Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2874

1.the linking of the blocks cryptographically makes the structure immutable. Changes to previous blocks can not be made without changes all of the following blocks.

  1. each block consists of:
  • hash
    -hash of previous block
    -transactions
    -nonce
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#2875
  1. Why is it important that the blocks are cryptographically linked together? - To maintain integrity and continuity of the chain remaining immutable.
  2. What does the block structure look like in bitcoin? - A block constructed of data, previous hash, current hash and nounce.
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#2876

  1. cryptographically linking blocks together via a hash function makes all data in the blockchain immutable, dissabling double spending making it secure and giving it integrity.

  2. A block is hashed from the hash of the previous block, the transaction and a nonce.

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#2877
  1. To increase security of the network and remain immutable
  2. Transactions, Hash of previous Block, Nonce number that need to be guessed
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#2878
  1. To ensure the integrity of the blockchain across the network.
  2. Hash links of each block in linked the previous hash of the block before it.
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#2879

Cryptographically linked insures securing the blockchain, to avoid changes and doubles spends etc.
Hash of previous block
Transactions
Nonce

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#2880
  1. It’s important, because if we use cryptographically links to create blockchain it is more safe and secure. If one link is broken, you cannot just ‘repair’ it without re-mining other blocks. While we use cryptographic links it’s extremely difficult to edit data in blocks.
  2. It is a hash of tx’s, previous hash, nonces.
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#2881

  1. Blocks need to be cryptographically linked to ensure proof of work, and in turn, legitimacy.

  2. Block structure is:

  • Hash of previous block
  • Data
  • Nonce
  • Hash (requirement)

And don’t forget the star of the show SHA256 - making those digests.

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#2882
  1. It makes it more difficult to corrupt and any changes would be of greater impact.
  2. TX-Hash-Nonce-previous hash.
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#2883

1.) It makes sure nobody can change a previous block and “sets them in stone”.

2.) NONCE, Transactions on the block, Hash from previous block

2 Likes
#2884

  1. It makes it impossible to change. If anyone makes changes in one block all the other blocks become invalid.

  2. Block number, nonce, the data of all the transactions, the previous hash, and the new hash.

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#2885

1: It is important that the blocks are cryptographically linked together in order to ensure that the integrity of transactions is kept. Any changes to the transaction(s) in a block will cause the hash in the next block to be invalidated and this will also affect subsequent blocks in the blockchain.

2: Each block contains all the transactions that were made under that block as well as the hash of the previous block.

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#2886
  1. Because the slightest change in a block invalidates all the next blocks, so all of those needs to be remined
  2. previous blocks hash, txs, nonce
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#2887
  1. By them being connected, they cannot be changed in the past.
  2. A series of information to include transaction details, previous hash, block size, etc.
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#2888

  1. Linking the blocks together creates the immutable chain of all transactions. It keeps the blockchain secure and accurate. Changing a transaction in a previous block would require rehashing all subsequent blocks which would not be possible by 1 entity.

  2. Block structure includes previous hash, all transactions added to that block, nonce, and output hash, which is then added to the next block.

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#2889

They have to be cryptographically linked to ensure that they are immutable after creation, ensures integrity.
The network always uses the longest chain (POW) + 51% of hashrate, each block has a hash based on previous block plus their transactions and must calculate the nonce and hope the number is less than the target.

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#2890

Homework on Blockchain and Mining Visually - Questions

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

When a cryptographic puzzle is complete it is PoW as it shows miners have used electricity to solve the puzzle. It also means nothing can be changed in previous blocks as it would break the links between all blocks following it.

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

Nonce
TX
Previous Hash

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#2891
  1. This makes it impossible to alter transactions or data in the block. Changing something from a previous block breaks the link to the forward blocks making the blockchain invalid.
  2. Hash is based on the previous block’s hash, transactions on the current block and the nonce. Miners have to guess the nonce and the hash should be lower than the target number.
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#2892
  1. Keeping the network secure
    2.previous hash+data+nonce
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#2893

Mining- Homework part 2

1- It is impportant becasue that is how the chain is built and how it is made so secure, making any alteration or tampering nearly impossible.
2- The hash of a block is obtained using as imputs, the hash of the previous block, the transactions in the block and the nonce number.

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