Blockchain Full Course 2026 | Blockchain Tutorial For Beginners | Blockchain Course | Simplilearn

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It's all completely free and it's a perfect first step to the world of blockchain development. So guys, before we dive in, here's a quick quiz question for you. The question is, which of the following best describes blockchain technology? Your options are a system for managing digital identities, a decentralized and transparent ledger for recording transaction, a traditional banking method, a type of cloud storage for data. Take a moment to think about your answer and once you're ready, we will get started. As of now, you see in the Bitcoin what we know in the Bitcoin, we already know about proof of work. One case, we know about the halfing concept. What is halfing? So now in this case you see halfing is also one of the uh concern and then we have limited supply of bitcoins. This is also we understand also we understand what is bitcoin minting. Okay. Now all these concepts we know and also I should write here the difficulty adjustment as well. difficulty adjustment and also we know about the case of nons as well. So nons is number that is used only once a random number. Now one more thing that we are using this is utxo and believe me this is you know uh I have seen many interviews where this question has been asked by the by the interviewer or the recruiter. So you should know this concept very well and we'll I promise you we'll be covering it in very easy language so that all of you have a very good understanding of this. So now you see I'm saying unspent transaction um output. So what is the full form or what is the abbreviation for this unspent transaction output? You see here UTXO. Okay. And now when I say UTXO what exactly is this? Now to understand this let's understand a uh I can say a imaginable scenario or a real life scenario. Now let's say I do have a note of 500. All of you listen this carefully. I do have a note of 500. In fact I do have a note of 500 three notes. So how much is my total amount? How much is total amount? So we are talking about fiat currency Indian rupees. So this is my physical currency and once we understand that then we'll come back to the physical currency. So total amount is what? 1,500. Okay. So I do have a 1,500. So I entered into a grocery market. So my total bill is 1,200 and I do not have any other amount apart from this and plus I am not paying anything online as well for certain reasons. No GPA, no UPI, no card payment, nothing is there. So how I will make the payment? How I will make that payment? I do not know. I have 500 notes. Total 1,500. So how many notes I should be giving to the shopkeeper? Sorry, how many notes I should give to the shopkeeper? All three. All three notes. Because we know 500 multiply 3 is 1500. So I cannot go with two also. I cannot go with the uh one also. So I will be giving total all 500 into three. So with respect to this the shopkeeper will be giving me a change. Okay. Change. Now how much will be the change? So this will be 300 rupees. Correct? Okay. So this 300 rupees the combination could be u a note of 200 or note of 100 or maybe the combination could be a note of 100 a note of one more 100 or a note of 100. Okay. So this could be possibility or even n number of combinations could be there. We we can just consider anything. So basically now you see these things I give a name. What name I'm giving? Input is or I can say input is 1,500 or in this case I'll take 500 3 500 into three only. So input what I have given to the shopkeeper three notes of 500 what I am reing as output what I'm receiving as output one my item or when I say what is whatever I have shopped for plus I am getting 300 rupee change okay what I'm getting 300 rupee change now note this term this is what 300 this is my change that I received after my shopping okay now in this case You see when I say 300 as a change so I'm associating this 300 with unspent transaction output. Correct? But now you will be thinking Bitcoin is not about any physical money. Bitcoin is all digital. So why do we are talking about change in something? But you see this is the beauty of the concepts. Now Bitcoin how do they follow the things? Let's consider this. So they follow the UTX2 model. As of now they follow the UTXO model and uh when you understand this you will also find that why they are following up this complicated method. But uh for certain reasons Bitcoin is falling up. So when I say UTXO model let's say I am this is I am Alice. Alice account balance is 10 bitcoin. Okay. Ellis 10. Uh, let me take it like this. Alice and Bob. Alice account balance is 10 bitcoin. Bob's balance is 5 bitcoin. Okay. Alice and Bob we have taken here. Now what is the target? Ellis is willing to transfer some amount to Bob. Okay, that is well taken. Now when I say 10 bitcoin, this 10 bitcoin is not like a digital money. 10 bitcoin is not like a digital money. It is more like a physical money. How this is being arranged into components. What is that component? So might be you see one component is five bitcoin, one component is two bitcoin, one component is 1 bitcoin, one component is 5 + 2 is 7 8 and 2 bitcoin. Is it making total 10? Is it making total 10? 5 + 2 is 7. 7 + 1 is 8. 8 + 2 is 10. So total is 10 bitcoin. Okay. So now what I have said as of now as of now I have just given you a situation that we have two user one is Alice one is Bob. Alice account balance is 10 bitcoin. Bob's account balance is 5 bitcoin and then I mentioned bitcoin is also maintaining some components to form a total account balance. So this is we have taken a shape of company. Okay. Now similarly the same thing should be applied to the Bob as well. So let's say component for Bob is 3 bitcoin plus 2 bitcoin. Okay. Now the case is Alice is willing to transfer Bob money of I say here two bitcoin or in fact four bitcoin. Correct. Now you see from this component which component should be passed to the Bob. In fact rather than making it four I make it something called as six or I make it 6.5. That will be better. Okay. Now you see so Alice wants to transfer Bob 6.5 bitcoin. Choose the component and let me know how would you proceed. Just thinking about your physical money which component you will choose. Ultimately this program has to be done by the this uh this conversion or the selection has to be done programmatically but as of now we are considering it so we are solving it. So which component or which combination should be chosen? 5 + 2 others also see 5 + 2 or anything else I should try which component we should choose 5 + 2 5 + 2 correct now you see if we go with this 5 + 2 so what we are transferring to this 5 bitcoin plus 2 bitcoin and once this transaction has been made. Now you see these two components are reserved. These two components are reserved. Once the transaction is verified, how much change will be coming to the Alice? Once the transaction is verified, how much change will be coming to the Alice? How much change will be coming to the Alice? 0.5. 0.5. So we can say that this is my UTXO unspent transaction output. This will be 0.5 bitcoin. So what will be the updated balance of Alice and Bob? Calculate the balance. What will be the updated balance of Alice and Bob? So you see Alice was having what? 10. So we transferred 6.5. So balance should be 3.5 bitcoin. What about Bob? How much will be the balance? What about Bob? So 5 + 6.5 is 11 uh this was 11.5 11.5 bitcoin and if I talk about the components now if I talk about the components earlier it was available so can I say that this is being replaced by 0.5 bitcoin and what has been achieved from this this is 5 bitcoin plus 1.5 bitcoin. Is it happen like this? Is it happen like this? Check check my component theory. Is it correct or should we change something over there? See what happened into this case. This I was transferring I was transferring what I have taken one component from this. Okay. Transferred two bitcoin transferred. But we have got a change also. That change is what? 0.5 bitcoin. So one bitcoin remaining same, two bitcoin remaining same. There this person has got what? Three bitcoin plus 2 bitcoin and then I have 5 bitcoin plus 1.5 bitcoin. So this way we are giving up here. Does Bob return 0.5? Uh Sanjie in this case. So whenever we say the component is designing so program is able to convert that 2 bitcoin to 1.5 bitcoin. So now you see in actually whatever we are talking do we have any physical currency? Do we have any physical currency? No we we are not having any physical currency. Everything is according to a program now. But how this B bitcoin is making it sure they have used bitcoin scripts to manage the component over there. And what is the reason of this complication? It could have done like a normal subtraction also. It could have done with a normal subtraction also. So they wanted to make sure there is no double spending problem. Now what is double spending problem? What is double spending problem? So we know that in Bitcoin average time for block confirmation is what? How many minutes? How many minutes? 