[0:00]Hello guys, welcome back to the channel. Kaise ho aap sabhi? I hope aap sabhi acche honge aur aap apni padhai kaafi acche se kar rahe honge. Finally hum Blockchain Architecture and Design ke subject ki series ko playlist ko start karne wale hai. Aaj hum is video me unit one ko complete dekhenge with three year PYQ's questions. To Blockchain Architecture and Design jiska subject code hai BCS 063. Is video se hum is playlist ko begin karne wale hai. Is video mein unit number one ko complete dekhenge. To aapko kya karna hai, is video ko complete dekhna hai, taaki ye unit aapki kaafi acche se ho jaye. To bina deri ke, karte hai video ko start. To sabse pehle jo term aati hai, vo humari aati hai blockchain ki. Basically blockchain hota kya hai? Blockchain samjhne se pehle, kuch aisi terms hai, jo aapko samajh lena bahut zyada zaroori hai. Jiski help se aap blockchain ko zyada understand kar paoge ki bhai blockchain humara hota kya hai? To sabse pehle jo humari terms aati hai, vo aati hai humari centralized network aur bhai decentralized network. Centralized network ka matlab kya hai ya decentralized network ka humara kya means hai? To agar mein centralized network ki baat karu, for example, aapki kya hai, aapki ek city hai. To city ke andar, poori city ka ek water tank hai, jahan se city ke andar jo district and town hai, vahan paani supply hota hai. To yaani poori city ka ek water tank hai. Usko hum bolte hai centralized network. Isi tareeke se network ke andar kaam karta hai, ki bhai ek main server hai, jo saare nodes se, saare network se connected hota hai. Vo kehlata hai humara centralized network. Ab bhai, jo aapka water tank hai poori city ka, agar uske andar koi dikkat aa jaati hai, to kya hota hai, poori city ko suffer karna padega. Poori city ke towns mein kya hoga, paani ki bahut zyada dikkat aayegi. To ye iska disadvantages hota hai. Ek hota hai decentralized network. Decentralized network ka matlab kya hai, bhai city ke andar jo jo town hai, town one, town two, town three, har town ka humne alag alag kya bana diya, ek water tank bana diya. Ki is town ka water yahan is tank se aayega, iska yahan se aayega, iska yahan se aayega. Yaani humne ek centralized ek jagah nahi banaya, humne distribute kar diya, alag alag jagah decentralized kar diya usko. Theek hai, to isme kya hoga, agar koi bhi ek town ka water supply band ho jayega, koi dikkat ho jayegi, but doosre vale to mein to dikkat nahi aayegi na? To usne is disadvantages ko overcome kiya kisne, decentralized network ne. To clear hai aapko centralized network kya hota hai aur decentralized network kya hota hai? Centralized network mein humara kya likha hua hai, a centralized network has one main server or authority that controls everything. Centralized network ke andar ek hi main server hota hai aur ek hi authority hoti hai. Yaani jo poora control hota hai, vo ek single person ke paas hota hai. Like jaise Facebook ho gaya, Google ho gaya, in sab ka ek centralized network hai, jiske andar vo apne jo bhi customer ka saare data ko kya karte hai, store karte hai. Aapne suna hoga bahut baar ho jata hai ki Instagram down ho gaya, Facebook down ho gaya, Twitter down ho gaya. To down hone ka matlab kya hai ki jo unka main server hai, usme kuch functionality mein kuch dikkat aa gayi hai, usme vo down ho gaya hai. Theek hai. Jaise ki aap, jaise maine isme likha hua hai, if the server goes down, everything stop working. Agar unka server hi down ho jata hai, to vahan working karna impossible hai. Jaise aap dekhte ho ki reels wagera phir nahi chal paati. To iska matlab aapko samajh aa gaya centralized network ka, ab ye aap example ke through samjha sakte ho aur ye diagram ke through ki bhai ek humara server hai, usse ye humare nodes hai, nodes yaani computers. Ye kya hai aapas mein connected hai. To ye hota hai humara centralized. Decentralized mein kya likha hua hai, a decentralized network has many connected computers, all storing the same data. Decentralized network mein kya hota hai, bahut saare networks aapas mein connected hote hai aur sabhi kya karte hai, same hi data ko store karte hai. Jaise maine aapko bataya ki city ke andar tank humne bana diye hai. Alag alag jo humare town hai, unke alag alag humne tank bana diye. Tank ke andar hai to paani. Isi tareeke se jo hum decentralized network mein network banate hai, servers banate hai alag alag, unke andar kya hota hai, data store hota hai, but same data store hota hai. If one computer fails, the network still works. Agar network ke andar koi ek computer humara fail ho jata hai, but still humare paas kaafi saare computers hai, jo aapas mein connected hai, to bhai vo working rahega. Clear hai aapko? Jaise ki ye hai humara decentralized network. To humare jo computer nodes hai, vo aapas mein ek doosre se kya hai, connected hai. Aur aapas mein connected hai, to isliye humara kya hota hai, agar koi bhi ye node fail ho gaya, to ye wala, ye wala, ye wala nodes to working mein hoga. To ye hota hai humara concept decentralized network. I hope aapko clear hoga ki centralized network aur decentralized network humara kya hota hai. Ab blockchain ki hum proper definition pe aa jate hai. Blockchain humara hai kya? Ab isme kya likha hua hai, blockchain is a distributed database or ledger shared across a computer network's node. Ab bhai iski jo definition hai, aapko lag raha hoga, kuch kuch terms hai jo kaafi difficult hai. To sabse pehle isme distributed database. Distributed database ka matlab kya hai ki bhai jo humara authority hai, yaani control hai, vo ek person ke paas nahi rehta, vo bahut saare person ke paas rehta hai. Usko hum bolte hai distributed database. Doosra hai ledger. Ledger ka matlab kya hai, for example ki ek shop hai, jahan se hum kya karte hai, bahut saari cheeze kharidte hai. To ek shop ka jo owner hai, vo kya karta hai, jo bhi cheeze kharidte hai, jo bhi sale purchase ho raha hai, vo daily ke daily ek diary mein note kar leta hai, ki is din meri itni ye cheeze khareedi aur is time khareedi. Theek hai, har din ka alag alag vo diary mein note kar leta hai. Isi tareeke se ledger hota hai humara, ledger hota hai humara kya karta hai, blockchain ke andar jo bhi humari transactions hoti hai, unko kya karta hai, note karta hai. Ek diary ki tarah kaam karta hai, ledger humara kiske andar, blockchain ke andar. Ab bhai jo like data hai, vo kisi bhi format mein ho sakta hai, file TXT format mein ho sakta hai, JSON format mein ho sakta hai. Kisi bhi format mein ho sakta hai. But ye time ke saath store karta hai ki bhai jaise maine aapko bataya na ki shopkeeper ne kya dekha ki is time mera ye, itna data yaani itne mere pens jo meri pen ki shop hai, ki mere itne pens is din, itne time, sale hue. Isi tareeke se blockchain mein kya karta hai, ledger kya karta hai, blockchain ke andar ye dekhta hai ki is time, is person ne ye data ya ye transaction iske andar store kari. Samajh aa gaya aapko, ledger ka concept hai kya? Ye kya hai, ek transaction hai. Transaction ki jo bhi history hoti hai, transaction ka jo bhi data hota hai, usko kya karta hai, store karta hai. As a diary ki tarah kaam karta hai. Samajh aa gaya aapko? To I hope aapko clear hoga, to blockchain kya hai, ek distributed database hai aur ledger share across a computer network nodes. Jo ledger hai, usko hum kya karte hai, computers network node ke andar share kar dete hai. Clear hai aapko? Ab best known for their crucial role in cryptocurrency systems, maintaining a secure and decentralized record of transactions, but they are not limited to cryptocurrency uses. Agar mein baat karu, to hum iske andar cryptocurrency system ka use karte hai, jo iski security ko maintain karta hai aur jo decentralized record of transaction hai, unko bhi kya karta hai, security provide karata hai.
