Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2029
  1. Why is it important that the blocks are cryptographically linked together?

Because it leverages the property of immutability of the network. Since blocks are verified with each block’s transaction history plus the previous block hash function then changing the information on one block causes the rupture or invalidates the connections with all other blocks. Trying to update a modification to the entire network is computationally unaffordable.

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

The block structure consists of the history of transactions plus the hash of the previous block.

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#2030

1.- So they work like a timeline, a timeline that makes sense and tracks every move.
2.- Index, hash, previous hash, TX number, timestamp, nonce, TX’s, Merkle tree.

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#2031
  1. It is important that the blocks are linked together because it proves the integrity of all preceding blocks. It also aligns the incentives of all miners to follow the protocol to hash for future blocks.
  2. The block contains: the previous block’s hash, the transactions in the block, and random nonce to solve for. These 3 must produce a hash lower than the target.
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#2032

  1. Because POW would not be possible without the links and the network would be highly corruptible by miners.

  2. The block structure contains it’s hash based on the previous hash + the data + nonce.

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#2033

  1. Why is it important that the blocks are cryptographically linked together? to avoid alteration of the data Block Inmutabitily!!!

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

Previous Hash

The aleatory number: Nonce

Data that is the transaction of the block

All this generates a new hash that is taken by the next block.

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#2034
  1. it makes sure a change in the blockchain is immediately noticed. makes sure it is immutable and secure
  2. block-link-block etc, whereby each blockhash is made up of previous blockhash + tx’s + nonce
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#2035

It is the genius that creates the security of the blockchain.

The block structure consists of:

  • The hash of the previous block
  • The transaction
  • The nonce
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#2036
  1. To create the chain part of blockchain, and ensure the immutability of the record. All previous transactions are forever stored and unable to be altered.
  2. They contain a timestamp, the hash of previous block, all new transactions, the nonce, and other metadata.
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#2037
  1. Why is it important that the blocks are cryptographically linked together?
    For integrity purposes to secre the network
  2. What does the block structure look like in bitcoin?
    Linked list with hash of each block and hash of previous block and a nounce. used to calculate a hash number below the target.
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#2038
  1. Why is it important that the blocks are cryptographically linked together?
    It’s important to secure the network - to ensure nobody can manipulate transactions. If one block is changed, the other blocks need to be mined again. Every block is hashed and linked to the next block. So the hash would be different for each following block. It’s almost impossible to be faster than the network, only the longest chain is the chain ever accepted by the nodes.
  2. What does the block structure look like in bitcoin?
    -block nr
    -nonce (nr. which need to be guessed by the miner that the hash result of the block is smaller than the target)
    -transaction data (incl. block reward)
    -hash of the previous block
    -hash of current block
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#2039

  1. This makes is virtually impossible for bad actors to alter the blockchain maliciously and for those blocks to be accepted into the blockchain as legitimate.

  2. Hash, Previous Hash, Nonce, transactions

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#2040
  1. Why is it important that the blocks are cryptographically linked together?
    History can not be changed easily becuse each block depends on his previous blocks.
  2. What does the block structure look like in bitcoin?
    Linked List. The hash of a block is based on the transactions of the previous block plus his hash and the nonce
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#2041

1.) Why is it important that the blocks are cryptographically linked together?
So that no transaction made in a previous block can be be altered without breaking all following links.
2.) What does the block structure look like in bitcoin?
Version, previous block hash, timestamp, difficulty, nonce, blocksize, transactions

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#2042
  1. So that the entire blockchain is the most secure, if any information in previous blocks is changed, all subsequent blocks must be changed and mined again.

~Header
~Version
~PrevBlockHash
~MerkleRootHash(Hash of Tx list in current block)
~Timestamp
~Bits
~“Nonce”

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#2043

  1. To ensure the integrity of the blockchain. That way there is no altering history.

  2. Hash of the block, transactions in the block, previous hash and nonce.

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#2044
  1. Why is it important that the blocks are cryptographically linked together?
    this provides the consensus between all blocks which confirms the transaction.
  2. What does the block structure look like in bitcoin?
    Bitcoin is made up of the transaction list, the nonce and the previous hash rate affecting the current creation of a hash. this along with solving the puzzle of the target will connect the block and so it is it’s construction.
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#2045

  1. In order to reach immutability and prevent manipulation.

  2. There’s the blocksize, blockheader (previous hash, nonce, timestamp, difficult, merkle tree root and version), transaction counter and transactions.

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#2046

  1. Because it makes it impossible to alter a previous block without breaking the complete chain.

  2. It’s a ledger with data in consensus, hashed together with previous block hash and a nonce. The hash you get from all this needs to meet the target level (lower than target) in order to be added to the chain.

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#2047
  1. Why is it important that the blocks are cryptographically linked together?
    If they were not linked together, you could go back and change something eg. Double spend.
  2. What does the block structure look like in bitcoin?
    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 accepted.
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#2048

  1. So that the data on the block cannot be changed. If a bad actor wants to double spend or change the data on previous blocks, it would not be feasible to do so as he would need to re-mine all the hashes of the blocks in front of it, which is impossible/does not make economic sense.

  2. It consist of a chain of blocks. Inside the blocks include the list of transactions, previous hash, nonce and current hash.

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