Homework on Blockchain and Mining Visually - Questions

Blockchain and Bitcoin 101
#1367
  1. Due importance to provide immutability
  2. Content of every block header and cryptografic joint between them. Whole structure is determined way when data are not continuously streamed, but periodicly chopped to blocks of data.
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#1368

Nonce is not equal to difficulty. Its a random number to help miners find the correct hash that is under the threshold. :slight_smile:

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#1369

Inputs and outputs are parts of a transaction, there is something else, that is crucial for the system to remain immutable. Can you figure out what it is? :slight_smile:

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#1370

I donā€™t understand the answer, what does open source have to with immutability in this regard?

Nonce is not the hash number but a random number used by the miners to help them find the new hash. :slight_smile:

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#1371

How are the blocks linked? :slight_smile:

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#1372

the current time, a record of transactions, a reference to the previous block and a nonce!

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#1373

By ā€œguessingā€ the proper nonce, who does it first, his valid hash is presented in header 4ever

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#1374

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    That way the blocks canā€™t be changed once theyā€™ve been mined. The ā€œolderā€ the block, the harder it is to change. So you could say that the cryptographic link fortifies the robustness of the blockchain. The information presented in the mined blockchain wont change, so everyone can trust it.

  2. What does the block structure look like in bitcoin?
    Each block consists of the hash of, the hash of the previous block and the miners list of transactions in the (soon to be) new block. To this hash the nonce is concatenated and the result is then hashed again. The new block in mined when the final hash is lower than the target, which depends on how many miners there are on the network.

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#1375

1- Because if you had made a change in a block all subsequent blocks will get invalid.
2-
in the block:
Block Size
Block header
Transaction counter
Transactions

in the Block header:
Version
Previous Block hash
Merkle root hash
Timestamp
Difficulty target
Nonce

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#1376

Thanks, so the nonce is part of creating the hash and the threshold adjusts to keep blocks being added at a rate of every 10 mins.

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#1377
  1. So that the whole system is secured and no hacking is involved
  2. A block bases its digital fingerprint on its transaction and from the data from its preceding block
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#1378

Homework on Blockchain and Mining Visually - Questions

  1. Why is it important that the blocks are cryptographically linked together?
    This ensures everything in the BC is secure and the records are kept correct to make the system viable and trust-less and believable?

  2. What does the block structure look like in bitcoin?
    Block 1 no previous hash with transfer details inside and a created nonse = new Hash, , block 2 inherits Block 1 Hash + data inside that generates a new hash with the guessed nonse for Block 2 , and this will repeat for Block 3 and thereafter with a scale of hardship to guess the nonse. I googled there are date stamps inside each block too

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#1379

  1. It makes the blockchain more reliable and if you change one block, you have to change all the blocks with new hashed relations between the them and that is impossible.

  2. The hash of previous block and current and list of data that consist transactions, fee, size, timeā€¦

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#1380

Correct! :slight_smile:

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#1381

Wouldnā€™t the hash be sufficient? :slight_smile:

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#1382

1.) it makes it imposable to change the algorithm thusly making it trustless.
2,) the block structure in Bitcoin contains data such as block size, timestamp, transaction and other artifacts of the previous hashes.

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#1383

  1. Why is it important that the blocks are cryptographically linked together?
    Cryptography ensures integrity of the blockchain (and the data in it). Because each new block contains the hash pointer of the previous block, any change in data in a block will change its hash, and that in turn will cause a change in the hash of the block after it and so on. The process to make bad faith changes is extremely energy/time/cost inefficient for the attacker. Plus the network can easily see the attempt at manipulation and will reject the block.

  2. What does the block structure look like in bitcoin?
    Each BTC block contains:

  • Block version (number)
  • Current time stamp
  • Previous block hash
  • Nonce
  • Merkle Root hash
  • Difficulty target
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#1384

Q: Why is it important that the blocks are cryptographically linked together?
A: To ensure immutability and security

Q: What does the block structure look like in bitcoin?
A: Transactions, Previous Hash, Hash, Nonce

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#1385
  1. This is important because it means that one block cannot be altered or else the link with the entire blockchain after that block will be broken.
  2. It consist of the hash of the previous and current block, list of transactions, nonce, amount of transactions, summaries, fee, times, sizes, version and reward.
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#1386
  1. Security.
  2. Contents of the block plus nonce plus previous blockā€™s hash.
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