[6:31]I hope aapko clear hoga. Ab ye jo aapko thoda bahut agar aapko koi bhi doubt hai, to ab aapko clear ho jayega ki bhai ye jo humara blockchain hai, ye hai kya? Aap samjhiye, imagine a blockchain like a digital notebook that everyone in a group share and update together. Ab ye jo digital notebook hai, ye sabke paas hai. Aapke paas bhi hai, mere paas bhi hai, sabke paas shared hai. Ek like ek company hai. Company ka ek blockchain hai. Blockchain unka, like blockchain ke andar vo apne data ko store karte hai, transaction ko store karte hai. To vo ek digital notebook ki tarah samjho ki vo jo us company ke saare employees hai, sabke paas vo shared hai. Theek hai, aur koi bhi usko write kar sakta hai, read kar sakta hai, update kar sakta hai. Theek hai. To sabse pehle aata hai shared notebook. Shared notebook ki maine aapko kya bataya, agar company ka ek blockchain hai, to vo sabke paas shared hai. Saare employees ke paas shared hai. To iska matlab kya hai, vo distributed database hai. Instead of one person keeping the notebook, many people have a copy. Ek kisi person ke paas nahi hai. Sabhi ke paas hai. To iska matlab kya hai, blockchain humara kaisa hai, ek distributed database hai. Next hai no single owner yaani decentralized hai. Koi ek person poora usko dhyan nahi rakhta. Bahut saare person, koi ek single person control nahi karta. Bahut saare person ke paas vo shared hoti hai, to bhai har kisi ke paas thoda thoda control hota hai. Theek hai. Ab isme kya hai, pages equal to block. Pages aur block ka concept kya hai ki bhai jab hum data ko store karte hai. Ab maine aapko bataya ki ledger kya hai, ek diary ki tarah. To diary ke andar to pages hote hai. To isi tareeke se humare blockchain ke andar pages nahi hote, jinko hum bolte hai, blocks. Blockchain ke andar humare kya hote hai, blocks hote hai, jinke andar hum kya karte hai, apne data ko store karte hai. Theek hai?
[8:05]For example, aap dekhiye to kis tareeke se hota hai. Ye humare is tareeke se blocks hote hai. Ye block one ho gaya, ye block humara two ho gaya, ye block humara three ho gaya. To ye kya hota hai, ye blocks hote hai, jiske andar apne data ko store karte hai. Ab jaise pages hote hai, pages aapas mein link hote hai na, jaise ek notebook ke pages hai, to ye aapas mein link hai na. To isi tareeke se kya hota hai, ye ek doosre se link hote hai. Yahan humari poori transaction history likhi gayi. Jab ye blocks, iski kuch limited size hota hai, ki bhai iska jo size hai, ye vo finish hota hai. Kitne size of transaction tak ye store kar pata hai, ya itne data ko ye store kar pata hai. Ab iski capacity finish ho gayi, then hum move karenge block number two pe. Then block number two mein apne data ko store karenge. Iski capacity full ho gayi, then block number three pe karenge aur ye aapas mein kya hote hai, ek doosre se link hote hai. Ab bhai jaise book ke page number hote hai, to yahan page number likha hota hai na, ki one, two, three, isi tareeke se isme kya hota hai, ek code unique code generate hota hai, ki jisse hum pehchan paate hai ki ye block number one hai, ye block number two hai, ye block number three hai. Like aap samajh sakte ho ki ye page number one hai, ye page number two hai, ye page number three hai. To clear hai aapko block ka concept? To isme kya likha hua hai, every time new transaction is added, it goes a new pages. Jab bhi hum new transaction ko add karenge, to vo kahan aayegi, ek new page pe jayegi. Agar humare previous wala block ki capacity complete ho chuki hai, then vo next mein move karega. Jaise ki ab ye mere page ka complete ho chuka hai. Page pe maine poori cheeze likh di hai. Ab yahan koi jagah nahi hai. To main kya karungi, next page pe move kar jaungi. Isi tareeke se block humara kaam karta hai. Clear hai aapko? Next hai permanent and secure, yaani immutable. Immutable ka matlab kya hai ki jisko hum change na kar sake. That is the concept of immutable. Once a page is written, it can't be erased or changed. Jab aapne ek baar page ke andar likh diya hai, to aap usko erase nahi kar sakte. Yaani block ke andar jo bhi aapne transaction likh diya hai, koi bhi data ko aapne store kar diya. Ab aap chahte ho ki bhai nahi, mujhe vo transaction hatani hai. Nahi, aisa nahi ho sakta.