10 minutes. So in that 10 minutes you see let's say now my when my account will be updated this 10 bitcoin when my 10 bitcoin will be updated right now my balance is 10 bitcoin. when this will be updated. Can I say that after the block confirmation? Can I say that after block confirmation? Yes, after 10 minutes. So meanwhile, if I am using my all the balance and I might use something like a double spending problem also in actual I have already spent five bitcoin. again I'm trying to you know change that and that logic is just checking my balance over there by arranging into the component. So they are trying to solve the problem of double spending and that is why they are using what UTXO model. Let me explain again here. So why what we are doing so basically UTX is the equivalent to digital form of change. Correctum correct. Yes this is the correct thing and very well spoken about this. So you see here what I'm trying to say we have taken example that we have two user one is Alice one is Bob Alice initially having balance of 10 bitcoin Bob is having five bitcoin so this time we are not having the total account balance like this the whatever is the balance this is being arranged into some partitions some components and it could be anything and how it is different from you know physical money like in physical money we have certain type of modes like only 500 only 100 only 200. So in this this is not like that. So there are programs where they are working into the same scenario to generate the components whatever is the component it is coming to the users. Now we have taken that Ellis is willing to transfer 6.5 bitcoin. So what we have chosen from this five bitcoin and two bitcoin and this is being sent to Bob their program is working and this program is making sure that 0.5 bitcoin is returned as a new component for the alice. So that is why the balance is being updated as 3.5 bitcoin and 11.5 bitcoin and ultimately we do have such arrangement over there. Okay. uh where is these components are stored you know this will be stored into my wallet only so let's say I created my account on the binance and this is my wallet so it will be stored into the same place how the initial components are decided say for Alice uh 10 bitcoin breaking it to various denominations Rajes so whenever u I got this denominations or whenever I received it so it was through the same let's say somebody transferred be 10 bitcoin as you are taking into the example. So this component is coming to me into some kind of form. So that form is directly coming to me. So whatever was the denomination that is coming to me. Another case you see when the minting is happening the bitcoin is minted. So that time the component is 3.125. That time the component is 3.125. Let's say I transfer to somebody else. So maybe I'm transferring this from this I'm transferring 1 125 from this I'm transferring 0.125 bitcoin. So what is the next component for me? What is the next component for me? Three bitcoin. Can I say that? Can I say that the next component is three bitcoin for me? Correct. Correct. Now let's see more examples there. more examples because we need to understand like this. Let's say Alice is new to the Bitcoin community. Okay, that time she purchased from somewhere and when she is purchasing that time again the component has to be come through whatever is the community giving. So let's say she just purchased one bitcoin as of now. Next time her friend is transferring her 2.3 bitcoin. So this way the component will be arranged. Now when she is transferring somebody let's say she wants to transfer approximately three bitcoin she wants to transfer approximately three bitcoin so she will be left with what she is using one bitcoin component as well 2.3 bitcoin component as well what she is transferring three bitcoin what will be the balance for her what will be the balance for her 0.3 0.3 So can I say that a new component is generated for her. Can I say that a new component is generated for her? Uh V. So all the components have UTXO label with them in wallet. Correct V. Correct. Correct. Do you understand the UTXO model? Now all of you very simple concept. U now give your thoughts on to this. So what is logic? Because transactions also can be traded. So it is based on single transaction denomination. For example, if I bought one bitcoin, 0.5 bitcoin, 0.25. So three denominations for me. Correct. Rajes. Correct. So don't you think they're increasing the complexity into the system? Don't you think Bitcoin is increasing complexity into the system? And uh the reason behind is that because the time period that we are considering that is very very high 10 minutes is very high time. So that is that is only you know one uh one thing we we can say that this is making them efficient for uh double spending problem. Okay. Uh so what is logic? Because fractions also can be traded or it is based on single transaction denomination. Uh Rajes can you please unmute yourself? I think it is better we interact then we can understand this. So hello yes. So I'm just saying that uh this is for the example which you have taken five uh 5 532 just an example correct but these transactions are happening. So denominations are not fixed. So idea is not about the replica of real money transactions of fixed denominations. So this is basically whatever you're transacting because it's in fractions also right you can buy 0.25. Yes. How many transactions are the denominations right? Correct. Correct. So this changes or UTX or whatever we are considering this only happens at the time of when say the change is coming. So that time they have not kept it okay. Uh like physical money we are fixing some kind of amount. This is not required into this case and they're just trying to solve one problem that is our uh what we can say double spending problem. and only the reason they are taking it because their uh their block confirmation time is very high. So this is one of them they have taken many step this is one step into a part of the same double spending problem. Uh Ashwin so when I have to get the total balance for a person do we need to add uh okay uh Ashwin this is not our responsibility so wallet will be automatically doing it. It is showing me the total balance only. But when I see that I can see all that you know fractions as well. So it will be automatically calculating for me. Uh Rajes do you want me to unmute if you're left with something? Okay. Okay. Thank you. Uh Ashwin you got the clarity onto this? See in case you have any question uh anything you you have some doubts it is better to discuss rather than sitting like that only then we can understand that what is uh what is the level of understanding of for each other yes Ashwin we can we can take a one more example for this see what is double spending problem let's say this is I'm having 10 bitcoin or I take less amount here okay so I take five bitcoin so this is Alice this. So we know that block confirmation happens only after 10 minutes. Okay. So what I did I transferred five bitcoin once I transferred five bitcoin one more time. I transferred one more time. This is five bitcoin. Okay. Now you see I have only five. But what I'm trying to do here, what I'm trying to do here, how my how much transfer I'm trying to do? Can I say that 15 bitcoin and you will be asking how it is possible? It is possible. My account is still not updated. I just created the transaction. I submitted it to the unconfirmed transaction pool and now it is still with the uh waiting for the verification. This is with the minor or this is you know sitting or this is into the unconfirmed pool. But what I tried here obviously it will be stopped at the minor over side but you are increasing what you're just increasing the complexity into the system. So Alice tried to transfer how many times? Three times with the what total amount causing a 15 bitcoin. Now if I say this component that it is entirely being freezed. This component is entirely being freezed. So this freezing is giving the power that this cannot be reused. Okay. Now I take one more example. Let's say Alice is having one more bitcoin. Alice has having one more bitcoin. Now she did what? She tried what? She tried what? This particular bitcoin to transfer at one side. Now if we follow the utxo model, this has been reserved. Reserved means I cannot use the component. But can I use this component? According to the UTXO model, can I use this component? Yes, I can use it. I can use it. So when I'm using this, this again become reserved over there. So now you see these two components are into the reserved side. So when it is into the reserved side, I cannot do the double spending. I cannot create the fake transactions here. I cannot create the wrong transaction here. So that is why the double spending problem is solved at a certain level. Another case you see another case you see uh let's take one more example in this case what is happening here this is case of what one bitcoin 5 bitcoin 1 bitcoin and two bitcoin now in this case I just want to transfer what one is five bitcoin then I want to transfer one bitcoin and then I want to transfer 0.5 bitcoin Okay, see this this very carefully I I want to show one more thing here. And then I want to do 1.5 bitcoin. Okay, this I want to transfer. So this is my let's say this is my transaction one. This is my transaction two. This is my transaction three. This is my transaction four. Okay, the sequence I'm also following up. Will it be okay? Can I do that five bitcoin according to the UTXO model? Can I do that? Five Bitcoin. Five Bitcoin. Can I do that? Yes, I can do that. One Bitcoin. I can do that. Two Bitcoin. This is for what? 0.5 Bitcoin. So now tell me, can I make the transaction four? Can I make the transaction four? No. Can I make the transaction four? No, I still have my account. I still have my amount. See, five bitcoin reserved. One bitcoin reserved. Now you see two bitcoin is also reserved here. 2 bitcoin is also reserved here. I need to wait for next 10 minute. Once I get my change then I can do the 1.5 bitcoin. Right? Have you understood this or I should explain this uh again. I'll come back to the questions everyone. I'll come back to the questions. Have you understood this? See what what we are trying uh trying to say here. I have some amount. Okay, it is solving my double spending problem also. But sometimes it may happen that I still have the amount just because my transaction is not verified still I cannot use it. So that is also a possibility here. Uh yes see what we considered here uh Manisha that we have component like five bitcoin, one bitcoin and two bitcoin that is making my total as 5 + 1 6 + 2 is 8 bitcoin. Okay. Now what kind of transaction I want to do? So in transaction one I want to transfer to ram. Transaction two I want to transfer to let's say sham. Transaction three I want to transfer to Bob. This I want to transfer to U some XY Z guy. Okay. So now in this case you see this is my transaction one. Second one. Transaction two. Transaction three. Transaction four. Total amount which I'm trying to transfer. This is 5 + 1 is 6. 