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07 - Cryptography/008 Asymmetric Encryption OB 1.4_en.srt

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+1
+00:00:00,000 --> 00:00:00,000
+Okay.
+
+2
+00:00:00,000 --> 00:00:02,000
+So we just covered symmetric encryption.
+
+3
+00:00:02,000 --> 00:00:08,000
+And if you remember correctly the key to choosing to encrypt is the same key that's used to decrypt.
+
+4
+00:00:08,000 --> 00:00:13,000
+When in this video I want to take a deep dive into the concepts of asymmetric cryptography.
+
+5
+00:00:13,000 --> 00:00:19,000
+Now I briefly mentioned that asymmetric and symmetric combines together in a hybrid cryptography system
+
+6
+00:00:19,000 --> 00:00:21,000
+to actually transport secure data.
+
+7
+00:00:21,000 --> 00:00:23,000
+So you actually.
+
+8
+00:00:24,000 --> 00:00:28,000
+Can't really do secure communication today technically without asymmetric.
+
+9
+00:00:28,000 --> 00:00:30,000
+So let's get a deep dive into it.
+
+10
+00:00:30,000 --> 00:00:32,000
+But what exactly is it you see?
+
+11
+00:00:32,000 --> 00:00:33,000
+Asymmetric encryption.
+
+12
+00:00:33,000 --> 00:00:34,000
+So the word symmetric means the same.
+
+13
+00:00:34,000 --> 00:00:36,000
+Asymmetric is going to mean different.
+
+14
+00:00:37,000 --> 00:00:38,000
+Is known.
+
+15
+00:00:38,000 --> 00:00:43,000
+First of all I want to mention is something we call public key cryptography.
+
+16
+00:00:43,000 --> 00:00:43,000
+All right.
+
+17
+00:00:43,000 --> 00:00:45,000
+Public key cryptography.
+
+18
+00:00:45,000 --> 00:00:50,000
+Now, keep in mind, if anybody ever says you read in any book, they say something like secret key
+
+19
+00:00:50,000 --> 00:00:53,000
+cryptography or private key cryptography.
+
+20
+00:00:53,000 --> 00:00:58,000
+That is symmetric public key cryptography is asymmetric.
+
+21
+00:00:59,000 --> 00:01:06,000
+This is a cryptographic system that uses pairs of keys, a public key which is given out widely, and
+
+22
+00:01:06,000 --> 00:01:08,000
+a private key which is only known to the users.
+
+23
+00:01:08,000 --> 00:01:13,000
+So everybody has two keys, a public key and a private key.
+
+24
+00:01:13,000 --> 00:01:17,000
+The public key encryption decrypts and it's given with anyone.
+
+25
+00:01:17,000 --> 00:01:20,000
+The private key can also encrypt and decrypt, and it's kept with the owner.
+
+26
+00:01:20,000 --> 00:01:21,000
+No one gets it.
+
+27
+00:01:21,000 --> 00:01:26,000
+Remember that everybody in the crypto system has two keys.
+
+28
+00:01:26,000 --> 00:01:32,000
+So for example, let's say I got me Mary and Bob.
+
+29
+00:01:32,000 --> 00:01:33,000
+Well easy.
+
+30
+00:01:33,000 --> 00:01:35,000
+I'm going to have a public private key.
+
+31
+00:01:35,000 --> 00:01:37,000
+Mary is going to have a public private key.
+
+32
+00:01:37,000 --> 00:01:42,000
+And Bob is going to have and Bob is going to have a public everybody has a public private key.
+
+33
+00:01:42,000 --> 00:01:46,000
+The way the encryption process works is different than symmetric and symmetric.
+
+34
+00:01:46,000 --> 00:01:50,000
+I generate the data, I generate the key I encrypted, give them the data, give them the key.
+
+35
+00:01:50,000 --> 00:01:51,000
+They use the key to decrypt the data.
+
+36
+00:01:51,000 --> 00:01:53,000
+This is going to work different.
+
+37
+00:01:53,000 --> 00:01:58,000
+And for that I want to I want to draw a little diagram here to get you guys an understanding of the
+
+38
+00:01:58,000 --> 00:02:00,000
+encryption and decryption process.
+
+39
+00:02:02,000 --> 00:02:05,000
+So let's go in here and let me just draw.
+
+40
+00:02:05,000 --> 00:02:07,000
+Let's say you have two users on a network.
+
+41
+00:02:07,000 --> 00:02:11,000
+There's Andrew and there's Mary.
+
+42
+00:02:11,000 --> 00:02:18,000
+Now the way the encryption process works here is that I'm going to have a public private Mary also has
+
+43
+00:02:18,000 --> 00:02:20,000
+a public private key.
+
+44
+00:02:20,000 --> 00:02:24,000
+But let's say I want to transfer data to Mary.
+
+45
+00:02:24,000 --> 00:02:26,000
+I want to give Mary the answers to the exam.
+
+46
+00:02:26,000 --> 00:02:27,000
+So.
+
+47
+00:02:28,000 --> 00:02:29,000
+How am I going to do it?
+
+48
+00:02:29,000 --> 00:02:31,000
+Well, I have data.
+
+49
+00:02:32,000 --> 00:02:34,000
+That I want to transfer to Mary.
+
+50
+00:02:34,000 --> 00:02:38,000
+What I'm going to do and says, hey, Mary, you you're free.
