Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1747

  1. blocks are cryptographically linked so any change in the prior block will invalidate the block and all blocks after that. this makes it very secure

  2. Each block contains: version, time, current difficulty target, hash of the previous block, naonce and a hash of the merkel root…

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#1748
  1. Why is it important that the blocks are cryptographically linked together?
    this ensures that if any block is modified, the following blocks will have to be re-linked, ensuring that the chain remains immutable bc re-building the links is extremely difficult.
  2. What does the block structure look like in bitcoin?
    the block contains the following inf: 1-Prev hash ; 2-Tx inf ; 3-nonce
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#1750

  1. The “cryptographic link” that linked a block to another is very important because this cryptographic link makes all blocks unique from any other block. Therefore, by changing even just a single transaction in any block will affect change to all the blocks that is linked to it. This makes bitcoin immutable.

  2. A bitcoin block structure always have a hash of the current block, hash of the previous block, list of transactions (data) and nonce.

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#1751
  1. Why is it important that the blocks are cryptographically linked together?

It is important to have the blocks crytographically linked so that it keeps the network secure and preserves the integrity of the data being linked between the blocks. Any changes to a previous block will invalidate that block until it can re-hash and catch back up to the chain, because even though that block has been invalidated, the chain will keep linking up to more blocks. A new hash being linked up will have their hash and the previous block’s hash in their block.

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

The block structure in bitcoin uses hash functions to create a unique finger print for a block and also creates the link between 2 blocks. Inside this block in bitcoin, there is its own hash, the hash of the previous block it is linked up to, a transactions list and most importantly a nonce. And the numerous guesses of that nonce is what gives incentive for miners to spend money on electricity to make their money from block rewards and transaction fees.

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#1752

  1. To notice changes in any of them. Since the digital fingerprint or hash of a block depends of every previous block in the blockchain (thus they are linked together), as soon as something changes, the hashes on every block will also change.

  2. The block structure contains the hash of the previous block, the data contained on that block, the nonce and the hash of the block.

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#1753

Did you forgot to answer? :stuck_out_tongue:

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#1754

What kind of hashes? :slight_smile:

#1755
  • Why is it important that the blocks are cryptographically linked together?

= To secure the network, if you make a change to one block, you will break the puzzles or links between all the following blocks.

  • What does the block structure look like in bitcoin?

A block is made up by the block header and the transaction data.

The block header contains:
Hash, Version, Previous hash, Timestamp, Difficulty Target, Nonce & Merkle root.

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#1756

1.- Protect the system from malicious intents. As the blocks are interconnected, by means of a highly difficulty mathematical algorithm to solve. It is necessary to chain the entire chain from one block onwards, this entails excessive computer power because of its difficulty, protecting the blockchain from being altered.

2.- The blockchain is encrypted by a header data structure:

  • Version 4 bites
  • hash of previous block 32 bites - (header of previous block)
  • hash merkel root 32 bites “data structure”, (each level of the tree is a hash of the previous level)
  • time current timestamp
  • bits target (difficulty of the current block)
  • Nonce - solution to the cryptographic puzzle.
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#1757
  1. Cryptographic link provides security of the blockchain. Any changes in one block would cascade through all that follow, therefore making it almost impossible to breach.
  2. Main components of blocks in bitcoin are transactions, nonce and hashes of current and previous block. There are also additional data e.g. timestamp or difficulty target.
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#1758

  1. It adds a very high difficulty to change the blocks. When a block is changed it will break the link between all future blocks and a re-mine will be extremely difficult.

  2. Basic block structure includes these things: previous hash, transactions, and nonce.

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#1759

To ensure all connecting blocks are immutable.

Each block contains the nonce, transactions, previous block, and is connected by a cryptographic puzzle or POW.

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#1760

Q: Why is it important that the blocks are cryptographically linked together?
A: Linking the blocks together makes it difficult to make changes to earlier blocks. If you change the data for example in the first block, then you have to re-mine all the subsequent blocks (because all the links will have been broken)

Q: What does the block structure look like in bitcoin?
A: The hash of the block is based on the data in the current block, the hash of previous block, and the nonce.

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#1761

1.It is important that the blocks are cryptographically linked together because it will prevent the data inside to be changed, it’s also verifiable because of encryptions and it will also provides integrity in datas.
2.the block structure in bitcoin are:hash, previous hash and data

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#1762
  • Why is it important that the blocks are cryptographically linked together?

Linking blocks cryptographically together makes it immutable and more difficult to alter a block

  • What does the block structure look like in bitcoin?

Header-Hash of previous block, Timestamp, Target, Nonce & Transactions

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#1763

It must only contain the previous block hash, not the block itself. :slight_smile:

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#1764
  1. To strengthen the blockchain .increases the security and immutability.
    2.Each block contains the hash of the current block , the transaction list of the current block the hash of the previous block and the nonce that needs to be guessed
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#1765

  1. To create a trust-less network that incentives everyone to play by the rules of the network and punishes accordingly when the trust is breach.

  2. The block structure looks like a list of transactions with its unique fingerprint connected to its previous and future blocks that has their own list of transactions and unique fingerprints. All the links that connect the blocks are the results of POW.

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#1766

  1. To insure immutability.

  2. Block #, Hash, previous hash, Tx, nonce,

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#1767
  1. To keep the blockchain secure, the hash of each transaction depends on the transactions in the current block, as well as the hash of the previous block. The makes it impossible to change or remove any previous transactions.
  2. Each block contains the hash of the previous block, the current block’s transactions, the nonce, and the current block’s hash.
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