So we come here in the eighth part and do that, so after replacing all the parts in the list and give
it the solve letters, the function combines a list of strings into a single string using a joint method
to create a simple substitution.
Now, this string is passed to the decrypt message function of your simple substitution cipher, which
is based here.
Finally, we get the return of the decrypted message string from the decrypt message is your function
and we now have all the functions we need to find an intercepted letter.
Mappings, hackle key decrypt a message.
So let's look at a quick example of how this functions.
Work in the interactive Chente.
So let's come to decrypting in the interactive.
Shall we have done the last part?
Everything in the interactive one.
Now let's return that and we use the particular mode text where we will be using the intersected mapping
variable to create a more olio shell examples or decrypt deciphered message that we had inserted.
So now at this particular point we will have to insert, say, let's go here and we would see our programmers
say, let's go back here to December subhi so simple sub Hackel dot.
Now we will be using the decrypt with.
Saifullah, dumpings, and he'll be able to pass the text, also the intercepted mapping one and the
text that we're going to pass is there already in notepad.
So let us just copy down the text over here in the single quotation marks after this.
Let's get to we are getting it as uncomfortable increases disappoint.
So the ciphertext decrypts to the message as you can see, the decrypt with cipher letter mapping function
Vorkuta perfectly and written a fully decrypted string.
But this example doesn't show how or what happened when we don't have all the letters that appear in
the ciphertext now to see that what happens, we are missing a cipher letter decryption.
Let's remove the solution of the cipher.
Letters emanates from the intersected mappings by using some instructions like we are seeing C intersected
mapping
one at the index M we are making is equal to blank.
Also intercepted mapping one index is also we are making it like.
And then again, we try to do it something like a simple sub Hadco, but we call this again decrypt
with this the text and intercepted mapping one so that this copied all the text here again.
So now you can see you're going to try to decrypt the cipher little with this you're getting there.
But somewhere on the school site on this part, the part of ciphertext wasn't decrypted.
Cipher letters without a decryption letter was replaced with that.
And so this is rather short ciphertext to hack normally encrypted messages.
Much would be much more longer.
So to hack Longmate encryption, you will need to create a cipher letter mapping for each cipher word
in the longer message and then intercept them altogether.
So the hacks and bizarre function calls the other functions are not programmed to do this exactly the
way as we have done it over here.
So with this, let us go to our program and the last part in our program after this Descriptivist Cipher
letter mappings is we are calling the main function to run the program if it's being run directly instead
of being imported as a module by another Python program.
So with this, we have completed our discussion of all the functions that this simple subcortical one
program uses is now.
From this, we must have understood that this is fairly complicated the way we have trying to hack or
substitution Saiful.
OK, you have also learned how to use a cipher letter mapping to model the possible decryption letters
for E ciphertext letters.
You also learn how to narrow down the number of possible keys by adding some potential letters to the
mappings, intercepting them and removing the sort of letters from other list of potential decryption
letters.
So the main advantage of a simple substitution cipher is it's a large number of possibilities.
The disadvantage is that it's relatively easy to compare cipher votes towards a dictionary file to determine
which side Four-Letter decrypt to which letter.
Now, now, in the next session, we would explore a more powerful alphabetic substitution cipher,
which is called less Virginia's Saiful, which was considered impossible to break for several hundred
years.
So that's it from this particular session.
Hope you have understood the program that we have done because there are many programs intersected with
each other for execution of one program.
So all of them you would find it illegal or just some hands on experience on them.
So that makes the concepts very much clearer if you practically do those things.
So we will see in the next session programming the Virginia cipher.
That's it from this session.
Thank you very much.