Hi everyone, welcome to Techbhasha and today we are going to talk about blockchain. There is a lot of under the table corruption. And what happens in this corruption is that there are a lot of transactions of black money.
Now, the record of all these transactions must be stored somewhere in some database. But why don't we consider that database reliable? The first reason is that we do not have access to that database. And the second reason is that the database admin can change the data anytime.
So it is not reliable. That's why we bring such a decentralized system. That means one person does not have authority and it is shared with everyone. And secondly, it becomes nearly impossible to change or modify it. So we will be able to trust such a system a lot. So such a system or a database is called a blockchain.
History of Blockchain
Blockchain came here in the 1990s when its research started. But it was implemented in 2009. In 2009, an anonymous developer named Satoshi Nakamoto made Bitcoin with the help of blockchain. So since then, the cryptocurrency boom has come to the world.
Understanding Blockchain
Now, if you understand blockchain in simple language, it's like there are a lot of records in a shop that shows which goods came, which goods went, where they came from, and where they go. So all the books of these records are called ledgers. So blockchain is the same ledger, and every single record of it is a single block. Now blockchain is a chain of blocks, meaning a chain of these records.
Components of a Block
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Relevant Information
If we talk about a single block, then some information or data is stored in this block. The first thing that is stored in the block is relevant information. For example, the information of the transaction will be stored in Bitcoin. That bitcoin came from whom and is going to whom. So according to such different use cases, different data is stored.
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Hash
The second thing that is stored in the block is a hash. Now we can understand hash as a unique fingerprint. So like we give our biometrics for an Aadhaar card and after that, we get an Aadhaar number. Similarly, whatever data is stored in the block in the blockchain, according to that a unique code, i.e., hash is generated.
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Previous Block's Hash
The third information that is stored in the block is the hash of the previous block. This means the hash of the previous block has now been saved in the next block. Now the next one will be saved in the next one. So in this way, a chain of blocks is being formed. The first block in this chain, which does not store the hash of any previous block, we called the Genesis block, which is formed first.
Security of Blockchain
So we can track the history of blocks in a way. That is why it is becoming easier to track information. It is becoming easier to keep all the information unique. It is becoming difficult to mess with it. That is why the blockchain is so secure. Now many layers of security are implemented in the blockchain.
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Hash Changes
So if we go inside the blockchain to change the data of any block, what will happen? The first thing is that as soon as we change its data, its hash will change. Hash change means that irrelevant and invalid information has come in the next block. Means the wrong hash came. And the next one also got the wrong hash. So in this way, wherever the change will take place in the chain, all the data in front of it will become invalid and wrong.
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Proof of Work
Now we can say that we will go and change everyone's hash. So if you go to change everyone's hash, it will take so much time that we cannot think. It takes 10 minutes to change the hash of one block in Bitcoin. So if there are 1 crore blocks, it will take us 200 years to change the hash of all the blocks. So this time thing is implemented with the concept of proof of work. Now proof of work means that you have to prove that you have spent at least 10 minutes to bring that change in that blockchain.
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Consensus Rule
The third added layer of security that comes in it is that all the people in the network have a complete copy of the blockchain. This means if you want to change one copy, you cannot do it. What you have to do is that you have to share the block that you want to change with everyone. Now everyone will get a vote on whether what you are changing in this block is correct or not. If the change is not correct, which means the majority of the people voted that you are tampering with our data, then what will happen? Then your change will be rejected and you will not be able to change. So this kind of voting system is called consensus rule in the blockchain.
Applications of Blockchain
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Cryptocurrencies
Blockchain is being used in many domains these days. The most booming domain is the cryptocurrency domain. If you take the example of bitcoin in cryptocurrency, then the value of bitcoin has increased so much these days. Now what has Bitcoin done? It has eliminated the middlemen. Earlier, if I had to send money from India to the USA, then we used to send rupees from here to the bank. The bank used to convert it into dollars and send it to the US. And used to charge a fee in between. Now if I have to send cryptocurrency directly, then I can send bitcoin directly. And the fee for it is much less than that of banks. Just like gold is transferred from asset to asset, bitcoin will also be transferred from bitcoin to bitcoin. There will be no conversion of currency.
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Real Estate
Other than that, the use cases that come are in the domain of real estate. The job of a notary is being done with the help of blockchain. So all the buying and selling records of real estate are stored in the blockchain. And with this, we can track the history of that particular real estate property.
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Hospital Management
The third use case is in the hospital management system. Where the patient's records are stored in the blockchain. So doctors can access relevant information. And the patient's data is also secure.
Smart Contracts
So we can use blockchains for projects, startups, and businesses. So we can implement a blockchain for ourselves from scratch by using a language. Or there are such blockchains that we can use with the help of code. So in these blockchains, there is a thing called a smart contract. We can understand smart contracts like real contracts.
That is, it has been completely converted into a digital form. In simple words, it is like a code that will define how the data will be taken. So you will put this code in the blockchain. And after that, all your data will be transferred through that code, through that algorithm. So there is a blockchain called Ethereum, which is very popular. Which we can use with the help of a social contract. And for this, there is a language called Solidity, which we have to learn. Now Solidity is a very easy language. If you have learned basic programming, then it is very easy for you to learn it. After learning this, you can implement it on Ethereum. And you can use the blockchain for your own applications.
Conclusion
So we have discussed all this information about the blockchain. If you want a small tutorial on how to implement a blockchain from scratch, then you can comment below. That's all for today. I hope this video has been helpful for you. See you in the next video. Till then keep learning and keep explo
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