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The ciphertext consists of the letters read from the top left box going down the column from the first

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column as well in the particular sheet that we have created.

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So how basically the code would be written now is it'll will start reading from top to bottom.

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So over here, say, for example, be a O.

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S next will be by see you as Sidiki are a h i s g then o n e n g.

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Now that symbol there and the dot.

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So this is all basically it is going to end.

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Now let us see this.

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We are related that not creating the particular encryption program here now to make the program for

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encrypting, you will need to translate this paper and pencil that we have done right now in the manual

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one into a python code.

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So now let's look again how to encrypt the string that we have using the key H to Python or characters

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position inside a particular string is it's no index.

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So we'll add an index as each letter in the particular string in its numbered index.

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So add the index for each letter in the string to the boxes in the original encrypting diagram.

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Now, for example, we would start over here and let's add here the index starting from say zero, then

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say one, two, three, four.

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So on in the last one.

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OK, so we would be adding the seven we have added.

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Similarly, we will do it for all of so we it will be from eight to 15, then 16 to twenty three and

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twenty nine because of this from starting from zero onwards.

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So just let's keep on writing the index values there that's done.

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10 15 move to the next one, say 18, 19.

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20, 21, 22, 20, three, four, five, six, twenty seven, twenty eight, and the last one.

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Twenty nine.

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So we have added the index to the each of these boxes.

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So these boxes show the first column which has the characters, which will be like zero eight, 16,

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20, for which the characters are capital P A or is the next column will have the characters on indexes.

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That is one nine seventeen twenty five which are Sivi c u.

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S.

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I notice the pattern emerging that the end column has all the characters in the particular string at

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index zero plus and minus one eight plus and minus one sixteen plus and minus one and twenty four plus

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and minus one.

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For example, if we write down something like over here, so zero plus zero equals to zero.

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Similarly seven plus zero equals two, one or two plus zero equals two.

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To similarly say three plus zero equals two three, four plus zero equals two four five plus zero equals

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two five six plus zero equals two six seven plus zero equals two seven.

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But when we come over here, say eight here also we C plus.

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So you will see eight plus zero.

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That's equal to eight.

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Now here we will add one to it and we would make it all rather we would make it something like, say,

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one plus eight.

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That's equal to nine.

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So we're going to take your one for substituting.

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So here again, we will see two plus eight.

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That's equal to in here.

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We will take, say, three plus eight.

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That's equal to eleven here.

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We would take four plus eight.

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That's equal to twelve.

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Similarly, five plus eight.

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That's equal to thirteen C six plus eight.

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That's equal to fourteen.

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And finally the seven plus eight, that's equal to fifty.

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But when we come over here, we again substitute zero plus sixteen.

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That's equal to sixteen.

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But over here.

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Let's make it one plus 16, that's equal to 17.

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Now we'll have to just decrease the size of it here.

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We would say to plus 16, that's equal to 80, then three plus 16, substitute for plus 16.

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It would be five plus 16.

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Then it would be six plus 16 and finally it would be seven plus 16.

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When we come down to the last row, we would make again zero plus twenty four equals twenty four.

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But over here we would substitute seven plus twenty four equals twenty five.

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Similarly say two plus twenty four, then say three plus twenty four and similarly four plus twenty

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four finally will make it this five plus twenty four.

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Now, in this way, we are going to get the index of each box, which will follow the predictable pattern.

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Now, there will be an exception for the last rule in the seventh and the eighth column, because when

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you see twenty four, that is seven minus one and twenty four plus eight minus one would be greater

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than twenty nine, which is the largest index in the string.

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Now in those cases you will have to only add zero eight 16 and in that is the scapegoat for that.

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So what's so special about the numbers.

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Zero eight sixteen twenty four in this case that these numbers you when you start from zero, you are

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the key.

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That is eight over here.

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So zero plus eight is what you get there.

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Similarly then you add eight plus eight, you get the 16.

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When you add 16 plus eight, you get the twenty fourth.

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Hence we are getting the first and zero then added to it, added to it and again added it as the key

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to it.

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So hence the result is coming like this.

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Fine.

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00:07:02,350 --> 00:07:08,410
Now the last one, when you say twenty four plus eight, it would be 32, but 32 is larger than the

84
00:07:08,410 --> 00:07:09,370
length of the message.

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So you will stop at twenty four there and for the end column strength starting at the index and continue

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00:07:16,600 --> 00:07:18,680
adding the eight to get the next index.

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Keep adding it as long as the index is less than the length of the message, that is less than 30 at

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which point move to the next column.

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00:07:27,190 --> 00:07:33,520
So if we can imagine each column in a particular string, the result will be the list of the eight string

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that we will be getting.

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For example, in the first one you would be getting the string as B A whole is then you would be getting

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00:07:42,050 --> 00:07:45,760
I see you as then city.

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00:07:46,120 --> 00:08:00,760
They are a then say h l s g c o n e then say n g the particular symbol and let's cooperate on the symbol

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00:08:00,760 --> 00:08:01,090
here.

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Similarly, here again, let's go on the same symbol

96
00:08:13,360 --> 00:08:19,740
two times, then you will have him and similarly here you would have the edge see E!

97
00:08:20,230 --> 00:08:23,820
So something like this is what basically we would be encrypting there.

98
00:08:24,040 --> 00:08:25,760
So now let's have a look.

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00:08:25,870 --> 00:08:28,860
And we would create a particular program for the same one.

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00:08:29,020 --> 00:08:33,130
And let's see if we get the similar output that we have created over here manually.

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00:08:33,940 --> 00:08:38,490
So now we would go for the source code for transposition cipher encryption program.

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00:08:39,370 --> 00:08:41,540
So we have come to the python environment.

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Now, let's create a new file here.

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00:08:43,750 --> 00:08:54,590
And we would start by forcing Emboli Paperclip, after which we would define the mean here.

105
00:08:55,010 --> 00:09:00,220
We want to define see my messages, dear.

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00:09:00,670 --> 00:09:04,570
Now, that's equal to the same string that we have taken, say, Biton.

107
00:09:07,120 --> 00:09:17,710
Hacking calls, message written, but also then we define here, say, my keister, and that's equal

108
00:09:17,710 --> 00:09:22,270
to eight as we have taken in the manual, one also that we should get the same output there.

109
00:09:22,510 --> 00:09:28,360
Then we would have the ciphertext Nestea and that's equal to now.

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00:09:28,370 --> 00:09:33,760
Here we are going to call it encrypt message SDR.

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00:09:34,060 --> 00:09:41,400
Which will he or we would be passing Mike ETR and my message STF.

112
00:09:41,980 --> 00:09:53,920
So after this we would see a print command and we would give you plenty cipher text to start with in

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00:09:53,920 --> 00:09:57,610
that concatenate or pipeline symbol.

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00:09:58,920 --> 00:10:05,460
And after that, we would copy encrypted text to the ciphertext clipboard, so we would say, here,

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use the paperclip dot copy method and see cipher text Steyr.