[9:56]Usko andar aap koi bhi cheez erase nahi kar sakte agar aap ek baar likh diya. Jisko vo kya karta hai, jiski help se use zyada security provide karata hai. Isliye hum bolte hai ki blockchain aaj ke time pe bahut zyada secure hai. Clear hai aapko ki immutable ka matlab kya hai? Aur ye jo humari chaar maine aapko points bataya, iski help se aap samajh gaye honge ki bhai blockchain hai kya. Blockchain ke andar kya hota hai, blocks hote hai, jo aapas mein connected hote hai. Ek ledger technology hoti hai. Ledger kya hota hai, ek digital book ki tarah hota hai, jiske andar hum apne transaction history ko likhte hai. Aur teesra point kya hai ki jo ye blockchain hota hai, kiska follow karta hai? Distributed system ko follow karta hai. Distributed system ka matlab kya hai ki bhai humara ek control, ek single person ke paas nahi rehta. Kaafi person ke paas humara thoda thoda control rehta hai. I hope aapko clear hoga ki bhai ye blockchain term kya hai aur centralized, decentralized, in sab ka meaning humara kya hai. Theek hai? Ab badhte hai apne pehle question ki taraf, jo ki humara 2021-22 mein long mein aaya tha ye. To question kya tha aapka, explain the distributed ledger technology. How is a blockchain ledger different from an ordinary one?
[11:03]Sabse pehle agar mein baat karu to distributed ledger technology. To ledger to hume samajh aa gaya ki hai kya. Ab distributed ledger technology kya hai. Distributed ledger technology is a way to keep this record book on many computers called nodes at the same time, instead of just one central place.
[11:53]Yaani distributed ledger ka matlab kya hai, jaise decentralized work kar raha tha na humne sabse pehle centralized aur decentralized network padha tha. To distributed ledger humara ek decentralized network ki tarah work karta hai, jahan humari jo ledger hai, vo ek single person ke paas nahi rehti, vo different different computers ke paas share rehti hai. To usko hum kya bolte hai, vo technology humari kya hai, distributed ledger technology. Jaise ki humari, for example, humari ek ledger hai, for aap samjhe ki is tareeke se humari ek diary hai. To ye diary ek single person ke paas nahi rahegi. Ye employee number one ke paas bhi hai, humare employee two ke paas bhi hai, sabki copies ke paas hai. Employee three ke paas hai. Is company ke andar agar n number of employees hai, to sabke paas ye kya hai, humari ledger kya hai, share hai. To isko hum kya bolte hai, ye kya hai humare distributed ledger technology. Clear hai aapko? Aur bhai, ye jo humare, ye to maine employees bataye, but yahan kya hote hai, computers hote hai. Computers ke beech mein hum inko kya karte hai, share karte hai. Aur inhi computers ko hum kya bolte hai, blockchain ke andar ye kya hai, humare nodes. Clear hai aapko? To ab hum differences dekh lete hai ki blockchain ledger aur ordinary ledger mein humare kya kya differences hai. Pehla hai where it's stored. Stored, vo pehle kahan hote the? Ordinary ledger ki agar hum baat kare, kept in one place, like a bank computer or shop's record book. Ye kya karti thi, centralized network ki tarah work karti thi, ki jo bhi humara data hai, jo bhi humari transaction history hai, usko hum ek hi jagah store karte the ordinary ledger mein. But aaj ke time agar hum block blockchain ledger ki baat kare, to store on many computers across a network. To isme hum kya karte hai, bahut saare computers ke beech mein usko kya karte hai, store karte hai. Yaani distributed ledger technology ka aaj ke time mein hum use karte hai. But pehle ke time mein hum kiska use kar rahe the, ek centralized way ka use kar rahe the, ki jo bhi ledger ki saari details hai, ek centralized way mein hum store karte the. Clear hai aapko? To pehla difference kya hai, store ke base pe ki bhai hum unko pehle kahan store karte the? Doosra hai who control it. Control, ordinary ledger mein kya tha, ek person hi control karta tha, kyuki vo ek hi jagah rakhi thi, ki ek company ka humne ek ledger bana rakha hai. Vahin saari details hai. To vo jo manager hoga ya jo bhi company ka owner hoga, sirf aur sirf vahi usko control karta tha ordinary ledger mein. But blockchain ledger mein kya hai, ki jo bhi computers hai, jo bhi employees hai, sabke beech mein share hai. To iska matlab kya hai ki control kisi ek person ke paas nahi hai. Koi no single control hai isme ki, bhai thoda thoda control sabke paas hai. Aap samajh sakte ho. Theek hai? Next hai transparency. Ordinary ledger mein jo transparency thi, vo thodi kam thi. Kyuki owner data ko sale kar sakta hai ya data ko kisi ke saath share kar sakta hai. But blockchain ledger mein kya hota, ki nahi kar sakta. Agar aap thode se bhi chhedkhani karoge, to bhai sabke paas vo cheez share hai, to kisi na kisi ko pata chal jayega ki bhai koi na koi iske saath chhedkhani kar raha hai ya koi bhi data ko idhar udhar kar raha hai.
[14:45]To isme kya transparency zyada hoti hai. Kis mein, distributed ledger technology mein. I hope aapko clear ho gaye ye teen differences. Pehle maine aapko kya bataya, store ke base pe, then control ke base pe, then transparency ke base pe. Theek hai? Ab niche kya likha hua hai, blockchain is a type of distributed ledger technology that organize data in a chain of blocks, making it super secure and unchangeable. Blockchain kya hai, ek tareeke ki distributed ledger technology hai, jo kya karti hai, data ko ek chain of blocks mein kya karti hai, organize karti hai. Jaise maine aapko bataya ki block kya hai, ek doosre se connected hote hai. To ye kya hai, ek tareeke se ek chain like structure bana rahe hai. To hum isko kya bolte hai, chain technology. Ki ye kya hai, chain of blocks ko ek doosre se connected karta hai, jiski vajah se ye kya hota hai, super secure hote hai. Aur super secure kaise hote hai ki bhai ye ek doosre se connected hai. Agar kisi ne is pe thoda sa bhi changes kiya, to bhai previous wale ko pata chal jayega ya uske aage wale ko pata chal jayega. To yahan kya, agar aap changes kar rahe ho, to vo kisi ek is pe hi effect nahi kar raha, uske previous wale pe bhi effect karta hai, jiski help se ise ye vo bahut zyada secure banata hai. Aur unchangeable, aapko pata hai ki block ke andar agar aapne kuch bhi cheez likh di hai, to aap usko change nahi kar sakte, yaani immutable hai.
