1 00:00:00,210 --> 00:00:04,140 Let us get started with the fundamentals of cryptography. 2 00:00:04,710 --> 00:00:09,780 Now, why do we use cryptography before we answer that question? 3 00:00:10,260 --> 00:00:13,160 Cryptography goes way back into the history. 4 00:00:13,470 --> 00:00:20,820 Basically, cryptography was used to deliver messages during wartime and battles. 5 00:00:21,630 --> 00:00:28,770 So when cryptography was basically used to deliver the message from a king to the army so that the enemy 6 00:00:28,770 --> 00:00:31,670 wouldn't understand what exactly they're trying to tell. 7 00:00:31,680 --> 00:00:34,350 And it goes way back to German. 8 00:00:34,420 --> 00:00:42,420 I'm sorry, it could be back to Greek and Roman period where Caesar cyphers and streamside for substitution 9 00:00:42,420 --> 00:00:44,610 ciphers were basically used. 10 00:00:45,270 --> 00:00:53,430 Apart from that, modern topography got a great boom in the in the 20th century or in the late 19th 11 00:00:53,430 --> 00:00:54,000 century. 12 00:00:54,390 --> 00:01:04,890 So if you've seen a movie, The Imitation Game of, uh, in which depicts the use of cryptography of 13 00:01:05,010 --> 00:01:06,330 Benedict Cumberbatch. 14 00:01:06,330 --> 00:01:10,950 So he has played the role of Alan Turing really well. 15 00:01:10,950 --> 00:01:16,800 And I must say that if you have interest in cryptography, you must go and watch that movie because 16 00:01:16,800 --> 00:01:26,370 it explains everything, how his team was able to break the Enigma machine of Germans and which successfully 17 00:01:26,370 --> 00:01:31,020 led the attack of Normandy and how England won the war. 18 00:01:31,890 --> 00:01:41,670 Apart from that, cryptography is basically nothing but conversion of a regular plain data into a complex 19 00:01:41,670 --> 00:01:46,740 series of random alphabets or whatever you pass into the algorithm. 20 00:01:47,970 --> 00:01:50,310 Output is a gibberish text. 21 00:01:50,310 --> 00:01:52,640 You don't understand what exactly is the output? 22 00:01:53,220 --> 00:02:01,070 And there are many algorithms used to do exactly the output to give the output. 23 00:02:01,980 --> 00:02:07,790 Again, cryptography is used to prevent the confidentiality and integrity of data. 24 00:02:08,250 --> 00:02:14,340 We have already seen the elements of information security in the introduction part of this course. 25 00:02:14,880 --> 00:02:16,710 So what is confidentiality? 26 00:02:16,830 --> 00:02:23,700 Basically, confidentiality is to avoid unauthorized access to the information which is supposed to 27 00:02:23,700 --> 00:02:25,500 be known for only authorised people. 28 00:02:25,830 --> 00:02:29,620 And integrity is maintaining the state of data. 29 00:02:30,330 --> 00:02:34,950 So to have to achieve all these objectives, we need to keep data secure. 30 00:02:34,980 --> 00:02:40,580 And how do we keep data secure by basically using cryptography? 31 00:02:40,590 --> 00:02:44,100 So that is the main reason we use cryptography. 32 00:02:45,270 --> 00:02:48,230 And cryptography has become very common these days. 33 00:02:48,240 --> 00:02:54,810 These transactions, you know, that happen through the Internet are all encrypted or whatever you send 34 00:02:54,810 --> 00:03:01,670 through emails is also encrypted and then decrypted at the receivers end in order to maintain the confidentiality. 35 00:03:01,680 --> 00:03:07,830 So almost everything, everywhere cryptography is used and it is very common. 36 00:03:07,830 --> 00:03:12,490 And hence that is why it is very important to understand cryptography. 37 00:03:13,350 --> 00:03:19,260 Now, as I told you in the last lecture, what most of the people do is to directly dive into the mathematical 38 00:03:19,890 --> 00:03:21,510 formulations of cryptography. 