This article is a complete journey that will allow you to learn about the process of creating a Bitcoin block and the ins and outs that make Bitcoin mining possible.
In previous articles we have analyzed the technology blockchain y how it is constituted. We also have an article dedicated to blocks that make up the blockchain and another dedicated to Transactions, which in turn make up the blocks. If you do not know these terms, we invite you to take a look at these three articles before continuing to have a clearer and more comprehensive knowledge of these elements that will help you understand: How do you mine a block?
On the blockchain, the miners are in charge of generating the new blocks by adding them to the end of the chain. And how does the protocol establish Bitcoin, they must carry out this process approximately every 10 minutes. Each mined block contains a detailed record of the different transactions carried out in each period. And that when added to the end of the blockchain they update their registration.
Block mining process
To create a new block, miners must go through a process to solve a math problem. When finding a valid solution for the network, a new block can be taken for granted that will be added to the blockchain by consensus. And for which, the miner who found the solution, will receive a reward for the new block. This reward is known as the block reward.
A new Bitcoin block is generated approximately every 10 minutes.. So every time one is found, it means the start of mining for another. Since these are mathematically related or chained together. But let's see in more detail how this process is performed:
First stage: Transaction
The process of mining a new block starts when a user wants to send a certain amount of cryptocurrency to another person. So send bliss transaction with the data from your wallet, waiting for the network to do and confirm. They remain there until a block is mined where they can be included and validated.
Second stage: Compilation
These pending transactions on the network are collected and grouped into a block of transactions by mining nodes. Multiple miners are likely to collect the same transactions. And they will all be unconfirmed until the block is mined.
Third stage: Training
Each miner will select the transactions they want to include and build their own block. If there are transactions already validated and included in the previous block, they will be removed from this one. This new block is known as a candidate, since it is not yet valid because it does not have a valid proof of work.
In the formation of this new block, a header must be included that contains the hash from the previous block, the merkle root and data for mining competition. I mean, the timestamp, the objective of the algorithm of PoW for that block (the bits), the software version and the nuncio.
Stage Four: Proof of Work
Once each miner has formed their own transaction block, they will need to find a valid signature for that block. In other words, carry out a proof of work. Each miner must carry out a mathematical calculation process that is unique to each block they formed. So, although the procedure is the same, the result will be totally different for each one. This complex calculation involves a lot of computational power, and therefore, a large expenditure of electrical energy. Which will also depend on the system difficulty for the time of mining.
The solution miners must find is known as hash. This function is very difficult to find, but once found, it is easy to verify by others. nodes.. So that they can verify that the output hash comply with the established system conditions.
To find a valid output hash, the miners perform the mathematical calculations repetitively over and over again using a nuncio. Which is a random number that they use and constantly change until they find an output signature or hash that is valid based on the condition. There is no way to predict which nonce will solve the problem, so they must use as many as necessary. And we are talking about billions of values! Incredible, right?
In the case of the Bitcoin network, the system determines that the output hash must contain a certain number of zeros at the beginning of the hash.
Fifth stage: Transmission
When a mining node manages to find a valid output hash for a block, it transmits that block together with the signature to the other nodes in the network so that they can validate it.
At this time, as long as the 21 million bitcoins have not been issued, the miner receives the reward established for mining, putting new bitcoins into circulation. This is registered on its own node, the other nodes on the network will do so in the next step.
In addition, regardless of whether all the bitcoins have been issued or not, the miner also receives all the mining commissions that users have put in the transactions that make up this block.
Sixth stage: Verification
The other nodes in the network are in charge of validate and verify that the block and hash meet the system conditions, verifying its legitimacy and if it actually contains the stated number of zeros.
Here also the proof of work is confirmed, that is, the computational power spent to find the solution, and it is noted that the miner who discovered the block can effectively make use of the recently received bitcoins.
Seventh stage: Confirmation
Once the new block is added to the blockchain, all the others that are added on top of it will count as a confirmation. At this point, we can come to think that since each miner started the process with their own block, they can continue mining. But it's not like that. Once a block is generated, all mining nodes must start the process by forming a new block of transactions. They cannot continue mining the previous block because each block must add the output hash of the block that precedes it.
This is why we know this technology as a chain of blocks or blockchain. Then, by the time the miner gets a valid hash, another number of new blocks may have been mined. So the output hash of your mined block will not match the output hash of the last added block in the chain. It will be rejected.
In addition, it is very likely that all or most of the transactions included in that block have already been added to others. Even if you succeed in mining the block most of your included transactions will not be able to be validated or confirmed.
Characteristics of the mined blocks
The blocks mined in the Bitcoin system must meet certain characteristics and conditions to be considered valid. Let's see what they are:
- Mined block header hash must be less than target. If it is greater, it will not be considered as valid.
- Block size must be within acceptable limits. In Bitcoin, a block must have a maximum size of 2 MB.
- La timestamp of the block should be less than two hours in the future.
- The first transaction added to the block will be the coinbase transaction. That will give the mining node the reward of the network. And there will only be one coinbase transaction per block.
- All transactions added to the block are valid.
- The header of each block will contain the hash of the previous block and the block height thereof.
All of these features are checked to confirm a block. And each mining node independently validates new blocks following exactly the same rules. So, makes sure that no mining node can cheat. What provides robustness and security to the network. Once the block is validated, the other nodes in the network will add it to their copy of the blockchain. And when this happens, it cannot be modified or changed.
Now you know the creation process that each and every bitcoin in circulation has followed. Each and every one of the bitcoins that exist have been issued following this process, to be later used or sold by the miner to other people, until it reaches your hands.
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