Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1829

1.) It is important for the blocks to be cryptographically linked together so no transactions can be changed without all others being effected. This leads to increased security and immutability.

2.) The block structure in bitcoin is a hash based on a combination of the previous hash, the transaction list of the current block, and the nonce.

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#1830
  1. Why is it important that the blocks are cryptographically linked together?

To maintain integrity and confirm that all transactions that have happened is immutable

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

New transactions, hash of the data, previous block hash and the nonce

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#1831

It’s important that blocks are cryptographically linked together since that makes it much more difficult for a malicious actor or group to change transactions. This is because changing one transaction would require changing all transactions after it, a task that requires unbelievable amounts of computing power that would be better put to use just playing by the rules and mining BTC.

Bitcoin’s block structure is the nonce, transaction data (e.g. list of transactions), and hash of the previous block.

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#1832

1 Because this ensures that nobody cand make a modification in any block without the hole chain being modified.
2 A block is: the hash of the provious block + transaction fees + the nonce

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#1833
  1. Security and integrity of the system so that valid transaction remains untamperable such as taking back transactions or stealing.
  2. Nonce, Data(instructions for transactions), previous block information including the previous hash in the network, the hash generated in the current transaction based on the nonce used.
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#1834

Only the previous block hash is required. :slight_smile:

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#1835

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
  2. What does the block structure look like in bitcoin?

ANSWER 1: it’s like a puzzle piece that needs to fit and each block is based on the hash of the previous block that it is linked to. If one is changed, then hash of each block after changes. Then the chain is broken.

ANSWER 2: The block #, the previous block hash and list of transactions, and the nonce along with the current hash

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#1836
  1. Why is it important that the blocks are cryptographically linked together?
    Makes the data immutable, data can never be changed
  2. What does the block structure look like in bitcoin?
    Hash – hash of previous block – transactions list - nonce
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#1837

Why is it important that the blocks are cryptographically linked together?
To increase the immutability and tamper resistance features of blockchain.

What does the block structure look like in bitcoin?

  • Hash of previous block
  • Hash of current block
  • Nonce
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#1838

1. Why is it important that the blocks are cryptographically linked together?
It keeps the blockchain/ledger secure and immutable. This is because it makes it very difficult for someone to change transactions in a previously added block.
When someone changes a transaction in a previously added block, it requires a lot mining power (electricity) to recompute all the hash outputs of all the subsequent blocks, including the block which had a transaction change.

2. What does the block structure look like in bitcoin?
Essentially it includes:

  1. Why is it important that the blocks are cryptographically linked together?**
    It keeps the blockchain/ledger secure and immutable. This is because it makes it very difficult for someone to change transactions in a previously added block.
    When someone changes a transaction in a previously added block, it requires a lot mining power (electricity) to recompute all the hash outputs of all the subsequent blocks, including the block which had a transaction change.

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

  1. nonce
  2. list of all the transactions
  3. hash of previous block
  4. new hash output of current block.
    he hash of the current block is determined by first three. There are more data that goes into a block but those are the fundamental ones.
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#1839
  1. To increase its manipulation resistance
  2. Most relevant, transactions, previous hash and nonce
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#1840

Cryptographically linked blocks are an integral part
of the blockchain which keeps it immutable and secure.

image
image1991×1969 700 KB

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#1841
  1. Why is it important that the blocks are cryptographically linked together?

So they all depend on each other and even a slightest change of their hashes invalidate the whole chain.

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

It’s a sha256 hashed data that includes the hash of the previous block + TXs + nonce.

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#1842

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

Is important because it builds the foundation of immutability of the data by sealing and linking content.

What does the block structure look like in bitcoin?

The block structure is made of the combination of two hashes (previous block + transactions & fees) and a nonce for the miner to target and validate.

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#1843
  1. Why is it important that the blocks are cryptographically linked together?
    This provides the integrity of the blockchain as the digital finger print of a block uses the hash of the previous block through the link.
  2. What does the block structure look like in bitcoin?
    It contains the previous blocks hash, a list of transactions and the nonce.
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#1844

To secure data immutability. Preventing it from being altered in future.

Nonce, transactions in current block, previous hash (linking the blocks).

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#1845
  1. It is important that blocks are cryptographically linked together to provide security to the network.
  2. The block structure for bitcoin consists of the previous blocks’ hash, the block data, the nonce, and the new block hash.
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#1846
  1. Why is it important that the blocks are cryptographically linked together?
  • so that non of the details of the previously mined block can be changed and to achieve immutability.
  1. What does the block structure look like in bitcoin?
  • block structure = hash of { previously mined blocks hash + trasnsections + nounce }
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#1847
  1. Why is it important that the blocks are cryptographically linked together?

The linking of a the directly previous block to the newly created block which will in turn be linked to the block after it you have provided a double hashed provenance security layer. This layer stops anything from being changed in previous blocks without being rejected by the consensus algorithm. Secondarily it becomes nearly impossible to make fraudulent transactions in a block that is newly being created as it would mean that the previous blocks wouldn’t have been valid.

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

[ Block Header ]

  • Hash of the previous block
  • Timestamp
  • Nonce
  • Required Difficulty level
  • Merkle tree Root Hash - a hash of a the Transaction section below

[Transactions ]

  • Coinbase Transaction
  • All other Mined transactions
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#1848

1. Why is it important that the blocks are cryptographically linked together?
Any change done to one block affects all other blocks that were added on top of it. This makes sure that you cannot simply alter the state of the currently approved blockchain.

2. What does the block structure look like in bitcoin?
block hash, nonce, prev block hash, tx list.

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