+
+51
+00:02:38,000 --> 00:02:41,000
+Okay, Mary, can you send me your public key?
+
+52
+00:02:41,000 --> 00:02:45,000
+Mary sends me her public key, and I encrypt the data with the public key.
+
+53
+00:02:45,000 --> 00:02:47,000
+And now I got cipher text.
+
+54
+00:02:47,000 --> 00:02:50,000
+I send it to Mary, a cipher text.
+
+55
+00:02:50,000 --> 00:02:57,000
+Mary then utilizes her private key to decrypt this data to get the plain text or the data.
+
+56
+00:02:58,000 --> 00:02:59,000
+So.
+
+57
+00:03:01,000 --> 00:03:02,000
+I put some lines here.
+
+58
+00:03:02,000 --> 00:03:07,000
+So that's the decryption process encryption and decryption process.
+
+59
+00:03:07,000 --> 00:03:12,000
+Now technically it doesn't actually work like this because we don't actually do this.
+
+60
+00:03:13,000 --> 00:03:15,000
+Uh, we use it in a hybrid method, but I'm going to cover that later.
+
+61
+00:03:15,000 --> 00:03:17,000
+But for now, just this is good enough.
+
+62
+00:03:18,000 --> 00:03:20,000
+Now I want to point out a couple of things here.
+
+63
+00:03:20,000 --> 00:03:23,000
+You notice that I never utilized any of my keys.
+
+64
+00:03:24,000 --> 00:03:26,000
+I utilize the person that was receiving the data keys.
+
+65
+00:03:26,000 --> 00:03:28,000
+I utilize their public key, right?
+
+66
+00:03:28,000 --> 00:03:29,000
+Did you see that?
+
+67
+00:03:29,000 --> 00:03:30,000
+Think about going to Amazon.
+
+68
+00:03:30,000 --> 00:03:33,000
+When you go to Amazon, you don't have any keys, but Amazon does.
+
+69
+00:03:34,000 --> 00:03:36,000
+Keep this in mind when I get to SSL.
+
+70
+00:03:36,000 --> 00:03:41,000
+So this is a really important system because there's a couple of things here I want to point out.
+
+71
+00:03:41,000 --> 00:03:46,000
+Notice the public key encrypted the data and a private key decrypted data.
+
+72
+00:03:46,000 --> 00:03:47,000
+That's a concept you need to understand.
+
+73
+00:03:48,000 --> 00:03:52,000
+So when one key encrypts, only the other key can decrypt it.
+
+74
+00:03:52,000 --> 00:03:56,000
+So when a public key encrypts, only the corresponding private key can decrypt it.
+
+75
+00:03:56,000 --> 00:03:59,000
+If the private key encrypts it and it does encrypt.
+
+76
+00:03:59,000 --> 00:04:03,000
+For those of you that say no in a digital signature, a private key does decrypt.
+
+77
+00:04:03,000 --> 00:04:03,000
+I'm sorry.
+
+78
+00:04:03,000 --> 00:04:04,000
+Encrypt.
+
+79
+00:04:05,000 --> 00:04:07,000
+If the private encrypt the public decrypts.
+
+80
+00:04:07,000 --> 00:04:13,000
+Remember that when one key encrypts, only the corresponding other key can decrypt it.
+
+81
+00:04:13,000 --> 00:04:17,000
+The public key cannot encrypt and decrypt at the same time.
+
+82
+00:04:17,000 --> 00:04:20,000
+The private key cannot encrypt and decrypt at the same time.
+
+83
+00:04:20,000 --> 00:04:23,000
+When one encrypts the other, one must decrypt.
+
+84
+00:04:23,000 --> 00:04:24,000
+And that's what you see here.
+
+85
+00:04:24,000 --> 00:04:26,000
+We take the data.
+
+86
+00:04:26,000 --> 00:04:29,000
+We encrypt it with Mary's public key.
+
+87
+00:04:30,000 --> 00:04:34,000
+She gets the ciphertext and she decrypts it with her private key to get the data.
+
+88
+00:04:34,000 --> 00:04:38,000
+So that's something that you must understand here.
+
+89
+00:04:38,000 --> 00:04:38,000
+Now.
+
+90
+00:04:39,000 --> 00:04:42,000
+That's the encryption process how it works.
+
+91
+00:04:42,000 --> 00:04:47,000
+But there are some advantages and disadvantages with this particular system.
+
+92
+00:04:48,000 --> 00:04:51,000
+First of all, its advantages.
+
+93
+00:04:51,000 --> 00:04:53,000
+Well, it solves a problem of key distribution.
+
+94
+00:04:53,000 --> 00:04:55,000
+You notice that we can all communicate.
+
+95
+00:04:55,000 --> 00:04:59,000
+There's no there's no need to share keys, right?
+
+96
+00:04:59,000 --> 00:05:05,000
+If you remember, the problem with symmetric encryption was how do we get the key across the network
+
+97
+00:05:05,000 --> 00:05:07,000
+and how do we get the key from this guy to this guy.
+
+98
+00:05:07,000 --> 00:05:08,000
+Well, this is not a problem anymore.
+
+99
+00:05:08,000 --> 00:05:11,000
+Now I just take somebody's public key and I encrypt it and give it to them.
+
+100
+00:05:11,000 --> 00:05:18,000
+Anyone that intercepts the connection between me and Mary can't decrypt it because they don't have Mary's
+
+101
+00:05:18,000 --> 00:05:18,000
+private key.
