1
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By the time the for loop is done, looping the ciphertext is variable will contain the complete string

2
00:00:06,180 --> 00:00:08,010
of encrypted message.

3
00:00:08,160 --> 00:00:13,740
So on each iteration of the loop symbols, variable is assigned a single character from the message

4
00:00:13,800 --> 00:00:14,240
Istria.

5
00:00:14,490 --> 00:00:21,060
If this character exists in Symbolistic, which is our symbol, set the index and symbols Izturis is

6
00:00:21,420 --> 00:00:28,860
and assigned to the symbol next on the next line over here where we are checking that that to encrypt

7
00:00:28,860 --> 00:00:37,430
the text, we need to calculate the index of the encrypted letter so we'll see the symbol index by key

8
00:00:37,590 --> 00:00:38,060
A1.

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And if we add it to be able to produce the given output and then it more to the result by the size of

10
00:00:48,000 --> 00:00:52,140
your symbols that represented by expression length in brackets.

11
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Symbolistic know modding by Lance Embellisher handles the wraparound by ensuring the calculated index

12
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is always between zero and up to, but not including the length of symbolistic.

13
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So the resulting number will be indexed in the simplicity of the encrypted character would just concatenate

14
00:01:10,650 --> 00:01:13,090
them to the end of the string in your ciphertext.

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Hestia.

16
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So everything in the previous that we have seen is done using a single line of code over here Modeselektor.

17
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So if your symbol isn't an obvious implicit symbol is concatenated to the end of the ciphertext or what

18
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else, the quotation marks on the hyphen in the original message are not in the symbols set and therefore

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they are concatenated directly to the string.

20
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So after this code is iterate through each character in the message string ciphertext, Astarita should

21
00:01:43,440 --> 00:01:51,530
contain the full encrypted string which returns encrypted string from the particular function that this

22
00:01:51,780 --> 00:01:52,770
encrypt messages.

23
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So now let us understand writing the decryption function.

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So here we have returned this value for the encrypt messages.

25
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OK, now you're the decrypt message start function that the crypto text is almost the same as our encrypt

26
00:02:08,250 --> 00:02:08,690
messages.

27
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So here we have this keys.

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We check the key estar, we create a plain text and here we are using the crypto one for finding the

29
00:02:18,940 --> 00:02:19,740
more involved.

30
00:02:19,830 --> 00:02:27,930
OK, so instead of multiplying by even the decryption process multiplies by the modular inverse of the

31
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more inverse is calculated by calling the crypto math one don't find more inverse, which we have already

32
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seen in the earlier session.

33
00:02:35,460 --> 00:02:42,210
Now after this, if you see the for loop, this is almost identical to the message is still the only

34
00:02:42,210 --> 00:02:48,600
difference comes over here when in the encrypt message, the symbol index was multiplied by one and

35
00:02:48,600 --> 00:02:55,590
then he even was added to it in the decrypt message function, the symbol index post, subtract the

36
00:02:56,070 --> 00:02:57,330
key one over here.

37
00:02:57,630 --> 00:03:04,110
And so subtracting after the key, even from the simple index, and then it multiplies it by remodeler

38
00:03:04,110 --> 00:03:10,240
and then add more to this number the size of your symbols, and that is the length of your symbolistic.

39
00:03:10,800 --> 00:03:14,550
Now this is how the decryption process undoes the encryption.

40
00:03:14,910 --> 00:03:21,960
Now let us look at how we can change it so it can randomly select the valid keys for a fine Saiful So

41
00:03:21,960 --> 00:03:24,690
we move on to generating the random keys.

42
00:03:25,260 --> 00:03:31,910
Now if you look at over here in your program, we have this get random ATSDR.

43
00:03:32,400 --> 00:03:38,790
Now it can be difficult to come up with a valid GUI for a fine cipher so you can instead use the get

44
00:03:38,790 --> 00:03:46,770
random estar function to generate a random butta wanted to do this, simply change that to this particular

45
00:03:46,770 --> 00:03:54,270
lake here we are seeing now if we just go about we are giving here see the value of my guest out here

46
00:03:54,540 --> 00:03:59,370
now instead of giving a key value here, we can see all this get.

