Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1287

  1. In this way is more secure and trustworthy. Any little change you want to make in a previous block will affect the cryptographic puzzle of the current block.

  2. A block contains the hash of the previous block, transaction list, nonce (a random number guessed by the miner) and together will hash a number that has to be lower than the target.

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#1288
  1. The links ensure security of the chain and ruling out the possibility of a double spend as each link would be broken and therefore invalid.
  2. The structure consists of the previous hash, the transaction inputs and the nonce.
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#1289

The blocks in the blockchain?

#1290

1- Nobody can not change anything because it can break the link to the next block.

2 - The hash of the block is based on the transactions of the block, include the preview hash and the nonce to be guessed.

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#1291

  1. Since each block is cryptographically linked to one another, it is more secure and makes it difficult to cheat or censor.

  2. Like a chain ā€¦ of blocks? Each block is constructed of sum of itā€™s own unique hash (big number) + previous block hash (big number based on all other previous hashes) and the nonce (random number it is trying to guess based on combo of hash + prev. hash).

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#1292
  1. Why is it important that the blocks are cryptographically linked together?
    It is important that the blocks are linked together for keeping them secure and unable to be edited. If each block contains the hash of the previous block if one of the older blocks is changed, all the subsequent blocks will be changed and in order to have all of them validated, the miner needs to mine all of them all over again and this is basically impossible. The blocks being linked together makes them basically impossible to be ā€œhackedā€
  2. What does the block structure look like in bitcoin?
    The block structure contains the current hash, the previous hash, the transactions and the nonce.
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#1293

Ok, I just didnā€™t understand what you meant by a string of blocks. String is something else in computer science :slight_smile:

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#1294

  1. It is important that blocks are cyptographically linked because if a block is altered then the hash will not match up with the previous hash in the next block.

  2. The block contains the previous hash, transactions, nonce and this will then create a hash for that block.

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#1295

1.It is important that blocks are liked cryptographically for the security of the blockchain. With that no transactions can be changed in a previous blocks this would break the link to the next block and all that follow
2. The hash of the block is composed by the data or transaction on the block the hash of the previous block and the nonce number that must be guessing

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#1296

The interconnectedness of the blockchain keeps the network secure. While the Bitcoin protocol can be hacked, the protocol is set up in such a way that to try and hack it would be counterproductive.

A block is composed of many parts. The two main part are the block header and a list of transactions. Inside the block header includes the timestamp, nonce, difficult target, merkle root, the hash of the previous block, transactions, etc.

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#1297

  1. Why is it important that the blocks are cryptographically linked together?
    It helps to preserve the blockchainā€™s integrity, and helps to prevent forgery.

  2. What does the block structure look like in bitcoin?
    Block number
    Nonce
    Transactions
    Previous block hash
    Current block hash

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#1298

  1. Network security depends on the cryptographic link between the blocks. It is ensuring that they can not be altered and the blockchain remains immutable.

  2. Each block contains hash pointer to the previous block, list of transactions and the nonce number. All this data is hashed to get the digital signature of the block and to be used in the following block as a pointer.

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#1299
  1. they provide redundant securities against any one point in the chain being altered, censored, or double spending. iow, redundant supports of the fidelity of the system.
  2. hash of previous block, hash of current block, data of current block, nonce of current clock.
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#1300
  1. Security. Prevent changes in previous blocks
  2. each block has transactions and uses the previous hash plus current hash plus nonce
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#1301

  1. Why is it important that the blocks are cryptographically linked together?
    To ensure data integrity and immutability

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

Consists out of the hash of the previous has, tx list and nonce

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#1302

  1. Why is it important that the blocks are cryptographically linked together?
    because it will ensure that no one can change the previous data and ensure there is no double-spending so this way we will have a secure network

  2. What does the block structure look like in bitcoin?
    -previous block hash
    -Tx
    -nonce

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#1303

  1. Because when every connected block has a different hashcode, you would need to change everything and guess every new code from the endless amount of data in order to do something not by the rules.

  2. You have the hashcode for the current block, hashcode for the previous block, nonce (random number) and the transactions that are the data included in your block.

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#1304
  1. Why is it important that the blocks are cryptographically linked together?
    Itā€™s important because the data cannot be altered and it links all the blocks together, so when you change something in one block, you will have to alter all the other block which is time consuming and you will lose out on your rewards, etc.
  2. What does the block structure look like in bitcoin?
    Each block has a hash (Digital fingerprint), also a previous hash, Transaction list.
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#1305

  1. It is how we can prove the validity of the chain. If one were to try and change some previous block, it would invalidate the chain from that block forward

  2. A block contains the previous blocksā€™ hash, a list of transactions, and a nonce

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#1306
  1. Because even a small change into a block has to point out the tampering attempt. Each block is characterized by a block-hash that depend on transaction hash a random number (NONCE) and, in particular, by the previous block-hash. The latter is the main reason why changing a blockā€™s contents brings to a change into all the next block on chain.
  2. A block is characterized by a progressive number, by an header block hash that at same time is the hash of previous block hash, transactions hash (merkle root) and the nonce. Into the block one can also find the list of all the transactions characterized by input and output address together with the fees.
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