+
+102
+00:05:19,000 --> 00:05:22,000
+So it solves the problem of distribution of the key.
+
+103
+00:05:23,000 --> 00:05:25,000
+You don't need to have a billion keys.
+
+104
+00:05:25,000 --> 00:05:28,000
+You don't need to have keys between people.
+
+105
+00:05:28,000 --> 00:05:34,000
+For example, all you need to do to find the number of keys and asymmetric that would be needed if you
+
+106
+00:05:34,000 --> 00:05:39,000
+are using just pure asymmetric if you have two users, four keys, right?
+
+107
+00:05:39,000 --> 00:05:44,000
+If you have eight people, each of them would just need two keys with 16 keys.
+
+108
+00:05:44,000 --> 00:05:45,000
+That's it.
+
+109
+00:05:45,000 --> 00:05:46,000
+This times it by two.
+
+110
+00:05:46,000 --> 00:05:46,000
+Easy enough.
+
+111
+00:05:47,000 --> 00:05:52,000
+So the key distribution, the key management is pretty easy.
+
+112
+00:05:53,000 --> 00:05:59,000
+It provides a method for digital signature which is important for authentication and repudiation.
+
+113
+00:05:59,000 --> 00:06:03,000
+It has the ability to do non-repudiation authentication.
+
+114
+00:06:03,000 --> 00:06:09,000
+And the reason is because there is something unique to you.
+
+115
+00:06:10,000 --> 00:06:13,000
+There's something unique to you which is your private key.
+
+116
+00:06:14,000 --> 00:06:16,000
+Let me give you guys an example of this.
+
+117
+00:06:16,000 --> 00:06:18,000
+Let's say there is Andrew.
+
+118
+00:06:19,000 --> 00:06:20,000
+Andrew has a memo.
+
+119
+00:06:22,000 --> 00:06:22,000
+That's me.
+
+120
+00:06:22,000 --> 00:06:26,000
+I have a memo that I want to give to everybody in the company.
+
+121
+00:06:27,000 --> 00:06:32,000
+If I encrypt now I have two keys, a public and a private key.
+
+122
+00:06:32,000 --> 00:06:38,000
+Remember, if my public key encrypts, only my private key decrypts, if my private encrypts, only
+
+123
+00:06:38,000 --> 00:06:47,000
+my public decrypts, my private key is given to no one in the entire world but my private, and my private
+
+124
+00:06:47,000 --> 00:06:48,000
+key is given to no one in the world.
+
+125
+00:06:48,000 --> 00:06:50,000
+But my public key is given to everyone in the world.
+
+126
+00:06:51,000 --> 00:06:59,000
+What I could do is this I could encrypt this memo with my private key to get ciphertext.
+
+127
+00:07:00,000 --> 00:07:01,000
+Okay.
+
+128
+00:07:01,000 --> 00:07:04,000
+And then I could give this out to everybody in the business.
+
+129
+00:07:04,000 --> 00:07:06,000
+Who can decrypt this memo?
+
+130
+00:07:07,000 --> 00:07:08,000
+Everyone.
+
+131
+00:07:08,000 --> 00:07:09,000
+Why?
+
+132
+00:07:09,000 --> 00:07:13,000
+Because it was encrypted with the private key, not the public key.
+
+133
+00:07:13,000 --> 00:07:14,000
+The public key.
+
+134
+00:07:14,000 --> 00:07:16,000
+Everybody has my public key.
+
+135
+00:07:16,000 --> 00:07:17,000
+Hence the name public.
+
+136
+00:07:17,000 --> 00:07:19,000
+Well, why would I do that?
+
+137
+00:07:19,000 --> 00:07:21,000
+Why would I encrypt something so the world can decrypt?
+
+138
+00:07:21,000 --> 00:07:23,000
+It kind of defeats the purpose.
+
+139
+00:07:23,000 --> 00:07:26,000
+No, the purpose is non-repudiation.
+
+140
+00:07:26,000 --> 00:07:29,000
+The purpose is you would be 100% sure.
+
+141
+00:07:29,000 --> 00:07:32,000
+And I cannot deny that that memo came from me.
+
+142
+00:07:32,000 --> 00:07:36,000
+If you use my private key to decrypt the data, I'm sorry.
+
+143
+00:07:36,000 --> 00:07:42,000
+My public key to decrypt the data, then, you know, it had to be encrypted with something only I have,
+
+144
+00:07:42,000 --> 00:07:44,000
+which is my private key.
+
+145
+00:07:45,000 --> 00:07:51,000
+So this forms the basis of a digital signature, which we'll talk about later in the course.
+
+146
+00:07:51,000 --> 00:07:53,000
+So it does that versus symmetric.
+
+147
+00:07:53,000 --> 00:07:55,000
+And you see symmetric encryption.
+
+148
+00:07:55,000 --> 00:07:56,000
+Everybody was sharing a key.
+
+149
+00:07:56,000 --> 00:07:58,000
+There was nothing unique to someone.
+
+150
+00:07:58,000 --> 00:08:01,000
+Everybody had basically the same key.
+
+151
+00:08:01,000 --> 00:08:03,000
+Everybody needed the same key to encrypt and decrypt the data.
+
+152
+00:08:03,000 --> 00:08:06,000
+They were part of that communication.
+
+153
+00:08:07,000 --> 00:08:08,000
+Now.
