Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#4018
  1. To secure the network as changing one block will change all other blocks thus making it difficult to cheat the network
  2. Current block is made with TX list + Previous block Hash + nonce.
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#4019

  1. It’s important that blocks are cryptographically linked together so that it is nearly impossible to alter the data within the blocks.

  2. The structure of a block from top down is: block size, block header, transaction counter, transactions.

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#4020

The blocks are based off the previous transactions hash . the hash gives security.
Because it linked all transactions.

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#4021

1 – By having blocks cryptographically linked together when someone changes something in a given block the links for the newer block become invalid. This person would have to mine this links again. In the mean time new blocks keep being added to the blockchain. Since the valid chain is the longer one the dishonest person would need to spend huge amounts of electricity to mine everything faster in order to achieve the longest chain. This is practically impossible as it would require 51% of the hash rate, and spend enormous sums of money in electricity and computing power.

2 – A block in the bitcoin network is composed by the hash of the previous block hash, the transaction list, and the nonce.

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#4022
  1. keeps the network secure by ensuring that each block is based on previous. also is the foundation of proof-of-work

2 like blocks linked together in a chain :wink:

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#4023

  1. Cryptographically linking the blocks together ensures that previous blocks can not be altered. Doing so would break the following links in the blockchain and remove the blocks. Rebuilding this would impossible without controlling at least 51% of the global hash rate. This gives the blockchain immutability.

  2. The block contains a transaction list, the hash of the previous block, and a nonce. These create the block’s hash, which must be below the target in order to be added to the blockchain.

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#4024

it isn’t funny this time?

#4025

  1. If blocks are not cryptographically linked together then it would be easy to alter a previous block. This would prompt you to change everysingle block after the altered block which is impossible.

  2. A block structure in BTC is as follows: Previous Hash - Current Hash - All transactions of the block - the Nonce of the block. These things when all put together produce the new Hash of a block.

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#4026

  1. Why is it important that the blocks are cryptographically linked together? When Mining a current block you take the hash of previous block, transactions from current block, and a random number miners have to guess (nonce) over and over again to create a new block making it practically impossible to alter and even if you had the hash to do so, you would generate more financial rewards playing by the rules

  2. What does the block structure look like in bitcoin? Hash of previous block, transactions from current block, and Nonce.

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#4027
  1. Why is it important that the blocks are cryptographically linked together?

To ensure the POW integrity of the blockchain.

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

A series of blocks containing transaction data linked together by hashes.

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#4028

  1. the linking together maintains the integrity of the blockchain

  2. Block structure is made up of a nonce, transactional data and the previous hash

2 Likes
#4029

  1. Why is it important that the blocks are cryptographically linked together?
    So they cannot be altered, changed or manipulated. This ensures POW in the entire system is honest and secure.

  2. What does the block structure look like in Bitcoin?
    Original block hash
    Version
    Prev_block
    Merkel root
    Time stamp
    Encoded target
    Nonce
    Block header
    Comput_hash

2 Likes
#4030
  1. Why is it important that the blocks are cryptographically linked together?

So that it is extremely difficult to mutate/hack the blockchain.

  1. What does the block structure look like in bitcoin?
  • Block file format : The block is represented as a file in JSON format
  • Merkle root : Merkle root represents the hash of the root of merkle tree created as a result of combining hash of children nodes. Leaf of the merkle tree represents the hash of the transaction. It takes up 32 bytes of storage. It forms part of Block header.
  • Time : Timestamp when the block is created. It takes up 4 bytes of storage. Forms part of block header.
  • Difficulty : Represents difficult target and takes up 4 bytes of storage. Forms part of block header.
  • Nonce : Counter which helped achieve the difficulty target. Takes up 4 bytes of storage and forms part of block header.
  • Previousblockhash : Represents hash of the previous block. Takes up 32 bytes and forms part of the block header.
  • Height : Height of the block
  • Size : Size of the block
  • Tx : List of hash values of the transactions included in the block.
  • Hash : Block identifier. It is created as a function of block header.
2 Likes
#4031

Homework on Blockchain and Mining Visually - Questions

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

To insure that you wont be able to change the network with deleting or add transactions that are not ment to be it the blockchain.

  1. What does the block structure look like in bitcoin?
    TX hash
    Prev block
    Nounce
2 Likes
#4032

  1. To secure the network and incentivize honesty.

  2. Hash = Previous Hash + Data (Transactions) + Nonce

2 Likes
#4033

  1. By including information from the previous block to the following block, any alteration on a past block invalidates the following blocks too, making it virtually impossible to change past transactions.

  2. The has in a Bitcoin block contains the hash from the previous block, the transactions from the current block and a nounce.

2 Likes
#4034
  1. Why is it important that the blocks are cryptographically linked together?
    To preserve the integrity of the blockchain by making it practically impossible to change data on it.
  2. What does the block structure look like in bitcoin?
    The digital fingerprint of a block is its hash, which is based on the previous block’s hash, a nonce and the block’s list of transactions.
1 Like
#4035

  1. To make it practically impossible to double spend and having previous blocks and their transactions altered. The network will be able to recognise if a miner is being fraudulent as the hash would change compared to the existing block.

  2. Block structure is a current hash that is constructed by a nonce, transactions within and the hash of the previous block.

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#4036
  1. It is important for the blocks to be cryptographically linked because each block relies on the specific hash of the previous block. If one piece of data changes in any of the blocks it changes the cryptographic signature of all of the blocks in the chain the proceed it. This link perpetuates the immutability and integrity of the blockchain as true and consensus.
  2. Bitcoin block structure consists of the transaction list, previous blocks hash, and a nonce that is lower than the target threshold supplied by the network.
1 Like
#4037
  1. Why is it important that the blocks are cryptographically linked together?
    This way you cannot simply go and change a previous blocks as the link needs to be upheld for the blockchain to be valid. If a previous block is changed, the other blocks need to be corrected to match the hash accordingly. This provides security to the network.
  2. What does the block structure look like in bitcoin?
    Each block consists of a list of transactions with a limited byte size. Each block has a hash which consists of the previous blocks hash, as well as the transactions within the block and a random number (nonce).
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