47
00:04:00,630 --> 00:04:13,380
Now, how have you define this, get random to give this and also we are giving here 60 percent is and

48
00:04:13,380 --> 00:04:16,920
we are presenting the value in the mixture.

49
00:04:17,160 --> 00:04:22,980
So now the program randomly selects and printed to the screen when it executes.

50
00:04:23,010 --> 00:04:25,590
Now, let us look at how they get random function.

51
00:04:25,590 --> 00:04:29,170
VOKES So let us go below and compare this function here.

52
00:04:29,460 --> 00:04:36,280
We have entered a loop in this very condition is through this infinite loop will loop forever until

53
00:04:36,280 --> 00:04:39,900
it is told to return to the user terminates the program.

54
00:04:40,170 --> 00:04:45,600
Now, if your program gets stuck in an infinite loop, you can dominate the program by placing controls

55
00:04:46,350 --> 00:04:47,330
on windows.

56
00:04:47,340 --> 00:04:53,970
OK, so get the random can function will eventually exit the infinite loop with the written statement.

57
00:04:54,330 --> 00:05:01,000
Now here we are determining the random numbers between two and the size of the symbols set for each

58
00:05:01,030 --> 00:05:02,640
event and V1.

59
00:05:02,970 --> 00:05:09,670
Now this code ensures that there is no chance that even a B one will be equal to the invalid value zero

60
00:05:09,670 --> 00:05:10,080
or one.

61
00:05:10,530 --> 00:05:18,660
The if statement checks over here that we have given it checks to make sure that the key is relatively

62
00:05:18,660 --> 00:05:25,170
primed with the size of the symbols set by calling the GCD function in the Cryptome at one module if

63
00:05:25,220 --> 00:05:32,040
given is relatively with the size of superset, then these two randomly selected keys are combined into

64
00:05:32,040 --> 00:05:38,490
a single schema multiplying given by the same size and adding we want to the product over here.

65
00:05:39,060 --> 00:05:45,000
Now this particular line that is a written statement, it basically returns the value from the get random

66
00:05:45,240 --> 00:05:46,260
astar function.

67
00:05:46,680 --> 00:05:53,010
Now, if the conditioned response was the old loops back to the start of the pilot and picks a random

68
00:05:53,010 --> 00:05:59,190
number for each one, and we want to give infinite loop, and that program continues looping until it

69
00:05:59,190 --> 00:06:02,250
finds random numbers that are also valid.

70
00:06:02,850 --> 00:06:09,060
Now, after that, the next thing that we have is just the similar one, which is calling the main function

71
00:06:09,060 --> 00:06:13,260
of this program was run by itself rather than being imported by another program.

72
00:06:13,680 --> 00:06:19,380
So this ensures that the main function runs when the program is running, but not when the program is

73
00:06:19,380 --> 00:06:20,550
important as a module.

74
00:06:20,880 --> 00:06:24,630
So now if we try to execute this.

75
00:06:26,150 --> 00:06:33,800
Now, we have done this for decrypting let us go back for encryption, so now we have used see the keys

76
00:06:34,160 --> 00:06:37,590
to seven to three in this case and the decrypted extras over here.

77
00:06:37,880 --> 00:06:43,940
So let's go back here and let's write down all proper text.

78
00:06:44,420 --> 00:06:45,950
Let's let this.

79
00:06:47,590 --> 00:06:49,840
And right down here.

80
00:06:50,440 --> 00:07:08,830
So this is and simple program for a fine Saiful encryption of the text, you will see the

81
00:07:11,800 --> 00:07:12,580
output.

82
00:07:15,850 --> 00:07:29,140
Shortly after executing Let's save this and we will change this to and let us run this.

83
00:07:30,040 --> 00:07:37,210
So now what gate has used for three three three is the Valerica, which it has used for encrypting this

84
00:07:37,210 --> 00:07:38,410
particular message.

85
00:07:38,740 --> 00:07:40,950
So with this, we have completed the spot.

86
00:07:40,960 --> 00:07:46,210
Now we will move on to the next session where we will see hacking this afine Saiful.