6.5. And total the same amount I want to transfer. I want to you know uh nullify my balance. Now in this case you see I made transaction one. This component reserved I cannot reuse it. I transferred one bitcoin. This component become reserved. I cannot reuse it. Again I made a transaction. This is transaction three. In this case I was trying to transfer what? 0.5 bitcoin. I'm only left with what? Two bitcoin. So now this is also reserved. I have next transaction. So this is transaction of 1.5. Logically I have the balance. But if you follow the UTXO model, my all components has been become reserved. So when it is reserved, this two bitcoin has been reserved. I cannot reuse it unless the block confirmation happened. When the block confirmation happen for this transaction three, what I will receive? I will receive a UTXO. That UTXO will be of 0 or in fact 1.5 bitcoin. Once I receive this component, then I can make this transaction. Correct? Uh Manisha, do you understand this now? Okay, now let me come back to the questions. How is it flagged as reserved when the block has not been updated till 10 minutes? Ashwin, see whenever I use it, this is being flagged. Whenever I'm using it, it it becomes flagged at that same time. Uh Jaggerat, what Alice has 20 bitcoin but she transferred three times five bitcoin into three times. So in that case uh jagernad this also depends on the component. If component is trying component is having the same thing that is okay. If component is allowing the same thing that is okay. So with this theory say I have two component five and five total 10. I put a transaction of 7.5 bitcoin and then I want to transact 2.5 I can't do the second or as both component is blocked. Correct. Correct Rajes. So I was explaining this only and you have rightly said this and then do we have any kind of bitcoin denominations jaganit? Uh nothing is fixed. So program can make any kind of denomination. So it's not having any fixed amount. If the double spending concept would not be there then a person with one bitcoin would be able to carry out infinite transaction. Correct consumer? Correct. So once we start the transaction then our wallet freeze bitcoin which are used for transaction. Uh correct vine. Okay. UTxo is received after confirmation of block. Why cannot it happen immediately at exchange. Sanj it see in the transaction we are just waiting for the same purpose only and we are not making the block transaction wise. We are making the block as a collection of the transaction. So my block is not carrying one transaction it is carrying multiple transaction and we are talking about the distributed ledger. So whatever we do have this is into into we can say that this is into collectively with every every node. Okay. uh like let's say if she uh like let's say if he she made a transaction of one bitcoin but as the double spending concept is not there so he will be able to transact that one bitcoin again because it is not deducted from his wallet see these scripts are what these are actually governing that all kind of UTXO and everything so for every transaction automatically programming is there which is being managed or which is managing that how uh the transfer will happen how the transaction will happen, how the UTXO will will be converted. So, automatically is embedded over there. So, as a user, you do not need to do anything for you. It is a normal graphical user interface. You just put your amount, click on send, uh put your uh sender address and everything. But by default, this is attached to the transaction and this is taking care of everything. Uh witness is something here we divide it. See this is we can say that public key script witness is the balance of that script. So you can say that this is hash of all the transaction that has happened. So you can more consider it as a hash value for the uh the script that is being executed over there. So there is one more concept Rajes that is segated witness seg. So I'll explain that that time you'll get more understanding of this. So to understand this we'll cover segwit. So segwit is actually related to uh we can say data compression. So I'll explain this as well. Earlier it will it was not there but now the bitcoin has revised their uh scripts and they're including here witness and this is part of segit which is more related to the data compression technique. But I'll explain this because because before understanding this segment we need to understand one more concept. Uh who is considered to be sender of UTXO amount. So this ashwan in this case the sender will be the transaction. Sender will be the transaction. So actually you know it recently happened not recently I'll say last year. Now we are into 2025. If I show you that that amount was you know very very high at that time see uh so we are talking about 21st July they have given the explanation and we can see how much of the asset so this is news of Hindu you see crypto exchange hack how much of the asset was lost and what happened next so lost over 230 million in a security exploit 230 million is a very very big amount after one of its wallet was targeted on 18th July and has decided to socialize its losses in what uh unorthodox damage. So why I'm talking about this? So since beginning we have seen that blockchain came into the picture because of the security and transparency. transparency we say that we we will not have any any kind of hacking or anything but this is also possible here so now one of the attack if I say do you think there is a possibility of the 51% attack on the bitcoin do you think there is a possibility of 51% attack logically you tell me is it possible or not logically Probability is always there. Correct? Probability is always there. So now what is 51% attack? So we say that when a minor propose a block that has to be evaluated by the rest of the miners. But now I'm saying that my 51% nodes into the system are corrupted. So can I say that my entire blockchain is a failure? In that case, can I say that my entire blockchain is a failure in in that case? Can I say that? So, yes. Yes. But if we see uh theoretically, it is possible. Theoretically, it is possible. But when we see that if somebody is actually trying to do that, they need a lot more resources. Especially with the Ethereum, especially with the Ethereum, you see, they need to buy all the ethers and everything. So uh in this case this becomes very difficult but this is also one of the attack and it might be possible somebody is taking over that that blockchain as well. So this is one of the type of attack. Another case I say here another case I say here mining pool. We all remember do we all remember what is mining pool? Mining pool. Can I say that group of miners working together? Can I say group of miners working together? So in that case you see group of miners they working together. Now let's say uh I I speak about that. So there was a time when China was the was having the highest mining pool. there was a time because now recently China has you know uh uh made it illegal to do the mining into their country. So now this this all mining pools has been shifted from China to the US. So now in this case you see geographically geographically can I say that we know the location of miners. Can I say that geographically we know the location of miners? Obviously I do not know the exact location but any anyh how we have a certain idea set that these minors are linked to one particular country one particular country so what I'm trying to say here from majorly miners were running through China but now this has been shifted to US okay now is there any possibility probability. So one we are just you know probabilities we are considering is there any possibility that internet or the ISP working into the US that can be hacked probability you tell me internet service provider we understand ISP of US can that that be hacked is there any possibility probability yes probability is there but if you US is having a very good security in terms of cyber security into the information security. So if we technically we talk about it is very difficult theoretically we say it is possible. Uh Jaganat ISP is internet service provider internet service provider. So like we have the Tata and Jio here. So which is which is providing us the internet