If you tried to entrap this with a nine letter and or three letter now everywhere, if let's take the
first one that is your nine letter, which is the A, B, C, D, E, F, g, h.
I again, repeat a, b, c, d, e, f.
And if we take another letter, another that is X, Y, Z, say again, x, y, z, x, y, z, x,
y, z and X, Y, Z.
OK, so now here's the first one for the on line letter.
You would have the ciphertext, something like c d i g g.
S l do l.
D I, f or G, then f e white, and similarly for this three little, you would have cicu f the a m
Airfix.
And que F.P., then Z Y.
And this would be your encrypted give it said now the dorkiest produced or different ciphertext are
expected and of course the hacker will know the original message or the key, but they will see that
over here you have this, the IG, which is repeating over here and the IG over here is repeating and
it appears at index zero and index nine.
So because mine minus zero is nine, the spacing between the sequence is nine, which would seem to
indicate that the original Q was a nine letter.
So in this case, the indication is correct.
However, if you look at this, you have the skew if the here and the Q FBO.
Now, if we even highlight this, it also produces the same repeat sequence that appeals at the next
zero on an index knife, but the spacing between this sequence is also nine, indicating the Gilston
used this civil ciphertext was also a nine letter kilo.
But we know that the key is only three letters, long averages X, Y, Z.
So the repeated sequence of calls with the same letters in the message that is the example are encrypted
with the same letter of key that is A.B.C. X, Y, Z, which happens when these similar letters in the
message and the key line up and trip to the same sequence.
Now this alignment can happen at any multiple of the real key length, like three, six, nine, 12
four, which is why all three letters can produce all the sequence with the spacing of nine.
So the possible length is due to is due not just spacing, but any factor to that spacing.
So the fact those of a nine on line three and one, therefore, if you find that it predicts the spacing
of nine, you must consider that the key would be of either nine or three beginning Morvan one because
we Ganassi with one little piece.
Justices' insightful.
Not the key is most likely to be most frequently occurring factors Nuvigil can determine by counting
the cost eight into the most frequently occurring factors of the spacing.
They are the most likely length of the beginning.
Now, moving ahead, we come to getting every end letters from a particular string.
Now that we have the possible keys of the beginner key, we can use this information to decrypt the
message one step at a time.
For example, let's assume the key is the silent phone and we are unable to crack the ciphertext.
We can try again assuming the Kelland is too late because the key is cycle through.
To encrypt the plaintext equivalent of four would mean that the starting from first letter, every fourth
letter in the ciphertext is encrypted.
Using the first subcu.
Every four letters, starting from the second letter of the plain text is encrypted using the second
answer.
So using this information, we will form a string from the ciphertext of the letters that have been
encrypted by the same subject.
So first, let us identify what every fourth letter in the string would be if we started from different
letters.
So then basically we combine all the letters endorsing the string.
It will reveal every fourth.
So as we have taken this particular key.
So if we have to identify every fourth letter selected, this is the first one, then your fourth letter
is this similarly, then we come to the next fourth letter.
Let's come to the next fourth letter here.
Then again, you have the E.
You have C v.
Similar to this, something like, again, then you have an.
Then you have said.
See, I after all you have are then you have each.
After which you are having sex again, then sick, then you have the X, this is the second one and
then you have the X.
Then you have a note also again in here, also similarly here also you have seen the then you have your
key.
See, I am the last one that see you.
Now, let us highlight this and let's make a difference.
Let's make it bold enough.
So this is all we have highlighted.
So next, we can find out every little, starting with the second little icon, like we have done the
same one.
So again, then you will have this one one letter just besides the one which we have selected now.
So in this way, we can find out the letters there.
That is the first letter we have the second letter.
We have the third letter.
We have a default letter we have now.
After this, we will go ahead and understand the next concept and this that is using the frequency analysis
to break it up.
Now, if it gets the correct length length, each of the four strings we created in the previous position
over here would have been encrypted with one subcu.
So this means that when a string is decrypted with the correct safety and undergoes a frequency analysis,
decrypted letters are likely to have a high English frequency med school.
So using that, we can again create another example like us, which produces decryption with the closest
frequency matched to English, are most likely to be the real suffix.
Like, for example, I n.w. an X result in the highest frequency school for the fourth string.
So note that these scores are low in general because this isn't enough ciphertext to give us a large
sample of text, but they will or they work well enough for this particular example here.
So the next step is to repeat this process for other three strings to find out their most likely suffixes.
Now, because there are five possible subpoenas for the fall, subject to 40 seconds and one for the
third one and five for the fourth one, total number of combinations becomes 50.
So in other words, we need to brute force 50 possibilities.
But this is much better than brute force and true somewhere around four.
Fifty six or nine sixty seven possible.
So now our task has now not narrowed down a list of possible subjects.
So this difference becomes even greater if the beginning is longer.
So now we will go ahead for writing down a source code for beginner hacking program.
So we'll create it in a new file editor and create a new file.
And don't forget to keep your check English, your frequency analysis demo, your beginning for demo.
And if I put files in the same direction, I want to see the current file and then you will execute
and understand what I was trying to created from this.
So in the next session we would start creating with the Code of Virginia Hackel.
That is second example, how to hack Virginia's for using this particular concept that we have done
manually.
Now we would implement the same thing into other python hacking.
That's it from the session.
Thank you very much.