1
00:00:00,180 --> 00:00:07,290
The next thing is the frequency per variable is now a list of Cuba's audio from the most frequent to

2
00:00:07,290 --> 00:00:13,170
the least frequent letters, the first volume in each duopolies, an individual presenting the frequency

3
00:00:13,170 --> 00:00:18,550
count, and the second value is a string containing the letters associated with that frequency.

4
00:00:19,230 --> 00:00:26,040
Now, coming to creating a list of sorted letters, the last step of the get frequency order function

5
00:00:26,040 --> 00:00:30,740
is to create a list of all the strings from the sorted list in the frequency pit.

6
00:00:30,900 --> 00:00:36,960
So we want to end up with a single string values whose letters are in the order of the frequency.

7
00:00:37,200 --> 00:00:43,230
So we don't need the integer values in the frequency, but the variable over here, that is the frequency

8
00:00:43,230 --> 00:00:50,460
or the list starts as a blank list and the default on the next line up against the string at the index,

9
00:00:50,460 --> 00:00:55,740
one of each tuple in the frequency pegged to the end of frequency or the list.

10
00:00:56,100 --> 00:01:03,960
Now, over here, if we move on to the next block, that is calculating the frequency match score of

11
00:01:03,960 --> 00:01:04,850
the message.

12
00:01:05,100 --> 00:01:11,220
So after returning this, we come over here for defining the English frequency match score function,

13
00:01:11,430 --> 00:01:19,170
which takes a string of message and then returns an integer between zero and 12 representing the strings

14
00:01:19,440 --> 00:01:20,770
frequency school.

15
00:01:21,090 --> 00:01:27,630
The higher the score, the more closely the little frequency and message SDR matches the frequency of

16
00:01:27,630 --> 00:01:28,800
normal English text.

17
00:01:29,040 --> 00:01:35,760
So the first step in calculating the frequency Mascord is to get the letter frequency ordering of message

18
00:01:36,120 --> 00:01:39,160
by calling here, get frequency auto function.

19
00:01:39,480 --> 00:01:44,950
OK, then restore the ordered string in the variable called frequency Oresteia.

20
00:01:45,960 --> 00:01:55,050
Then we have the matched score SDR variable that starts at a zero and is incremented by the for loop

21
00:01:55,050 --> 00:02:02,910
beginning on the next line, which compares the first six letters of the OR in string and the first

22
00:02:02,910 --> 00:02:05,080
six letters of the frequency order.

23
00:02:05,130 --> 00:02:09,470
Oresteia giving a point for each letter they have in common.

24
00:02:09,870 --> 00:02:12,450
OK, so that is what we are doing over here.

25
00:02:12,750 --> 00:02:18,570
They might go to zero zero for common to start in line before six letters.

26
00:02:18,900 --> 00:02:24,210
If the common letter is in the frequency order this year, the first six letters incrementing.

27
00:02:24,720 --> 00:02:30,560
Now if you just recall, the colon six is the same as zero colon six.

28
00:02:30,990 --> 00:02:38,220
So the full six letters from it and the frequency of the strings represent respectively, if any of

29
00:02:38,430 --> 00:02:40,020
those that edit or I.

30
00:02:40,030 --> 00:02:45,930
N is also in the four six letters of frequency or the string, the condition on this particular line

31
00:02:45,930 --> 00:02:49,350
will come through and increment them at school.

32
00:02:49,710 --> 00:02:55,980
Similarly, the next lines over here, except in this case that check for the last six letters from

33
00:02:55,980 --> 00:03:03,590
the on string, that is the weak excuse it are in the last six letters of the frequency of Aristos.

34
00:03:04,080 --> 00:03:08,360
And if that was so much, then again your incrementing the value of Metzker.

35
00:03:08,670 --> 00:03:12,090
OK then finally you're returning the value of Matsuko variable.

36
00:03:12,330 --> 00:03:18,090
So we ignore the 14 letters in the middle of frequency order when calculating the frequency.

37
00:03:18,090 --> 00:03:24,680
Matsuko frequency of these letters are too similar to each other to give some meaningful information.

38
00:03:25,170 --> 00:03:29,250
So likewise we have returned the value of Matsuko to start over here.

39
00:03:29,400 --> 00:03:36,630
And in this session we have also learned how to use this function to short list values in alphabetical

40
00:03:36,630 --> 00:03:40,140
order, numerical order and how to use the rebels.

41
00:03:40,140 --> 00:03:45,690
And the key of the key argument to start with the list values in different ways.

42
00:03:45,990 --> 00:03:53,280
We have also learned how to convert the dictionary to list using the keys, values and items, dictionary

43
00:03:53,280 --> 00:03:53,850
methods.

44
00:03:54,450 --> 00:04:00,220
We have also learned that you can pass functions as values in the function codes.

45
00:04:00,570 --> 00:04:07,800
OK, now in the next session we will be using this frequency analysis module and we will write in this

46
00:04:07,830 --> 00:04:11,820
session to have the whole Viginia, for example.

47
00:04:12,330 --> 00:04:18,900
So the next session that will be basically for over hacking the beginning and just will give you a reference

48
00:04:18,900 --> 00:04:21,220
of how can you have the original Saiful?

49
00:04:21,400 --> 00:04:25,440
Another or two methods exist to have the Virginia safe.

50
00:04:25,770 --> 00:04:33,180
One method uses the brute force dictionary attack to try every word in a dictionary file as a beginner,

51
00:04:33,870 --> 00:04:41,160
which works only if the key is an English word, such as something like that one or this the second

52
00:04:41,160 --> 00:04:47,850
or the more sophisticated method which was used by the nineteenth century mathematician Charles Babbage.

53
00:04:48,120 --> 00:04:48,660
Volks.

54
00:04:48,660 --> 00:04:57,300
Even when the key is a random group of letters, something life like the v u w if or be in a V or something

55
00:04:57,300 --> 00:04:57,740
like this.

56
00:04:58,080 --> 00:04:59,880
So in the next session we would.

57
00:04:59,970 --> 00:05:06,660
I don't program, which will be phone hacking, the Virginia Saiful using both the methods that we have

58
00:05:06,690 --> 00:05:07,320
discussed.

59
00:05:07,530 --> 00:05:09,620
One is the brute force dictionary attack.

60
00:05:09,840 --> 00:05:17,310
Second is no sophisticated method which was developed in 19th century mathematician that this Charles

61
00:05:17,310 --> 00:05:24,190
Babbage also with with all these topics, we will also be covering the dictionary attacks, the because

62
00:05:24,210 --> 00:05:31,800
that is an examination, the calculating factor, also how to set data types and dissect functions and

63
00:05:32,040 --> 00:05:34,430
how to use the extent to list methods.

64
00:05:34,680 --> 00:05:37,980
Also the item to store product functions.

65
00:05:38,220 --> 00:05:44,590
All this we would be covering in our hacking cipher session, which would be covered in the next session.

66
00:05:44,730 --> 00:05:46,760
That's it from the session here.

67
00:05:46,770 --> 00:05:54,390
We have seen how to create a frequency analysis for some most frequently used letters and frequently

68
00:05:54,390 --> 00:05:55,110
used letters.

69
00:05:55,440 --> 00:05:58,530
And using the same technique, we would move on with the next session.

70
00:05:58,570 --> 00:06:00,420
Now, that's it from the session.

71
00:06:00,450 --> 00:06:01,380
Thank you very much.