services. So these are the ISP. So in this case you see we're talking about the throughout connection which which could be possible. So let me just give you more examples for this. Uh one of the attack is fishing attack. So fishing attack is what? Fishing attack is what? Have you received some kind of u lottery message? Have you received some kind of let's say uh your loan has been processed? you click on this link to get the further information. So all of us we receive this kind of you know messages. Similarly emails are also there. Emails are also there and uh even you might have received uh today what is what is going on? You receive a call from a couer kind of a guy and uh he will mention that you your couer is there and if you need to return this or something you need to press that and uh do this. So these kind of things we see very normally. So what is fishing? Fishing is basically sending unauthorized links to someone. So that when they click on it actually your amount or you will get the financial loss. So in this case you see sometimes what happened let's say I do have uh I take example Exodus. Exodus comes in which category of wallet? Exodus comes in which category of wallet? Web, mobile or software? Which category? Which category? Both. Correct. That is that is also right. So this uh I assume that this I do have with the web based wallet or I do have some kind of mobile application. Now somebody sent me what? A link. a link on the same or I can say that a unauthorized link. So this is onto my WhatsApp and because of this unauthorized link what happened over there I actually clicked on that link and now this is making a automatic payment. This is making a payment from my mobile wallet to that account. So this is you see this could be done with the fishing site. This could be done with the fishing site. So there is a possibility that I have all these kind of a wallets and somebody is trying to intercept me. They will be sending me unauthorized link. If I click on the same link I will be thinking that there is nothing is happening but on the background my applications is being used and the amount is being transferred. So uh now another question if from my account I saw that uh some cryptocurrency is being transferred to a wrong address. Some cryptocurrency is being transferred to a wrong address. So can I get it back? Can I get it back? Can I complain it to someone? Is there any possibility like that? Something wrong happened. I by my mistake or by fishing there is a address where the transaction has been done. So can I get back that money? No, you cannot get back that money. So that is entirely not possible into the cryptocurrency system and even we do not have any any kind of you know uh compli uh regulatory framework as well where we can complain or something in our uh I'll say let's say in India we have the RBI to complain over there even if you see when you have some ATM card or something it has been lost so you can complain and you can immediately you know shut it down. These possibilities are there but nothing exists with the case of what the cryptocurrency. So that is why fishing is a very dangerous one into the case of Bitcoin. Okay. Now you see uh there is a civil attack also. This is very interesting one. This is very interesting one. So the syil attack listen this very carefully. So we all know the 51% logic. Do we all know the 51% logic? Now I am giving two statements. Correct me or give me your understanding onto this. So I'm giving two logic. One the one logic is that if my nodes are honest 51% will be achieved soon. If my nodes are dishonest, can be achieved with some delay. With some delay, think about it and then let me know. Two logics I have given. One, if my notes are honest. Honest means whatever is the right or wrong, they are taking the decision and accordingly giving the verification. Let's say uh these nodes are having a proposed block. So what is what do I mean by the honest and dishonest node? So this is let's say this is a honest node. So this honest node will be giving the right decision. So if the proposed block is correct so it will be taking as correct. Dishonest node will be giving a wrong decision. Wrong decision is what? So in this case this node already computed that proposed block is correct but still it is saying it incorrect. Okay. So in this case now you read the read the statement. Now you read the statements. So now what is happening with this syllable attack is we can say that a smaller version of 51% a very smaller version. So now let's say there is a Bitcoin community and they have a competitor. The competitor is let's say XY Z. Now they want to they want to run their business and they want to disturb the Bitcoin's business. So what they did they created a civil attack. So civil attack is having dishonest nodes into the system. So they are not becoming minor for their reason. What they are becoming minor whenever they have come across the proposed block they will be voting as wrong way. They will be root vote voting into the wrong way only. So when they are doing it so ultimately they are getting delay to achieve the 51% attack. So in that case what will happen? this 51% attack let's say it has to be achieved at 1010 now it might be go to the 1030 so I'm just taking a example for this or maybe 1020 so they are causing delay into the transaction or we can say the block confirmation uh no this is not to steal the bitcoin this is just to delay the see if the uh now you see if we have the average time of block confirmation of 10 minutes we are still okay with that. But if it if it increases to 1 hour so can we say that can we say that trading market will hit cryptocurrency trading market will hit if that time becomes 1 hour it will obviously it will be it will be hit. So there is a possibility that the other competitors they're not trying to steal anything they're just having what they're just having some malicious node into the system. these nodes just trying to disturb the working of other nodes. So that is the case of civil attack. So civil attack if I just brief it this is creation of dishonest node into the system and these dishonest node will be doing the task into the wrong manner. But anyhow they cannot take the wrong decision because to take the wrong decision all the dishonest node should be 51%. And that is very high to achieve. So they cannot achieve it and smaller what they can do they can do the civil attack how they achieve it to delay block confirmation correct uh when you think of I have a network let's say I try to dry draw it into paint see so let's say this is minor this minor has already win the game and he is broadcasting the network network with a proposed block this is one this is one this is one this is one this is one this is so these all are nodes here so I'm not taking 100 nodes now I'm taking just few nodes now you see in this case let's say how we are moving geographically it is getting the proposed block it is sent to this so this is also dishonest it is sent to this dishonest this is also dishonest this is also dishonest so in In case it was not dishonest. In case it was not dishonest. So by this time by this time it might have achieved the 51% thing. By this time it might have reach achieved the 51% but now it has to wait to go through this also go through this also. Go through this also and only in the end ultimately it is having what? It is having the right answer. So as of now you see the if we at this time if we see the quantity will remain same only quantity will remain same means the voting is 50% or whatever voting I'm talking about. So correct and incorrect voting that is entirely similar. So that is why we had having to say that delay is introduced here. One more case you see that broadcasting is happening and it will take time to reach from pier A2 or pier 1 to pier 10 in between whatever peer I am receiving that are dishonest. So as of now I cannot make any decision by that time because ultimately what we want we want 51%. So we are still waiting to get the confirmation from others. Right. Uh Vinnie, I hope you understood this. Okay. So I just delete this. So now we have seen the civil attack as well. Uh fishing you already understood. See in the fishing how many things could be used. So chat fishing, message fishing, email fishing, social media fishing, Google adword fishing. So all those could be medium for this. What is message fishing? What is m message fishing? Can I say my text message? The medium is my text message. The which we are receiving on the phone. Email we all understand social media. So now you see on the Instagram also we are getting you know these kind of messages. So Google adword is also one of the example. So yes we do have multiple links sent through the message. Correctum correct. So normal text message when it is coming through the email this is this is your uh the links are coming to from the email over. Okay. Now I come to the rooting attacks. So now what is the rooting attack? So this is basically targeted to the no. Now you see this is not being targeted to a user or something. This is onto the network. Now in the network you see this is what BGP router. Now BGP stands for border gateway protocol. This stands for border gateway protocol. And now in this case you see we are actually having uh when I'll just come to this border gateway protocol. Now in this case you see this is based on what this is trying to give the directions to the packet. So when it is trying to give the directions