Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2292
  1. It’s important as it improves the security of the blockchain. It means no transaction can be changed in the previous block as it would break the link to the next block
  2. The hash of the block is based on the transactions in the block plus the previous hash. Then the nonce must be guessed to move onto the next block
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#2293

  1. Why is it important that the blocks are cryptographically linked together?
    In this way, the integrity of the chain is assured because no single transaction can be retrospectively amended or changed in ‘isolation’; Any change will affect the whole chain and be rejected by the network

  2. What does the block structure look like in bitcoin?
    The block structure consists of + + , where is a random number generated in sequential guesses by the miner until the entire hash achieves a target value

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#2294

  1. Why is it important that the blocks are cryptographically linked together?
    It is important to maintain the security and integrity of the blockchain.

  2. What does the block structure look like in bitcoin?
    Previous block hash, and the transactions and nonce of the current block being mined.

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#2295

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

Secure the network , censor ship ,double spent, no history alteration

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

Index =>Timestamp=>Previous Hash=>Hash=>Data

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#2296
  1. It is important that the blocks are cryptographically linked because it ensures the integrity of the data in the blockchain since if you change any previous block in the chain every subsequent block would then need to be re-mined since the hash values will all have changed.

2.The structure of a block in bitcoin contains the list of transactions, the hash of the previously mined block and the nonce, which is essentially a random number which is used to try and get the hash low enough to be below the target threshold, and thus it will be accepted.

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#2297
  1. by linking together you confirm pow, all tx in it, and security of previous blocks (no changes)
  2. Hash<- prev hash<-tx list<-nonce
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#2298

  1. So that data cannot be modified.

  2. Nonce, Data, prev hash and hash.

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#2299

  1. This insures that any changes would affect any blocks that followed it on the chain & would therefore invalidate those blocks already mined & the whole blockchain.

  2. Like a series circuit, with each block consisting of transactions of current block, Hash of previous block & nonce.

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#2300
  1. It is important for the immutability of the network. It makes it impossible to change older blocks.
  2. Block:
    • header
      • reference to the previous block hash
      • Merkle tree root
      • difficulty / target hash
      • timestamp
      • nonce
    • transaction counter
    • transactions
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#2301

  1. Why is it important that the blocks are cryptographically linked together?
    To make transaction to be unchanged on previous block.

  2. What does the block structure look like in bitcoin?
    A block on bitcoin contains hash of current block plus data of current block plus nonce and hash of previous block

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#2302

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
  2. What does the block structure look like in bitcoin?

1-To ensure that any alteration to any element will render the chain invalid, breaking and altering all subsequent hashes, thus securing the immutability of the data structure.

2- (Previous hash + TXs+ nonce)  Hash

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#2303

Block is data which contains its own hash, its own transaction details and the hash from the previous block …in Bitcoin this will have an input and and output and a utxo linking these

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#2304
  • Why is it important that the blocks are cryptographically linked together?
    It is important for giving a system a sequred network, mehanizm is relied on PoW, there is only one truth achieved by concensus algorithm and changing one input changes all chain which leads to impossible breaking into system and maddling with the data which makes it decentralized
  • What does the block structure look like in bitcoin?
    Block contains hash of the previous block, list of transactions, nonce
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#2305

1. Why is it important that the blocks are cryptographically linked together?
This securely creates an immutable ledger which requires immense effort to break.
2. What does the block structure look like in bitcoin?
A block header contains the current and previous block hash as well as the nonce. Additionally, the list of transactions incorporated into the block are structured into a merkle tree which is a hash of all transactions in a hierarchical format.

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#2306

[quote=“ivan, post:1, topic:8433”]

  • Why is it important that the blocks are cryptographically linked together?
    As new blocks are created and hashed, all the links within the blockchain are inter-linked with one another. When one transaction within a block changes all the subsequent blocks after that are rendered invalid. In short,it is immutable.

  • What does the block structure look like in bitcoin?
    the block is made out of data,previous block hash,nonce,transactions

1 Like
#2307
  1. The integrity, immutability, and security of the blockchain is dependent on the cryptographic link between blocks. This strong link is the combination of hashing data on the block with the hash of the previous block and a nonce selected by a miner. In such a system, manipulating data at any block is practically impossible.
  2. The Bitcoin block structure is made up of transactions, the hash of the previous block, a timestamp, and a nonce selected by the miner.
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#2308
  1. it makes the data immutable because the block and pervious block hash value is co-related
  2. block structure
    version
    block hash
    the previous block hash
    difficulty
    nouce
    transations
    …
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#2309
  1. To secure the network and to prevent a person attempting to alter a previous block.
  2. Nonce + hash of previous block + txn = new block
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#2310

Homework on Blockchain and Mining Visually - Answers

  1. Why is it important that the blocks are cryptographically linked together?
    Answer: It prevents anyone from changing previous data. If data gets changed in a previous block then the hash of the block will change which will invalidate all block links down chain.

  2. What does the block structure look like in bitcoin?
    Answer: Each block is hashed. This hash is created from the transactions in the block, the hash of the previous block and the nonce.

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#2311
  1. Cryptographically linking blocks together is the main security feature of “blockchain”. This is what makes the chain immutable. Because each block contains the hash of the previous block and thus all following blocks are linked together.
  2. the BTC block structure contains the previous block hash, the list of transactions to include in the current block and the nonce. I believe the block also includes the time it was mined.
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