1.Why is it important that the blocks are cryptographically linked together?
This ensures the blockchain’s integrity.
2.What does the block structure look like in bitcoin?
The block consists of the previous block’s hash, the hash of the data in the current block and the nonce.
Homework on Blockchain and Mining Visually - Questions
It makes it very difficult to change information contained in a specific block as all future blocks are linked to the hash of previous blocks. If they were not linked together, it would be easier to change information contained in a block without affecting any other blocks.
A block contains transaction information, the hash of the previous block and the nonce. The hash of this information is then compared to the target and if below target, the block is accepted and recorded on the blockchain. If above target, a new nonce is guessed then the information is hashed again and compared to the target.
Because if it not linked together, it would be hard to trace every transaction and it would be easy to alter each block.
The structure is looks like binary tree, connected together.
It is important that blocks are cryptographically linked together as this ensures that any change in a block will cause the link between it and the next block to break. This is because they no longer match. All subsequent blocks from the one altered would then have to be changed (re-mined) or there will be no chain.
The block structure in Bitcoin looks like this;
Magic Number (to identify the type of data structure)
Block size (in bytes)
Block header (including the version number, previous block hash, Merkle Root (used to compile all the transactions in the block), time stamp, difficulty target (PoW algorithm), and a nonce (a 32 bit number starting with a “zero”)).
Transaction counter (how many TX in block)
Record of transactions in the block
The “link” between blocks connects “the hash of the previous block header” with the “current block header”.
Yes, but why? Its important to understand why the blocks are linked to each other. The reason why is to prevent a node from changing the past transactions in the previous block. When a new block is produced we purposely take the previous hash of that block when calculating a new hash. That way when someone wants to change what happened in the block that is 100 blocks behind all 100 would get invalidated as they wouldn’t meet the difficulty target. A miner would have to perform a 51% attack and catch up to the current chain in order for him to truly change that block.
There are many parts of the block but the most important ones are:
Nonce: A random number which a miner tries in order to guess a low enough hash.
Transactions: A list of transactions that the miner accepted.
Previous Hash: A previous hash of a block which will ensure that this block breaks the rules if the last blocks is modified.
The hash of this block: A hash that the miner is currently trying to find in order to prove he has put in the work and in order for the next block to be linked.
Yes. Changing a block would invalidate all the other blocks behind it.
Yes, to make sure no one can change the previous blocks.
The most important ones are; nonce, transactions, previous hash, and the current hash.
Good answer, I liked it. Keep it up.
Block are chained together. But what is the structure of a block? The most important parts are the nonce, transactions, previous hash, and the hash that will be made when the current block gets mined.
Very nice explanation. It is possible if you can achieve to get 51% or more of the hash power. But yes, its pretty hard to change something in the past.
Because it secures the blockchain. By linking the blocks together whit the information from the previous block it gets harder to brake the chain.
Each block has a hash (a digital fingerprint of that block). And the hash is based on all the transactions in that block and the hash of the previous block.
This provides a vital function in ensuring that blocks cannot be changed providing integrity. It avoids any issues such as double spend risks.
The structure is made up as follows: [ ] - [ ] - [ ] - In each block there will be the previous hash, transactions and the nonce, which the miner is trying to guess so they win the ability to add their block to the chain. Each block is linked with the previous hash.
Cryptographically linking the block secures the entire chain from bad actors and preserves the integrity of the data inside the chain.
The bitcoin block structure contains the transactions, the nonce, the hash of the previous block, and the hash of the block itself.
It’s important for blocks to be cryptographically linked together to make the blockchain secure, ie, prevent double spending, prevent censorship, prevent alterations to already-confirmed blocks. In theory it’s possible but cryptographically linking the blocks makes it impractical.
Block Structure:
It ensures the integrity and security of the chain. Decoding the cryptography is sufficiently difficult that it is not possible to hack the chain.
It contains the previous key, all the transactions, and a nonce. The block is encrypted using a hash function.
Q1: Its important that blocks are cryptographically linked together as this secures the integrity of the chain (everybody playing by the rule), that no one can change the data (double spending etc) and makes the chain immutable.
Q2: The data structure of Bitcoin is the hash of (TX’s of the block, the nonce and the hash of the previous block).
Why is it important that the blocks are cryptographically linked together?
It ensure that the blockchain is correct and true. Any attempt to change the blockchain would have effect on all the following blocks highlighting the error.
What does the block structure look like in bitcoin?
The hash number is the link between a block and the following. The block itself is composed by hash of the previous block + transactions with digital signature + nonce number + hash of the new block calculated on the base of target number.