+
+154
+00:08:08,000 --> 00:08:09,000
+It sounds good.
+
+155
+00:08:09,000 --> 00:08:12,000
+No key distribution problem, right?
+
+156
+00:08:12,000 --> 00:08:13,000
+No problem distributing the key.
+
+157
+00:08:13,000 --> 00:08:15,000
+Okay, that's no problem doing that.
+
+158
+00:08:15,000 --> 00:08:17,000
+We don't need a billion keys.
+
+159
+00:08:17,000 --> 00:08:18,000
+We don't need a lot of keys.
+
+160
+00:08:18,000 --> 00:08:23,000
+If we don't, you know, we have a lot of users, so key management is easy.
+
+161
+00:08:24,000 --> 00:08:28,000
+Uh, we have this easy thing of doing digital signatures.
+
+162
+00:08:29,000 --> 00:08:32,000
+But why don't we use it to encrypt bulk data?
+
+163
+00:08:32,000 --> 00:08:37,000
+In today's world, we actually don't use asymmetric encryption to encrypt larger data.
+
+164
+00:08:37,000 --> 00:08:43,000
+Now, basically any data for that matter, the actual private information per se, we don't actually
+
+165
+00:08:43,000 --> 00:08:49,000
+use it to encrypt bulk data or large amounts of data because it is very slow.
+
+166
+00:08:50,000 --> 00:08:56,000
+You see, it's computationally intensive, much more than symmetric encryption, making it slower for
+
+167
+00:08:56,000 --> 00:08:57,000
+large amounts of data.
+
+168
+00:08:57,000 --> 00:09:00,000
+It requires also a careful management of those private keys.
+
+169
+00:09:01,000 --> 00:09:03,000
+If your private key is compromised, you need a new pair.
+
+170
+00:09:03,000 --> 00:09:05,000
+And it's because of.
+
+171
+00:09:06,000 --> 00:09:08,000
+This point right here.
+
+172
+00:09:08,000 --> 00:09:09,000
+See that point right there?
+
+173
+00:09:09,000 --> 00:09:13,000
+This computationally intensive?
+
+174
+00:09:14,000 --> 00:09:20,000
+Uh, problem is really what doesn't make it replace symmetric.
+
+175
+00:09:20,000 --> 00:09:22,000
+Somebody say is asymmetric going to replace symmetric.
+
+176
+00:09:22,000 --> 00:09:27,000
+No it's not because it's you really can't use it for large blocks of data because it's too -- slow.
+
+177
+00:09:28,000 --> 00:09:31,000
+So if you notice these two algorithms, they cancel each other out.
+
+178
+00:09:31,000 --> 00:09:33,000
+So one is fast, one is slow.
+
+179
+00:09:33,000 --> 00:09:36,000
+One has a problem with with distributing keys.
+
+180
+00:09:36,000 --> 00:09:40,000
+One doesn't have this problem distributing keys one can't doesn't have something unique to the user.
+
+181
+00:09:40,000 --> 00:09:41,000
+But this one does.
+
+182
+00:09:41,000 --> 00:09:46,000
+It seems like all the bad is good here and all the bad, all the good is bad there.
+
+183
+00:09:47,000 --> 00:09:48,000
+You get the point.
+
+184
+00:09:49,000 --> 00:09:50,000
+So what do we do?
+
+185
+00:09:50,000 --> 00:09:52,000
+Well, there's a way to combine them again.
+
+186
+00:09:52,000 --> 00:09:54,000
+Hybrid cryptography is a video on that.
+
+187
+00:09:54,000 --> 00:09:55,000
+Talk about that later.
+
+188
+00:09:56,000 --> 00:09:57,000
+Now.
+
+189
+00:09:57,000 --> 00:10:05,000
+Because things like it has ability to be unique to people, because it has that digital signature and
+
+190
+00:10:05,000 --> 00:10:06,000
+the safe distribution of keys.
+
+191
+00:10:06,000 --> 00:10:10,000
+It basically is a cornerstone for protecting all data on the internet today, because things like SSL
+
+192
+00:10:10,000 --> 00:10:11,000
+can't work without it.
+
+193
+00:10:12,000 --> 00:10:14,000
+So keep that in mind for now.
+
+194
+00:10:14,000 --> 00:10:18,000
+I need you guys to understand what a what asymmetric is.
+
+195
+00:10:18,000 --> 00:10:19,000
+Quick recap as we end this.
+
+196
+00:10:20,000 --> 00:10:22,000
+Asymmetric is based on the principle of two keys.
+
+197
+00:10:22,000 --> 00:10:27,000
+Everybody in the asymmetric realm has two keys a public key and a private key.
+
+198
+00:10:27,000 --> 00:10:31,000
+The public key to give out to anyone the private key they keep only to themselves.
+
+199
+00:10:31,000 --> 00:10:36,000
+When one key encrypts, only the other one can decrypt, they both encrypt and decrypt.
+
+200
+00:10:36,000 --> 00:10:36,000
+So now.
+
+201
+00:10:38,000 --> 00:10:39,000
+Pros and cons.
+
+202
+00:10:39,000 --> 00:10:45,000
+The good thing is that it's easy to distribute keys because if the keys the secrets are not shared,
+
+203
+00:10:45,000 --> 00:10:47,000
+you can give your public key to anyone.
+
+204
+00:10:47,000 --> 00:10:50,000
+But if they encrypt, only your private key can can decrypt it.
