- Why is it important that the blocks are cryptographically linked together?
so that nobody can change the previous blocks.
- What does the block structure look like in bitcoin?
like a chain?
1 Like
-
Why is it important that the blocks are cryptographically linked together?
The cryptographic links between the blocks are essentially the proof of work that has been done to link the blocks after each other. -
What does the block structure look like in bitcoin?
- Block height
- Block header: version, previous block hash, merkle root hash, timestamp, difficulty target, nonce
- Transactions
1 Like
How does a particular block in a chain look like? 
Why is it important that the blocks are cryptographically linked together?
Because it gives inmutability to the block chain, a block can’t be modified without modifying the hashes of the next blocks, it would end up on being rejected by the rest of the nodes.
What does the block structure look like in bitcoin?
A block contains four things:
- Its hash
- The transactions data
- Previous block hash
- The nonce number
1 Like
Homework on Blockchain and Mining Visually - Questions
-
Why is it important that the blocks are cryptographically linked together?
This is what I found all this I will have to go back and see Ivan’s Lectures. from google:
Because each block links to its predecessor, data in the blockchain is immutable. The hashing function is a unique digital signature unique for that transaction that means that a change in any transaction will produce an entirely different hash , which will alter the hashes of all subsequent blocks . -
What does the block structure look like in bitcoin?
A block is a container data structure, which brings together transactions for inclusion in the public ledger, known as the blockchain. The block is made up of a header; containing metadata, followed by a long list of transactions. A block can be identified in two ways, either by referencing the block hash, or through referencing the block height.
The blockchain data structure is a back-linked list of blocks of transactions, which is ordered. It can be stored as a flat file or in a simple database. Each block is identifiable by a hash, generated using the SHA256 cryptographic hash algorithm on the header of the block. Each block references a previous block, also known as the parent block, in the “previous block hash” field, in the block header.
1 Like
- Why is it important that the blocks are cryptographically linked together?
It makes it harder/impossible to DS or change older block since it would break the coming links and therefor won’t be accepted by the blockchain.
- What does the block structure look like in bitcoin?
Previous hash
transaction list
nonce number
It’s own hash number
1 Like
- Why is it important that the blocks are cryptographically linked together?
It ensures the integrity of the network by preventing changing records of transactions and double spending.
- What does the block structure look like in bitcoin?
It has a hash based on previous hash, transactions in transaction list, and NONCE less than TARGET.
1 Like
Nonce is a number miners use to help them find a block hash below the target, not the nonce itself.
- So that the difficulty of tampering with blocks becomes a near impossible task, thus preserving the integrity of the blockchain.
- Blocks are constructed of Hashs. These hashes are made from the transaction list, the previous blocks hash, and a nonce.
1 Like
-
Why is it important that the blocks are cryptographic-ally linked together?
Cryptographic links allows an algorithm to attest to the validity of the chain rather than a central authority. Everyone has access to the algorithm, anyone can attest the validity. If Nodes are always running then the algorithm is always validating, and if a majority of nodes are required to sign off on a new addition to the chain, everything is automated by the algorithm. -
What does the block structure look like in bitcoin?
A new block structure is composed of 1MB of transactions from the mempool plus the previous block’s hash plus a nonce all sent to a SHA-256 function which provides a unique signature for the block. The signature is always below the target value set by an algorithm at the point in time when the block was created.
1 Like
-
This ensures the integrity and security of the system. You cannot edit one block without editing all blocks.
-
The block structure consists of the list of transactions, the previous block’s hash and the nonce.
1 Like
- It is important that they are cryptographically linked together so that any change in previous blocks can not be done. A change in previous block affects all subsequent ones. Thus anyone trying to cheat the system would have to re-mine subsequent blocks which is practically impossible.
- The block structure consists of the hash of the previous block as well as the current block’s transactions and the nonce, which is basically a guessed number. If the number is guessed correctly, a hash will result that meets the requirements of the current target. This resulting hash becomes the “previous hash” for the next block.
1 Like
-
For the immutability of the network. Tx can be added, but not removed from the blockchain. To change the data of any previous block would require to re-mine the entire chain of successors. This is not profitable by any mean.
-
BLOCK = hash of the previous block + Tx + nonce (random number in guessing the puzzle)
In Block Explorer you can find these data, when checking blocks:
- Hash
- Confirmations
- Timestamp
- Height
- Miner
- Number of Transactions
- Difficulty
- Merkle root
- Version
- Bits
- Weight
- Size
- Nonce
- Transaction Volume
- Block Reward
- Fee Reward
1 Like
-
Why is it important that the blocks are cryptographically linked together?
To ensure the network safety. This will prevent for example double spending, modifying data and altering history. -
What does the block structure look like in bitcoin?
Previous block hash
Current block hash
Transaction history
Nonce
Time stamps
1 Like
Block explorer usually abstracts data to make it more user friendly to read, but you got the gist of it. You did missed the most important thing, the previous block hash that is the link that links the blocks in a chain 
If you want to get detailed information about the block structure you can check the Mastering Bitcoin book on Github:
https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch09.asciidoc#structure-of-a-block
BLOCK = hash of the previous block + Tx + nonce
This is what I wrote, it is even in bold
1 Like
-
It is important that the blocks are cryptographically linked together because it makes the next block down linked to that by taking the hash from that previous block. This very much increases security and strength of the chain as it makes the individual blocks of the chain difficult to manipulate.
-
The structure of a block in Bitcoin consists of:
-
The hash of the previous block
-
The transaction information for the current block
-
The random nonce number that the miner has to continue to guess until the hash of their block is less than the target hash given
1 Like
-
because then if one block in the changes then all following blocks will change which provides security and immutability to the network.
-
a block structure contains the block height, the block hash, the previous block hash, a nonce, an index, a timestamp, and a block reward or coinbase transaction, plus other transactional data including fees adding up to about 1Mb. Or more basically a header plus transactions.
2 Likes
One block after another after another.
But I guess that I read the question in a different way…
Do you know how can we know if the answers that we give are correct or not?
The question is how a specific block in a chain looks like.
We are checking your answers so if you got it wrong, we’ll let you know.
1 Like