Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2593
  1. that blocks will make a chain and be secured.
  2. Previous hash+list of transactions+ nonce
1 Like
#2594
  1. Why is it important that the blocks are cryptographically linked together?

Cryptographic puzzles secure the blockchain by linking the blocks together. No transactions can be changed and any attempt to do so would break the chain.

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

Hash of the previous transaction, a list of the current transactions, the nounce number which is determined by the miner.

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#2595

  1. this is part of what creates the digital “stone” that cannot be altered

  2. from bitcoin wiki- |Field|Description|Size|
    | — | — | — |
    |Magic no|value always 0xD9B4BEF9|4 bytes|
    |Blocksize|number of bytes following up to end of block|4 bytes|
    |Blockheader|consists of 6 items|80 bytes|
    |Transaction counter|positive integer VI = VarInt|1 - 9 bytes|
    |transactions|the (non empty) list of transactions|-many transactions|

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#2596
  1. Why is it important that the blocks are cryptographically linked together?

They are cryptographical linked together to ensure blocks transaction data are immutable and tamper-proof once recorded into the blockchain. If one previous block is changed, the entire chain from that changed block and subsequent blocks will be broken. Thus attribute to blockchain security, resistance to change, integrity and trustworthiness.

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

The block structure have a block number, nonce which is a random number, list transactions, previous hash value links to the previous block and the current block hash value derived from the previous hash value and the list of transaction data.

2 Likes
#2597

  1. Because the links are what secures the blockchain. No censorship, no double spend, no removing TXs

  2. It consists of TXs, hash and previous hash, nonce

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#2598
  1. To confirm transactions and produce new blocks added to the chain using the PoW consensus.
  2. A back-linked record of blocks of transactions recognized by a hash. Each block mentions a former block, the parent block, previous hash. Transaction list, Nonce ( a random number 32 or 64bits) and a timestamp when the block was built.
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#2599

  1. Why is it important that the blocks are cryptographically linked together?
    To make the blockchain secure each block links to its pervious block, data in the blockchain is immutable. The hashing function means that a change in any transaction will produce an entirely different hash, which will alter the hashes of all subsequent blocks.

  2. What does the block structure look like in bitcoin?
    List of current transactions, the hash of the previous block, and a nonce

2 Likes
#2600
  1. The links are expensive and ensure the integrity and validity of the blockchain.
  2. The block structure contains the block number, nonce, transaction data, previous hash, and new hash. The long chain displays the proof of work (PoW).
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#2601

  1. It is important becouse it is harder to change a transaction in previous blocks.

  2. Blocks have data (all transactions in it), hash of the previous block and and nonce.

2 Likes
#2602

  1. It is important that the blocks are cryptographically linked together because it secures its integrity so that it ensures that some cant go back and change a transaction on a block as it would break the link between blocks and affect blocks in the future until it is fixed.

  2. Block structure is transaction data, the previous hash, and a random nonce. All of this then creates its own Hash for the current block

2 Likes
#2603
  1. Why is it important that the blocks are cryptographically linked together?
    To ensure network security and immutability to prevent manipulations with transactions in the blockchain
  2. What does the block structure look like in bitcoin?
    Block Number, Nonce, Data, Previous Hash and his own Hash
2 Likes
#2604
  1. Why is it important that the blocks are cryptographically linked together? It secures the network. Any change, anywhere in the chain, “breaks” all later hash values in all later blocks. Thus once a block is accepted, it becomes essentially immutable.
  2. What does the block structure look like in bitcoin? A single linear chain.
1 Like
#2605

Homework on Blockchain and Mining Visually - Questions

1. Why is it important that the blocks are cryptographically linked together?
This ensures the security of the network and the integrity of the data. As each block has the hash of the previous block, you will be able to validate if the previous block remains unchanged. If you run the hash function over the previous block, and this value is different than the hash value recorded in the current block, you will know that somebody tried to change the content of the previous block.

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

  • The hash value from the previous block
  • A list of 1…n transactions (being the first one the amount of BTC that the miner receives by the Block Reward -which is newly created currency- and the Transaction Fees)
  • A random value called nonce, which is the only one that the miner may change, in order to solve the cryptographic puzzle (say, achieve a hash value lower than the target)
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#2606
  1. Why is it important that the blocks are cryptographically linked together?
    It works like a linked list. It connects the block to the chain. Also if a block is alternated, than all the hashes of the subsequent blocks of the chain will change.
  2. What does the block structure look like in bitcoin?
    Linked list of blocks. Each block’s hash is composed of its transactions, the previous block hash and the Nonce ( a random number, which will impact the hash value of the block)
1 Like
#2607
  1. It is important because the hash from every block is made from the hash of the previous block and by that way you can’t change the information previously added to the system because you will be changing ang creating an entirely new system.
    2.Tx hash+nonce+prev hash=new hash
1 Like
#2608

How does a specific link in this chain look like? :slight_smile:

#2609
  1. Why is it important that the blocks are cryptographically linked together?

This to make sure data can’t be changed in the past. Even the smallest change will result in a change of all the subsequent blocks.

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

a block contains: the block number, the nonce guessed, a list of transaction, the hash value of the previous bloc and the hash value of the block itself.

1 Like
#2610
  1. Why is it important that the blocks are cryptographically linked together?

To ensure nothing can be changed in previous blocks.

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

Each block’s hash is based on the previous block’s hash, the transactions in the current block, and a random number called a nonce.

1 Like
#2611

  1. It establishes the order of the events as well as make it super hard to alter previous blocks

  2. a singly linked list

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#2612

How does a particular list look like? What are their links? :wink: