Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2794

But transactions don’t have any time :stuck_out_tongue:

#2795
  1. Why is it important that the blocks are cryptographically linked together?

To secure the network (no double spending, no changing or removing mined transactions etc)

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

Each block contains: Previous block hash, current block transaction list and nonce.

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#2796

  1. It’s important that the blocks are cryptographically linked together, because it insures security in the blockchain. Each block requires information from the previous block in order to solve the current block. If information is changed, the chain is broken and a miner must spend more money on electricity to re-mine the blockchain correctly.

  2. The block structure in bitcoin needs the previous hash from the block before, the current block being created’s transaction list, and the nonce that is guessed by computer’s randomly generated number to land within the target range and ultimately get the final hash number to complete the block.

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#2797
  1. So if one is changed, all the subsequent blocks change, making it impossible to insert a corrupted code.
  2. It has the hash code from the previous transaction, the nonce and the transactions.
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#2798

  1. For the security of the whole blockchain, that make sure no data has been alter.

  2. Made of previous hash, the transaction list and the nonce (random number)

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#2799
  • Why is it important that the blocks are cryptographically linked together?

The Link holds the content of the previous block and the new block needs the hash from the previous block to be finished.

  • What does the block structure look like in bitcoin?

A block creates its own hash made up of 3 things: the previous hash, all the transaction that took place in that block, and the nonce.

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#2800

It is important that blocks are cryptographically linked together because it makes it practically impossible to alter a block after it has been mined, as it would affect the next block, and so on.

The structure of a bitcoin block consists of two main parts: the block header and the transactions.

In the block header there are four elements: the hash of the previous block, a nonce, which is the solution to the puzzle the miner had to solve in order to be able to create the block, a set of metadata, like the block and timestamp, and the Merkle tree, which ensures the integrity of the transactions.

On the list of transactions, the first one is new bitcoins going to the miner, then the rest of confirmed transactions from other users.

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#2801
  1. so they cannot be corrupted, changed, removed, etc
  2. block contains the previous hash, list of transaction, and the nonce. also a current hash
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#2802

Cryptographically linked blocks secure the network by preventing double spend attacks and incentivizing miners.

Each block contains the previous hash, a list of transactions, and the nonce that is guessed by the miners to compute a hash (based on all the data listed) less than the current target that is based on a difficulty level proportionate to the hash rate of the network.

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#2803
  1. Why is it important that the blocks are cryptographically linked together?
    It ensures every TX to be irreversible and immutable. Once a block has been appended into the blockchain with its hash, there exists no way of successfully modifying TXs within a block.
  2. What does the block structure look like in bitcoin?
  • Magic number - This is an identifier for the Blockchain network.
  • Blocksize - Number of bytes following up to end of block
  • Blockheader – Consists of 6 items:
    o Block version number
    o Previous block hash
    o Merkle root hash
    o Block timestamp
    o Bits
    o Nonce
  • Transaction counter
  • Transactions
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#2804

Why is it important that the blocks are cryptographically linked together?
To provide immutability and integrity by ensuring virtual impossibility of breaking the chain.

What does the block structure look like in bitcoin?
Previous hash + block header + TX list as chosen by miner + target number + nonce + block size + TX counter

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#2805
  1. Because of security reasons. Changing transactions in previous blocks will break the link to the next one and all that follow.
  2. Previous hash, transactions and nonce.
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#2806

To ensure safety and usecase in the network.
To create unique outputs, so you cannot change, censor og stop the transactions.

  1. The block is made from data from the previous block( Previous hash, Transactions and the nonce and then it adds those factors together and use them for the next block and the next and so on.
1 Like
#2807

[quote=“ivan, post:1, topic:8433, full:true”]
Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    Each block has a hash which is based on all the TXs that happened on this block and also on the hash of the previous block, if a link is broken the block becomes invalid then rejected by the network

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

Block number
Nonce
Data
Previous hash
Current Hash

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#2808
  1. Cryptographically linked blocks serve as a proof of work of miners. That is a secure way to ensure that data of the blocks won’t be edited or changed, since each link is based on a content of previous blocks.
  2. Transactions in the block, Hash of the previous block and the nonce.
1 Like
#2809

  1. Why is it important that the blocks are cryptographically linked together?
    So previous transactions cannot be changed.

  2. What does the block structure look like in bitcoin?
    Previous hash
    block header
    block number
    TX list as chosen by miner
    target number
    nonce,
    block size

1 Like
#2810

1.To keep the block secure and trustless.
2. It looks like a square that contains block #, nonce, data , then hash

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#2811
  1. Why is it important that the blocks are cryptographically linked together?
    This is at the core of cryptocurrency. Security. Digital signature holds identification and integrity. The link goes from wallet to private key to public key to bitcoin address and this process can’t be reverse. Immutability.
  2. What does the block structure look like in bitcoin?
    It contains the following: Block, Nonce, Data, Previous Hash, Current Hash.
1 Like
#2812
  1. It makes the network secure. Its hard to change something in the past with a lot of computing power and used electricity, plus catch up with newly created blocks doing work only based on own computing power.
  2. Block contains: nonce, previus hash and new transactions.
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#2813
  1. Why is it important that the blocks are cryptographically linked together?

The cryptographic linking of the blocks lends to the integrity of the entire blockchain by making it difficult (effectively impossible) to alter an historical block, as doing so would require the remining of all subsequent blocks.

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

A single block (beyond the genesis block) is comprised of that block’s transactions, a nonce, and the hash of the previous block. All these values are used to calculate the hash of this block.

1 Like