[15:42]It's famous because it's used in things like bitcoin, where no one can fake or doubt spend money without the networking notices. Aapko pata hai ki bhai aaj ke time mein blockchain famous kyu hai? Kyuki hum iska bahut like bitcoins ke andar use kar rahe hai, Ethereum ke andar use kar rahe hai, to ye kya hai, bahut zyada famous ho chuki hai, kyuki bahut zyada hume security provide karati hai. To I hope aapko clear hoga ki bhai ye distributed ledger technology humari kya hoti hai aur ordinary ledger aur blockchain ledger mein humara kya kya differences hai. Theek hai? Ab badhte hai apne next topic ki taraf, jo ki humara design primitives and protocols in blockchain. Ab bhai design primitives and ye kya hote hai, design primitives to dekh lete hai. Design primitives are the basic building blocks or components used to create a blockchain system. Protocols are the rules or agreements that these components follow to make the blockchain work smoothly. Ab blockchain system ko design karne ke liye kuch to component chahiye honge na. To vo jo basic components hote hai, basic building blocks hote hai, blockchain system ko create karne ke liye, hum unko kya bolte hai, vo kya hai humara design primitives. Ab protocols ka simple matlab kya hota hai? Protocols ka matlab hota hai set of rules. Protocols are the rules or agreements that these components follow to make the blockchain work smoothly. Ab blockchain system banane ke liye aap component ka to use kar rahe ho, but component kuch to rules honge, jiski help se aap component ko ek doosre se connect karoge. Kuch to, koi like, kuch to agreement ya kuch to aap kahin se to dekh ke aap kisi cheez ko connect karoge. Jaise puzzle wagera hoti hai. To unke paas ek copy aati hai na, booklet aati hai na, jiske andar bataya jata hai ki aap kis tareeke se usko connect karenge ya koi bhi aap new toy lete hai, to uske andar bataya jata hai ki bhai yahan se charging hogi, yahan se ye hogi. To kuch protocols ka to use karte hai na. To isi tareeke se blockchain system ke andar hota hai. Blockchain system ke andar jab bhi hum component ko ek doosre se connect karte hai, to kuch set of rules ko hum follow karte hai. To unko hum kya bolte hai, protocols. Theek hai? Ab kuch key designs hote hai, primitives blockchain ke andar. To pehla kya hai blocks. Blocks maine aapko bataya blocks kya hai, ek tareeke se page hai. A block is like a page in a record book that stores a list of transactions. Block kya hai, ek tareeke se book ke andar jo ek page hota hai, isi tareeke se humara block hota hai, jo kya karta hai, transaction ko store karta hai. Each block has a unique code that link it to the previous block, forming a chain. Har block ke paas ek unique code hota hai, jiski help se hum pehchan paate hai ki bhai ye block ye hai. Aur aapas mein dono ek doosre se kya hote hai, connected hote hai. Theek hai? Ye cheez to main aapko pehle hi bata chuki hu. Next hai transaction. Transaction kya hoti hai ki aapki kitni sale hui, kitni purchase hui, kitna transfer hua money, kitna data update hua. Vo sab kya kehlata hai humara transaction. Nodes kya hoti hai? Nodes are the computer in the blockchain. Jaise maine aapko bataya ki jo bhi computers hote hai, hum blockchain ke andar unko kya bolte hai, nodes bolte hai. Network that that store a copy of the ledger and help verify transaction. Jo kya karte hai, har computers ke paas jo bhi ledger ki copy hoti hai, usko store karte hai aur verify karne mein ye help karte hai ki bhai ye jo humari transaction hai, ye humari verified person se aayi hai ya nahi aayi hai. I hope aapko clear hoga ki block, transaction aur humara nodes ka matlab kya hota hai.
[18:40]Last isme component aata hai humara cryptographic key. Cryptographic key ka matlab, humari key kya hoti hai? Sequence of number. Key ko hum kya bolte hai, sequence of number hi to bolte hai, usi ko hum key bolte hai. Ab do type ki key hoti hai. Ek public key hoti hai, ek private key hoti hai. Public key kya hoti hai? As the name suggest, public key, ye sabke liye share hai. Meri public key aapko bhi pata hogi, aapki public key mujhe bhi pata hogi. That is called public key. Private key kon kya hoti hai? Jo meri private key hai, vo mujhe pata hogi, aapki jo private key hai, vo aapko pata hogi. Ab key ka mainly matlab kya hota hai? Jaise aap lock ko, jo tala chabi hota hai na, lock ko lock karne ke liye, aap key ka use karte ho na? To usko kya karte ho ki bhai jab key aap lock ke andar daloge, tabhi vo open hoga. Isi tareeke se ye hota hai ki aap apne message ko lock kar dete ho by using the public key or private key. Theek hai? I hope aapko clear hoga ki iske components humare kya hai. Next hai protocols in blockchain. Protocols maine aapko abhi bataya, protocols kya hai, set of rules, jo hum use karte hai blockchain system ko design karne ke liye. Pehla aata hai network protocol. Network protocol kya batata hai? Defines how nodes connect, communicate, ki jo bhi aapke computers hai, vo kis tareeke se communicate karenge. Kis tareeke se data ko share karenge aur kis tareeke se unke beech mein synchronization bana rahega. To vo kya batata, vo kon batayega humara network protocol. Next aata hai incentive protocols. Incentive protocols ka matlab basically hai kya, ki bhai aap samajhte ho ki agar aapki classroom hai, classroom ke andar ek board ke upar chart chipka hua hai. Ki bhai, jis bhi student ki 95 attendance hongi, jo proper uniform mein aayega, jo acche marks layega, to usko hum star de denge. Yaani usko kuch reward de denge. Isi tareeke se incentive protocols work karta hai. Ki jo bhi blockchain ke andar security ke purpose ke liye bahut accha kaam karega, to usko hum kya denge, ek reward denge. Ab reward yahan koi chhota mota nahi hota, ki chhota mota reward de diya. Yahan reward mein bitcoins milte hai. Theek hai. To vo kon kis kiski help se hum decide kar paate hai, vo kon hai humara incentive protocols. I hope aapko clear hoga. Next topic aata hai aapka security in blockchain architecture and design. Security ka matlab kya hota hai basically?
