Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#905
  1. Why is it important that the blocks are cryptographically linked together?

Because of the security of the blockchain. Meaning no transactions in the previous blocks can be changed as it would break the link to the next block.

  1. What does the block structure look like in bitcoin? The block is made out of a list a of transactions.
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#906

  1. Why is it important that the blocks are cryptographically linked together?
    If changes are made to previous blocks, the links will break and then inherently the network will break.

  2. What does the block structure look like in bitcoin?
    Blocks of transaction data, nonce, and previous block hash.

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#907

  1. When a block gets created the block gets a hash. This hash is unique. If something is being changed in the blockchain the hashes are changed as well. Everything moves out of sync and the unbreakable chain would be corrupted.

  2. Transactions + Previous Hash + Nonce

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#908

  1. Cryptographically linking the blocks together maintains the security of the chain ensuring the blocks remain immutable.

Previous Hash
+ TXs
+ Nonce = Hash < Target

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#909
  1. Why is it important that the blocks are cryptographically linked together?
    The previous blocks info (hash) will be linked to the following blocks, so that to keep the integrity of the blockchain.
  2. What does the block structure look like in bitcoin?
    The hash of previous blocks + transaction lists + nonce.
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#910

  1. It is important for the blocks, within the blockchain, to be cryptographically linked because it means no one can change any of the data in the previous blocks without invalidating the subsequent blocks. Cryptographically linking all of the blocks together provides security, integrity and immutability to the blockchain.

  2. The main structure of a block in Bitcoin contains: current block header, nonce, current block data (tx’s, time stamp, difficulty target) and a hash of previous block. Then a hash is created for all of this data that is concatenated together. If this hash is lower than the target threshold, then the block is accepted, otherwise nonce is changed and a new hash is created for the process to be repeated and tested again.

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#911

Security and integrity of the network. The longer the blockchain, the more secure. Also harder to change previous entries in the block chain.

Blocks include: transaction section, previous block hash (used to find this block), nonce (used to solve POW) to solve for next block.

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#912
  1. Why is it important that the blocks are cryptographically linked together?

Ensures the security and immutibility of the network

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

-The Hash of previous block
-New transactions
-Nonce

Generates a new hash

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#913

it allows for no changes in the blocks

A block is made up of the following:
previous hash
Tx list
Nonce
all added together have to be equal or less than target number

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#914
  1. To protect the security of the blockchain. This way, the blockchain remains immutable, meaning no blocks can be modified afterwards as that would require re-mining all subsequent blocks.
  2. It contains the transactions in the block, plus the previous hash, the nonce.
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#915

1. Why is it important that the blocks are cryptographically linked together?
It’s POW; the linkage allows the blockchain to be unmodifiable and allow to track all the txs.

2. What does the block structure look like in bitcoin?
Hash of A. Previous hash, B. List of transactions C.Nonce

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#916
  1. Why is it important that the blocks are cryptographically linked together?

When blocks are cryptographically linked together, it is resistant to censorship, fraud, double-spending and hacking efforts.

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

In Bitcoin, every block has the transaction data, the nonce and the hash from the previous block.

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#917

  1. Because a hash of each block contains a previous block hash thus making it very secure

  2. In a bitcoin block there are transactions, previos block hash and a random number called nonce that miners have to guess. All these 3 inputs are then beeing hashed for the block hash to be less then a set treshold. Miners do that by trying for millions of times until eventually sucessful.

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#918

  1. It is important that the blocks are cryptographically linked together to prevent a node changing the content of a block. when a block is changed it changes the hash on other blocks.

  2. The block structure consist of the data, the hash, and a randomly generated number.

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#919
  1. so that no one can change the data in one block because it will change the followings

2 Nonce - Transactions - Previous Hash

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#920

  1. So that the blocks remain immutable, to change one would mean to change all and as is practicably impossible.

  2. Previous block hash. Nonce number, transactions, transactions counter block size, block header, current target

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#921
  1. For Security
  2. Contains the current trx-es, hash of the last block, and nonce
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#922

  1. Why is it important that the blocks are cryptographically linked together?
    Because it makes the blockchain very secure. If someone wanted to change a particular block, he or she also would have to change all the following blocks, which in reality would be close to impossible.

  2. What does the block structure look like in bitcoin?
    The block consists of transactions, the hash of the previous block, the hash of the block itself and the nonce, which is a number that miners have to guess.

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#923

Questions

  1. Why is it important that the blocks are cryptographically linked together?
    If someone tries to change something in a previous block, the link for that block and onward blocks will be broken. Its to make sure every block is accurate with eachother.

  2. What does the block structure look like in bitcoin?
    Hash of previous block, nonce, target, block size, transactions,

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#924
  1. it is important that the blocks are cryptographically linked together, because of security and immutability. This incentivise miners to play with the same consensus and this allows blockchain to provide decentralised system with trustless ecosystem.

2.The block structure has block number, transaction data, nonce and previous and current hash.

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