The word blockchain is familiar to all of us. Blockchain is a technology that allows us to store our information, data, and transactions. The blockchain can be described as follows. ‘A secure, irrevocable, permanent, chronological account book’.

As the name implies, there are many blocks within the 'block‌ chain'. These may be connected to each other like a chain. Let us now turn to the history of the blockchain. The idea was first mooted in 1991. But it was not very successful then. However, the concept of blockchain was revived in 2008-2009 with the introduction of the cryptocurrency Bitcoin.

It looks like a blockchain, just like the name blockchain. There are 3 main things that are saved (saved). The first is 'data', the second is 'hash' and the third is 'previous block hash value' (previous hash value). The 'data' stored in each block changes according to the chain. For example, if it is a 'Bitcoin blockchain', the data saved in it will be the details of those Bitcoin transactions. It contains information about who sent the Bitcoin, who received it, and how much Bitcoin was transferred. Data will be saved accordingly on other blockchains. For example ‘geographical record’ (information on whose name the land is, in whose name it was before, etc.), or something similar.

What is Hash and How it works

Hash 'can be described as the fingerprint of a block. Each block has its own hash value. The hash value is based on the data stored in it. Each block has a different hash value, so each of these can be understood and selected. The hash value is found by solving many 'cryptocurrency puzzles'.

The third factor is the 'previous hash value'. It helps to connect blockchains. Preserves the value of the second block in the third block. As well as the third in the fourth block. Therefore, they can be connected like a chain. The 'previous hash value' of the first block is zero (0000). These three are the main components of a blockchain.

Now let's see how the information is secured in this. If any information in the block changes, its hash value also changes. If an information (data) is added to a block then it is difficult to change it. This causes the hash value to change, affecting the relationship of the adjacent blocks.The ‘block-value’ of all blocks is its primary security. The cryptocurrency bits must be solved to find each hash value. Each block takes about 10 minutes to solve. This is called the "Proof of Work" which is the second level of security.

What Is Peer to Peer Network

he bank is usually the third most trusted institution when we make a transaction. We can only transact through banks. When we make a transaction, the banks check whether it is valid or invalid. Transactions can only be made if the bank agrees that the transaction is valid. But in the case of a blockchain, other members of the same chain will check whether it is valid or invalid.This gives equal importance to all members of a 'network'. There are no major trust agencies like banks here. Blockchain technology uses a peer-to-peer network. All of these individuals are connected through a 'peer to peer' network. Blockchains are always open. So all the data in blockchain technology will be open to everyone.Therefore, when a new member is added to this network, he / she will have access to the details of all the transactions done so far.

If you need to modify the data in any block, it is not enough to make changes only within your blockchain. Because copies of it are available to everyone. So the members have approached everyone and need to change your copies in their hands.
This process is very difficult and makes the blockchain more secure. This will keep your data (information) safe in the blockchain so that no one else can modify your blockchain without your permission.

Smart Contract

One of the key applications of the blockchain is 'Smart Contract'. This is a simple program. It may be saved (saved) in each block. Bitcoins are exchanged automatically (automatically) in transactions according to that program. Securely records how many coins are being exchanged and by whom.

Blockchains are transactions that can only be done with the help of new technologies and cryptocurrencies. At the same time you can protect your data very securely. Maybe in the future all the banks will disappear and a revolution of blockchains will be possible. Large-scale studies in this field are being conducted all over the world today.

Thank you for reading