Now let's define blockchain using real world examples for better understanding. Let's take the case of vaults in a bank. The traditional approach is that you go to the bank with your Vault Key to access your possessions. Only you have the access to your world through your key, and you cannot see what is inside the other walls. Now imagine a situation where all the bank walls are transparent. You can see actual components of each wall.

But still, you only have access to your own world. Same is the case with public blockchains where you can see everything happening inside the network, but only have access to your account tokens and keys. Some other real world examples could be the bank account statements, which are duplicated across hundreds of computers. Everyone records every transaction you make. There's no one can tamper with Do records. And another example could be a book analogue in a library.

People come to the library to borrow a book. If someone removes a page from the book, then the people lending the book after the culprit can identify that the book has been tampered with, and the pages missing from the book. In this example, the book acts like a blockchain. And every page inside the book is a block the text on each page our transactions. Some other examples could be a Google document or a spreadsheet shared between multiple users where your workbook is a block chain. Each worksheet is a block and linked with the next worksheet.

And the data in your worksheet are your transactions. Let's go back to the analogy of bank walls. Whenever you go for opening a bank vault, you get a key associated with the same You can use that key to open and deposit the contents inside your world. Inside the bank, the walls are filled with different rows of walls, and each person has their specific world where they store their contents or some useful information. Moreover, in over analogy, we take these as transparent bank vaults, where you can see the things being stored in all the walls, but you can only access your content or information. This is the fundamental concept of cryptocurrencies to every person has a unique key associated with them, and using that key they make the transaction or receive the funds.

Moreover, the public block chains like Bitcoin and aetherium are open for all so anybody can see the contents information of all other transactions and addresses throughout the network and verify the information also permits blockchains have emerged. Still most of the public blockchains are viewable to every participant in the system. Why is blockchain known as web 3.0? The initial disruption started back in 1994. When the internet came into being, this was called as web 1.0. By the year 2000. tech giants like Google, Facebook, and Amazon emerged and led to the second disruption known as web 2.0.

These disruptions still had a problem of centralized control. Now, new technology like blockchain is trying to put the power back in the hands of the users. Why is blockchain known as web 3.0? First of all, there is no central point of control in blockchain as compared to traditional services. If you are going to use email services, you are bound to trust Google and Microsoft to make sure that your emails remain private. If you are going to use storage services, you are putting your trust in Google and Dropbox to keep your data safe.

We have seen how the confidentiality of data and hacks have been significant cause of concern for these central organizations. By using blockchain, we are removing the trust from Central authorities and third parties, and making sure that the data is protected and made available through consensus of the participants. Moreover, ownership of the data helps in the reduction of taxing data frauds. The second reason of disruption is the account of ownership. Once the data is over blockchain, it's immutable. And anybody can verify an audit the data.

Block chains can also store the data with digital signatures, which provides the ownership of data if some other person tries to upload the same data in the future. Then verifiers can see the history of data and state the ownership rights. This can help to reduce land and patron disputes. As blockchain is based upon open, secure and proven cryptography algorithm, the chances of hacks and data breaches are meager more Moreover, protocols like consensus and permission based services almost made blockchain invincible. These security parameters also former reason for calling blockchain as web 3.0. Most of the attacks over blockchain till now have been due to some implementation issues.

For example, one of the crypto Exchange servers was hacked, where the private keys of the users were being stored. attackers were able to perform transfer of cryptocurrencies using those private keys. Moreover, the ownership of data also helps in the reduction of tax and data fraud. The fourth reason is uninterrupted service. blockchain is available through peer to peer network. So anybody who is connecting to the blockchain has a node running with them.

And every node stores the complete data associated with blockchain. For example, you have hundred nodes connected to a blockchain network. Now, five of these nodes goes down. But you still have 95 nodes, which will provide all the data and guarantee the availability of services. These are the reasons why blockchain is called web 3.0. There are specific examples shown in this image on the left, you can see in the web 2.0 we have the browsers like Google Chrome, storage as Google Drive and Dropbox, video and audio calling functionalities providers like Skype.

Now they are being replaced by more advanced decentralized applications such as brave for browsers, storage in ipfs for storage and expertise for video and audio calls, distributed applications like steam it and Akasha no challenge even social networks like Facebook and Twitter. All the services mentioned here are currently running and trying to change the ecosystem in a way we interact and share the data. That was about some of the real world analogies related to blockchain. We also saw that why blockchain is web 3.0. In the next lecture, we are going to have a brief peek into the blockchain and lay the groundwork of learning blockchain