Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#3336

Homework - Mining Part 2
Bitcoin Basics
Why is it important that the blocks are cryptographically linked together?

So that the previous blocks are not altered in anyway. The consensus algorithm designed on the blockchain makes it secure. Although double spending is theoretically possible its just not feasible to do, so it makes much more sense to stick with the rules and protocol which also gives initiative for miners to follow the designed way.

What does the block structure look like in bitcoin?

Inside the block structure you will find the previous block hash, data which is the list of transactions and the Nonse.

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#3337

Q1. Why is it important that the blocks are cryptographically linked to together?
A1. It is to prevent change in the chain each connecting link has a connection with all the previous block links starting with the genius block of the chain.

Q2. What does the block structure look like in Bitcoin?
A2. There is a block number to ID the block, nonce number is guess by the miner using previous data to calculate, data is the list of transactions, the previous block hash and the current block hash.

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#3338

Cryptography utilizes mathematical encryption in order to ensure that data is secured by a unique hash, which prevents double spending.

The block structure stores data with a unique hash, which is replicated in the subsequent block.

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#3339
  1. It is a security feature because each block is based from the hash of the previous block and any change to a block will nullify all following blocks.
  2. Previous block hash + TX data + Nonce= new block
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#3340
  1. It is important because it provides integrity/immutability and does not allow fraudulent actions by simply creating more difficulty and cost to mine a meaningful reward.
  2. Previous blockā€™s hash + nonce + list of txs --> new blockā€™s hash
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#3341
  1. Blocks need to be cryptographically linked together because it secures the chain and ultimately provides more resilience to changes in previous blocks. All blocks are connected, so if one block is changed the hash for every block that follows is also changed.
  2. The block structures considers the nonce, the transactions present and also the hash of the previous block.
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#3342

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

  • This makes it impossible to change the data in any block without changing data in multiple blocks, thereby making the cost of such an operation practically impossible to perform.

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

  • There is a block number, a random nonce number, the data in the block, the hash for the previous block, and the new hash.
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#3343
  1. It is important that the blocks are cryptographically linked together to ensure prior blocks are not changed.
  2. The bitcoin block structure is comprised of the nonce, transaction data, and previous blockā€™s hash.
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#3344
  1. Because if they were not linked together, changing the blocks would be an easy feat, so in order to prevent that all the blocks are linked which makes changing older blocks almost impossible.
  2. Block structure looks like a square with chains on two sides. These chains correspond to the hash of the adjacent previous block. Inside of this square there data such as: version, timestamp, difficulty target, nonce, block size, header, transactions and a few other things, such as the hash of the previous block and the hash of the block itself.
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#3345

Why is it important that the blocks are cryptographically linked together?
The idea of block chain is to have a public ledger whereby all the past transactions are connected and linked to the current transaction. It is a system whereby every transactions can be visible to public. Changing of the past data is also made almost impossible because the links will cause future block details to change.

What does the block structure look like in bitcoin?
Block structure of bitcoin looks like boxes with data inside (version, time stamp, target, nonce, block size, transactions etc.). The 2 ends of a block are connected to the block before it and the block after it, each containing the same types of data. The hash of the block is linked to the hash of the previous block, and the hash of the next block is linked to hash of current block, and so on

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#3346

1- Cryptographically linked blocks prevent fraud, false data entry, and any modifications later on. Whenever something like this happens, the whole chain will collapse because the links are cryptographically produced and depend on all previous entries in the chain.
2- The block structure in bitcoin is a series of blocks linked together. Each block contains a list of transactions, the hash of the previous block, and a nonce. These blocks are linked together by solving a cryptographic puzzle that depends on information from previous blocks and previous links.

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#3347

  1. This is what makes the blockchain immutable. Because every block contains the hash from the previous block, if a past block is changed, every block after would need to be remined.

  2. A block is made up of a list of new transactions taken from the mempool, the hash of the previous block, and what is called a nonce. A random number that is guessed by the mining node repeatedly until the new block produces a desirable hash.

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#3348
  1. To ensure the whole system follow the rules, it supports security.
  2. A temporal chain of connected information. Hash of the prior block + transactions + a nonce
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#3349
  1. this ensures integrity. Changing one of the previous blocks makes following ones / the block chain invalid. The effort of changing one and all consecutives would be insane/impossible
  2. block consists of hash of previous + transactions + nonce resulting in a new hash
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#3350

  1. Why is it important that the blocks are cryptographically linked together?
    It makes it impossible to alter one block without corrupting all subsequent ones. This way no one can enter or remove a transaction fraudulently.

  2. What does the block structure look like in bitcoin?
    The block has previous blockā€™s hash, a nonce, a list of transactions and a new hash.

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#3351
  1. Ensures the block remain immutable.
  2. Naunce ā€œmagic numberā€, Transactions, Hash of previous block, Block header, Transaction counter, Blocksize, Current Target.
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#3352
  1. Why is it important that the blocks are cryptographically linked together?
    If they are not linked together people will be able to change information on a previous mined block. This would enable fraud. Because they are linked together you canā€™t change a previous mined block, without making all of the other blocks invalid. It would cost a lot of money and time to actually change a previous mined block. This is near to impossible and therefore highly unlikely that this would happen. Because they are linked together the blockchain is a very safe place.
  2. What does the block structure look like in bitcoin?
  • Hash of the previous block
  • Transaction list of the block
  • Nonce
    These three result in a new hash
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#3353
  1. It is important that the blocks are cryptographically together so it means people canā€™t go back and change previous blocks because it will change the hash of all the blocks after it showing thereā€™s a problem or someone has been tampering. As new blocks are formed every 10 seconds and all miners are competing to put the next block in this means it is impossible to change previous blocks as you cannot keep up with the pace of the blockchain.
  2. It has previous block hash, itā€™s own hash made from that blocks UTXOā€™s.
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#3354
  1. it is important that the blocks are cryptographically linked together so the security can not be compromise as if any changes / alterations in the block will effect all the block that follow .
  2. the block structure consists of a hash from the previous block, transections in the new block and a nonce
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#3355

Homework on Blockchain and Mining Visually - Questions

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

This keeps the blockchain secure as any changes will change the whole chain from the point of the chain, making that part of the block invalid, meaning it will have to be reminded. This secures the chain.

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

It contains following:

all the tx in the block
the hash of the previous block
a nonce or magic random number

A hash is then created from the above three items to create a digital fingerprint of that block.

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