Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#4282
  1. they are linked so nobody can go back and change the transactions on the ledger, double spend, or claim that they have more bitcoin than they own.
  2. TX hash, Inputs, Outputs
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#4283
  1. To ensure integrity and the correct order of transactions.
  2. A block includes a nonce, transactions and the previous hash.
#4284

  1. Why is it important that the blocks are cryptographically linked together?
    It is required to maintain the immutability of past blocks.

  2. What does the block structure look like in bitcoin?
    Hash of the previous block, list of transactions, timestamp, and nonce.

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#4285

1 - To ensure the security of the blockchain
2 - each block is linked to the previous one with with its hash

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#4286

  1. Blocks should be linked because it is only in that way that altering a single block would break all subsequent blocks. This means that a malicious miner not only needs to alter one block in the past, but all blocks after it.

  2. Bitcoin blocks contain the hash of the previous block, the transactions list, and a nonce - the number miners manipulate.

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#4287

  1. Since they are cryptographically linked it makes it practically impossible to change the history of transactions.

  2. The block structure contains the transactions, previous hash, and the nonce.

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#4288
  1. For security reasons, and specially to be inmutable, data integrity
  2. It depends on the previous hash block, the nonce and the transaction data.
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#4289
  1. Its so importan for securing the network. Its the only way to make it that safe as it is. A double spend attack gets with the difficulty much more expensive and worthless.
  2. It looks like a big chain which connects all the blocks from the first one to the present one.
    We have in a every block the previous hash, transactions and the nonceā€¦
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#4290

  1. Because it prevents fraud. You cannot change a block without changing all of them.

  2. Block A -> Block Aā€™s hash + Transaction hashes + nonce = block b -> Block Bā€™'s hash + transaction hashes + nonce and so forth

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#4291

00 Why is it important that the blocks are cryptographically linked together?
If blocks were not cryptographically linked together, than an attacker would be able to change the content of a transaction in the middle of the block chain much easier making the system vulnerable to attack.
01 What does the block structure look like in bitcoin?
A rudimentary block structure contains the following:
a) A nonce number.
b) A hash for the previous block.
c) A list of transactions.
d) A hash of the current block.

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#4292

  1. It ensures the security of the blockchain as an attacker would have to change all the blocks following the one they are trying to change, which is practically impossible for one computer to do.

  2. Each block is made up of transaction data, hash of the previous block and the nonce.

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#4293

  1. For the safety of the network. This way you canā€™t manipulate the network, because if you would be able to change one block then te rest of the blocks will change with it and that would make the chain invalid.

  2. The previous block has, list of transactions and the nonce.

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#4294
  1. It creates a secure, unbreakable system.
  2. Previous hash, transactions, nonce.
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#4295

  1. Cryptographic linkage ensures integrity of the blockchain. This makes network more trustworthy through maths thus no cheating.

  2. Blockchain looks like a double linked datastructure where each block contains previous hash along with current transactions value.

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#4296
  1. Why is it important that the blocks are cryptographically linked together?

This makes sure that changing a block is almost impossible. Because they are linked, when a block is changed all links need tob e remined

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

Nonce, blocksize, block header, transaction counter, transactions

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#4297
  1. Why is it important that the blocks are cryptographically linked together?
    Having all the blocks linked creates the security of an ā€œinterlacedā€ checking. It makes it identically strong as stone engravement: nothing can be erased, we can only add to it
  2. What does the block structure look like in bitcoin?
    The block structure is composed of all the transactions of the chain + the hash of the function to produce the particular block
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#4298

  1. Why is it important that the blocks are cryptographically linked together?
    For the security of the blockchain, that way no ttxs can be changed in previous blocks bc it would break the coherence and link to the next block and all that follow.

  2. What does the block structure look like in bitcoin?
    The hash of the block is based on the ttx in the block + the previous hash an the nonce that needs to be guessed below a threshold (difficulty).

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#4299

to assure the whole goes at one.

previous hash, transaction, nonce

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#4300

  1. When something in the link is altered, everything linked to it is also now altered. This would make it beyond difficult to accomplish.

  2. The previous hash, current transactions, and a random number (nonce) to complete the block.

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#4301
  1. It is important for the blocks to be cryptographically linked together so that if a transaction in a block is changed the block will be invalidated and dropped. This maintains the integrity of the block.
  2. Block header
    transactions UTXOā€™s
    previous hash
    hash
    nonce
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