to the packet let's say this is being hacked. Can I say that packet will be going to a wrong direction? Packet will be going to a wrong direction. Can I say that if this particular router is being hacked, that router's responsibility was just to give the direction like where it should transfer to the next. Now this is doing a wrong task. So in this case you see this is also one of the type of attack where rather than targeting a particular scenario the router or these kind of a devices are being hacked by the hackers and this this can be maliciously maliciously send this packet to some other location. So this is not only with the blockchain this could happen with any type of data. This is not only with the blockchain. Okay. Uh V I'm coming to your question. Once validator validates block then only he send it to peer node to validate it. Uh correct Vinnie. So maybe you wanted to say minor validates the block then only he send it to the peer node to validate it. So it is just like a proposed block. So all other miners need to revalidate it to get the 51% voting. Okay. Uh this also I I believe we have already discussed what is full node to become minor what you need to become full node or light node. To become minor what you need to become full node or minor full node. Full node. full node is downloading the entire blockchain. Uh Rajes, this PPT is available on your uh portal, but I'll show you where it is available. Okay. Full node. Full node. Okay. What what is light node? Who is light node then? Who is light node? Viewers. So can I say that if I am on the uh blockchain explorer I am I am working as uh light node. I'm on the blockchain explorer and can I say that I am a light node? So yes I'm on the light node. Now you see uh one more thing we see here. Let's say I want to join the network. I want to become the miner. What I want to become? I want to become full node. So full node. So we have seen a website. We'll visit the uh Bitcoin website. What we will do? We will download the Bitcoin software. Now when we are downloading the Bitcoin software, the server will be connecting me to a node. The server will be connecting to me a node. Now you see I requested a C node. C node is providing me all the addresses. See now what are the addresses? We talked about that this is peer to tier network. So I should have if I am becoming a minor I should have addresses of all other peers. I should have addresses of all other peers. Okay. So but who will be providing me all those addresses? how I will be connected. I'm saying that I want to become a part of peer-to-peer network. So, we will when I'm downloading the Bitcoin, I will be linked to a seed node. So, seed node will be providing me address list of all the peers so that I can form a connection with those peers as well. So every time a new node or a new minor joins the network the same process happens. So requesting the C node retrieving the address list selecting the peer node and updating updating the network. Now why I'm saying updated the updating the network. So let's say I have 101 peers. Now one more is added. So there is one more connection. So 101 + 1 that is equal to 102 peers. Now can I say that recent peer will be also added also added in the also added in the address list. Can I say that recent peer will be also added in the list? Can I say that? Yes, it has to be added because it is just what address list over there. Ashin, I'll come to your question. Just give me a second. Uh, now in this case, you see the same process we are following up here. So, seed node connected with this node. Give me the address list. By this address list, it is getting connected to all other list as well. So, this is making a updated copy into the network. Mining we all understand. Now let me come to the Ashwin's question. Uh when a block when then when then a block is broadcasted to a node does it forward to another node only after it has completed completed validating the node? No Ashwin it is into the process. So let's say I received a block I'm working on that and meanwhile it is being transferred to others as well because for my verification also it takes time. So it is not wasting into that broadcasting is sending to everyone. So what whatever I have I'll update with my answer correct or incorrect. So that I'll update to the bitcoin. Okay. Now we'll come to the orphan block. This is also left. Do we have facility to select our peer nodes? uh when it is automatically selected but if you need to select the immediate peer that you can you can select the immediate peer. So one term is immediate peer. Immediate peer is that is closest to your your connection. So that you can choose but uh see you will not be knowing the exact thing over there. Everything is encrypted. So you're not knowing IP address or something. You're know not knowing that okay this person is belong to which city or which country but it is showing you the nearby route. Every information is encrypted. Okay, next concept is orphan block. Uh, can I move to this? Next concept is orphan block. Can I move to this? Okay, now you see now you see in this case uh this is the concept which we left when we started with the proof of work. The question was what if more than one minor solves the puzzle at same time. Okay. So one case we asked is it possible? So the answer is yes it is possible. So what will happen in that case? So initially it is very difficult for Bitcoin to recognize this. So what happened into that case? Now you think of a case that I have minor A and minor B. So these miners solved the puzzle. Let's say uh nons. He also received the nons. He also got the nons. So both of them created their block. So they started they are not aware about the things here. The broadcasting has been started. What is broadcasting? What is broadcasting? Now, now you should understand this. What is broadcasting? Can I say that? Sending the proposed block to the multiple one. block to the multiple peers forwarding to another node. Yes. So, broadcasting is what? Uh, let me write it here as well. So, for your later understanding. So I'm writing here broadcasting is broadcasting is sending proposed block to all peers. Okay. Block to all peers. All right. Now this is also doing the broadcasting. This is also doing the broadcasting. Now there is problem. Now how many miners are doing it? two minors currently if you see you can add you can work on only adding up one block. So there is a function we can say or a programmically with the help of program there is a function call we say function call that is known as synchronization call we call it sync call. So that happens in the blockchain with all the peers and what it checks it checks the it checks the all blockchain peers or all peers all peers are having the same state of the blockchain or not. Peers having the same state of blockchain or not. Okay. So when it is recognizing so it got what it got let's say minor A is adding block X minor B is adding block Y. Now in this case they found out they find out the sync call the sync call that is a program that find out that block block x block x which is related to minor a block x is having introduced into 50 peers. block Y is there into 30 pairs. Okay. So now you see two different blocks are being floated into the blockchain. One is block X, one is block Y. Block X is through minor A. Block Y is through minor B. Reason was there that they solved the nons at the same time. But it has been recognized with the sync call only. So sync call is being done after a fixed amount of time. Okay, now you see they need to choose one. Which one is easy to delete or which one is easy to discard? What should I discard? 50 pier or 30 pier? What should I discard? 50 pier or 30 pier? Which is better to discard? Which is better to discard? 30 pier. 30 pier. So now which block is this one? Which block is this one? Block Y. Block Y is associated to which minor? minor B. So I say here block while will be discarded by the synchronization call and this is known as orphan block now. Okay. So now you see this is being discarded. So these all 30 tiers will be also updated by block X whenever the time comes. Meanwhile, all those transactions which were part of orphan black block, listen this carefully. Let's say I have total 1,000 transactions that were part of orphan block. Now they all will be transferred to the unconfirmed transaction pool. they all will be transferred to the unconfirmed transaction pool. So now you see in this case what is happening in this case this example you see can you see here block 3 A and block 3 B can you see here block 3 A and 3B. So this is being discarded and it is known as orphan block. So this being sent to back to the unconfirmed transaction so that the same state remain with the blockchain. Okay. I hope now you understand this concept. What is the orphan block? So what will be your answer if you you want to give in two lines. What is orphan block? What is orphan block? But how you can define this discarded block? Yes, discarded block. Correct. So in case you see if uh three miners are doing at the same time so same thing happen will that only one will be chosen as the final block correct. Uh now proof of stake is having the pro orphan block or not? Proof of stake is having the orphan block or not? No they are not having it is not having. And also let me tell you one thing. Uh earlier Ethereum was Ethereum 1.2 1.0 Ethereum 1.0 was using proof of work. That time orphan block was known as uncle block in the Ethereum. See in