Greetings friends! I am Priyatosh welcoming you to your own channel which is Not so tech. Here you will get interesting & technical knowledge in simple to understand words Friends, today’s topic is one such technology which is, in the whole world, changing the ways of transacting just like how internet changed the way information is used, in a revolutionary manner Look at these news paper cuttings and tell what is common in them Oh yes, they are all connected with usage of Blockchain So what is Blockchain? How does it work? How to trust it? and how can it be useful to us. come, lets get its detailed knowledge. Ok friends, you must be shopping online? Than you must be aware that between you and the seller there are many middleman If we buy directly from manufacturer then we can save on both money and time but is it possible? lets take another example lets assume you liked a car you reached the seller to buy it deal was struck you paid the amount and brought car home but what is this…? after a few days you came to know that the car had met with an accident once than is it possible to have a ledger or register which contains in a transparent manner the entire history, from leaving the factory, and till date written in an immutable manner is it possible? oh yes, all this can be made possible with blockchain so let’s see what is this blockchain Blockchain is a distributed ledger which contains records of transaction data prepared as blocks linked together and the block links are connected with cryptography We will see this in details a little ahead but for now i would like to tell you in addition to the distributed ledger blockchain is always time stamped blocks can only be appended whatever transactions the block contains or the details of transactions that everyone can see it is not possible to modify the transaction data updation of the ledger is done with cryptography and this collective consensus and after proof only transaction is approved then you get original copy from blockchain there is no middleman in this there is no third party involved in any way all transactions are transparent in totality meaning whosoever is on the network can view or check the transactions it is easy to view and check and it saves you both, time and money Satoshi Nakamoto named person or a group of persons in the year 2008 invented cryptocurrency called Bitcoin Bitcoin used blockchain as a distributed ledger let us see the cryptocurrency or blockchain which is seen as a distributed ledger how is it different from centralized ledger Mostly traditional ledgers are used in business, offices or banks they are centralized, and are named client server also server means a powerful computer it has all rights and has the latest copy of the ledger recording or checking the transactions can be done by authority only these are trusted to a good extent but these can be accessed by unauthorized means means these can be hacked apart from this data in the server can be tempered with it can be modified or deleted and single point of failure, means due to server or any problem associated with server being the reason can cause the entire network to shut down In distributed ledger without any server all nodes are connected to each other all nodes have same rights but capacities may differ all nodes have the latest ledger copy and as seen earlier they are transparent transactions are secured with cryptography and to modify old data is nearly impossible let us have a look at the differences between ledgers Friends, let us now see how the blockchain is formed firstly, request for transaction is put up on the network transaction can be of any type, like money, land, house, vehicle, etc. now this transaction is verified this is done by specialized nodes called miners they are like the accountants of the network apart from this, proof of work, which is like solving a difficult math problem and after consensus only the transaction is approved with consensus the transaction is added with cryptography to a new block thus created Ok now that i am mentioning cryptography again and again so let us gain some knowledge on that and let us see why it is so important for blockchain Friends, Google for SHA256 generator now go to the site of your choice type any string on space marked for Data then note its SHA256 now make any small change in the string and again generate SHA256 SHA256 code would have totally changed now Friends, you can keep an entire book for Data its SHA generated will remain the same till no change is made in the book and the second interesting fact is, SHA for the original string always remains the same but given the SHA you cannot know about the original string Ok, so what has this got to do with our blockchain friends, blocks in the blockchain use hash somewhat like this see, this is our block n and block n-1 which is just its preceding block in block n, block n-1’s, i.e., its immediately preceding block’s hash is copied similarly, block n’s hash which is transaction and block n-1’s hash combined result, is copied to block n+1 Block’s hash is hash result of the transactions and previous block’s hash there are certain other parameters but those those complications we will not enter into now now we will see that if a block is added to the blockchain, then why any change is not possible Here we have our blockchain copied a small change is introduced in block n’s transactions as a result block n’s hash changes which is not equal to the previous hash value this block is therefore marked as bad similarly block n+1 is also marked bad and all blocks ahead are marked bad That is why blockchain is regarded as immutable Friends, blockchain is, in almost all fields, being used speedily and soon in every field, its some or the other usage you will definitely see. Let us see some examples of blockchain In these you will see many sites, like hyperledger, which is an open source project with blockchains it is supported by IBM similarly, colu is a decentralized payment system for local communities Cryptokitties, this is a game of blockchain in this, cryptokitties can be collected or traded apart from these, 1000s of businesses have started using blockchain Blockchain has a major application called Smart Contracts Smart contract is an agreement between two parties there is no middleman in this and it is copied on public distributed ledger and when a preset condition is met, This contract is automatically executed Since this smart contract is copied on many nodes and there is no possibility to change it therefore no party can deny it So friends, lets see our blockchain in summary Blockchain is a distributed ledger, digital ledger In this, records can be only and only appended There is no possibility of any change and with cryptography its links are added Friends, thanks for watching the video I am sure you must have enjoyed the video Please do like it and Subscribe to my channel so that my latest videos reach you first So friends, lets meet again in next video, till then Thanks!