Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1487
  1. To keep the integrity of the block and to prevent it from being altered.
  2. Previous block, block, data, nonce, tx, has number
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#1488

  1. It is important to link blocks cryptographically to make it virtually impossible to change the transaction data.

  2. In Bitcoin, the creation of a new block involves hashing the transaction data together with the hash from the previous block plus the nonce to find the target number or less. Each block is made up of a header containing the hash which is linked to the following block and the rest of block contains all the transaction data.

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#1489

  1. Because in that way integrity is granted. Nobody can change a single block without change the whole structure of the blockchain that wouldn’t be connected anymore.

  2. A block contain:

  • Nonce
  • Data (TX list)
  • previous hash number
    *Hash number of the block.

Solving the nonce puzzle you can get an hash number that allow the miner to append the new block to the previous one.

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#1490
  1. Why is it important that the blocks are cryptographically linked together?
    This important because to prevent hacking, double spending, immutability, and to ensure integrity of the Tx and data in the blockchain.
  2. What does the block structure look like in bitcoin?
    1. Current Hash
    2. Previous Hash
    3. Transaction List
  3. Nonce
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#1491

  1. To make the chain secure and safe for everyone. To avoid double spending.

  2. Block number, Nonce , Data , Previous block hash , Hash.

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#1492
  1. Because the contents from the previous blocks are used in the puzzle to solve for the next block. It also ensures information cant be changed.
  2. Block reward, transaction fees, previous block hash and nonce.
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#1493

Why is it important that the blocks are cryptographically linked together?
It is important in the verifying aspect of the Bitcoin ecosystem. If the actors in the network that is securing the network by verifying the current one and only truth it needs to first have an simple way of not needing to check every single binary code in the entire blockchain (ledger) so that it hasn’t been changed in some way. Therefore linked the latest hash with the previous hash then the latest hash is indirectly linked with the entire chain, taking away the need to check the validity of the entire history of blockchain every single time one needs to verify it.

The main reason why it is important is the security of the immutability on the history of the blockchain. In an unlinked blockchain with a huge amount of mined unlinked blocks, someone could potentially just “re-mine” one block in the middle and the complete blockchain is still a valid one. That could lead to several valid “history” of the blockchain and an actor in it wouldn’t know which one is the single truth of the “history”. With a linked blockchain the history of it is immutable.

In a way we use the concept of exponentiality in the security of Bitcoin because when we use the previous puzzle outcome in the new puzzle as input all the way throughout the chain we make it exponentially harder the longer down the chain we want to rebuild. With an unlinked chain to rebuild the first block and solve its puzzle wouldn’t be any harder than building the latest block and solving that puzzle. The use of the exponentially harder rebuilding aspect is true as long as we still got the rule in the protocol that we always continue to build on the longest chain as the one and only truth. The rules of the protocol just melts together beautifully to something that when one person understand it can say that trust no longer needs a human being, because now we can just trust the protocol, math and the network itself.

What does the block structure look like in bitcoin?
The block structure in Bitcoin include all transactions that are considered valid by the network actors and chosen by the miner at the moment, together with some other information like a timestamp (I guess that is used to see if difficult levels on the puzzle needs to change for the average block time on 10minutes is reached), the previous blocks hash, the last thing is a random input that the miner has guessed to get the current blocks hash under a desired hash value.

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#1494

  1. It is important that the blocks are linked to together to secure the blockchain and prevent anyone to alter any data in a previously mined block.

  2. A block consists of

  • the hash of the previous block
  • the hash of the data(txs) of the current block
  • a random nonce, to fulfill the target
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#1495

  1. To insure immutability.

  2. Block, nonce, data, hash of previous block, hash of the current block.

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#1496
  1. The reason it is urgent the block be cryptographically linked together is to be certain blocks can stay unmodified
  2. A block structure in bitcoin can be visualized as set of transactions with inputs and outputs
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#1497

  1. Why is it important that the blocks are cryptographically linked together?
    To assure no changes are made in previous blocks

  2. What does the block structure look like in bitcoin?
    Prev block hash
    Tx list
    Nonce

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#1498
  • for security
  • a block that consists of [a nonce + transaction data + previous hash] linked by a puzzle that is derived from the previous block and link --> repeated
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#1499

1.it prevents data from being alter.

2.in the block we have previos hash , transactions and nonce . the hash of current block base on all these factors.

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#1500

  1. Why is it important that the blocks are cryptographically linked together?
    this prevents the data from being tampered with, ensuring the security of the network

  2. What does the block structure look like in bitcoin?
    block hash/header, previous block hash, nonce, hash of transactions

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#1501
  1. It is important for the security of the blockchain. When they are link together that way no data can be changed in previous blocks because it would break the links to all following blocks.
  2. Block structure in bitcoin consist of previous hash, transaction list (data) and from the nonce that needs to be solve.
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#1502

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

This is the centeral plan of PoW and Mining. The ledger is open to everyone and also needs to be strong and almost impossible to change. Than keeping the database by blocks mined by incentives based on cryptographilly linked makes it encourage to change it toward selfish attitudes.

What does the block structure look like in bitcoin?

It looks like very-complicated-sewed pattern tile. Like been sewed in one way linear, to change a color of a motive you need to sew again the unstiched pieces were at next. Or like a book, every page number signed by a previous page’s signed number with a strong cryptography than no one can change any page order of the book.

The content of a block is signed header, signed txn list, nonce and previous blocks’ sign. Every sign cryptographically depends on previous ones which makes the chain theory.

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#1503

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    • Because blocks need to dynamically change hashes as blocks are completed. As well, to insure that hashes ARE changed in forward blocks if previous blocks are tampered with or changed.

  2. What does the block structure look like in bitcoin?
    • Blocks are composed of a Block #, Nonce #, Data (within the block), Previous Block Hash and Hash for the entire Block. In this way all Blocks are connected by their own hash as well as previous hashes.

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#1504

1- To secure the network, so if a transaction is changed the link to the block will broke.
2- Blocks contain boxes with the block number, Nonce, Prev., and Hash of the block.

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#1505

  1. It prevents any changes to blocks because then all the other links blocks previous will change.

  2. Previous hash, transactions, nonce -> block hash

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#1506
  1. The make it impossible to change data in a block.
  2. transaction list
    nonce
    Previous hash
    current block hash
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