What is a block?
A block is an essential part of a blockchain. It contains some, or in some cases all recently completed transactions not yet written to blocks. It can be compared with one page of a cash book, since all payment transactions can be validated here and cannot be manipulated afterwards.
In principle, closed blocks are attached to the end of the existing blockchain. This increases the length of the chain over time. A noteworthy feature here is that completed transactions can no longer be changed or removed.
This ensures all data is forever anchored in the blockchain. In order to amend faulty transactions, one must be revised by a new transaction or cancelled by a new publication of the blockchain.
What is the structure of a block?
Basically, all blocks consists of a block header that contains a list of all recently closed transactions. It also contains a reference to transactions that were completed in the previous one.
The first ones of a blockchain are also known as the genesis blocks or original blocks. The blocks also contain the check digit at the end of said block. This must be at least equal to or lower than the current difficulty level after completion.
After the block has been completed, it’s easy to check the answer. In addition, there are several solutions possible for any of them blocks, although only one valid answer is required.
The current blocks time must be taken into account when mining. This indicates how many blocks can be completed within a certain period of time.