[20:58]Security is a core part of blockchain design because it ensures the system is trustworthy and reliable. Security ka, security basically bahut important role play karta hai blockchain architecture and design mein. Ye kya ensure karta hai ki bhai system jo hai, aap kisi bhi system ke andar agar aap work kar rahe ho, to vo trustworthy aur reliable hai. Blockchain architecture is designed to prevent cheating, hacking or data loss. Jo aapko, security, vo aapko kis se prevent karta hai, cheating se, hacking ka aur data loss se aapko kya karta hai, prevent karta hai. I hope aapko clear hoga. Kuch key security features hote hai blockchain ke andar, jo usko zyada secure banate hai. To pehla kya hota hai, decentralization. Decentralized ka matlab kya hai ki hum koi bhi ek person ko saari authority ya control nahi dete. Hum kya karte hai, ek central server nahi banate. Hum kya karte hai, bahut saare nodes ko ek doosre se connected kar dete hai. To that is called decentralization. Cryptography, cryptography ka matlab kya hai ki cryptography kuch techniques ka hum use karte hai, hashing ka, digital signature ka, SHA-256 kuch algorithms hote hai, jinka hum use karte hai. Kya karne ke liye, usko security provide karne ke liye. Jaise abhi maine aapko bataya public key, private key bhi jo hai na, vo cryptography ka hi part hai. Next hai immutable. Immutable ka matlab kya hai ki bhai block ke andar koi bhi agar aapne information transaction add kar di hai, to aap usko change nahi kar sakte. To ye bhi ek security hai, yaani usko security provide kara raha hai. To ye kuch key security features hai, jo blockchain ko bahut zyada secure banate hai.
[22:26]I hope aapko clear hoga. Humara next topic hai consensus mechanism. Ye kya hota hai? Consensus protocols ensure only valid transaction are added. Consensus protocols se, consensus mechanism hume kya batate hai ki blockchain ke andar kon kon si valid transaction ko hume add karna hai. Abhi consensus mechanism, abhi hum isi unit mein last topic hai, hum usme kaafi acche se padhenge. Abhi aap sirf itna samajh lijiye. Next hai permission in blockchain. Basically permission ka matlab kya hota hai? Permission to bhai ye batata hai ki kon kon kya kya cheeze access kar sakta hai, kon read kar sakta hai, kon write kar sakta hai.
[23:06]Update to koi kar hi nahi sakta kyuki vo immutable hai. They determine whether anyone can join the network or if it's restricted to specific people or organization. Ye determine karta hai ki bhai koi bhi humara is network ke through join ho sakta hai aur agar koi bhi organization ya koi bhi like, company kisi bhi specific person ko restrict kar deti hai, to vo, ye ensure karna ki bhai vo humara blockchain ke andar ko blockchain ke data ko transaction ko read ya write na kar paye. To vo bhi kon ensure karta hai, permission in blockchain. I hope aapko clear hoga. Permission ka matlab simple hai ki bhai kon access karega, kon read, kon write. Simple. Ab badhte hai apne next topic ki taraf, jo ki kaafi important topic hai. Yahan se question humare 2021-22 aur 22-23 mein lagatar do saal pucha gaya hai. To ye hai kya? To sabse hum isse padhenge Merkle's Tree ko. To Merkle's Tree hote kya hai? A Merkle Tree is a way to organize and verify large amount of data efficiently in a blockchain. Merkle Tree kya hai, ek aisa way hai, jiski help se hum ek large amount of data ko kya karte hai, organize kar paate hai.
[24:14]Aur usko verify kar paate hai ki bhai blockchain ke andar kuch hum aisa data to ya transaction to add nahi kar rahe, jo humara kya hai, jo uske liye unsecure hai. To vo kya hota hai, Merkle's Tree. Ab bhai, ye kis tareeke se kaam karta hai ya ye properly hota kya hai, vo dekh lete hai. Imagine you have a bunch of transaction in a blockchain block like 100 payments. Theek hai, aapke blockchain ke andar bahut saari transaction hai, like 100 of payments transaction hai. To aapko kya karna hai, instead of storing or checking each transaction one by one, a Merkle Tree organize them into a structure that makes it faster and easier to verify everything. Ab bhai, 100 payment hai ya 100 transaction hai, to aap 100 time har ek ek ek transaction ko check karoge. To instead of ki aap ek ek transaction ko check karo, aap Merkle's Tree ki help se kya kar sakte ho, in structure, ek structure ki form mein isko kya kar sakte ho, organize kar sakte ho. Ek tree like structure ye bana deta hai aur hume de deta hai ki ye aapki jo transaction hai, aap inko verify kar lo. Jiski help se hum unko fastly verify kar paate hai aur easily dekh paate hai ki bhai humari jo transaction hai, vo sahi hai ya secure hai ya unsecure hai. Simple, I hope aapko clear hoga. Ab bhai ye kis tareeke se work karta hai, pehla kya hota hai iska step, turn data into hashes. Jo bhi data hota hai ya jo bhi transaction hoti hai, vo kya karta hai, har transaction ko hash mein convert kar deta hai. Ab hashing kya hoti hai ya hash kya hota hai, vo abhi hum aage padhenge. These hashes are the leave at the bottom of the tree. Like ye tree like structure abhi hum batate hai, to bottom se top ki taraf hum badhte hai. Sabse pehle jo bhi humara bottom ki jo bhi transaction hoti hai, unko kya karta hai, ek hash mein convert karte hai. Then kya karte hai, pair and combine. Do do hashes ko lete hai aur unko kya karte hai, ek new hash banate hai. Combine karte chalte hai. Theek hai? Teesra steps kya hota hai, keep going up. Aap us, ye steps ko karte raho, jab tak aapko ek single hash nahi mil jaati hai, yaani single root nahi mil jaata hai, tab tak aap uska tree banate raho. Then the Merkle Root. This single hash is like a super fingerprint for all the transaction in the block. Jab aap poora tree like structure bana doge, jab aapka ek single root ban jayega, to aap usko kya bologe, vo mera single root kya hai, ek Merkle Tree hai, ya Merkle's Root hai.
[26:10]Clear hai? Sabse pehle kya karna hota hai, jo bhi transaction hai, unko hash mein convert karna hota hai. Then hash mein convert karke har ek ko do do ko combine karna hota hai aur tab tak combine karna hota hai, jab tak hume ek root node nahi mil jata. Theek hai? Ab aap is diagram ke through poora isko samajh sakte ho ki kis tareeke se work karta hai. Merkle's Tree jo bhi humari transaction hai T1, T2, T3, T4. Humne T1 transaction ko kya kara, hash mein convert kar diya. Ab hash mein koi aise nahi ki bhai kuch bhi kar diya, jaadu waadu kar diya aur ye hash mein convert ho gaya. Nahi. Hum SHA-256 algorithms ka use karte hai, isko convert karne ke liye. T1 ko humne kis mein convert kar diya? H1 hash mein. Then T2 ko H2 mein. Then T3 ko H3 mein, T4 ko H4 mein. Uske baad kya karna hai, hume in dono ko combine karna hai. T1, jo H1 aur H2 ko, isko combine kar diya, H12. Isi tareeke se H3, H4 ko, H34. Then in dono ko bhi combine kar diya, ek single node mein, H1234. To ye kya hai, humara ye hai humara Merkle's Tree. Yaani jo bhi humari transaction hai, usko ek tree like structure mein convert kar diya. Jiski help se hum is transaction ko verify kar sakte hai ki ye humari sahi transaction hai ya nahi hai.
