Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#2714

  1. Its what makes the Blockchain integer and secure

    • previous hash
    • transactions
    • nonce
1 Like
#2715
  1. Why is it important that the blocks are cryptographically linked together?
    This makes it so you cant change transactions on confirmed blocks. It makes the network secure.
  2. What does the block structure look like in bitcoin?
    Transactions are pooled together in blocks by all miners. They will also containt a hash which is that blocks digital fingerprint. This hash was created via the previous blocks hash by some kind of equation? They are connected somehow. The new block also contains the tx reward of new BTC as well as any TX fees from the list. The new block will also contain a nonce and keep guessing the nonce.

I tried lol

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#2716

What do these boxes contain? :wink:

#2717

Yes, basically the previous hash is used as the input to a new one (+ other data in the block header). When the nonce for the block is found, there is no need to guess the nonce for that block anymore, miners construct a new block and continue the search for a new nonce :slight_smile:

1 Like
#2718
  1. Why is it important that the blocks are cryptographically linked together? With every block partly depending cryptographically on the previous one, if any bad guy tries to scam updating info on a previous block, he/she needs to update all the next blocks too.
  2. What does the block structure look like in bitcoin?
    It contains the transactions included by the miner and also a firs TX with ni input which is the reward for the miner (I think it’s called inflation). Also a link from the previous block and the nonce
1 Like
#2719
  1. Why is it important that the blocks are cryptographically linked together?
    no data alteration
  2. What does the block structure look like in bitcoin?
    Hash of ( prev hash Tx, Nonce)
2 Likes
#2720
  1. Why is it important that the blocks are cryptographically linked together?
    This way no one can change a previous block without changing the whole blockchain.
  2. What does the block structure look like in bitcoin?
    It contains the hash of the previous block, all the transactions in that block, the nonce and the hash of the block
1 Like
#2721
  1. Why is it important that the blocks are cryptographically linked together?

To make sure that everyone follows the rules and can’t alter or delete any transaction.

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

Consists of the previous hash, transactions and nonce.

1 Like
#2722
  1. Why is it important that the blocks are cryptographically linked together?
  • to ensure that no previous blocks have any changed hashes
  1. What does the block structure look like in bitcoin?
  • the block includes data from the previous block, current data in this particular block, and a nonce and target.
1 Like
#2723

It only includes the hash of the previous block, having all data copied from one block to another would be extremely inefficient. :slight_smile:

#2724
  1. It’s important for the blocks to be linked for security of the network. When a something is changed from one block, then all the blocks after that block are changed as well, because every block is hashed from the previous block.
  2. A hash of a block is based on transactions, the previous block hash, and the nonce.
1 Like
#2725

1. Why is it important that the blocks are cryptographically linked together?
Cryptographically linked blocks ensures that the data is true, verified, and unchanged. There is a history of transactions that can be traced back to it origin and that has been verified by a network of nodes. Each block has a unique “Hash” that represents a digital fingerprint. Moreover, each block includes the hash of the previous block along with the list of transactions from it’s own block. In other words, the hash of a block is based on the transactions of that block and the previous hash. Thereby, ensuring the blockchain data integrity.

2. What does the block structure look like in bitcoin?
Each block structure is as follows:
Hash (Digital Fingerprint) --> Block = (Previous Block Hash + Transaction List of the Current Block + a Random Number know as a Nonce)

Miners work hard at solving a cryptographic puzzle that requires them to provide a solution that is less than a random target number. The provided solution is the total sum of the Hash for a Block being presented. If that sum is less than the target and the miner is first at solving that puzzle, then it is added to the blockchain and the miner is rewarded with a financial incentive.

1 Like
#2726
  1. Why is it important that the blocks are cryptographically linked together? It is critical that the blocks be linked together by means of hashing previous block hash with current block data and nonce to generate the current block so that previous transactions can not be altered without invalidating the entire blockchain.
  2. What does the block structure look like in bitcoin? Each block contains nonce, previous block hash, transaction data, current block hash.
1 Like
#2727
  1. Why is it important that the blocks are cryptographically linked together? The blocks are linked together to maintain the integrity of the blockchain.
  2. What does the block structure look like in bitcoin? The block structure in bitcoin contains the previous hash, the current transactions data and the nonce.
1 Like
#2728 
1. Why is it important that the blocks are cryptographically linked together?
	○ It makes the chain immutable
2. What does the block structure look like in bitcoin?
	○ 4 bytes - Block size
	○ 80 bytes - Block header
	○ 1-9 bytes (VarInt) - Transaction counter
	○Variable size - transactions
1 Like
#2729

  1. It is important that blocks are cryptographically linked because this prevents someone from changing a block in the middle of the chain–you can’t rewrite past transactions in crypto! If for example, a hacker tried to change a block in the middle of the blockchain, the altered chain would create a new hash code for itself; this wrong hash code would break the link to the next chain. But even more than that, this new hash code influences the next block’s hash code–another link breaks. In fact, all the way down the chain, a single change will set off a cascade of broken links. Literally, the entire rest of the chain, starting from the altered block, down to the newest blocks, would all be broken. This fact makes hacking blockchains practically impossible.

  2. A block contains three things: the previous block’s hash, the current block’s transaction list, and the Nonce (randomly assigned number).

1 Like
#2730

  1. Why is it important that the blocks are cryptographically linked together?
    To make provenance immutable.

  2. What does the block structure look like in bitcoin?
    It is all transactions in a mempool, plus the hash function of the previous block, plus the nonce and a hash function for any subsequent blocks.

1 Like
#2731

  1. Why is it important that the blocks are cryptographically linked together? - By Cryptographically linking blocks it ensures the security and integrity of the chain and thus the network.

  2. What does the block structure look like in bitcoin? Hash / Previous Hash / TX list / Nonce

1 Like
#2732

  1. Blocks being linked together maintains the integrity of the ledger, preventing people from breaking the rules through instances of double-spending etc.

  2. The block structure consists of the previous hash, TXs in the current block, as well as a nonce that is less than the target. These components give the new block its unique hash.

1 Like
#2733
  1. So you can`t change past transactions and double spend. You secure the network.
  2. Block is made out od data from previous hash, list of transactions (UTXO`s) in this block and nonce. When its made it has new hash.
1 Like