the Bitcoin the name is always same. In the Bitcoin this name is always orphan block. But in the block uh Ethereum 1.0 it was known as uncle block. But now if you see now if you see Ethereum 2.0 that is following up proof of stake. So it is not having I'll say no uncle block here. So I'll not say no orphan block. I'll say no uncle block here. Okay. Will time to get 51% approval will be higher in this case? Uh yes Rajes, this time it will be higher. This time it will be higher because two two blocks were floating over there and then synchronization call was there was there. So uh the discussion has also happened. So it can take more time. So that is why you see the time that is 10 minutes given that is only average time. It's not always fixed. You'll get 10 minutes only. It can be more than that also. It can be less than that as well. So it depends on the runtime conditions. Okay. Do we all got the clarity of the orphan block and uncle block? Have we got the clarity of orphan block and uncle block? Any question as of now? Uh what if when block y also have 50 peers at the same time? Shambu that time it will be choosing randomly. One of them will be chosen randomly and uh it's good part you have asked this question. So that time it will be choosing randomly. Changing the complete consensus algo of a crypto is just like remaking the crypto itself or it needs only some modification due to which the complete consensus algo is changed. Talking about Ethereum uh and assuming in that case they do the forking forking means that let's say u what happens obviously the previous things we cannot change it. So I assume that till Ethereum 1.0 2 they have 1,000 blocks and after this this is 1,001. So whatever they are doing they are changing with this block not with the previous block. Whatever they are doing that they are changing with 10,0001 block. So whatever policies they have they implementing into the current but the older version they are not uh I'll say changing or something. So this is like shifting from one protocol or one consensus algorithm to other soft folky correct dh. So I do have some questions uh with you. How is bitcoin address generated? How is bitcoin address is generated? You have four options. Hash of public key, hash of private key, hash of the person's name, hash of any random value. So correct hash of public key. So this is hash of public key. Bitcoin address is always generated with the hash of public key. Okay. Uh what does a Bitcoin block header consist of? So you read it carefully. What does a block Bitcoin block header consist of? So as of now I am getting A as answer C and one. So let me show you the A is correct one. A is correct one. See version previous block hash ML root time stamp difficulty and nons. See this is carrying nons as well. So it's like it is carrying uh major majorly all the options. So that is why A is chosen here not C or any another answer Ashwin difficulty is that that is having some values what will or how the nons will be solved. So this is based on that when I say that difficulty so difficulty doesn't mean that it will be decided on the basis okay make it complex or make it increase or decrease so it is having a value on based of that nons is calculated so it will be let's say I have a number uh I say 0 0 this this this is this and one I say that difficulty This is x x. Which is which which one you think which is more complex to solve? Which one you think is more complex to solve? If we talk about some puzzles or something. So this is all about the digits. This is all about the digits. So this is this kind of difficulty level we uh achieve into the case of bitcoin. Uh, how frequently is the block mining reward? Reward is half. I think this you will give me the correct answer. It should be having the correct answer with everyone. B. Yes. The last halfing happened on this. I'm asking you when was the last time the halfing happened? April 24. April 24. Okay. Which of the following statements is true in the context of Bitcoin? Which of the following statement is true in the context of Bitcoin? minus must solve a mathematical puzzle to generate a block with leading zeros. Correct? Correct. All of you are correct. Let me show you this thing. Atomic wallet. So this is also you know one of the wallet here. So uh this PDF I'll share with you all. First you read the statement and then I'll take you to the document. So whenever you get the time uh you can try this. So you are a blockchain expert and have been asked to download and set up the atomic wallet to conduct a transaction of bitcoins. Uh just a second I think my screen is not visible. Okay. Uh yes to download the configure the atomic software or wallet create a new auto atomic wallet explore a transaction of bitcoins and other currency using the atomic wallet. I think same kind of task I have given to the exodus as well. So you just can go through it. So this is the website atomicwallet.io. You can download it and you see this is available into multiple uh operating system Windows, Mac OS, Ubuntu, Debian and Fedora. Similarly onto the applications as well. So this screenshot is for the uh Ubuntu machine. So in uh in our case it will be very simple into the case of Windows. So you do not need to follow all those steps if you are onto the Windows machine. But in case you are on to the case of I'll say uh Ubuntu platform. So you'll be following the same path. And once you have it so you can create a new wallet. You can provide the password. This is like a sign up process. Once you provide the password, you will open the wallet there and you'll be able to see you remember in the Exodus also we were seeing the same kind of thing bitcoin all other cryptocurrencies and everything. So explore a transaction of bitcoins and other currency using atomic wallet so that you can do some conversion. So here you see in this screenshot 200 USD has been converted to bitcoin. Similarly the Indian currency as well. Then click on swap from the left panel. Swap is what? Changing from one currency to another currency. So this we are trying with the 10 ether to the bitcoin over there. So this price might be have increased this time. So after this you need to go through the NFT gallery. NFT is your nonf fungeible token gallery. There you can see something related to the how to buy a NFT. So transaction can only occur if there are enough bitcoins. So just the exploration. So one one of the you know uh one of the another wallet you can try. So this uh entire PDF I'm sharing and plus link as well. So in case you want to try it right now that also you can do. Let me give this link. uh ashwin the swapping works with the uh current price of the market. So whatever is the current price I will be getting the equal equality to that and these exchanges are responsible to perform that task. Yeah. In case of blockchain so these exchanges are working for me. So every every uh cryptocurrency can be converted to other cryptocurrency. The market price is already set for the same. Uh Anumuan we do not need to download the Ubuntu or anything. We do have labs with us. So actually when we are working with the Hyperledger fabric that is only workable into the Ubuntu. So we are having lab machines those lab machines can be used for the same purpose. We do not need to do any kind of installation or something. So we will be uh going to our portal and then we will seeing the lab uh shorty it is almost same only it is almost same only just it is your choice like which which particular wallet you want to choose and let me show you this thing as well because uh might be some people are not aware of the PPS and everything and I'll show you the labs also just a Okay. So, you have your all LMS there and I'm logging into my portal. So, as of now what do we know about the Ethereum blockchain? So this Ethereum blockchain is also coming into the category of what we can say public blockchain. But how it is different from the Bitcoin. So we do have two three differences we can easily see. The one it is right now working on proof of state. This is having only transaction fee as reward money. It is also giving us opportunity to what we can say this opportunity for the creation of programs. So that programs are known as smart contract. Smart contract. Maybe you have heard this term multiple times into into the blockchain word. So we we can make we can make the contracts over there smart contracts reward money. Okay. And also now you can see this is something combination of cryptocurrency plus smart contract. So I'm writing SC for the smart contract. Also when we talk about that the community is known. Community is known means so this is not like a anonymous one. So we do have very renowned uh I can say stakeholders into the Ethereum community. So this community is known. So I can say that by default trust is also there. Okay. And uh can I say that this is second highest cryptocurrency right now in the market Ethereum can I say that it is second highest cryptocurrency into the market. So yes this is also one of the fact and uh they have achieved it very soon as in comparison to the other cryptocurrencies because of the concept of the smart contract. Then in uh in the next case you see one more thing we see the Ethereum also give me the support for creation of NFT or even I say FT FT stands for funible token and nonfgeible token. So we we are able to create these two as well by the help of the smart contracts as. So these are some some uh things that we already already understand with