Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2653
  1. Thru the integrity of each block and to ensure the security making it impossible to replicate a block.
  2. The block is made of data, previous block hash and the nonce
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#2654

  1. To ensure the security of the blockchain.

  2. A chain of blocks. Each block contains the hash of the previous block, a list of transactions and a nonce.

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#2655
  1. Because of data integrity. One would need 51% of the hashing power in the system to change the input of a block.
  2. Transaction input, nonce and the previous block’s hash
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#2656
  1. The linking of blocks allows all users to quickly see if a miner/node has altered a previously mined block as all of the block hashes after that block will be incorrect due to the change in the hash of the altered block.
  2. All blocks contain the previous blocks hash, which links all blocks together, the list of transitions, stored in a merkle tree, and a random nonce value, which are all combined and a new hash is generated for that information, which becomes that blocks final hash value which is then linked to the newest block.
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#2657

  1. Why is it important that the blocks are cryptographically linked together?
    Otherwise it will be easy to change the transactions of a block: you would only need to guess the correct nonce of the changed block. By linking them all together, you need to guess nonces of all next blocks too. This is nearly impossible, thus ensuring integrity of the blockchain.

  2. What does the block structure look like in bitcoin?
    A block consists of: the hash of the previous block, a transaction list, a guessed nonce, and a hash of the current block (which is the hash over the previous 3 elements)

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#2658
  1. It makes the system secure and extremely hard to alter, If one part changes - everything after will change.
  2. A block’s structure is made of:
  • Transactions within the block
  • Previous block’s hash
  • Nonce (constantly changing until the block is mined)
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#2659

  1. The blocks must be linked with cryptography because thats what makes the block chain tamper proof. If anything is changed in the block it changes the hash of that chain and all proceding chains

  2. The block structure is a series of blocks containing a nonce, text, and the hash from the previous block which is used to create the hash of the block and so on

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#2660
  1. So that there is proper security measure taken in case someone tries to rewrite data from their blockchain. Once it is put out for approval, it will be disregarded because all of the other linked miners dont match up ledgerwise with the fake blockchain.
  2. The block number, the nonce, the data (transaction ledger), previous hash, and hash output.
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#2661
  1. Why is it important that the blocks are cryptographically linked together?
  • It is important because every block is linked with an actual hash and previous hash which cannot be removed or change, this is more secure in the blockchain system.
  1. What does the block structure look like in bitcoin?
  • The block structure shown as follow:
    Previous hash,
    Transaction
    A Nonce (which is random number given by the miner)
    which is used to create the hash of the block.
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#2662

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

Its for the security of the blockchain. That way no transactions can be changed in previous blocks because it would break the link to the next block and all that follow.

What does the block structure look like in bitcoin?

The block is made up of a header; containing metadata, followed by a long list of transactions.

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#2663

Homework - Mining Part 2

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

Because any change to a block, and the Links and other Blocks forward brake down. This mechanism was created to prevent any change to the network.

What does the block structure look like in bitcoin?

2.1. Hash of Previous Block
2.2. TX list
2.3. Nonce
2.4. Hash of Current Block

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#2664

Do you know what are the block metadata? :wink:

#2665

A simple example of metadata for a document might include a collection of information like the author, file size, the date the document was created, and keywords to describe the document. :wink:

#2666

Also simplify
Previous Hash
Transaction list
Nonce and current hash

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#2667

1: The link between block is like alarm. if somebody tries to change something in the link will break, block will become invalid and will alarm everybody about the breach.
2: Block consist of the llink or header, more than 500 TXs, a previous hash, Tx price.

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#2668

  1. The linking of the blocks creates a chain. When the chain is broken it alters everything in the chain which affects the integrity. The relationship within each block, when a hash is changed, causes the data structure to change. In order to fix the block, takes much time and effort.

  2. The block structure consist of hashes, UTOX, previous hashes and the cryptographic puzzle or nonce that has to be figured out.

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#2669

  1. Why is it important that the blocks are cryptographically linked together?
    To keep the blockchain honest so we don’t have to rely on trust but rather verify that something happened the way that it was said to have happened. By not making the links cryptographically linked it would render the blockchain useless because anyone could edit it with ease.

  2. What does the block structure look like in bitcoin?
    Previous hash combined together with current transactions, then combined with a nonce to get the next mined block under the set difficulty based on how many miners there are.

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#2670

  1. So that if absolutely anything is changed in one block it changes all the blocks. One tiny difference changes the Hash and each block contains not only its Hash but the Hash of the previous block.

  2. Block#
    Nounce
    Data (transactions)
    Hash of previous block
    Hash of current block

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#2671

Homework on Blockchain and Mining Visually - Questions

1. Why is it important that the blocks are cryptographically linked together?
It is important that all the blocks are cryptographically linked together to secure the network. It means that whenever a block is changed it changes all the blocks linked. The network will reject this. It can only be changed if every block is re-mined and this is practically impossible.

2. What does the block structure look like in bitcoin?
A block in bitcoin consists out of data (UTXO’s), previous block hash, and a nonce. A block carries data from one block to the next using hash function SHA-256 - data - hash - new block mined and confirmed.

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#2672
  1. Why is it important that the blocks are cryptographically linked together?
    to secure the blockchain, if data is changed in a previous block, the entire chain will be invalid which is impossible to duplicate or remedy by a bad actor, more over because of a other security feature, the longest chain will be accepted on the blockchain.
  2. What does the block structure look like in bitcoin?
    Nonce
    transactions (UTXO)
    hash previous block
    hash current block
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