Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2150

[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?
    Immutability. This prevents modification of individual older blocks, double spending. It promotes integrity of the entire chain.

  2. What does the block structure look like in bitcoin?
    Block is composed of:
    Nonce

  • Data (transactions, fees, rewards)
  • Previous hash
    =hash of the block

The next block is composed of:
Nonce

  • Data (transactions, fees, rewards)
  • Previous hash
    =has of the new block

So all blocks are linked to all other blocks

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#2151

  1. Cryptographic links secure the network - no censorship, no double spending, no altering history because you can’t change the contents of one block without changing the contents of every subsequent block.

  2. Each block contains - block number, nonce, transaction data, hash of the previous block and hash of the current block.

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#2152

  1. Why is it important that the blocks are cryptographically linked together?
    To ensure blockchain remains immutable because once one link is broken, the next block will also be broken.

  2. What does the block structure look like in bitcoin?
    The hash in each block comes from previous transactions that happened.

Block # 1
Nonce: 095663
Data: Transaction to 1 to 2
Prev. ???
Hash: 0000
Mine :eye:

1 Like
#2153
  1. It is important that blocks are cryptographycally linked together, so to secure the blockchain.
  2. Block includes a hash that is based on previous transactions plus all transactions in the block and the nonce to be guessed.
2 Likes
#2154

  • Why is it important that the blocks are cryptographically linked together?
    so the transactions in the blocked could not be changed. for the security

  • What does the block structure look like in bitcoin?
    the block consists of the previous hash, transaction list and nonce.

2 Likes
#2155

  1. Because it ensures the immutability of the blockchain. If blocks are cryptographically linked together they make a mathematical puzzle that makes impossible to go back and change the data of a previous block.

  2. The block has it’s particular hash + the hash of the previous block + data (transaction list) + nonce and we mine them all together until we guess the right ( number lower than the target)

2 Likes
#2156
  1. Having the blocks linked together with a hash is what makes Bitcoin secure.
  2. There is a header at the top with the time stamp, nonce, Merkel Root, and Target. Below that is the transactions.
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#2157
  1. It is important that all links within the network are linked together in order to mine with your hardware efficiently enough to earn the block reward and transaction fees involved in creating a new block on the blockchain network.
  2. The block structure on bitcoin is linear, but very long, dating to its creation of the genesis block, of which looks like one long interlinking chain(s). Within the Block itself you have the Hash(fingerprint of a block) which is Sha256 data of the current block along with the previous hash from the last block. The end of the puzzle which is the Nonce(number between 1 & infinity) is what all miner blocks compete to find the right answer in order to be included in the chain.
1 Like
#2158

  • Why is it important that the blocks are cryptographically linked together?
    To avoid changes in previous blocks.

  • What does the block structure look like in bitcoin?
    hash ( hash (previous block) + tx1…+txn + nonce) < Target

1 Like
#2159

You forgot to mention the header also contains the previous block hash that is important to link the blocks in a chain :wink:

3 Likes
#2160

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

This prevents miners from tampering with the transactions in the block.

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

Each block contains the hash number of the previous block, transactions and a new hash number that needs to be generated based on the target. The new hash number needs to be anything less than a certain target number.

1 Like
#2161

  1. It is important that the blocks are cryptographically linked because it makes the blockchain immutable.

  2. The block structure in Bitcoin contains transactions and tx hash, previous block hash and nonce. I know there’s more but that’s what we just learned!

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#2162

  1. it is important because it adds to the security and keeps the blockchains integrity so it can never be double spent without having to do work that could last a lifetime.

  2. it looks like the hash of the previous block, the transaction lists, and a nonce that all has to create a hash that is lower than the target or threshold.

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#2163

  1. They have to be linked because then it makes it hard to change individual blocks (by changing the block, hash of block is changed and also hashes of any other following blocks are changed).

  2. Block structure is made of hash, previous hash, nonce and data (transactions).

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#2164
  1. to ensure that any change cannot be forced backwards. If a previous block changes , the hash also changes automatically and the link will break, leaving the block invalid.

actual hash
previous hash
tx list
nonce

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#2165

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

  2. What does the block structure look like in bitcoin?
    Block contains previous block hash, nonce and transactions.

1 Like
#2166

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

  • So that the information inside a block cannot be altered. If you try to change something in the block, the link will break.

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

  • The block structure in bitcoin contains:
    • a list of transactions
    • link to previous hash
    • nounce - random hash number that has to be guessed and it has to be below certain target.
1 Like
#2167

Homework on Blockchain and Mining Visually - Questions

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

As all newly created blocks (apart from the genesis block) point to the preceding block, it is not beneficial for anyone to alter a block with information (TX’s) to his/her benefit, as for a result the fraudster would need to mine the block again and all off it’s following blocks, as they otherwise would not be confirmed anymore. This is what makes the blockchain secure from forgery.

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

A Block Header (contains version number of the software, or rules, which govern the blockchain, a hash of previous block’s header, a hash of the root (merkle tree root) of the blocks TXs, Difficulty target, Timestamp, Nonce), a Transaction counter, the TXs

2 Likes
#2168

  1. Why is it important that the blocks are cryptographically linked together?
    Cryptographically linked blocks make it nearly impossible to make changes to block. This increases the security and integrity of the blockchain

  2. What does the block structure look like in bitcoin?
    A block contains all the transactions and the hash of the previous block

1 Like
#2169

  1. Why is it important that the blocks are cryptographically linked together?
    Keeping blocks linked together keep the network secure and prevents double spending.

  2. What does the block structure look like in bitcoin?
    Each block has a block number, transaction data, a nounce, the previous blocks hash information and information about the current block.

1 Like