Tutorial 1- What Is Blockchain?

Key Takeaways

hello all my name is krishnak and welcome to my youtube channel so guys yesterday i made a polling vote saying that how many people require entire blockchain playlist so finally uh there were many people more than 5000 people voted for yes they could really require a blockchain playlist so considering that particular request i'm going to make this entire playlist there will be more than 20 plus videos we'll be learning everything with respect to blockchain we'll be doing practical implementation how you can actually create your own cryptocurrency and uh you can also create your smart contracts and all with the help of python uh i'll tell you one thing that why did i learn blockchain because blockchain has some amazing feature with respect to security and which we are going to discuss today in this particular video we are going to discuss what exactly is blockchain and we are going to discuss about some of the properties right so that is the reason why i learned and probably in the future as we go ahead you know uh what we we will do actually is that we'll try to use but blockchain and ai try to combine it and try to see how we can use it in different different domains so that is the final target that probably after the end of the playlist will be going and we'll be learning all these things so yes welcome to this series please make sure that you subscribe the channel press the bell notification icon if you have not done yet and yes i'll try to make this particular series quite entertaining i always like to write in this blackboard or let it be a white board you know and in that specific way we will definitely be able to learn a lot of thing so the first question uh today is that what is blockchain okay so if i really want to make you understand what exactly is blockchain it is nothing but it is a continuous continuous growing list of records so continuous growing list of records list of records we say this records as blocks okay we say this records as blocks it is a continuous growing list of records which are also called as blocks this have some properties okay and we are going to discuss about this properties some properties what are those properties this this entire list of records hap have the first one is that you know this is completely some of the properties of blockchain this entire list of records or blocks are cryptographically linked crypto graphically linked this is the most important property okay we'll discuss about this we'll discuss in more depth you know the algorithm that is specifically used for blockchain you know wherein we are able to mine bitcoins or do different kind of transaction related to bitcoins is sha 256 i already made a video regarding sha-256 but we'll try to see this in the upcoming videos how you can actually implement it uh how you can actually use this cryptographic algorithm okay the second property is that this is completely decentralized this is the second most important property that is completely decentralized what does decentralized actually mean see guys in the case of suppose if a is transferring some money to b right this entire transaction is controlled by a central authority right which is nothing but bank right so in the case of blockchain if you are using bitcoin if you are basically transferring from a to b there there is no central authority it is completely decentralized decentralized basically means that it has something called as distributed database please note on the terminology that i'm actually using okay it has a distributed database okay that basically means no central authority it has a distributed database suppose a person wants to send b b one person wants to send c person c person wants to send the person suppose let's say that they are sending bitcoin and in the future further we'll also be seeing what is the difference between bitcoin and blockchain also right when we are adding records and blocks right the miner gets some kind of rewards and those rewards are called as bitcoins right and they can definitely use it for different different purpose right now now you can see that what is the market cap of bitcoin so if i go to this distributed database what does this basically mean is that suppose a person is sending b person some bitcoins right or b is sending some bitcoins to cc sending some bitcoins to d right they have a decentralized that basically means the entire blockchain copy will be present with respect to each and every person then the entire blockchain and this blockchain will be noting down all the transactions that is basically made from different people to different people right the entire copy will be present with respect to every with respect to all the persons who will be having who will be making those kind of transaction so this is the most important thing that is decentralized and distributed database if you're not able to understand don't worry i'll be talking about more examples i'll be talking about in depth as we go ahead the fourth and the most important point if you really want to understand this it has an immutable ledger so the fourth point is that it has an immutable ledger so if i want to draw a blockchain how does it look like let's see so this is my block suppose as i've told you it is cryptographically linked let me just rub this and let me show you okay so if i want to draw a basic structure of a bitcoin how it looks like or sorry of a blockchain so this is my first block right then this block will be cryptographically will be cryptographically linked to the other block so this will be cryptographically linked to the other block right then again it will be cryptographically linked to the other block right now like this the list will be the blocks will be continuously growing as you know as probably miner will mine more and more blocks okay i'll tell you about the process of mining everything will be taught in this entire series just follow the playlist one by one video everything you'll be able to follow now if i talk about this blocks what are the important information that are present in this particular block since this is the first block this is called as genesis block