this and with the help of proof of stake we know that there is nothing like no uncle block and in this case uh no parallel parallel block creation will happen creation will happen. So these all things we are already aware about. Okay. Now in the same case you see is it payment cryptocurrency or only utility based token currency? Uh if you are Rajes if you're talking about payment as in payment cryptocurrency yes we can make it both both the way we can have it. So ether can also be done uh non-f fungeible tokens can also be done. So both are possible here. All right. So now we know that uh what is the cryptocurrency for Ethereum? This is ether. So have you heard about EA? Have you heard about EA? Maybe not. So this is actually enterprise Ethereum alliance. So this is a community. Now what kind of community? What kind of community? See I we know that bitcoin is having very high price but on the back of our mind it is also there that we still not aware who is the owner uh what we we are still afraid one day they will come and they'll close everything but these kind of assumptions are always there now when I say ethereum so I go with this same thing this is the term that we are using enterprise Enterprise Ethereum Alliance. Yes, this I'm looking for. Now you see what is this term. So I'm just sharing this link also. I'll share in this case you see how many members we have and what kind of member we are seeing. Okay. So now you see what names you can see. Microsoft, Sendender, Ranger Fish, uh Ara Capital, Block App, Consensius, this is also one of the company Ethereum Foundation obviously and EY uh I I believe all of the name you have already heard of. So now you see these all are part of this alliance enterprise Ethereum alliance. So when I say whenever they are taking a decision in that decision these all members are part of this these all members are part of this can I say that because of these big names I do have more trust now into the community because of these big names can I say that I do have more trust into the community can I say that so yes now it's like that if we compare it from the Bitcoin and if we compare it from the So we we come up u we come up that okay the now I I have some kind of reluctant things onto the bitcoin we I know the prices are very high but what is the future we are still unsure but when I come to the ethereum because of the you see all the uh ecosystem and everything everything takes us with the with the having more understanding and more trust factor over there. So this is the beauty of enterprise ethereum alliance. So you should you know read this what is the membership FAQ how to become a member. So these these things we should go through I'm sharing this link as well and I am putting up in the chat plus in the document also. So whenever you get time so you go through this. Okay. Uh do we have and Shan for this we do not have white paper or if you are asking the Bitcoin one or the Ethereum Ethereum no white paper so they are g they given everything into the documentation I'll share that documentation. Okay. So now u this kind of you know collaboration it gives us more trust with the same. Now similarly you see if we see the applications multiple these domains the people you see JP Morgan they are from the finance background healthcare energy technology banking sector so we'll see multiple players into the same domain. So uh Intel is also part of this Rajes. Yes, correct. But now they are also looking for a decentralized solution not for everything. See once we come up with an understanding of all kind of a blockchains we will ultimately conclude that blockchain is not solution for every problem but it is solution for few problems and in that case blockchain is the perfect solution. So this is this is we can say a customized theory everywhere we cannot put blockchain but there are some scenarios where blockchain is the ultimately a very good option or very good solution. So these uh you know companies and every they have at least one project they which is working into the blockchain domain. So you see Intel, Microsoft, JP Morgan, Asenture also we are seeing here. uh similarly you see BNV BNY Malon this is also a a good group uh so these features we receive from the same second now now I come to the smart contract I come to the smart contract so as of now I just mentioned that smart contract is what it's just a program it's just a program but if I compare this program with any another language program it is entirely different not in terms of uh syntaxes or something obviously syntaxes will be different but in terms of running in terms of deployment so we'll see uh today how it is different now when I say languages so there are three languages that we use majorly into building up the smart contract one is solidity one is Julia one is wiper and if you see the market in the market Julia and the solidity is doing good and we are going through the solidity into our uh course caliculum. So we'll be learning the same part here. Okay. Now before I explain you the theoretical part, let me take you to the how does the smart contract look like? Why I'm saying it is different. So what I'm doing all of you see it very carefully because I know that some of you are not from the uh programming background but we'll understand it in very very easy language. These are uh what percentage uh is built in solidity. Uh Rajes, it is not about the percentage. I can say that if I need to give a probable idea, so I can say that uh most of the IT companies, they are looking for I can say that they're looking for the solidity engineer. But even if you have the experience with the Julia, you can apply for the blockchain engineer role. So for especially for the Ethereum uh I have seen JDs in the India it uh solidity is always preferred and also with the Canada and in some European countries especially with the research group they ask the jury as well. Okay. Okay. Now see what you need to do what I do now I open this website into incognitive mode and I'll explain it why I'm doing it. So I'm doing control shift N and remix. See this is the website remix.ethereum.org. Let me put up here as well. Remix.ethereum.org. So you see my screen first then I'll give you time to do as well. See first you will get up some you know cookies you need to accept. So I click on accept. Now you see first option you are getting here in order to understand your need better. We would like to know how you typically use Remix. So 1 2 3 4. So you choose here the correct option. So uh we will be going with the learning because we are at the learning stage. I click on that. So this is giving me a uh tour of the interface you see here. So this is a welcome icon. I click on next. This is solidity compiler. Compiler means checking all the errors. Deploy your contract. I'll tell you what is deployment. So this is my interface which I am getting for the program. Now you see there are certain terms that we will be using with this one case. So we know that what is folder? So in solidity or in remix I should say remix is workspace is a term that is given to the folder. Okay. Now in this case you see in this case you see when we say workspace folder now in that case what will happen? What is remix? Remix is a IDE. ID is what? Integrated development platform. So I can build my entire program onto the same platform. Earlier it was available into two version. Desktop. Desktop means I need to install the software in my system and now it is more famous with the web- based version. So what is the beauty of the web- based? I do not need to do installation. I'll just put up uh limix.ethereum.org and it will be working. Okay. Now in this case, let me make it zoom like this. Can you see a contract folder here? Yes, Anuan. Correct. Just like VS code. Can you see the contract folder here? Contract folder. All of you. Contract folder. Now whenever you are making a program a new program it should be inside this folder. It should be inside this folder. Okay. And what is the extension of solidity file? This is so maybe whatever name you are giving you can give it something let's say uh first or any another name you can give. So let me try to make a folder here or a file here. So what I can do I can right click and you see here new file and I name it first dot so and I click on enter. So when I click on enter now you see you see you have one page here. You have one page here. So this is the place where you need to write the program. This is the place where you need to write the program. Okay. Now what we have seen but you see by default you are having only one folder. Folder is what? Workspace default workspace. So I can create my own folder as well. Let's say I click on this like here. Can you see this create blank or create using this and everything? So I'll go with the create blank. I go with the see how to make a new folder. Click on create blank and let me name it uh January 25. Click on okay. And you see here this time you're not getting anything no sample anything. So you can directly start creating there as well. So now what I can do there is nothing like a contract folder. So that time that is okay. You can just create it like this new file. So I will be making it let's say second dots. So that also you can do or another method. Click on workspace create using template. I click it again here. Create using template. So there also I can choose something like this. So later on we will try all these things here. Right now we are not doing anything with the