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Now, for example, say, if we create or something like, say, the let's go to your and he I don't

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down our cipher letters here and below, we would write down the potential decryption letters and here

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we would take forced c h g, h, h you and your we would take the other word that we have created that

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is b b y the M or m m y.

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Then let's take B or B B Y and and A and and y.

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So over here, if you look at it, each has a potential decryption letter of B, M, B or N, similarly,

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G has a potential decryption letters, you or A or you have the potential decryption letters.

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Why?

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So all the others are four letters besides this have no potential decryption letters in this particular

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example.

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Right.

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So a cipher letter mapping shows all the letters of the alphabet and their potential decryption letters.

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So as we start to gather encrypted messages, we'll find potential decryption letters for every letter

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in the alphabet.

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But the only cipher letters that is edgy and you are part of our example.

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We don't have potential decryption letters for other cipher letters.

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So notice that you has only two potential decryption, only one over here.

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That is why, because there are no overlaps between the candidates, which many of which ends with the

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letter by itself.

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So over here we can use a dictionary value to represent the site letter mapping us follow.

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For example, we may use your C4 or say G or in single codes we can use it something like it should

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be you then all a for example or for that case.

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If we take each, each can be equal to C be then M, B and similarly we can write down C you, which

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should be equal to either one.

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Now this dictionary has tremendous value that is apart from G h and you you will also have from ABC

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to does it and all the others will be basically blank.

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You may have C for example, E, which is equal to blank or C let's give comma B, B also has blank,

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then C comma C also has blank.

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Let's give A commonly also has blank like this for all the others apart from Chenu.

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So it shows the potential decryption letters for the G H and you and all the others will have like this

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blank as we have represented here.

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So because we can reduce the number of potential decryption letters for the cipher letter to just one

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letter by cross referencing the cipher little mappings to other encrypted words, we can find what that

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cipher letter decrypts to.

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Even if we can solve all twenty six cipher letters, we might be able to hack most of this letter mappings

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to decrypt most of the ciphertext.

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So now that we have covered some part of the basic concepts and some terminologies which we would be

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using in this session, let's look at the steps involved in hacking this process.

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So let's have an overview of the hacking process.

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So the hacking are simple.

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Substitution cipher is pretty easy.

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Using the four patterns, we can summarize the major steps of hacking process as number one, find the

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work pattern for each cipher vote in a ciphertext.

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Number two, find the English word candidates that each cipher vote would decrypt to number three,

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create a dictionary showing potential decryption letters for each side.

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Four letter to act as a cipher letter mapping for each cipher vote.

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Number four, combine the five four letter mappings into a single mapping, which we will call, say,

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for example, intercepted mappings.

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Number five, remove any sort cipher letters from the combined patterns on mappings.

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And finally, number six, decrypt the ciphertext with this solved cipher letters.

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Now, the more cipher vault in the ciphertext, the more likely it is for mappings to overlap with one

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another and the fewer the potential decryption letters for each ciphertext.

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This means that in a simple substitution cipher, say one line of text.

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So the python hacking advanced level code, this is hacking a simple substitution cipher.

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This whole particular line, before dividing into the source code, will have to look at how we can

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make the first step of hacking process easier.

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So again, in this we would be using the dictionary file used in the earlier session to get the word

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pattern for every word in the dictionary file and then saw them in the list.

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So coming to our verb pattern module now to calculate the word pattern for every word in the dictionary

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of the file, which we have, we would create another file which will check the or make the word patterns

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dot python file, and then we will place that particular file, which will have a program to get word

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pattern, for example, and it would return the damage of old patterns, which we're passing it as the

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parameter.

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Now, after creating this file, then only we can go ahead for creating a hacking example for a simple

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substitution cipher.

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So in the next session, we would see creating of the make vote part file and then we will use that

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file along with the dictionary files, which we have from the earlier sessions, and then we will create

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our hacking example for simple substitution cipher.

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So that's it from this session.