Blockchain are incredibly popular today. We hear everywhere this term: Blockchain. But what is blockchain? How does it work, what problems solve and how can it be used? In the next article we will explore the concept of blockchain.
When was this technology first used?
As the name suggests, a blockchain is a chain of blocks containing information. "Block" means block, and "chain" means chain.
This technique was initially used in 1991 by a group of researchers and was meant to temporarily mark digital documents, so that it could not be modified or falsified later. The purpose of that time was for this technology to validate and authenticate documents in a secure, immutable and transparent way without the need for a trustworthy authority.
However, the technique remained unused until 2009, when Satoshi Nakamoto adapted it to create cryptocurrency Bitcoin. A blockchain is a distributed register that is public, and anyone has the opportunity to access it. It has an interesting property: once information has been recorded in a blockchain, it becomes very difficult to change it.
What is blockchain?
How does it work? Let's look more closely at a block. Each block contains information, the hash of the block and the hash of the previous block.
The information stored in a block depends on the type of blockchain. Bitcoin blockchain, for example, stores details about a transaction, such as the one who sends, the recipient and the sum of transferred cryptocurrencies.
A block also has a hash. You can compare a hash with a digital fingerprint or a unique registration code. It has the role of identifying a block and all its properties, besides it is always unique, like a fingerprint.
What is Hasu?
The third item in each block is the hash of the previous block. This actually creates a chain of blocks, and this technique makes such a safe blockchain. Let's take an example. In the image above we have a chain of four blocks. Each block has a hash and hash of the previous block. Therefore, block number 3 indicates block 2, and block 2 indicates block 1. The first block is special because it cannot indicate a previous block, because it is the first. This block is called the Genesis Block.
Now, let's say you change the block 2. This will change the block hash, which will make block 3 and all the other blocks become invalid, because they no longer keep a valid hash of the previous block. So, the change of a single block makes all the next disabled blocks.
But the use of hashs is not sufficient to prevent changes. Today's computers are very fast and can calculate hundreds of thousands of hashs per second. Thus, you could change a block and recalculate the hashs of all blocks to make the blockchain again valid.
To prevent this, blockchain use a mechanism called "proof-office". It slows down the process of creating new blocks. In the case of Bitcoin, it takes about 10 minutes to calculate the proof of work and add a new block in the chain. This mechanism makes it very difficult to change the blocks, because if you change a block, you must recalculate the proof of work for all blocks.
Therefore, the security of a blockchain comes from the creative use of hashs together with the proof-office mechanism. But there is a way in which the blockchain is secured, and this is their distribution. Instead of using a central entity to manage the chain, blockchains use a peer-to-peer (from user) network to which anyone can participate. When someone joins this network, he receives a complete copy of the blockchain, and that person is running a bitcoin knot, that is, he downloaded all the transactions from the first transaction and has a copy of the computer register.
What happens when a new block is created?
Now, let's see what happens when someone creates a new block. This new block is sent to everyone on the network. Each knot checks the block to ensure that it has not been changed. If all is okay, each knot adds this block to its own blockchain. All nodes in this network create consensus. They agree on valid blocks and those who are not. The modified blocks will be rejected by other knots in the network.
Therefore, in order to successfully change a blockchain, you should change all the blocks in the chain, restore the work proof for each block and take control over over 50% of the peer-to-peer network. This is almost impossible to achieve!
Blockchain is also in a continuous evolution. One of the latest developments is the creation of smart contracts, the so-called "smart contracts". These contracts are simple programs that are stored on blockchain and can be used to automatically change coins, depending on certain conditions.
Where can I buy bitcoin or other cryptocurrencies in Romania?
Now you know what a blockchain is, how it works at a basic level and what problems it solves. If you want to buy bitcoin or other cryptocurrencies, you can enter Abarai , there you will find all the support you need.
