Hello, in this lesson we are going to cover what is cryptography. We've talked about cryptocurrencies and how one of the foundational cryptocurrencies is cryptography. And it's one of the foundations of blockchain and several other applications. Essentially, cryptography is a mathematical algorithm secure data. So we can end the video right here and talk more about it. Now I'm joking, we are going to cover a lot more about it.

First of all, it's been around for thousands of years. It's not a new concept. It's transformed over the years. It's helped win wars as well. And essentially, cryptography is an amazing system. First of all, let me start off by using a simple example, which is not secure.

So imagine if we have Person A, they write a letter and they send it to personally so we have this letter here. And we're using Some sort of intermediary here. So imagine it's the postal service where the Postal Service is in your country. So you're so what person is doing, they are interesting, this Postal Service to not open the letter and read it and reseal it, you can pretty easily do that. So Person B, probably wouldn't be able to tell that that has happened or person a with it. So you're trusting the postal service or whatever the intermediary is, whether the intermediary friend and they're going somewhere they can give it to Person B or whether the intermediary is another company doesn't matter where resolved internet gap does not matter.

And you want the information to be secure. But what lifted it open it and maybe you didn't know? They seen the information in there. It might be something insignificant like Hello, how are you? For, or it might be something like some sort of login details. Or it might be something private between Person A and Person B.

So this is where something like cryptography could come in. So you would essentially, so imagine if we have this text, hello world, you then cryptography, we could secure it with some sort of key that is agreed upon by all parties. So all parties would have to agree upon this key and believe they're secure and difficult to guess. And maybe this now becomes free 245 comma x, the A, D, A, E, F, G, x, x, x 000, f two this no longer resembles this. If I were to see this, just as it is, I will never guess that it actually means hello world. But somebody with this key could encrypt information and get this what essentially looks like garbage.

And then somebody with this information could use the key again to decrypt it and get the original message. So there are very forms. So you could do something like a Caesar Cipher, which essentially just shifts the letters have a method X amount. So if you just shifted by one, H, will become I, II will become F, l will become m, etc, etc. That's a very basic form of encryption for that has been used a lot and a lot of children use it to just experiment and you get around and say the average person reading it, but there are more complex form as well, those complex forms really don't matter. Essentially, you have two main concepts and they are in corruption which is this way of going from readable data to something that's not readable and you have decryption which is going the other way from what looks like garbage data to reload data.

So essentially, cryptography transforms readable data to look looks like garbage and is only readable to retrieve it original meaning. So, this essentially crypt typography There are two main aspects to this. Two main two main aspects that you need to know. And there's something called a cipher. The cipher is essentially the rules that are used to encode the information. So the rules and the other one in the Caesar Cipher will be move the letters X amount in the alphabet.

And you have something called a key which allows you to actually encrypt and decrypt data are how to actually use the rules to encode and decode information. Maybe there's several rules in what oddities are rules, how do you use those rules. So cipher are the rules. He is how you the rules. So the key allows us to encrypt and decrypt data. So easy example of a postal service.

Let's just use one more example. Imagine if we have a box This box is secured with a padlock. And this padlock has a four digit PIN. So a four digit numerical pin which has a possible combination count of 10,000. So unless you're brute forcing it, you would have to know the pin itself. So I might have to pin is something really SQL like 1234.

If Person A was to open this using the pin 1234, they could open it, they could maybe put a letter in there, and they could close it. And then Person B, who also knows this pin to this number, trusted party could open it and access the information. Nobody that doesn't have the correct pin and don't try and brute force it could access this information. You could technically they have is just a general sort of safe immobile to physically break into it or not pack it in the way of like getting the pin, you could maybe break into using some sort of hammer or soul or something like that. ignoring those scenarios, the only people that can use it are Person A B, anyone else they interest, I say another example of cryptography or securing in the real world and cryptography uses cryptography uses ciphers as a digital digital lock key to encrypt and the crypt data.

So we essentially replace this. So the padlock. And so this is essentially you can think of this as a cipher. This is the key, and it replaces that in a digital form using mathematics to secure data. So that's what cryptography is, in its core essence. If you have any questions, feel free to reach out to if there are any concepts that you didn't understand in the video, feel free to go over them again and just have a look.

That's always the best way of learning. And as usual, thanks for watching, and I will see you in my next awesome lesson.