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All right, so the main idea behind the Fidelman exchange algorithm was the question of how to exactly



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share the key, because as we all know, that symmetric encryption uses only one key to encrypt and



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then decrypt the document.



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So how exactly people will share the key because the key is not shared securely.



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There is no point in having encryption system at the first place.



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So these two people, Diffie and Helmond, outstanding people, outstanding brain and excellent thinking.



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They came up with an exchange of algorithm in such a way using generators and prime numbers that it



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was possible to generate the exact same security at the both parties.



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And so let us say we have Bob here and then we have Alice over here.



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So now we can see that is.



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Yeah.



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So this is Bob's private key, which is with Bob.



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And this is let's say now we have Alice's private key with her.



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So we have Alice.



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So this is Bob's private key and then this is Alice Private.



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So they have their own private keys with them.



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Now, the next step is we have this cloud, which has the generator.



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That is the algorithm.



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And this we have the prime number.



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Now, all these things are known to public.



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So whatever you see here, whatever you see here, it's public.



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So anyone, even the attacker can see the generator algorithm and the prime number.



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But attacker cannot see Bob's private key and bolt analysis, private key.



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So what they do is they take the generator here.



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So just let me take my pen.



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So what they do is they take generator.



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So Bob takes the generator and as well as Alice takes the generator algorithm, they combine.



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So what Bob does at his end is he uses one algorithm to combine and form this color to form this.



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You can see this key or you can see this output.



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Similarly, Alice takes the generator and her private key to form this output at Horwitt.



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Now, what do they do is since this has the Bob's private key and what do they do is they share these



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two outputs to respective each other.



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So even if the attacker sees this orange color, he will only find out the generator.



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He won't find out the output.



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Because now you may say that if Bob sees the red color and Bob sees orange, obviously the next element



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is going to be yellow.



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It's not like that.



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Output is a string is a number, is a hash value.



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So even if Tacker gets to see these two values and the generator, he is not able to guess he he won't



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be able to guess their private keys.



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Consider this.



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I may see that I have taken 5min of red color and Danimal of yellow color, but I can see that what



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I have got is I've got orange color and I've known five red color.



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But what about the yellow color?



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It can be 10.



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It can be ten point one, nine point eight anything.



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So in that way, what exactly?



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Once you mix two colors, it's very difficult to get those colors back.



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Right.



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You may try yourself a gondek of water in two balls in one block and big yellow water and then another



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ball.



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You can take red water and mix those two waters and you get a uniform color.



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After that, try separating out those colors.



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It's impossible to get the original colors.



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So this step after this step now both of them.



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Now, Bob has Alice's output and Alice has Bob's output.



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So, again, what Bob does is Bob takes his private key analysers output and Alice takes Bob's output



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and her private key.



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Together, they do again do the same procedure here.



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And in this way, they get the same shared secret.



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This output is always going to be same at both the ends.



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In this way, the Diffie Helmund key exchange algorithm was designed.



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Now, both of them have the same shared secret key, and that is why they can do this.



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Symmetric encryption, right?



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This.



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This was the most simplest explanation anyone can give you using the color theory, because don't visualize



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these colors, don't think as actual colors.



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The main reason behind this is you have to take these values.



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Again, I can't see, let's say generator stands for G.



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Bopp's private key stands for Y, so y and ah will give you Y are OK.



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So now Alice will have y r and this is R and G, so this is G.



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That is why Bob will have to G now vi.



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So this Shirkey is why are G and this is again why are G.



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So both these things are seen in this way you get the same shared secret.



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Now once you have the same shared secret G you can carry out symmetric encryption.



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This was the algorithm proposed by Diffie Hellman.



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It's a really outstanding algorithm and therefore this algorithm and Ezzy, along with symmetric encryption



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overtones, the processing power of asymmetric encryption.



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So even if you want to get your asymmetric encryption, symmetric, encryption can be used along with



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the development algorithm.



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And that is why this secret secret key can be used.



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This was the working of the film, the exchange algorithm.



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All right.



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In the next lecture, we are going to talk about a new tome known as Harshing.



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So stay tuned.



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Keep moving forward.