Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1989
  1. It’s important the blocks are linked together to protect the security of the blockchain. All newly mined blocks are linked to the previous block. If you modify a transaction on the previously mined block, a miner cannot append a new block to the chain.
  2. First, you have the hash of the previous block, then you have the hash of the new block and you must guess the nonce in order for it to be added to the blockchain.
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#1990

You are describing the transaction, not the block. Most important thing to remember is that the block contains the hash of the previous block which links them together in a chain. :wink:

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#1991
  1. If you change one block then you would have to change all previous blocks, a process that would be far too costly with both time and money.
  2. Square - line - Square :rofl: :rofl: :rofl: Sorry, man, couldn’t resist that.

seriously but 2. Hash, previous hash, block transactions.

I’m away for a coffee now :flushed:

2 Likes
#1992

cheers :coffee: :slight_smile:

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#1993

Right back at you, Alko89 :coffee: :grinning:

1 Like
#1994

Homework on Blockchain and Mining Visually - Questions

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

This insures data integrity and network-wide security on the blockchain, in that through this process, it becomes nearly impossible to corrupt the data in any way.

This process fosters trust in the network, and due to the implausibility of being able to hack the blockchain (due to the excess and cost of the hashing power required to do so), encourages participants to behave in accordance with the rules governed by the blockchain protocol.

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

The block structure includes:

The Block Number
This designates the block’s chronological position in relation to other blocks in the chain.

The Nonce
This is a number used only once, which, when combined with the other information in the block, has successfully resulted in a hashed value that is lower than the randomly generated target for this particular block.

Transaction Data
A list of valid transactions, fitting within the maximum block size of 1MB.

Hash of the Previous Block
This is the result of all the data in the previous block being processed with the SHA-256 cryptographic algorithm.

Hash of the Current Block
SHA-256 is used again to process all the above data, including the hash of the previous block.

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#1995

  1. It makes it extremely hard for someone to change a previous transaction. any change to a block changes the hash that is in the header of that block, which in turn changes all the proceeding blocks.

  2. each block contains the hash of the previous block. In the block you have a list of transactions for that block the nonce, and the hash for the current block

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#1996

Why is it important that the blocks are cryptographically linked together?
to setup a blockchain of integrity, to secure the network to ensure no double spend

What does the block structure look like in bitcoin?
linked list with hash of each block and hash of previous block in the blockchain. In bitcoin it will have UTXO and a current block reward of approx 12.5 BTC plus any transactions rewarded.

2 Likes
#1997

Why is it important that the blocks are cryptographically linked together?
Because by changing just one bit in any of the blocks will change the hash of the changed block plus all the following blocks, which will break their connections.

What does the block structure look like in bitcoin?
It contains:

  1. Current blocks hash
  2. Previous blocks hash
  3. List of transactions
  4. A nonce (random number)
3 Likes
#1998

The current block reward is 6.25 since the last halving :slight_smile: and the number is exact but the miner also gets fees so the final payout is a bit higher.

#1999

1.The blocks need to be cryptographically linked s that no one will change it in future. Every block is linked to the previous block.
2.A block contains the hash of previous block and the the transaction that needed to added to the blockchain from mempool.

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#2000
  1. to keep order in the blockchain so no one can change it
  2. hash with inputs and out puts
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#2001

  1. The fact that the blocks are linked together cryptographically is what makes blockchain tech. and bitcoin so revolutionary. Transactions are immutable and unalterable as it is infeasible and unlikely anyone will ever successfully alter the bitcoin network specifically.

  2. The block structure of bitcoin is a chain of blocks all cryptographically linked to one another, that are all dependent on their previous blocks hash. This long chain of blocks originating from the genesis block, is almost entirely permanent in that no one will be able to alter or change any previous block or transaction. Each block contains a hash, which is based on the previous blocks hash, new block transactions, and the nonce which changes with network difficulty.

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#2002

What is the input to the current block hash? :slight_smile:

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#2003
  1. Makes it extremely difficult to alter. Provides security.
  2. Previous hash, new transactions and random nonce.
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#2004

  1. For the security of the block-chain, ensuring that the data cannot be changed once accepted by the network, therefore, immutable.

  2. Block number, nonce, transaction data, previously mined block data and the hash of the existing block.

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#2005

  1. It is important that the blocks are cryptographically linked together because this makes the blockchain secure and safe from outside attacks.

  2. Basic block structure-previous block hash - transaction list - nonce (which must be below a Target to be processed as the next block)

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#2006
  1. It is important for blocks to be cryptographically linked because it protects all of the data in each block from being altered.
  2. Each block is made up of the hash of the previous block, the nonce (which is mined) the transaction data of that block, and then hash of these which is sufficiently low as to be accepted into the chain and becomes the hash of that current block.
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#2007

Why is it important that the blocks are cryptographically linked together? Allows for security of data in the block chain as trying to change or manipulate the data will break the chain created after the block which would then become invalid
What does the block structure look like in bitcoin; Hash of the previous and current blocks, TX data, Nonce

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#2008

  1. It is important the blocks are cryptographically linked together so that the likelihood of the blockchain being modified is close to none. Being cryptographically linked together causes a chain reaction of incomplete blocks once one block is modified. Because the blockchain has 24/7/365 access globally, it is vital that it is as secure of a network as possible.

  2. Correct me if I am wrong, I am not 100% if this is what the question is asking…
    A block on the blockchain contains a previous hash from the previous block (which is also linked to all the previous blocks of that blockchain), a list of current transactions, and a nonce. A block generates a hash out of that previous hash, transaction list, and nonce.

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