What is a Blockchain?

What is a Blockchain?

Blockchain is basically a technique to store information. To store the data in a decentralized manner. Decentralized means that there will be no central authority to control the entire data and information.

Take RBI for example.

Our Indian rupees, this note of ₹500, is printed by the RBI. RBI guarantees that its value is ₹500. Neither ₹501 nor ₹502. It's even written on the note that RBI guarantees it.

So RBI is basically a central authority controlling all the Indian rupee notes around the world. RBI can change the value of the notes if it wants to Can increase the note production or decrease it.

But on the other hand, currencies like Bitcoin, are decentralized. There are no central agencies or authorities controlling Bitcoin. It is possible because Bitcoin is based on Blockchain and Blockchain is the technology that actually makes Bitcoin decentralized.

There can be many ways to store information. Writing down something on paper is a way to store information. Writing something on an excel file on the computer is a way to store information. On an excel file, your information is structured in the form of a table. You know the tables.

Similarly, in a Blockchain, the information is structured in the forms of blocks. Each block is made up of three main things.

First, any data or information you store in the block.
Second, each block has its fingerprint known as Hash. This is the way to uniquely identify a block among other blocks. Every block has its own fingerprint.
And third, each of these block stores the fingerprint of the block before it.
This is a Blockchain.

This block will have its own fingerprint and of the block behind it. And thirdly, any information you put into it will be stored here. This is how all the blocks are linked with each other. And the most unique thing about this is that

If you want to change the data in any block, if you try to tamper with the data, then the fingerprint, or the hash, of the block will change.

And if the hash of one block changes the hash of the next block will also change. And the next and eventually the entire blockchain will be destroyed. For this reason, it is next to impossible to alter or tamper with the data in a blockchain.

Because once a block is defined and becomes a part of the blockchain It cannot be altered after that. The second major reason for Blockchains being secure is Decentralization. You will not find a blockchain stored in only one computer.

Blockchains are stored in a network of computers. All the computers around the world belonging to the participants of the blockchain will have one copy of this blockchain.

Instead of one central authority, it is managed and run by a network of computers collectively. The people who are connected to the blockchain through their computers and those who allow the blockchain to run on their computers they are known as Nodes.

Some Nodes among them are Minors. Whenever new data is added to the blockchain, it's the work of the Miners to verify it. Whether the person adding the data has done so properly or not.

Or whether it is an attempt at tampering. All the Miners verify and record this. Any computer connected to this network can see the data added to the blockchain.

There is no need for any third party. No need for any Central Authority. You too can connect your computer to the network and verify this.

what about your privacy?

The information in the Blockchain is not only secure but also is privacy protected. It can be so because each computer in the network has its own Private Key, and a Public Address.

Think of them as the email address and email password. When you log into your email account, you enter your email id and the password and only you can log into your account. It is the same with Blockchain.

But when you share your email id with others you share your public address, not your private key. And this Public Address is a random combination of numbers and digits.

Somewhat like this.
So if you vote for some candidate using your Public Address through the Blockchain system, then even your name will be private.

The other computers on the network will see that this Public Address has voted for this candidate. But who the person is behind the Public Address, their name, age, address, nothing will be revealed.
Privacy will be maintained.

What will happen when a person tries to alter the data in the Blockchain? How can the system prevent it from happening?

Let's take the example of the Bitcoin Blockchain. Suppose ₹50 is to be transferred from A to B. A new block will be created with A and B's Public Addresses and the amount being transferred ₹50 in this case. Now, the other computers on the network will record this.

They'll record that A initiated the transfer to B and the amount transferred. And then they'll verify the transaction. But if one of the computers says that the transfer isn't from A to B instead from A to itself.

But the other computers on the decentralized network recording the transaction will refuse the claim because they can see that the transfer is between A and B.

This is why the system will listen to the other computers and allow the transaction from A to B. If one wants to alter or do fraud in the Blockchain, one would need the majority of at least 51%.
This is also considered a disadvantage of Blockchain.

If someone hijacks or hack 51% of the computers on the network fraud can be done or allowed to be done on the network. But realistically, to hack 51% of the computers on the network is next to impossible Because all of them are decentralized, they're not connected to each other.

It is not that if one is hacked, the others are hacked as well. They will have to be hacked individually at their locations. And in a large Blockchain, like Bitcoin's,

where millions of computers around the world are connected on the network there it is almost impossible. Because who can hack millions of computers from every corner of the world?

The larger the Blockchain and the more computers and people connected to the network it will become increasingly difficult to hack the Blockchain.

You may also wonder that the computers connected to the network they keep on verifying the new blocks added to the Blockchain 24*7 they verify which block is authentic and which isn't.

In the coming time, we're moving towards a decentralized future. It means that many websites and applications on cloud-based platforms soon will move to Blockchains.

What do you think is the potential of Blockchain in the near future?

I believe that after the next 5-10 years the same applications that you use today, be it social media, censorship or copyright issue, video upload, streaming platform or any platform that you can name.

All those companies will have to use Blockchains because the user today trusts and believes in the companies that are transparent with their work Not those who hide from the public eye and modify their processes.


For this reason, some people believe that Blockchains can revolutionize the world. Like how the Internet had changed history. Now we can't even imagine life without the internet. Similarly, people believe that soon it will be difficult to imagine life without Blockchains.