Homework on Blockchain and Mining Visually - Questions

[alve_lagander]

1. So that after a previous block is changed the links break so that the cheater has to mine the blocks again which costs a lot of money.
2. A block contains the previous blocks hash and a list of transactions.

[Mikevanbike]

1. it makes it almost impossible to cheat and to create fake TXs. it makes it more secure.

2. the blockes are made of data(TXs), the previus block hash and are connected with the links in between.if
   something is wrong the block will not be accepted by the chain.

[REGO350]

1. If one letter is changed in one block, the whole blockchain which comes after would be unlinked. This prevents cheaters from over writing the blockchain network.

2. A block is made out of previous hash, transaction list, and nonce. The hash of this block needs be less than the target.

[UnSt0pP4bL3]

1-) Why is it important that the blocks are cryptographically linked together?
= To make it immutable and avoid double spending.

2-) What does the block structure look like in bitcoin?
= (Tx in current block + Previous + Nonce) = Hash of current block, which should be less than the target.

[cashworth]

1. It is important they be cryptographically linked as the link represents the puzzle solved based on the transactions of the previous block.

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

[Tesh]

1. Why is it important that the blocks are cryptographically linked together?
   So that calculations including nonce’s previous hash rates and tx) have to be made to add to the blockchain and this increases security

2. What does the block structure look like in bitcoin?
   It includes the nonce, the prev hash, the current hash and transactions in that block.

[RickyE]

Homework part 2

1. Why is it important that the blocks are cryptographically linked together?
   Because if the hash or anything changes in the block then all the ones after changed.
   It creates the security for the block chain.

2. What does the block structure look like in bitcoin?
   Block #
   Nounce #
   Data
   Previous Hash #
   Hash #

[TheHoff]

1. Why is it important that the blocks are cryptographically linked together?
   Avoids changes to the previous blocks, this ensures the integrity
2. What does the block structure look like in bitcoin?
   Transaction list, previous hash and the nonce that gets hashed below difficulty target

[ryanmercadante]

1. It is important for blocks to be cryptographically linked together so that it is nearly impossible to change data in previous blocks. This is done with hash functions.
2. A block in the Bitcoin blockchain has a nonce value, a list of transactions, and the hash of the previous block in the blockchain.

[Danilojinhong]

1- to prevent manipulation of previous blocks, so any new block takes hash rates txs from the previous block and also the link.

2-

[TheBiographer]

1. Why is it important that the blocke are cryptographically linked together?
   My answer: In order to secure the network, so it makes it practically impossible to go back in time and re-mine and change the content of old blocks.

2. What does the block structure look like in bitcoin?
   SHA256(data) = Hash
   The hash of a block contains:

• Previous hash
• Transactions
• Nonce (random number)

[HO5]

1.Why is it important that the blocks are cryptographically linked together?
2.What does the block structure look like in bitcoin?

1. History can not be altered. This serves the security of the blockchain.

2. The hash of every new block is based on:
   the hash of the previous block,
   the transactions of the new block and
   the nonce.

A block is like a ledger page and contains only transactions that have not yet entered any prior blocks.

[Alex_Chaz]

1. because the blocks of transactions are data that is not meant to be tampered with, it must maintain integrity of the network and data of the chain
2. a bitcoin block contains the hash of the previous block, and transactions of the current block

[Athenophia]

1. Why is it important that the blocks are cryptographically linked together?
   -Because it ensures the security of the network

2. What does the block structure look like in bitcoin?
   -The block is comprised of the block number, the Nonce (randomly assigned number as the header), the data of each transaction in the block, the previous block’s hash, and that block’s hash

[alh1127]

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

It ensures the integrity of the network.

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

The block structure consists of a previous hash, the transaction list in the current block, and a nonce.

[Den_Wal]

1. Why is it important that the blocks are cryptographically linked together?
   This ensures that changes cannot easily be undertaken “post-ex” - as they are all linked to each other if I change one in the chain, all the other ones have to be recalculated, making it visible to all that changes in an old block have been made.

2. What does the block structure look like in bitcoin?
   The block structure is a chain of blocks - the hash of the block is based on the transactions in the block plus the previous block - when these are combined / hashed they make a “nonce” that needs to be guessed by the miners

[Lakov]

1. Blocks in cryptography are linked together in specific maner, so slightest change in the information in the previouse Block all the further links will be broke and need to be redune again wich it is not profitable.
2. The block structure in bitcoin is: hash function from the information in the block plus hash number from previouse block and the guessed number of the Nonce wich need to be lower than the Nonce. Nonce should be difficult level apr 10 min gues per block. If its more than 10 min Nonce gets higher number if gets faster than 10 min Nonce number is lowered.

[Loresmen]

1: so that they cannot be reversed and that the blockchain’s security is stronger

2: Each block is made on top of each hash over and over

[Thu]

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

When the blocks are linked together cryptographically, it then becomes a chain called proof of work. This ensures the integrity of the data on the blockchain and secures the network.

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

The bitcoin structure inside a block consists of the previous hash + current transaction data + nonce (this is what miners have to guess).

[sascha_z]

1. it ensures that nobody is tampering with previous blocks, as this would change the block´s unique hash and therefor all following connections and blocks. it would be impossible to generate the following block hashes as the rest of network progresses and creates new blocks. one would always end up with a shorter blockchain that would be denied by the nodes.

2. the block contains a header, metadata, the reward (newly mined btc), transactions and the nonce.