+
+205
+00:10:51,000 --> 00:10:57,000
+This is good because if there's something unique to your private key now, you can use it for non-repudiation,
+
+206
+00:10:57,000 --> 00:10:58,000
+like with digital signatures.
+
+207
+00:10:59,000 --> 00:11:00,000
+But what's bad about it?
+
+208
+00:11:00,000 --> 00:11:02,000
+Well, it's too slow.
+
+209
+00:11:02,000 --> 00:11:06,000
+It's very, very computationally intensive.
+
+210
+00:11:06,000 --> 00:11:09,000
+And for those reasons you cannot use it to encrypt bulk data.
+
+211
+00:11:09,000 --> 00:11:14,000
+So that way we have to find a way to encrypt bulk data, which we'll talk about coming up later in hybrid
+
+212
+00:11:14,000 --> 00:11:15,000
+cryptography.
+
+213
+00:11:15,000 --> 00:11:19,000
+But before we do that, let's take a look at some of the asymmetric algorithms.
+

07 - Cryptography/009 Asymmetric Algorithms OB 1.4_en.srt

@@ -0,0 +1,268 @@
+1
+00:00:00,000 --> 00:00:07,000
+Okay, let's take a look at different asymmetric algorithms that you need to know or at least understand
+
+2
+00:00:07,000 --> 00:00:07,000
+for your exam.
+
+3
+00:00:07,000 --> 00:00:13,000
+Now, you don't need to know the math behind them or how it works, but you do need to know what they
+
+4
+00:00:13,000 --> 00:00:15,000
+are and maybe some pros and cons about them.
+
+5
+00:00:15,000 --> 00:00:19,000
+So let's go ahead and get started on this now.
+
+6
+00:00:20,000 --> 00:00:27,000
+The world's most famous asymmetric algorithm is RSA d most famous algorithm out there.
+
+7
+00:00:27,000 --> 00:00:34,000
+I would say 80% of communications that utilizes certificates is basically going to run on RSA.
+
+8
+00:00:34,000 --> 00:00:43,000
+Now, RSA is based on the difficulty of factoring the product of two large prime numbers.
+
+9
+00:00:43,000 --> 00:00:47,000
+Now, I'm not going to get into the math, but that's something you probably might see on a question
+
+10
+00:00:47,000 --> 00:00:47,000
+here and there.
+
+11
+00:00:47,000 --> 00:00:52,000
+It does use as large key sizes from 1024 to 4096.
+
+12
+00:00:52,000 --> 00:00:57,000
+Most of the RSA keys that I see is going to be 2048 bit.
+
+13
+00:00:58,000 --> 00:01:04,000
+This is widely used in things like digital signatures, key exchanges and of course SSL, TLS.
+
+14
+00:01:05,000 --> 00:01:10,000
+The other one is elliptic curve cryptography, now elliptic curve.
+
+15
+00:01:10,000 --> 00:01:13,000
+This is based on a different form of math.
+
+16
+00:01:13,000 --> 00:01:18,000
+The elliptic curves over a specific field a finite field.
+
+17
+00:01:18,000 --> 00:01:24,000
+It offers a higher degree of security with a smaller key size compared to RSA now because it's a different
+
+18
+00:01:24,000 --> 00:01:25,000
+form of math.
+
+19
+00:01:26,000 --> 00:01:32,000
+It has the advantage of being very secure with a small key versus RSA.
+
+20
+00:01:32,000 --> 00:01:34,000
+For it to be secure, it needs a big key.
+
+21
+00:01:34,000 --> 00:01:39,000
+For example, like I said, most of the RSA keys ECC is 2048 bit.
+
+22
+00:01:41,000 --> 00:01:50,000
+Notice that this one here, it says here that 256 bit key in ECC is considered as secure as a 3072 bit.
+
+23
+00:01:50,000 --> 00:01:52,000
+So that's a giant thing if you think about it.
+
+24
+00:01:52,000 --> 00:01:57,000
+256 bit is has the same security as 3072.
+
+25
+00:01:57,000 --> 00:01:58,000
+Now if you're thinking, well, why does that matter so much?
+
+26
+00:01:58,000 --> 00:02:07,000
+Because the bigger the key, the more CPU you need, the more memory you need to store that key.
+
+27
+00:02:07,000 --> 00:02:10,000
+Now if you're thinking, well, it's only bits, it's not that much, right?
+
+28
+00:02:10,000 --> 00:02:19,000
+If you get four gigs of if you have four gigabyte of memory, that's 32 billion bits of memory in your
+
+29
+00:02:19,000 --> 00:02:19,000
+computer.
+
+30
+00:02:19,000 --> 00:02:20,000
+And this is only four.
+
+31
+00:02:20,000 --> 00:02:21,000
+But remember, if you're a server.
+
+32
+00:02:22,000 --> 00:02:28,000
+And you have thousands or millions of connections, and you're managing all the keys for all these connections,
+
+33
+00:02:28,000 --> 00:02:30,000
+which is going to get bogged down pretty quickly.
+
+34
+00:02:30,000 --> 00:02:31,000
+All right.
+
+35
+00:02:31,000 --> 00:02:32,000
+Did you know four gigs is 32 billion?
+
+36
+00:02:32,000 --> 00:02:33,000
+Did you know that?
+
+37
+00:02:34,000 --> 00:02:36,000
+Four gigabyte is 32 billion bits.
