Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1247
  1. Why is it important that the blocks are cryptographically linked together?

The cryptographic links form the security of blockchain. If the information of a block changes even by one decimal the hash of the block will change at the same time and brake the cryptographic link of blocks. This broken blockchain will become disqualified within the node network.

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

-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]

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#1248
  1. Why is it important that the blocks are cryptographically linked together?

To make it almost impossible to change a transaction in the blockchain -> immutability

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

current block hash
previous block hash
transactions
nonce

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#1249

  1. Why is it important that the blocks are cryptographically linked together?
    It forces consensus. For instance a signature on a transaction could be different in one peer and the same in the next 4 peers. The 4 peers win the day and the abnormality is thrown away.

  2. What does the block structure look like in bitcoin? Block # - Nonce - Data - Hash of previous block (unless your at ground 0)- Hash of current block.

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#1250

While this is how the blockchain looks like, do you think you could name a few important things that create a block? What is the block made of?

Loved the drawing. :raised_hands:

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#1251

  1. Because that is what makes the chain immutable. If you change the contents of one block you break the link to the next block and all subsequent blocks because you altered the cryptographic hash of that block and all the others when you changed the contents.

  2. Block #
    Nonce
    Transactions
    Prev:
    Hash:
    and a “Mine” button.

These have entry fields after them like a database entry form and are arranged in a box with a series of identical boxes that represent the blocks of the blockchain.

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#1252

I am not sure if I understand your example. We cryptographically link the block to make the chain tamper proof. Any change of data in the previous blocks will break the chain from that point onward. :slight_smile:

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#1253

Great attention to detail. It is known as a genesis block and it has no previous hash. :raised_hands:

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#1254

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

A blockchain, as the name implies, is a chain of digital “blocks” that contain records of transactions. Each block is connected to all the blocks before and after it. This makes it difficult to tamper with a single record because a hacker would need to change the block containing that record as well as those linked to it to avoid detection.

What does the block structure look like in bitcoin?

  1. block number
  2. hash of the previous transaction
  3. current transactions
  4. nonce
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#1255

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

All succeeding blocks must be linked to the previous block to protect the network.
this is how it can achieve immutability.

2 What does the block structure look like in bitcoin?

a) hash of the previous block.
b) Nonce- It is used as a guessing numerical value to be adjusted or recalculated to find a value lower than the target.
c) Data- current transaction being processed.

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#1256
  1. Why is it important that the blocks are cryptographically linked together?
    So that each block contains the previous blocks information and that it would be highly unlikely for anybody to change anything from an older block and break the chain.
  2. What does the block structure look like in bitcoin?
    .The previous blocks hash
    .New transactions
    .nonce
    .which is all hashed to create the next block.
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#1257

1. Why is it important that the blocks are cryptographic-ally linked together?

By linking the blocks together with cryptographic hashes makes it practically
impossible to make any changes to historic blocks in the blockchain, ensuring
accuracy & security of said blockchain, and in turn creates trust.

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

CURRENT BLOCK HASH: 
   PREVIOUS BLOCK HASH
   NOUNCE
   DATA:
      TRANSACTION 001
      ...
      TRANSACTION nnn
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#1258
  1. it is important to keep the blockchain “correct” , because one change in a previous block will change all the subsequent blocks. And therefor it is practical impossible to deliberately corrupt the blockchain.
    2 it consists of a hash of the previous block, the nonce and all the new transactions.
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#1259

  1. To incentivize honesty to secure that there is no double spending.

  2. It looks based on the hash of the transactions, the inputs, the outputs, the nonce and the previous hash.

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#1260
  1. This helps prevent the data from being altered. Data immutability
  2. The hash of the block is based on the transactions in the block plus the previous hash and the nonce that needs to be guessed.
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#1261

  1. Why is it important that the blocks are cryptographically linked together?
    Answer - because this way at least a couple of objectives are achieved: a) integrity of the system b) immutability of the data.

  2. What does the block structure look like in bitcoin?
    Each block consists of the following elements:

a) hash of the previous block
b) list of tasks that need to be performed in this block
c) Nonce - random number
d) Target number
e) when mathematical puzzled is solved then the block gets his own hash (sort of an overall hash for the block)

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#1262
  1. Cryptographically linking the blocks together insures that previous blocks can not be altered.
  2. The block structure in bitcoin is made up of new transactions and information, the previous hash and a nonce.
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#1263
  1. Cryptographical linking of blocks assures the integrity of the blockchain is maintained based on mathematical functions.
  2. The block structure would include the hash of the previous block, the current hash of the transactions, and the hash output. That is input, output, and hash of the current block. I would assume the block must contain information about the block itself: a timestamp, version, size, header, nonce, and so on.
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#1264

1- It is important that the block are cyptographically linked because that contributes to the immutability of the block chain .
2- The block contains : the hash of the previous block, a transaction list, and a nonce.

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#1265

It is important that the blocks are cryptographically linked together because it keeps integrity of the block chain. It makes it impossible to change anything in a block without affecting other blocks. Even smallest change has huge effect on the entire chain.

Block structure in bitcoin: the block contains transactions, the current hash, the hash of the previous block and the nonce.

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#1266

  1. so no one can dubbel spend and make it harder to change the chain

  2. it has the privius blocks hash and transaktions and the nonce

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