Homework on Blockchain and Mining Visually - Questions
To ensure the integrity of the data in the blockchain. It makes sure that no one could change or delete any transactions.
Hash of previous block, a list of txs, the nonce and the hash of current block.
1.) It is important to keep the integrity of the provenance because the algorithmic encryption relies on the integrity of the proceeding block in as part of the security.
2.). A block consist of a block header, the previous transaction in hash and the current transaction in hash the time, nonce and how many bits, a null pointer, a coinbase and a the merkle tree id contained in the block, or the transactions it contains, that are being included in the block as verified.
I found this video very helpful if anyone is interested.
It is important because if you were to alter a transaction in one block then all the following blocks will have to be relinked which means youāll need to resolve all the cryptographic puzzles. Which will be literally impossible to catch up with other miners in the blockchain.
The block structure looks like this
2.) Signature Block\ Header and the transaction block/Block
Why is it important that the blocks are cryptographically linked together?
A: Due to these cryptographic links, any change to a previous block, would invalidate all subsequent blocks, making it practically impossible to get the change confirmed by the network. The fact that each block is linked to its predecessor provides security to the network.
What does the block structure look like in bitcoin?
A: A block header with the previous hash, a timestamp, transaction data, difficulty, and the nonce.
Homework on Blockchain and Mining Visually - Questions
Why is it important that the blocks are cryptographically linked together?
This helps with the immutability of the chain, changing one block changes the hash on all of them. It also makes it nearly impossible to modify a block and double spend.
What does the block structure look like in bitcoin?
Magic No ( 4 bytes - 0xD9B4BEF9) constant
Block size ( 4 bytes )
Block header ( 80 bytes )
Transaction count ( 1- 9 bytes )
Transactions
But the blockheader is the most important one to answer this question.
Because we want you to say that it has the hash of the previous block + nonce etcetera.
The header has 6 items:
Version
hashPrevBlock
hashMerkleRoot
Time
Bits (target)
Nonce
Because it secures the immutability of the blockchain. It is what makes it so difficult and expensive to change any data in a block that was already accepted on the blockchain. If someone would change any data on a previously mined block he would have to mine that block and all the blocks after it. That is all thanks to this cryptographic link the blocks make by always using the hash of the previous block in their own hash.
A new block will always be produced later in time than the previous block, approximately 10 minutes later. When creating a new block, the miners calculate a hash function of the hash of the previous block, the data inside the current block and the nonce. The block will then only be accepted if the blockchain makes sense to the rest of the nodes, it is the longest blockchain and the hash of the current block is lower than the target.
This way we have a chain in time which consists of blocks containing data and that are linked together by hash functions.
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The Block also contains the previous Block Hash.
1. Why is it important that the blocks are cryptographically linked together?
So that you cannot change past transactions (immutability, no double spend)
2. What does the block structure look like in bitcoin?
Every block has:
The Block Header contains:
Hi there!! But what is the structure of a block? What params or values does each block contain? (you already mentioned someā¦
Thanks Fabrice
I will try to give more detailed answersā¦good to see someone is paying attentionā¦
Cheersā¦
Blocks are cryptographically linked so that if there is any change in data from a previous block, that block and every one there after would become invalid. This incentivises miners for follow rules and protocols, and also strongly increases the security and validity of transactions.
Hash
Previous Hash
Transaction List
Nonce
The hash of the block is determined by all of the above!
So that the computational power needed to alter information is increased - therefor making it extremely difficult to alter information on any single block as it would make all previous hashes invalid.
The block is made up of a hash of transactions, the hash of the previous block and the nonce.
to secure the blobkchain, stopping anyone from ameding any transaction on the blobkchain as each block link is based on the previous blocks thus any change will break all subsequent links in the chain.
each block consists of the: block version, time stamp, difficulty target, pervious block hash, hash of the merkel root, nonce, transaction list.
Blocks are linked together crptographically for security. Any small change to a block creates a different hash that is recognised by the network as incorrect. The cost to a miner in hardware and electricity to reconstruct a portion of the chain (assuming enough hashing power to overtake the hashing power of the other miners) would be prohibitive.
A block is constructed with the following elements:
a) Version - this identifies a version of consensus rules used to construct a transaction.
b) Time - the difference in time from the miner creating the block to the time to the 1st January 1970 in seconds. Displayed as time and date.
c) Bits - the difficulty target as a number
d) Nonce - this is the discovered value that the miner used to validate the block
e) Previous block hash - the hash of the previous block header
f) Hash of the merkel root - the hash of the transactions inside the block
The above constitute the block header and then are followed by the transactions beginning with the Coinbase transaction.
It contains a reference to the hash of the previous block, the data (transactions), a hash of this data, the nonce, a timestamp and the difficulty target for this block.