+
+38
+00:02:37,000 --> 00:02:39,000
+If you don't know, you better study some A-plus.
+
+39
+00:02:39,000 --> 00:02:41,000
+Learn your conversion.
+
+40
+00:02:41,000 --> 00:02:44,000
+Uh, so EC is getting more popular.
+
+41
+00:02:44,000 --> 00:02:50,000
+I want to mention it was taught that EC was going to replace RSA at some point due to its efficiency.
+
+42
+00:02:50,000 --> 00:02:54,000
+I haven't really seen that yet, but supposedly EC is replace it.
+
+43
+00:02:54,000 --> 00:02:54,000
+Why?
+
+44
+00:02:54,000 --> 00:02:58,000
+It's going to give you more security, smaller key size and it basically does everything.
+
+45
+00:02:58,000 --> 00:02:59,000
+RSA.
+
+46
+00:03:00,000 --> 00:03:01,000
+Thus.
+
+47
+00:03:01,000 --> 00:03:06,000
+Now the other two are also famous, just not as famous as those two.
+
+48
+00:03:06,000 --> 00:03:09,000
+Diffie-Hellman was the first.
+
+49
+00:03:10,000 --> 00:03:10,000
+The first.
+
+50
+00:03:10,000 --> 00:03:15,000
+I'm pretty sure the first is, uh, asymmetric algorithm out there.
+
+51
+00:03:15,000 --> 00:03:17,000
+It was created by two guys, Diffie and Hellman.
+
+52
+00:03:18,000 --> 00:03:23,000
+Uh, this here was created for the passing of secret keys or symmetric keys.
+
+53
+00:03:23,000 --> 00:03:24,000
+That was its objectives.
+
+54
+00:03:24,000 --> 00:03:29,000
+It wasn't really meant to encrypt data or do any of the other things like RSA and ECC does.
+
+55
+00:03:31,000 --> 00:03:35,000
+Uh, it's most used again is to pass the secret keys that was out there.
+
+56
+00:03:35,000 --> 00:03:37,000
+The other one was Elgamal.
+
+57
+00:03:38,000 --> 00:03:45,000
+And this here was basically based on Diffie-Hellman, uh, and it provides a basis of other algorithms.
+
+58
+00:03:45,000 --> 00:03:47,000
+And this is really where this one was.
+
+59
+00:03:47,000 --> 00:03:50,000
+So the most used is going to be RSA.
+
+60
+00:03:51,000 --> 00:03:54,000
+ECC and Diffie-Hellman.
+
+61
+00:03:54,000 --> 00:03:58,000
+Out there, there's going to be the most used one for your exam.
+
+62
+00:03:58,000 --> 00:04:05,000
+I really don't need you guys to memorize all the bit, strings and or key sizes out there for these
+
+63
+00:04:05,000 --> 00:04:11,000
+algorithms, but I do need you guys to know this is a symmetric this is an asymmetric algorithm.
+
+64
+00:04:11,000 --> 00:04:12,000
+Here are the pros.
+
+65
+00:04:12,000 --> 00:04:15,000
+And here is the cons of using symmetric and asymmetric.
+
+66
+00:04:15,000 --> 00:04:17,000
+That's generally what your exam asks.
+
+67
+00:04:17,000 --> 00:04:19,000
+So make sure you note them for your tests.
+

07 - Cryptography/010 Hybrid Cryptography OB 1.4_en.srt

@@ -0,0 +1,488 @@
+1
+00:00:00,000 --> 00:00:07,000
+In this video, I'm going to teach you how to combine asymmetric and symmetric to form the perfect cryptosystem.
+
+2
+00:00:07,000 --> 00:00:09,000
+This is called hybrid cryptography.
+
+3
+00:00:09,000 --> 00:00:12,000
+And before I get into it, I want to point out something.
+
+4
+00:00:12,000 --> 00:00:14,000
+A lot of security guys don't know this.
+
+5
+00:00:14,000 --> 00:00:20,000
+A lot of people read books and different watch different videos about symmetric and asymmetric and things
+
+6
+00:00:20,000 --> 00:00:24,000
+there and think that, for example, asymmetric is implemented by itself.
+
+7
+00:00:24,000 --> 00:00:25,000
+It's not.
+
+8
+00:00:25,000 --> 00:00:26,000
+Let me show you guys something.
+
+9
+00:00:26,000 --> 00:00:28,000
+So here is the Wikipedia article on hybrid cryptography.
+
+10
+00:00:28,000 --> 00:00:30,000
+I know, I know what you're gonna say, okay.
+
+11
+00:00:30,000 --> 00:00:33,000
+You know, it's not the best system out there, but it's it's good enough.
+
+12
+00:00:34,000 --> 00:00:35,000
+Hybrid cryptosystem.
+
+13
+00:00:36,000 --> 00:00:37,000
+I'm just going to go down here.
+
+14
+00:00:37,000 --> 00:00:38,000
+I want to read this part here for you.
+
+15
+00:00:38,000 --> 00:00:46,000
+Notice it says all practical implementations of public key cryptography today employ the use of a hybrid
+
+16
+00:00:46,000 --> 00:00:47,000
+system.
+
+17
+00:00:48,000 --> 00:00:50,000
+All okay.
+
+18
+00:00:50,000 --> 00:00:56,000
+Basically any time we use asymmetric encryption it's never basically used by itself.