this is called as genesis block now in this particular block you have information like block number right you have information related to transaction like what how many people wants to send how many bitcoins or how many other cryptocurrency to what people all those transaction will be noted down over here there will be one more uh important information which is called as uh previous hash key hash key when i say cryptographically linked that basically means we are using this algorithm to create a hash key and this hash key is developed by nsa okay nsa i'll talk about the full form but this is the question to you what is the full form of nsa you can write it down then apart from this previous hash it will also have the current hash key of this particular block and this hash key is generated by all this information one very important information that is again present in the entire block that is called as nonce and this nonce plays a very important role okay in deciding the hash right in deciding the hash right so nonce is nothing but number one's used this is the full form of nonce so if i want to talk about this non it is nothing but number one's number only once used i guess okay so number only once used so i am just trying to draw the basic block information now when i say cryptographically linked means what over here you can see this hash key right this hash key will be referred in the next block okay so in if i talk about the previous hash key over here it will be the hash key of the previous block then what will be the previous hash key for the first block it will obviously be zero okay 0 how many characters i'll talk about it okay similarly like this all the information this current hash key will again be linked to the next block similarly it will be going on so that is the reason why we say it is cryptographically linked and since it is cryptographically linked it cannot be changed so any kind of transaction that has happened once right it will remain like that that is the reason why we call it as immutable ledger right all the transaction once it is recorded in the block it is going to remain no one can change it because it is cryptographically linked and it has its property of immutable ledger i'll talk more about it why you cannot change it because it's very difficult so if you're trying to change the hash if you're trying to change the transaction information from here then this current hash will definitely change if the current hash is already changing then what you have to do you have to also change the previous hash key of the next block right so i will be explaining the detail process why you cannot hack the entire blockchain it is a very difficult process so in terms of security if you have decentralized distributed database and immutable ledger along with cryptographically linked it is very difficult to break it with respect to security that is the most important thing that we have to basically come up with so this is the basic information regarding blockchain right one more point where does bitcoin comes this block are just not created like this guy this block are successfully mined by miners suppose a new block is mined suppose a new block is mined then what will happen is that as the person mines new block as the miner mines new block right they are rewarded with some kind of bitcoins so bitcoin so if i talk about bitcoin they are like rewards probably right now based on the bitcoin monetary policy as far as i know i think somewhere if you are mining successfully one block you actually get somewhere around 12 bitcoins that does not mean that this process is very simple guys i'll talk about it the process is very difficult you know you really need to use some amazing gigs which includes asic machines not gpus also gpu will also not be coming into existence asic machines right then this asic's machine will actually help you to uh you know mine this kind of blocks and again for mining the block it is a very simple process which again i'll be discussing in the upcoming videos right so if anybody talk about bitcoin or anybody talks about blockchain you really need to understand that it is a continuous list of records growing records which is also called as blocks which are cryptographically linked it is decentralized it has a distributed database and it has an immutable ledger that is the reason no one can actually hack it right and this hash key is just like fingerprint guys see i'll talk about it okay suppose if you consider a person right a person a person a how do we uniquely identify this person name usually you can use dna or the other thing dna can forget about dna i'll not take dna as an example but if i take unique thing like fingerprint right then we can definitely identify person a suppose if i take some digital file if i want to uniquely identify the digital file then what i can do i can basically use the hash algorithm and based on that i will actually create a hash key so this is just like a finger unique fingerprint for a digital file it may be a pdf file it may be a text data it may be audio data it may be a video data it may be any kind of data that are that occurs digitally right so this is the basic understanding so this is just the first tutorial i did not want to put much and much information regarding this but a simple understanding of what is blockchain in the upcoming video in the second video which is again going to come tomorrow there we are going to understand the applications of blockchain right and then we are going to understand we are going to continue the further series right so in the next video we are going to understand what is the application of blockchain and we'll try to understand with respect to this as we go ahead guys we are going to code entirely and create our own blockchain and try to see that how we can create smart contracts how we can create cryptocurrencies and many more things so i hope you like this particular video please make sure that you subscribe the channel share with all your friends guys and trust me i will try to complete this series as soon as possible as i can so yes i'll see y'all in the next video have a great day thank you one doll all bye