39 00:03:21,540 --> 00:03:24,950 Well, if you are really an expert, you can do that. 40 00:03:25,290 --> 00:03:32,610 But what I suggest to you is you first understand what cryptography is and then you may try to learn 41 00:03:32,610 --> 00:03:34,350 the mathematical point of view. 42 00:03:36,130 --> 00:03:43,990 So cryptography, as I said, is very important for data privacy nowadays, we all know how important 43 00:03:43,990 --> 00:03:45,290 data is to you. 44 00:03:45,760 --> 00:03:52,330 That is why if you want to maintain a data privacy, you have to have cryptography in place. 45 00:03:53,020 --> 00:03:57,030 Now, I'm not saying cryptography is the only solution to prevent data. 46 00:03:57,670 --> 00:04:00,460 It can lead to privacy of data. 47 00:04:00,460 --> 00:04:07,450 And that is why when it comes to ISO twenty seven thousand one, that is information security management 48 00:04:07,450 --> 00:04:15,280 systems, they do have cryptographic controls in place in order to check whether the organization is 49 00:04:15,280 --> 00:04:20,350 following those controls while maintaining the integrity of information systems. 50 00:04:21,070 --> 00:04:21,610 All right. 51 00:04:22,030 --> 00:04:29,850 So let us not let us have a look at the elements that helps us to achieve during cryptography. 52 00:04:29,860 --> 00:04:35,020 So basically, cryptography helps in maintaining the information confidential. 53 00:04:35,560 --> 00:04:40,150 It also helps to avoid any unnecessary edits to the data. 54 00:04:40,150 --> 00:04:47,230 And hence it is in keeping the data integrity using cryptography. 55 00:04:47,710 --> 00:04:54,160 You can also achieve availability of data so that if data is secure, it can be available to you when 56 00:04:54,160 --> 00:04:55,960 and wherever it is needed. 57 00:04:57,640 --> 00:05:02,290 We can also maintain the authenticity of people using cryptography. 58 00:05:02,770 --> 00:05:09,650 We have already discussed about authentication and access control previously in this code. 59 00:05:09,670 --> 00:05:14,860 So if you want to know more about that, I suggest you to go back to that section. 60 00:05:15,580 --> 00:05:16,080 All right. 61 00:05:16,480 --> 00:05:23,120 So, yes, authenticity, validating the user's identity, using cryptography is also very common. 62 00:05:24,250 --> 00:05:27,160 I hope you've understood why we need cryptography. 63 00:05:27,160 --> 00:05:29,260 Basically keep these elements in mind. 64 00:05:29,620 --> 00:05:36,460 So if anyone asks you the main reason behind using cryptography, you just have to answer these three 65 00:05:36,460 --> 00:05:36,970 points. 66 00:05:36,970 --> 00:05:45,220 Cryptography helps in achieving confidentiality, integrity and availability of information security. 67 00:05:45,250 --> 00:05:49,130 And you'll get full marks, OK, in the next lecture. 68 00:05:49,150 --> 00:05:56,210 What we'll do is we'll start with these two types of cryptography, which are of very common. 69 00:05:56,280 --> 00:05:58,430 Again, there are many types. 70 00:05:58,450 --> 00:06:05,620 OK, I'm repeating this word course is not for those people who want to master cryptography. 71 00:06:05,630 --> 00:06:06,100 All right. 72 00:06:06,100 --> 00:06:11,140 Because it would take a lot of time to have a course on cryptography. 73 00:06:11,170 --> 00:06:18,070 We are just going to go through fundamentals so that we will understand cryptography really well, because 74 00:06:18,070 --> 00:06:24,000 it is more important for you to understand cryptography than to have complete knowledge. 75 00:06:25,240 --> 00:06:29,050 So in the next lecture, we will talk about these two types of cryptography. 76 00:06:29,350 --> 00:06:36,460 And I'm pretty sure that my explanation will make it really easy for you to, you know, keep those 77 00:06:36,460 --> 00:06:39,040 concepts in your in your mind. 78 00:06:39,040 --> 00:06:41,990 It will really help you to clear the things. 79 00:06:42,340 --> 00:06:42,940 All right. 80 00:06:43,450 --> 00:06:46,830 Keep this momentum going and doing a great job here. 81 00:06:46,840 --> 00:06:49,600 You have almost completed the course now. 82 00:06:49,600 --> 00:06:55,930 It's just some sort of lectures which are remaining will soon get done with the entire course. 83 00:06:56,230 --> 00:06:58,980 I will see you in the next lecture.