+
+19
+00:00:56,000 --> 00:01:03,000
+All implementations of it that we use in the real world, and not just the theoretical world is based
+
+20
+00:01:03,000 --> 00:01:05,000
+on a hybrid cryptosystem.
+
+21
+00:01:05,000 --> 00:01:09,000
+And in this video I want you guys to learn what that is like.
+
+22
+00:01:09,000 --> 00:01:11,000
+What exactly is a hybrid cryptosystem.
+
+23
+00:01:11,000 --> 00:01:14,000
+And I want to draw you guys a quick diagram how it's done.
+
+24
+00:01:15,000 --> 00:01:16,000
+So let's get let's get into this.
+
+25
+00:01:16,000 --> 00:01:19,000
+So what exactly is a hybrid cryptosystem.
+
+26
+00:01:19,000 --> 00:01:24,000
+Well as you can imagine it takes the it takes the good of symmetric.
+
+27
+00:01:24,000 --> 00:01:27,000
+The good of asymmetric combines them.
+
+28
+00:01:27,000 --> 00:01:29,000
+Remember one there basically were like opposites.
+
+29
+00:01:29,000 --> 00:01:31,000
+What's good here is bad here.
+
+30
+00:01:31,000 --> 00:01:31,000
+What's bad here.
+
+31
+00:01:31,000 --> 00:01:32,000
+What's good here.
+
+32
+00:01:32,000 --> 00:01:34,000
+So if we combine them we get the perfect system.
+
+33
+00:01:34,000 --> 00:01:35,000
+That's really what it is.
+
+34
+00:01:36,000 --> 00:01:43,000
+Basically, when we combine them, we're going to use the asymmetric algorithms for the secure key exchange.
+
+35
+00:01:43,000 --> 00:01:47,000
+And then we're going to use the symmetric for encrypting the actual data.
+
+36
+00:01:47,000 --> 00:01:52,000
+Remember something symmetric is good at encrypting bulk data.
+
+37
+00:01:52,000 --> 00:01:53,000
+Asymmetric is not.
+
+38
+00:01:53,000 --> 00:01:56,000
+But asymmetric doesn't have a problem of key exchange.
+
+39
+00:01:56,000 --> 00:01:59,000
+Now if asymmetric has to encrypt.
+
+40
+00:02:00,000 --> 00:02:01,000
+Just a symmetric key.
+
+41
+00:02:01,000 --> 00:02:04,000
+It's cool because a symmetric key is pretty small.
+
+42
+00:02:04,000 --> 00:02:07,000
+It's only 256 bits or 128 bit.
+
+43
+00:02:07,000 --> 00:02:12,000
+It's not the size of a picture, which could be four megabytes, which would be 32 billion bits.
+
+44
+00:02:12,000 --> 00:02:18,000
+So remember this in the process that I'm about to cover now, I'm going to cover this exact process.
+
+45
+00:02:18,000 --> 00:02:21,000
+The text is listed here right now.
+
+46
+00:02:21,000 --> 00:02:24,000
+So I want to show you the hybrid cryptography system.
+
+47
+00:02:24,000 --> 00:02:28,000
+Now let's say there is Andy.
+
+48
+00:02:29,000 --> 00:02:31,000
+And there's Mary.
+
+49
+00:02:31,000 --> 00:02:35,000
+So we have Mary M-a-r-y and Andy.
+
+50
+00:02:35,000 --> 00:02:38,000
+So I have a public private key.
+
+51
+00:02:38,000 --> 00:02:39,000
+Public.
+
+52
+00:02:39,000 --> 00:02:40,000
+Private key.
+
+53
+00:02:41,000 --> 00:02:44,000
+Now, reality is, I don't really need keys here.
+
+54
+00:02:44,000 --> 00:02:47,000
+I'm just putting it there because everybody technically the system has it.
+
+55
+00:02:47,000 --> 00:02:51,000
+But remember, if you're on the internet and you're using things that you don't have any public private
+
+56
+00:02:51,000 --> 00:02:52,000
+keys in your machine.
+
+57
+00:02:53,000 --> 00:02:54,000
+Now here's how it works.
+
+58
+00:02:54,000 --> 00:03:00,000
+So let's say I have data that I want to transfer to Mary.
+
+59
+00:03:01,000 --> 00:03:04,000
+Here's what I'm going to do on my computer.
+
+60
+00:03:04,000 --> 00:03:07,000
+I am going to generate a symmetric key.
+
+61
+00:03:07,000 --> 00:03:11,000
+This symmetric key is known as a session key.
+
+62
+00:03:11,000 --> 00:03:15,000
+The session key is a symmetric key like an AES session key.
+
+63
+00:03:16,000 --> 00:03:22,000
+What I'm going to do is I'm going to encrypt this data with this to form ciphertext.
+
+64
+00:03:24,000 --> 00:03:25,000
+Okay.
+
+65
+00:03:25,000 --> 00:03:32,000
+So ciphertext is the data is encrypted with the symmetric key to form ciphertext.
+
+66
+00:03:32,000 --> 00:03:36,000
+What I'm going to do is I'm going to then say hey Mary, send me your public key.
+
+67
+00:03:36,000 --> 00:03:39,000
+Mary sends me her public key, but I'm not going to encrypt the data with it.
+
+68
+00:03:39,000 --> 00:03:41,000
+The data has already been encrypted.
+
+69
+00:03:41,000 --> 00:03:44,000
+What am I going to encrypt the symmetric key if you said that.
