Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2734

input and output addresses

#2735
  1. It is important because theyā€™re kind of patchpasted and if any of these blocks is ever edited it will break the links this block has with itā€™s following blocks.
  2. Tx Fees
    Inputs and Outpus
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#2736
  1. Why is it important that the blocks are cryptographically linked together?

For the security of the blockchain so nothing can be altered on the blockchain.

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

a block includes current hash, previous hash, transaction list, and the nonce.

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#2737

1- For security. That way no transactions can be changed.

2.The hash of each block is based on the block transactions plus the previous hash of the previous block and the nonce that needs to be guessed.

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#2738
  1. The link connecting blocks is a hash of the previous block ingredients and the hash of the block previous to that one. If any data is changed, the hashes of each subsequent block are changed, showing the data has been changed. The hashes of each block maintain the validity of the data in each block.
  2. Block structure - Each block contains previous block hash, transaction data and nonce.
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#2739
  1. ensures security by uniqueness of each block as well as their link.
  2. each block has its previous blockā€™s hash, its transaction list and its own block hash (based on prev. hash, tx list and Nonce) and nonce. This then is input into the next blockā€™s hash.
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#2740

There are also other parts, fees are basically just part of the transactions that are stored in the block data.

The most important part to remember is in the block header that contains the hash of the previous block (along with merkle root of transactions, timestamp, target and nonce) which is used in the block hashing process that links the blocks in a chain. :wink:

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#2741
  1. It is important for security reasons ā€“ data cannot be altered.
  2. Block structure in bitcoin: Bloc header (Version, Previous Block Hash, Merkle Root, Timestamp, Difficulty index, Nonce), Transaction Counter, Transactions.
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#2742

  1. Why is it important that the blocks are cryptographically linked together?
    The cryptographic link between blocks means that the present block in a certain sense ā€œremembersā€ the entire history of the blockchain. This happens because any change in the past will alter all future hashes. This means that a present block seeking to be appended to the block will not be accepted by the network unless it is consistent with the entire history.

  2. What does the block structure look like in bitcoin?
    A block contains transactions, and a hash

Ivan didnā€™t say this, but wouldnā€™t the block also have to contain the target and the nonce? Otherwise, other nodes could not verify that the chosen nonce is a valid solution to the puzzle.

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#2743

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together? Only need to trust the math and not an individual. Makes it more secure.
  2. What does the block structure look like in bitcoin? Each block is linked together by solving cryptographic puzzles based on previous transactions.
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#2744

  1. To ensure data immutability, which prevents the data from being altered in the blockchain.

  2. The block structure is made up of transactions, transaction counters, block header, block size, nonce, difficulty target, timestamp, merkle root hash, previous block hash, version.

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#2745

  1. The more the blocks is linked to each other the more secure the network and the more it will be immutable.

  2. First is the block number then comes the nonce next is the transactions then the previous hash then the hash of the block.

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#2746
  1. To make changing a block virtually impossible, because all the blocks after will also change.
  2. A blockā€™s consists of the previous blockā€™s hash, tx list, and nonce.
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#2747

Yes all the data that is part of the block hashing process is stored in the block header. :slight_smile:

#2748
  1. So that any little change on any block would disqualify all the succeeding blocks after the erroneous block.
  2. A block in Bitcoin is structured thus: has of the previous block, current transaction, nonce.
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#2749

  1. Why is it important that the blocks are cryptographically linked together?
    The link makes it extremely difficult to change anything on any individual block

  2. What does the block structure look like in bitcoin?
    block number + previous block hash + list of transactions + current nonce

block number contains further information:
previous block hash
merkle root hash
timestamp
nonce
difficulty
block size
number of transactions
block weight
block reward
block fee

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#2750

  1. Why is it important that the blocks are cryptographically linked together?
    Nobody can change any of the information in the pervious blocks or it will change the hash of that block and every block that follows it. This allows for a truly decentralised blockchain that doesnā€™t rely on a central bank or government to manage it.

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

The hash of a new block is made up of the hash from the previous block plus the TX list inside this new block, plus the nonce. This then generates a random number which becomes the new hash for this block.

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#2751

  1. Why is it important that the blocks are cryptographically linked together?
    It is important because it helps provide security as a component of consensus to ensure the ledger has not been altered in anyway.

  2. What does the block structure look like in bitcoin?
    Each block contains the current time, a record of some or all recent transactions, and a reference to the block that came immediately before it. It also contains an answer to a difficult-to-solve mathematical puzzle - the answer to which is unique to each block, also called the ā€œnonceā€.

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#2752
  1. Why is it important that the blocks are cryptographically linked together?
    Cryptographical linking provides chain security. Each link and block relies on the previous block and link and so on. Any change in previous blocks, no matter how far back in the chain will cause a break through the rest of the chain.
  2. What does the block structure look like in bitcoin? A block consists of the previous blockā€™s hash, the transaction list, and the nonce.
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#2753

1.This secure the network together. Each block is based on the previous block, which is based on the previous block and so forth. Therefore the longer the blockchain exists the and the more activity it contains the harder it is for the blockchain to be altered. Each block is dependent on the previous one.
2. The block structure involves the previous hash, a list of TX, and the nonce.

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