[27:47]Clear hai aapko? Application kya hai, Merkle's Tree are used in distributed system where same data store exist in multiple places. Merkle's Tree ko hum kahan use karte hai, distributed system ke andar use karte hai, jahan humara same data multiple place ke andar store rehta hai. Merkle's Tree can be used to check inconsistency. Jo bhi data ke andar inconsistency hoti hai, usko check karne ke liye hum iska use karte hai. Aur aaj ke time mein hum bitcoins aur blockchain ke andar iska kaafi zyada use karte hai. I hope aapko clear hoga ki Merkle's Tree humara kya hota hai, kis tareeke se work karta hai.
[28:16]Agar ye aata hai, to aapko ye proper is tareeke se bhi diagram ke through aapko kya karna hai, explain karke aana hai. Ab badhte hai apne next question ki taraf, jo ki humara 2021-22 mein pucha gaya tha. To discuss the type of blockchain, distinguish between blockchain and database. Aapko blockchain ke type batane the aur blockchain aur database ke beech mein differences batane the. To sabse pehle agar main baat karu, sabse pehle aata hai humara public blockchain. Public ka matlab kya hota hai, jo accessible to everyone, koi bhi access kar paye.
[28:50]Vo kehlata hai humara public blockchain. Ek aisi blockchain, jo all over the world, aap kahin pe bhi hai, kisi bhi country mein hai, but aap us blockchain ko use kar pa rahe ho. To us blockchain ko hum kya kahenge, public blockchain. Open to everyone, anyone can join or add information. Sabke liye open hoti hai, koi bhi usko join kar sakta hai, koi bhi uski information uske andar kya kar sakta hai, add kar sakta hai. Jaise ki bitcoin. Think of it like a public park, anyone can visit or use it. Jaise ki aap samajh sakte hai ki koi public park hai, uske andar koi bhi aa sakta hai. To isi tareeke se public blockchain aisi hoti hai ki all over the world, aap kahin pe bhi ho, kisi bhi country mein ho, aap us blockchain ko use kar sakte ho. Usko hum kya bolenge, public blockchain. Private blockchain kya hoti hai? For example, koi bhi company hai, usko kya karna hai ki bhai jo mera data hai, jo meri transaction hai, vo sirf aur sirf main hi dekh pau ya meri company ke jo bhi employees hai, vahi dekh paye. Bahar ka koi bhi dekh na paye, yaani restrict karna chahta hai. To vo kon si blockchain ka use karenge? Private blockchain ka use karenge. Private blockchain kya hota hai, koi bhi access nahi kar pata. Jiske paas permission hoti hai, vahi access kar pata hai. But public blockchain mein kya hota hai, permission ki hume zarurat nahi padti. But private blockchain mein permission ki hume zarurat padti hai. Restricted to specific people or organization, only invited user can access or add data. Isme kya hota hai, bahut saare organization aur people ko restrict kar diya jata hai. Sirf aur sirf jo bhi access ya authorized user hota hai, vahi usko kya kar paate hai, isme information ko add kar paate hai aur isko join kar paate hai. Theek hai? Jaise ki private clubs hote hai ki jo bhi permission, jiske paas card wagera ho gaye ya jisne pay kiya hoga, vahi uske andar enter kar sakta hai. To I hope aapko clear hoga ki private blockchain humari kya hoti hai. Hybrid blockchain kya hota hai, jo ki public aur private blockchain ke advantages hote hai. Agar hum unko mix kar de, to vo humara banta hai hybrid blockchain. Ye combine karta hai public aur private blockchain ke dono ke features ko. To isme kuch data public hota hai, kuch data humara private hota hai. I hope aapko clear hoga ki public, private aur hybrid blockchain humara kya hota hai. Agar mein baat karu blockchain aur database ke differences ki to vo hum dekh lete hai. Blockchain aur database ke beech mein kya kya differences hai. To pehla hai control ke base pe. To blockchain kaisa hota hai humara decentralized hota hai. Decentralized ka matlab kya hai ki koi bhi ek single owner nahi hota. But database kya hota hai, humara centralized network ko use karta hai. Jiska ek person ya ek company uska owner hoti hai. For example, Amazon ka apna database hai, Flipkart ka apna database hai. Theek hai? Access kya hoti hai, isme transparency. Har koi data ko dekh sakta hai, data ko read kar sakta hai, write kar sakta hai. But ye kya private hoti hai. Ye sirf aur sirf authorized user usko kya kar paate hai, access kar paate hai. Changing data, isme very hard hota hai change karna data ko, kyuki aapko pata hai ki blockchain kya hai, humara immutable hai. But isme kya hai, database ke andar aap kabhi bhi changes kar sakte ho, access kar sakte ho, update kar sakte ho. Speed kya hai, iski slow hoti hai. Ye kaafi fast hota hai. Example kya hai, bitcoin aur iska bank record, online shopping websites. Ye sab kya database ka use karti hai. I hope aapko clear hoga. Ab badhte hai apne next topic ki taraf, jo ki humara basic crypto primitives, hash aur digital signature. To yahan aapko hash function aur digital signature ki baat karna hai ki bhai ye hote kya hai. To main hash function ko aapko ek example ke through diagram ke through samjhaungi, to aapko poori iski scenario aapko clear ho jayega. Ab hash function mein humara kya hota hai, ek message hota hai. Message ko hum ek hash function ke andar pass karte hai. Ye H kya hai? Ye humara hash function hai. Ab jo bhi humara message hota hai, usko hum hash function mein pass karte hai aur vo hume kya deta hai, ek hash value generate karke deta hai. Ab bhai ye hash value, ab hum bolte hai ki hash value kya hai. For example, mera jo message hai, vo hai mera hello. Theek hai? Hello message maine hash function ke andar pass kiya aur usne kya kar diya, ek hash code generate kar diya. Ab hash code jo hota hai, vo kya hota hai, kuch alphabets, kuch special characters, kuch numericals value ka kya hota hai, combination hota hai. For example, usne mera isme convert karke de diya. Theek hai? Hello ko isme convert karke de diya. To ye message tha, ye mera kya hoga, hash code generate ho gaya by using the hash function. Ab isme ek cheez aur hoti hai ki bhai hash function ke andar ek fixed hota hai. Ki bhai ye jo hash code generate karega, vo 5 bit ka karega ya 10 bit ka karega ya 15 bit ka karega. For example, ki mera jo message hai, vo 200 bit ka hai. Agar mein 200 bit ka hash function ke andar apna message ko pass karungi, to vo tab bhi, for example, ye 10 bit ka hi hash code generate karta hai, to vo tab bhi 10 bit ka hi karega. Aur agar mein, for example, mera 5 bit ka message hai, to bhi vo kya karega, to bhi vo mujhe 10 bit ka hi hash code generate karke dega. Iska matlab kya hai ki jo message hai, vo depend nahi karta. Message ki length kuch bhi ho, hash code ek fixed hi length ka generate hoga. Agar ye hash function humara 10 bit ka generate karta hai, to ye aap kitni bhi bit ka input de do, but vo kya karega, 10 bit ka hi generate karega. I hope aapko clear hoga ki bhai ye hash function humara kya hota hai. Iske andar vahi sab likha hua hai.