sample. See can you see here basic and blank generic one these two basic and blank. So blank or basic we can choose. Let's say I can go with the basic also. So this I name it January 2025. I click on okay here. Now you see can you see the contract folder now can you see the contract folder now contract folder see the uh panel there contract folder so I will be making my file here so what I'm trying to say whenever you are creating a new workspace what you will be choosing either you can go with the blank or you can go with the this generic template that is basic this open zeppelin and everything we will use later on. Okay, not right now. This is actually used for the uh fungeible token and the nonfgeible NFT creation. So when you're using these samples that time you will be using this. Okay. So right now we will be working onto the either this basic one or this blank one. Okay. Now you see why I have asked you to run on the incognito mode. Now whatever I'm saving here, what do you think where it is stored? I created a file. Let me go back to this January 25. I created a file second. Where it is saving? What is the location of this file? What is the location of this file? So it is being stored into my browser's memory. So do we understand the cache memory of the browser cache memory of the browser it is saving all the cookies and everything. So in case I delete history of my browser see if I go with the control H I do the history thing and I delete everything my all the files will be deleted. So what is advisable? Now I'll show you my I'll I'll show you my Chrome browser. Now you see here this time I'm opening remix here. So this is not incognito mode. Now in this case uh Jagdish will that be saving in login credentials? Yes Jagish correct correct. So whatever account you have logged in from now can you see multiple uh multiple workspaces here. Can you see multiple workspaces here? So everything is stored into my browser's history. Everything is stored into my browser history. Let's say I go with this July batch. I click on the contract and you can see multiple files here. You can see multiple files here. So these all programs are saved here. But this is part of what? This is part of my Chrome browser's history. And now you'll be asking what if I delete? So everything will be deleted. So it is better to take the backup of this. How I can take a backup? Now let's say I click on this July batch. Can you see this download option? Can you see this download option? The right click I have done. I have right clicked onto the workspace and there is a download option. So with this I can download it offline as well or I can go through a GitHub also. Have you heard about GitHub? Have you heard about GitHub? So in the GitHub I can also publish. So I can use uh directly connectivity from you know from my remix to the GitHub. Okay those who have not heard I'll just show you how does this look look like. So, GitHub is a uh we can say a online platform that allows you to save your programs and everything and it will also allow you to create the version control as well. So, multiple organizations uses it or they can uh you know they can also use a competitor of the same as well. So, in this case you can make your account and you can also store your all the programs there. So, what will happen in that case? Remix will be directly connected to the GitHub and when it is connected by default from the same option I will be uploading onto the GitHub. Correct. Uh in case of GitHub do we need to make it public repository? No Ashin this is entirely up to you. You can make it private as well. You can make it private as well. All up to you. So I normally what I do I uh downloaded my system. Normally I downloaded my system. So uh nilashwari commit we need to do from the GitHub only it will just will be uploading commit we need to do it from the GitHub. Can we also import the existing solidity program for GitHub? Yes, with that also we can do so we do have you see open a file from a system upload a folder. See there is a option this you can do from your local system. Similarly you can link it with sign into the GitHub. Can you see this? As of now, I have not signed in. So once I have signed in, that time I'll be getting all the choices. So I have not linked it as of now. I used to download it uh into my system only. Can we not store in our machine to begin with so that it not stored in browser history? Uh by default Ashwin it will be stored in browser history by default because this is a web- based platform and later on uh you can take the backups. Uh sakam earlier there was software version but right now it is not working. Earlier there was a software version also. So let me show you remix uh desktop or maybe you can try this older version as well. You can try this electron app. I'm sharing this l link uh sakam. If you want to try you can do that. Uh but I prefer to work on this because we we we need to do you know metam mask connectivity and everything that time it is more workable for us. So as of now whenever you are writing your programs I'll advise you that make sure that you're taking backup of of this or you are not just deleting your history like that and if you're doing it in incognito mode it will not be saving anything. Okay. Uh because ultimately the memory that is being used here that is the cache memory of your browser. Now uh do one thing all of you do one thing all of you do do one thing at least to be familiar with this open remix in your system open remix create create two workspace create two workspace name you can take anyone try deleting deleting one workspace Create solidity file in workspace. Try to download try to download workspace in your system. Okay, very small exercise. Just I wanted to sure that you are opening the your uh you're being familiar with the tool. Then I'll tell you how to write the program and everything. Does every uh chish remix on incognito mode means uh when we open our browser in incognito mode that is not saving any kind of a cachy memory or that is not recording anything. So if you're not recording your program will not be saved. Does every blockchain has their own ID for the smart contract development? Yes. Yes. Sudesh uh like hyperledger fabric there we can work with the eclipse also and also you know u we we can run the solidity program in visual studio as well. So that is also possible. So it's not like that fixed it is that uh some options are available which one you want to choose like for example Python is workable in uh Anaconda also Jupiter also or you can go with the Google collab. So we are using here web- based one that is remix. Okay. So let me give you this link again. Uh remix.ethereum.org. Make sure you open the correct link. Just do it this small exercise. So you need to open remix. create two workspace any name you can give you need to delete one workspace uh deletion I have not told you so you need to explore this and then create a solidity file in the workspace make sure you are giving the extension as s to the solidity file and then try to download a workspace okay uh learning choose the learning one so you can go with the learning So this will be asking only one time. Next time it will be storing all the uh features for you. So it is displayed on the word file what you are supposed to do. uh yes Jaganat Jaganat you share your screen I'll guide you no problem you share your screen I'll guide you that will be better so you have the rights to uh sharing as Yes, I can see your screen. Yeah, I'm in this page. M. So, you already created a workspace, right? No, I have tried but I don't know what I'm doing. Okay, no problem. Let's click on this workspace. Uh on the uh below the file explorer left hand side top file explorer there is workspace there is three lines. Three lines there. Three lines. Workspace. Yes. Click on this. You click on create using bl uh template. Create using template. H. And uh then can you make it this remix AI down remix AI that is popping up uh on the right hand side. Right hand side there is a window appearing like this now. Just make it down. There is a icon there. Arrow kind of thing. Yeah. Now click on this basic create. Create. Yeah. So you can name it whatever you want to give and click on okay. Initialize workspace as a new git repository. No that is fine. That is fine. We are not initializing anything as of now. So now you see you have a contract folder there. uh second one. Second folder. Scroll down. Down this one. Right click. Right click. New file. So this you can name your solidity file. Okay. Solidity file. Doss dot o. Enter. H. So this is the space where you can write the program. I'm not a programmer. Uh so I'll I'll give you the code and everything. Don't worry. So basically we we are understanding how this platform works. Okay. All right. Yeah. Thank you. This h this much I had to do. This is my work, right? So I asked you to create two workspaces and then also explore how to delete one workspace. Okay. Can I do it now? Yes. Yes, you can do it. See there is uh there is a option. Okay, you create the other one. Then we'll delete. Okay. What do I have to? So any name you can take. So this is basically naming a file every time just you need to make sure you're taking extension as Slleshwari no we do not have any uh as such rules so you can take it and you can take the space as well. So now I can download it also. Yes. So this is you need to right click on this JD1. Right click. So…

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