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So let's talk about this decision to save lives.

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We have already seen the substitution for substitute the brain by some other characters, so the characters

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are brain substituted by other characters.

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And the weakness of these operations over there can easily be brute force.

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So you can try all the combination of substitute characters and you can get a meaningful plaintext in

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one attempt and then the advantages can easily be encrypted.

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So let's see some examples of these obstetrician's efforts to get more idea about this.

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So first one, we're going to see the scissors four, and this is the very basics if you people that

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come to know when you're.

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So what deciphered the stories you need to write down all the alphabets.

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And these alphabet contains something indexes.

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So Index B's, one index and so on up to the this index.

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So we have indexes of integer are from zero point zero one, two, three, four, five, six and so

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on.

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So if you have a plain text and you pick, you have to apply character-based.

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So you take the first character and find that index.

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So after finding that index, you need to determine some key.

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So this is where you need to determine some key and you need to add that index to it.

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So index Peski, you get some value and what you want you want to do better is because if the value

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of index is like 20 and if there is value of the gift, then it will go out of this table.

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Right.

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Because the limit is twenty and we get 30 on addition.

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That's what we need to moderate the word politics so that we only consider the remainder of this division.

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So first we take the index of, uh, the character in the plain text and we manually determine some

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key.

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And then we add that index and key and then we the world with 36, such that the cipher text will be

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only in this range.

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So let's take a look at this example.

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So this is the table zero contents here and one B to C and so on.

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So I'm going to take an example.

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The plain text is empty, Wajir, so think it as an abbreviation.

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I know I have already determined the key is equal to six.

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So we need to do the Caesar's apparatuses for each and every character.

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Let's take you.

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So in the previous table, let's find out the index of it.

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So is it the index?

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And you need to press the key, which is six six zero six six and after only 26, 26 goes in zeros and

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then 206.

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And why do we take a look at the six in the table?

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You get the value.

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So write it down.

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So over here in the plaintext has been converted into G in the same for the same that you take them

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to at least four and then you add six, which you 18 and then 26 since the trust, then 26 goes 18 and

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zero times and leaves the room under 18.

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So the answer is 18.

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And if you take a look at the table, 13 values is so you write it down.

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So instead of your keeping us in the same way, you can do the every letter.

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Let's take a look at this.

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Right.

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The index of what you can differ.

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And if we are six, you get thirty.

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So our boundary has been zero.

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So the answer got all the different.

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So that's what we will do.

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The Modular 26, because we get only reminders from Dero to quantify.

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If you do a right, that's what we will do.

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The Model 26.

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So that might be good for.

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So 26 once is equal 26 and plus four gives thirty.

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Right.

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And for is eat the same that the 12.

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And then if you are six you get 31.

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And if you want to do it but only six you get the value of a year.

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So in that way we get the ciphertext final.

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Yes, yes.

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Yes.

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So you should have.

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We already have here we are adding us to Egypt, Loihi and the transfer of Savannakhet ciphertext will

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be.

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Yes.

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That if we send the key also to our receiver and then he just adds minus in the same way to get this

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plaintext, he put the minus and to the wider region and he get the value of the plaintext.

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So this is one of the example orders of protection.

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The weakness lies because the keys machsom keys, if you can produce, even though if you put the infinity,

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this modular condition, six use only that can be possible.

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So you can just apply the key to this plaintext and you can generate 25 different sets of ciphertext

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in those different sets.

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One set will be the meaningful because our plaintext will be meaningful.

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I took just this an example to show you the starting letters and letters and letters.

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So in reality, the plain text will be meaningful, that that's why Hacker will use this.

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If he knows the key and if he knows that we have used the same text, he simply put forces and he gets

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for in 24 hours.

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It's easy to find a meaningful sentence.

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Right?

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That's why it is easy repropose.

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And next example, we are going to seize the nerve center and what we're going to do is we're going

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to create a table and the rules and columns are created by Alphabet's.

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You need to create a table with the date and the rules and columns should also be the same and key should

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be exactly the same plain text.

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So it contains 10 characters.

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The key should be also 10 characters.

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If not, repeat the key.

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That means if the character in this print distance and the keys for we need to repeat it again.

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Four and you get the key is it so you get the remaining rate.

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That means you need to fill up two margaritas and you can distribute the two more characters are the

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key.

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So that's how you make sure that the exact, uh, the print accident and the current are equal and no

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mapping should be done between the plain text alphabets column and the keys are true.

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So you take each alphabet of plaintext and you cancel the column of the drawer of the table and the

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key are Pavitra and offer the mapping.

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You will get the one value and that value is the same for text.

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So let me explain.

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So this is the table.

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I have taken this photo from the Internet because I cannot I cannot create this in this much trouble.

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So you have those ABCDE, you do it again and your columns here to get.

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Now let's take an example.

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So print technical.

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Okay, this is my name.

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And the keys I take since the incident is less than plaintext, we need to repeat the key.

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So what we're going to do is we need to change it.

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So in this case, we got the.

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Exactly the multiverse.

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If you have only killed two, you need to Nicole here.

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You need to put it here.

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You just simply repeat until the plaintext characters are equal to key characters.

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So first, I want to take this first half of it and second half of it, which look at the end column.

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So in this end column, I need to look at the hits or so and column and hetero.

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So and Khorram, sorry, so much so, so I take this and call them.

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And so it is you.

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So my brain trying to transform into you in the same way I cut my throat.

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So we decided to call them and they throw it.

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And in the same way.

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So here is it's a kid column and drop and kid column, which are.

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So it's all you can find all this and let's see the last one I Iroh.

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Your column, Iroh.

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And so the ciphertext of the plane technically is UCU are PBT, so these two survivors are example of

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substitution ciphers.

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There are so many substitutions out there, but I cannot tell everything.

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There are not more than experts.

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So I took this to mean SEYFERT because I want to show you a whole substitution.

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Ciphers will work and no one can prove Forcett and you can also check it.

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Other substitutions I put on the Internet as well.

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But my intention is to show you that how this operation works.

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That's all for this video.