[33:25]Aap padhoge, to aapko kaafi acche se clear ho jayega. Main baat karu agar digital signature ki, to digital signature kya hota hai, jaise ki aap normally check wagera pe sign karte ho, verify karne ke liye, ki bhai jo sign kar raha hai, vo authorized user ne kiya hai.
[33:40]To isi tareeke se hum digital world ke andar ek signature ka use karte hai, kiski, kiski help se, digital signature ki help se. Ab ye kya hota hai, isko bhi hum ek diagram ke through properly samajh lete hai. Ab for example, vahi same Rohan aur Mohan. Rohan ko ek message bhejna hai Mohan ko. To hai, vo ye message hai. Theek hai?
[34:50]Ab ek humari hoti hai digital signature generation algorithm. Jiski help se hum kya karte hai, sign ko create karte hai. Ab Rohan kya karega, Rohan ko message bhejna hai Mohan ko. To Rohan apni private key ka use karega. Aapko pata hai, do key hoti hai, public key aur private key. Public key to Rohan ko Mohan ki pata hogi, Mohan ko Rohan ki pata hogi. But Mohan apni private key ka use karega, jo sirf usko hi pata hai. Rohan private key aur message ka, private key aur message ko kis mein dalega, DS generation algorithm mein dalega. Ye algorithm kuch mix karke kya degi, hume S degi. S yaani sign. Sign generate karke degi. Phir hum kya karenge, ye message aur ye sign ko dono ko combine kar lenge aur kya karenge, Mohan ke paas pahuncha denge. Mohan kya karega, is message ko public key ka use karke, kiski public key, Rohan ki public key ka use karke is message ko decrypt karega. Decrypt yaani usko message ko ek sahi format mein convert karne ki koshish karega. Agar vo sahi format mein ya meaningful format mein convert ho jata hai, to iska matlab vo valid hai. Agar vo nahi ho pata, to iska matlab vo invalid hai. Ye is tareeke se humara digital signature work karta hai. Clear hai aapko? To bas aapko ek cheez yaad rakhna hai isme ki Rohan apni private key ka use karta hai aur Mohan jo hai, Rohan ki public key ka use karke message ko authenticate karta hai. I hope aapko clear hoga ki digital signature humara kya hota hai aur vo kis tareeke se work karta hai. Ab badhte hai apne next topic ki taraf, jo ki hai humara hash chain to blockchain. Ab hash chain to blockchain humara hota kya hai? Pehle dekh lete hai humara hash chain kya hota hai. Hash chain is a basic concept where pieces of data are linked together using hashes. Hash chain kya hai, ek basic concept hai, jahan humara pieces of data ek doosre se kya hote hai, link hote hai. Kiski help se, hashes ki help se. Ab ye kya hota hai, jo bhi humara pieces of data like ye one piece of data, ye one piece of data hai, iska kuch hash hai, iska kuch hash hai. To ye kuch hash ke through kya hote hai, ek doosre se linked hote hai aur ek chain like structure humara banate hai, jisko hum bolte hai hash chain. Jisme do word aa rahe hai hash aur chain. To hash ka matlab hai ki hum hash function ka use kar rahe hai data ko hash code mein generate karne ke liye aur chain yaani ye chain like structure hume kya deta hai, banakar deta hai. Think of it as a chain of information, where each information is connected to the next by a unique fingerprint. Aap ek tareeke se samajh sakte hai ki ye humare chain ki tarah hai, jahan humari piece of information ek doosre se connected hai aur ek chain like structure humara bana liye, bana rahi hai.
[37:09]To usko hum kya bolte hai, hash chain. Ab hum ye dekh lete hai, kis tareeke se work karta hai. Sabse pehle kya hota hai, each piece of data is hashed to create a unique code. Hum kya karte hai, jo bhi humara piece of data hai, like ye humara piece of data hai, pehla piece of data liya, humne kya kara, iska hash code generate kara. Hash code kis tareeke se karte hai, vo maine abhi aapko bata rakha hai ki hum kya karte hai, hash function mein pass karke har data ka kya karte hai, hash code generate karte hai. Uske baad kya hai, the next piece of data included the hash of the previous piece. This create a chain because each piece is linked to the one before it. Kya hota hai, jo humara data hota hai, vo next wale se connected hota hai. Kis tareeke se connected hota hai? Hash se to connected hota hai. But hum kya karte hai, jab bhi hash ke andar apne data ke andar kuch information likhte hai. To yahan to humne likh di bahut saari. Ab jo next wala isse linked rehta hai block, iske andar kya likhenge, iski kuch summary likh dete hai. Jaise hoti hai na ki bhai isme humne poori information le li aur isse related, yaani iski kuch aadhi information humne isme rakh li, taaki ye ek doosre se kya rahe, connected rahe, ki bhai jo humari transaction ki information isme bhi hai aur transaction ki information humari isme bhi hai. To ye ek doosre se kya rehte hai, linked rehte hai. Theek hai? Third kya hai, if someone tries to change any piece, it has would not match, the chain breaks, showing something wrong. Agar kya hoga bhai, koi bhi iske andar change kar dega. For example, iske andar kuch bhi change kar diya, to bhai kya hoga, isse related to ye hai, ye data bhi, fir iske andar data ko pata chal jayega ki is data ke andar bhi changes hue hai. To ye dono ek doosre se match nahi karengi. Agar is data mein ya is data mein koi bhi like, differences aa jate hai, to koi bhi changes ho jate hai, to ek doosre se linked nahi ho payengi. To vahan hume pata chal jayega ki bhai kya hai, humare data ke saath kuch chhedkhani hui hai. To ye humara hota hai, humara hash chain in blockchain. I hope aapko clear hoga ki hash chain humara kya hai. Ab dekh lete hai, hash chain to blockchain kya hota hai. A blockchain is like a hash chain with extra feature. Blockchain humara ek tareeke se hash chain ki tarah hai, jiske andar humne kuch humne extra feature add kar diye, making it more powerful and suitable for things like bitcoins. Taaki ye bahut zyada powerful ho jaye, kis kiski tarah, bitcoins ki tarah. Kyuki blockchain to aapko pata hai kya hai, but iske andar hum kuch hash chain ke kuch important feature ya kuch new new extra feature add kar dete hai, jiski help se humara jo blockchain hai, vo ek bahut powerful ban jata hai. I hope aapko clear hoga ki hash chain to blockchain humara kya hai. Simple hai, hash chain kya hai, ek chain like structure hai, jiske andar hum har data ko hash code mein generate karte hai.
