Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1949

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

This ensures that the blockchain cannot be tampered with to change data. It makes the blockchain immutable.

What does the block structure look like in bitcoin?

Information/Data such as Tx Hash, Hash of the previous block and a random number referred to as the nonce. The hash that is generated from these inputs will be compared against the current target.

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#1950

1.For security purposes, when the link of the previous block and the current block is broken, the chain of will be invalid. Next, it can also prevent double spend and preserve transaction data integrity.
2.Previous block hash + current block Hash + nonce + timestamp + transactions + block size & header

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#1951

  1. It is important for the blocks to be cryptographically linked to ensure security on the network because if previous data is changed it will change the rest of the hashes.

  2. The nonce, transaction data and the previous hash.

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#1952
  • Why is it important that the blocks are cryptographically linked together?

This ensures the integrity of the ledger - since the hash of every block includes the hash of the previous block, changing a block would invalidate all of blocks following that block and such a chain would not be accepted by the network.

  • What does the block structure look like in bitcoin?

A block consists of two main parts:

1. The block header, which contains six values:

  1. Version number of bitcoin client
  2. Hash of the header of the previous block
  3. Hash of the merkle root of the current block
  4. Timestamp of the current block
  5. The target for the current block
  6. A nonce for which the hash of the block header is under the target

2. A list of the transactions the miner has included in the block

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#1953

  1. Because new hashes are based on previuos hashes. That is why it is impossible to change data in the previuos blocks.

  2. It is based on previuos hash, transactions and nonce.

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#1954

  1. Those cryptographic links are what makes it exponentially more difficult to edit any previous block as time passes and this ensures the immutability of data on the blockchain.

  2. Each block is made up of the latest transactions included by the miner as well as the hash of the previous block and the nonce. This data is all hashed to produce the “hash” that will be added to the transactions mined in the next block.

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#1955

Homework on Blockchain and Mining Visually - Qs

  1. Why is it important that the blocks are cryptographically linked together?
    It is important to secure the network as each block contains the hash of the previous block and it will become exponentially more difficulty to change a transaction in a block in the chain over time.

  2. What does the block structure look like in bitcoin?
    Previous Block Hash (Plus)
    Transactions List (Plus)
    Nonce (Random Number Guessed by Miners, lower than the target)
    =
    New Block Hash

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#1956
  1. Why is it important that the blocks are cryptographically linked together?
    It ensures data immutability
  2. What does the block structure look like in bitcoin?
    Block ID / number
    Nonce
    Data
    Previous block hash
    Block Hash
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#1957
  1. By being cryptographically linked together, the blockchain becomes more secured, discouraging frauds.

2.The block structure, in bitcoin, contains the previous hash, the transaction list and the Nonce, which has to be guessed. All these elements will be hashed together and compared with the target.

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#1958

1- Cryptographic links are deterministic, pre-image resistant, collision-resistant, and are essential for chain security & integrity
2- Each block has the hash of the previous block, the list of current transactions, and a nonce

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#1959

  1. Because it assures the security of the transactions, making it fraud resistant.

  2. Block number - nonce - data - hash - previous hash. Changes in any part of the structure will reflect on all the following blocks.

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#1960

Homework on Blockchain and Mining Visually - Questions

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

The fact that the blocks are linked together is crucial for the network security and trust. Cryptography in this case provides a feature that enables immutability and prevents double spending.

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

  • Hash of previous transaction
  • List of transactions
  • Nonce
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#1961
  1. Why is it important that the blocks are cryptographically linked together?

These links ensure that one single block cannot be changed without the whole chain ahead being changed. Once this is nearly impossible to be done, these links basically ensure the immutability of the blockchain.

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

Basically, the block contains:
. All transactions data;
. Nonce (number that miners have to guess at mining process)
. Hash of previous block (ensures cryptographic link between blocks)

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#1962
  1. For Security and Integrity.
  2. The nounce, data(Transactions), the hash of the previous block and the hash of the present block.
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#1963

  1. Why is it important that the blocks are cryptographically linked together?
    It secures the blockchain. Mining is based on solving a puzzle and the puzzle is based on block content and the links between the previous block and the next block.

  2. What does the block structure look like in bitcoin?
    A linked list that has the hash for the previous block, UTXO, transaction list, and a nonce.

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#1964
  1. Cryptographically linked blocks help with data consistency. And it helps with security in a way that if you want to change an old block then you’ll need to re-mine all the subsequent blocks by yourself.
  2. The block consists of previous block hash + nonce to calculate a hash number below a threshold.
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#1965
  1. Why is it important that the blocks are cryptographically linked together?For integrity, organization, and POW.
  2. What does the block structure look like in bitcoin?It looks like a string of blocks.
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#1966

How are these individual blocks structured? What makes them immutable? :slight_smile:

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#1967
  1. Why is it important that the blocks are cryptographically linked together?
    By cryptographically linking each block, it ensures immutability because no block can be changed without breaking the whole blockchain and costing the miner more money than it is worth. Since each block is cryptographically linked there is no way to change a previous block without changing each block that follows.
  2. What does the block structure look like in bitcoin?
    Each block consists of, each individual transaction hash, the hash of the previous block, and the nonce resulting in a new hash for that particular block. Along with some other data such as block size, block header, timestamp etc., which is also represented in the hash of the block.
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#1968
  1. Why is it important that the blocks are cryptographically linked together?
    each block has hash which have to follow to next block. With that rule it helps keep blockchain together and play by rules to not brake chain
  2. What does the block structure look like in bitcoin?
    it contains tx’s, previous block hash and nonce
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