All right, so the main idea behind the Fidelman exchange algorithm was the question of how to exactly
share the key, because as we all know, that symmetric encryption uses only one key to encrypt and
then decrypt the document.
So how exactly people will share the key because the key is not shared securely.
There is no point in having encryption system at the first place.
So these two people, Diffie and Helmond, outstanding people, outstanding brain and excellent thinking.
They came up with an exchange of algorithm in such a way using generators and prime numbers that it
was possible to generate the exact same security at the both parties.
And so let us say we have Bob here and then we have Alice over here.
So now we can see that is.
Yeah.
So this is Bob's private key, which is with Bob.
And this is let's say now we have Alice's private key with her.
So we have Alice.
So this is Bob's private key and then this is Alice Private.
So they have their own private keys with them.
Now, the next step is we have this cloud, which has the generator.
That is the algorithm.
And this we have the prime number.
Now, all these things are known to public.
So whatever you see here, whatever you see here, it's public.
So anyone, even the attacker can see the generator algorithm and the prime number.
But attacker cannot see Bob's private key and bolt analysis, private key.
So what they do is they take the generator here.
So just let me take my pen.
So what they do is they take generator.
So Bob takes the generator and as well as Alice takes the generator algorithm, they combine.
So what Bob does at his end is he uses one algorithm to combine and form this color to form this.
You can see this key or you can see this output.
Similarly, Alice takes the generator and her private key to form this output at Horwitt.
Now, what do they do is since this has the Bob's private key and what do they do is they share these
two outputs to respective each other.
So even if the attacker sees this orange color, he will only find out the generator.
He won't find out the output.
Because now you may say that if Bob sees the red color and Bob sees orange, obviously the next element
is going to be yellow.
It's not like that.
Output is a string is a number, is a hash value.
So even if Tacker gets to see these two values and the generator, he is not able to guess he he won't
be able to guess their private keys.
Consider this.
I may see that I have taken 5min of red color and Danimal of yellow color, but I can see that what
I have got is I've got orange color and I've known five red color.
But what about the yellow color?
It can be 10.
It can be ten point one, nine point eight anything.
So in that way, what exactly?
Once you mix two colors, it's very difficult to get those colors back.
Right.
You may try yourself a gondek of water in two balls in one block and big yellow water and then another
ball.
You can take red water and mix those two waters and you get a uniform color.
After that, try separating out those colors.
It's impossible to get the original colors.
So this step after this step now both of them.
Now, Bob has Alice's output and Alice has Bob's output.
So, again, what Bob does is Bob takes his private key analysers output and Alice takes Bob's output
and her private key.
Together, they do again do the same procedure here.
And in this way, they get the same shared secret.
This output is always going to be same at both the ends.
In this way, the Diffie Helmund key exchange algorithm was designed.
Now, both of them have the same shared secret key, and that is why they can do this.
Symmetric encryption, right?
This.
This was the most simplest explanation anyone can give you using the color theory, because don't visualize
these colors, don't think as actual colors.
The main reason behind this is you have to take these values.
Again, I can't see, let's say generator stands for G.
Bopp's private key stands for Y, so y and ah will give you Y are OK.
So now Alice will have y r and this is R and G, so this is G.
That is why Bob will have to G now vi.
So this Shirkey is why are G and this is again why are G.
So both these things are seen in this way you get the same shared secret.
Now once you have the same shared secret G you can carry out symmetric encryption.
This was the algorithm proposed by Diffie Hellman.
It's a really outstanding algorithm and therefore this algorithm and Ezzy, along with symmetric encryption
overtones, the processing power of asymmetric encryption.
So even if you want to get your asymmetric encryption, symmetric, encryption can be used along with
the development algorithm.
And that is why this secret secret key can be used.
This was the working of the film, the exchange algorithm.
All right.
In the next lecture, we are going to talk about a new tome known as Harshing.
So stay tuned.
Keep moving forward.