[39:34]Uska aur fir ek doosre se link kar dete hai. Theek hai? I hope aapko clear hoga. Ab basic consensus mechanism humari kya hoti hai? A blockchain is a shared across many computer and each computer has a copy of the same data. A consensus mechanism is like a voting system that ensures all computers agree on the same version of the blockchain. Especially when adding new data. It prevent cheating. Ab blockchain ke andar koi bhi new data ko add karna chahte ho ya kisi block ko add karna chahte ho, to jo bhi us data se, us blockchain se connected saare computers hai, hum kya karenge, unse ek tareeke se voting lenge, ki kya ye data hum iske andar add kar sakte hai? Kar sakte hai ya nahi kar sakte? Bhai agar sabki sehmati hogi, to hi uske andar data add hoga. Isse kya hoga, cheating se prevent karta hai ye. Aur bhai, jo bhi valid data hoga, vahi iske andar add hoga. Ye ye ensure karta hai. Theek hai? I hope aapko clear hoga. Ab basic consensus mechanism humari kaafi hoti hai, POW, POS, POA. Ye second unit jo aap padhoge na, vo consensus mechanism ke hi upar hai. But thoda overview maine aapko yahan de diya, thoda hum basic consensus mechanism ko dekh lete hai.
[40:43]Varna inko hum detail mein unit number two ke andar dekhenge. To pehli humari consensus mechanism hai, POW, proof of work. Proof of work ka matlab kya hai ki bhai, blockchain ke andar blocks hote hai. To bahut saare kya hote hai, miners hote hai. Miners yaani nodes hote hai. Nodes kya karte hai, nodes koshish karte hai ki blockchain ke andar main block ko add karu, main block ko add karu. Kyuki jo blockchain ke andar blocks ko add karta hai, usko reward milta hai.
[41:15]Reward mein kya milta hai, usko bahut saare bitcoins milte hai. To har koi chahega ki bhai main block ko add karu, main block add karu. To uske liye kuch like, usko kuch solve karna padta hai. Ek computational puzzle dete hai hum computational puzzle milti hai. Jo bhi miners sabse pehle us puzzle ko solve karta hai, vo ek step aage badh jata hai. Isi tareeke se kuch steps hote hai, jo sabse pehle un steps ko complete kar leta hai, vo kya karta hai, us block ko blockchain ke andar add kar pata hai. Aur jab vo blockchain ke andar us block ko add karega, to use kya milega? Reward mein kya milenge? Bitcoins milenge. To isi tareeke se humara proof of work humara kaam karta hai. Yahan maine sirf aur sirf ek like introduction sa de diya hai iska ki bhai ye hota kya hai. Theek hai? I hope aapko clear hoga. Proof of stake, hum Ethereum ke andar use karte hai. Theek hai? Ab ye kya hota hai? Instead of competing with computers power, computational power, isme hum koi puzzle wuzzle nahi dete solve karne ke liye. Isme kya dena padta hai, aapko kuch amount deposit karna padta hai, ki aap mere itna amount of deposit. Cryptocurrency hoti hai na, aapko vo dene padte hai, ki meri itni hai. Jo bhi miners sabse zyada apne amount ko deposit karta hai, vahi aage badhta rehta hai aur usko hi chance mil jata hai. Kis cheez ke liye, blockchain ke andar block ko add karne ke liye. Samajh aa gaya proof of stake aapka kya hai? Ki bhai yahan hum computational power, computational puzzle ko solve nahi karaate, simple aapko kya karna padta hai, ek amount deposit karna padta hai. Jiska jitna zyada amount hoga, amount ko hum kya bolte hai stake. Jiska jitna zyada stake hoga, uske utne zyada high chances honge ki vo blockchain ke andar block ko add kar paye. Last hota hai humara proof of authority, POA. Ye kya hota hai? A few trusted people or organization are chosen to add new blocks. Ab mere saath kuch mere organization ke andar bahut saare persons aise hai, jo mere saath starting se like 15-20 saal se kaam kar rahe hai. To mere kuch trusted person hai. To main kya karungi, un trusted person ko choose karungi ki yahi mere trusted person, meri organization se, mere blockchain ke andar new blocks ko kya karenge, add karenge. To vo kehlata hai humara proof of authority. I hope aapko clear hoga ki consensus mechanism humari kya hoti hai. Inko maine abhi aapko bataya, fir se bata rahi hu, ye hum unit 2 mein poora unit 2 consensus mechanism ke hi upar hai. Unit 2 mein hum inko poora detail mein dekhenge. I hope aapko clear hoga. Yahan ye unit humari complete hoti hai. Yahan humne poori unit ko cover kiya hai with three year PYQ's questions. Agar aapko koi bhi doubt hai, aap comment section mein bata sakte hai. Ab humne ye new subject start kiya hai. Play ki koshish karenge jaldi se jaldi is playlist ko main complete kara sakungi, to sirf aapko kya karna hai, channel ko subscribe karna hai, video ko like karna hai aur apne friends ke saath share karna hai. Milte hai agar aapko humare notes chahiye to description mein aapko link milega, wahan se jaake aap humare notes ko buy kar sakte hai. Aur description mein aapko humara Instagram ka link bhi milega, jahan aap jaake hume follow kar lijiye. Wahan aapko kya kya, wahan aapko internship update, job opportunity aur kaafi saare memes bhi dekhne ko milenge. Milte hai ek nayi video mein. Thank you for watching this video.
