow.
2.The hash of the block is based on the transactions in the block plus the previous hash and the nonce that needs to be guessed.

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#3910
  1. this linking guards against a miner violating any rules.
  2. each block contains the previous hash, all data (txs) and a nonce.
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#3911

1. Why is it important that the blocks are cryptographically linked together?
Because in this way we can assure that modify the data contained in the previous blocks is almost imposible.

2. What does the block structure look like in bitcoin?
Block _Hash
Noce
Hash of the previous block
Transaction

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#3912
  1. To ensure blocks remain immutable.

2 Transactions, block header , transaction counter, block size, naunce/ magi number, current target and hash of previous block.

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#3913

A1. A blockchain is a digital tx of records that’s arranged in chunks of data called blocks. These blocks then link with one another through a cryptographic validation known as a hashing function. Linked together, these blocks form an unbroken chain – a blockchain. If these blocks lose the connection of each other, then blockchain would fail. So it is a very important for these blocks are cryptographically linked together.

A2. Block structure is composed of blockchains in all nodes. Each block has Block Height and Header Hash plus Previous Block Header Hash plus Timestamp, Difficulty Target, Nonce and Merkel Root plus New Transactions. All blocks are connected each other, so they are called Chain of Blocks, blockchain.

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#3914

  1. Why is it important that the blocks are cryptographically linked together?
    This is important as it ensures finality/immutability amongst the network and allows for transparency through traceability. It is also a large benefit to the security of the network as it prevents bad actors from imitating certain blocks.

  2. What does the block structure look like in bitcoin?
    Each block is comprised of the previous blocks has, its own hash, as well as transactional data info and the nonce of the specific block.

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#3915

Questions:
. When solving a puzzle, the link is based on the contents of previous blocks. This also supports proof of work as it is important to spot any malicious content and prevent double spending.
. Each block is made up of a hash which contains data based on the transactions and each block is identified by a unique finger print. There is also a nonce which is used to guess the target value for transactions as this nonce value must be lower than the target value.

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#3916
  1. Why is it important that the blocks are cryptographically linked together?

Helps prevent data from being manipulated or altered, ensures integrity in the work

  1. What does the block structure look like in bitcoin?
    Prior block hash, transaction list in current block, nonce
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#3917

  1. Why is it important that the blocks are cryptographically linked together?
    The cryptographic linking allows the integrity of the entire chain to be verified. Any attempt to change the history becomes obvious, the next block would contain the wrong has, invalidating the chain.

  2. What does the block structure look like in bitcoin?
    Significant items in the block structure include:

  • The hash of the previous block, used to verify integrity
  • A nonce number that is changed in each attempt to get a block hash under the target
  • The transactions that contribute to the reward the miner receives
  • A hash of the root of the tree of transactions
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