+
+70
+00:03:44,000 --> 00:03:44,000
+Correct.
+
+71
+00:03:44,000 --> 00:03:46,000
+So I have ciphertext data.
+
+72
+00:03:47,000 --> 00:03:51,000
+And now I have ciphertext symmetric key.
+
+73
+00:03:52,000 --> 00:03:54,000
+What I do is now I send this to Mary.
+
+74
+00:03:54,000 --> 00:04:03,000
+Mary receives the ciphertext symmetric key and she receives ciphertext data.
+
+75
+00:04:03,000 --> 00:04:04,000
+You guys see that?
+
+76
+00:04:04,000 --> 00:04:04,000
+Yep.
+
+77
+00:04:05,000 --> 00:04:07,000
+How does Mary get the data?
+
+78
+00:04:07,000 --> 00:04:14,000
+Well, now Mary utilizes her private key to decrypt the symmetric key.
+
+79
+00:04:14,000 --> 00:04:18,000
+Remember, the symmetric key was encrypted with her public, so it could only be decrypted with her
+
+80
+00:04:18,000 --> 00:04:19,000
+private.
+
+81
+00:04:19,000 --> 00:04:23,000
+And now Mary has the symmetric key.
+
+82
+00:04:23,000 --> 00:04:26,000
+She then uses that symmetric key to decrypt the data.
+
+83
+00:04:26,000 --> 00:04:27,000
+Now she has the pure data.
+
+84
+00:04:28,000 --> 00:04:32,000
+So that is the process of asymmetric.
+
+85
+00:04:32,000 --> 00:04:34,000
+So let's sorry hybrid cryptography.
+
+86
+00:04:34,000 --> 00:04:36,000
+Let's do a quick quick review.
+
+87
+00:04:37,000 --> 00:04:37,000
+Okay.
+
+88
+00:04:37,000 --> 00:04:39,000
+So remember I don't need keys.
+
+89
+00:04:39,000 --> 00:04:40,000
+So what do I do.
+
+90
+00:04:40,000 --> 00:04:44,000
+I have the data I generate a symmetric key on this machine.
+
+91
+00:04:44,000 --> 00:04:50,000
+I then encrypt that symmetric key uh with Mary's public key.
+
+92
+00:04:50,000 --> 00:04:52,000
+See that I took it I gave it to her.
+
+93
+00:04:52,000 --> 00:04:56,000
+She gave it to me, I encrypt it, and now I have ciphertext data.
+
+94
+00:04:57,000 --> 00:05:01,000
+Uh, I have the ciphertext data, and I have ciphertext symmetric key and send it to her.
+
+95
+00:05:01,000 --> 00:05:03,000
+Now I want you to watch this connection.
+
+96
+00:05:03,000 --> 00:05:08,000
+If there's a hacker right here, the hacker is seeing ciphertext data and ciphertext symmetric key.
+
+97
+00:05:08,000 --> 00:05:10,000
+Everything you basically see is ciphertext.
+
+98
+00:05:10,000 --> 00:05:12,000
+He never sees plaintext.
+
+99
+00:05:12,000 --> 00:05:16,000
+When she receives it, she uses her private key to decrypt the symmetric key.
+
+100
+00:05:17,000 --> 00:05:21,000
+And then uses that symmetric key to decrypt the ciphertext data to get the data.
+
+101
+00:05:21,000 --> 00:05:30,000
+So I got data from me to her using a combination of of symmetric and asymmetric keys.
+
+102
+00:05:30,000 --> 00:05:33,000
+This is the most efficient way of doing this.
+
+103
+00:05:35,000 --> 00:05:40,000
+Now hybrid cryptography system combines this.
+
+104
+00:05:40,000 --> 00:05:43,000
+All right combines the efficiency of symmetric key.
+
+105
+00:05:43,000 --> 00:05:44,000
+So we get notice the data.
+
+106
+00:05:44,000 --> 00:05:47,000
+The bulk data was using the symmetric.
+
+107
+00:05:47,000 --> 00:05:55,000
+And of course that incredible key exchange process or easy management of the keys in asymmetric was
+
+108
+00:05:55,000 --> 00:05:55,000
+use.
+
+109
+00:05:56,000 --> 00:06:01,000
+One of the great things is that even if a symmetric key is compromised, it only affects one session
+
+110
+00:06:01,000 --> 00:06:03,000
+every time I encrypt data.
+
+111
+00:06:03,000 --> 00:06:05,000
+Every session I make a brand new session key.
+
+112
+00:06:06,000 --> 00:06:08,000
+This is very scalable and used in numerous systems.
+
+113
+00:06:08,000 --> 00:06:17,000
+In fact, all implementations of things like SSL, all web connections nowadays is basically that what
+
+114
+00:06:17,000 --> 00:06:21,000
+I showed you there, that diagram I wrote are just basically just draw it for you, as is the basis
+
+115
+00:06:21,000 --> 00:06:23,000
+of the SSL handshake.
+
+116
+00:06:23,000 --> 00:06:29,000
+There's more to it, but that's basically the basis of how the whole SSL handshake works.
+
+117
+00:06:30,000 --> 00:06:32,000
+So all types of converters, email, VPNs and so on.
+
+118
+00:06:32,000 --> 00:06:40,000
+Anywhere that we have a symmetric anywhere that is symmetric uses asymmetric encryption, we'll have
+
+119
+00:06:40,000 --> 00:06:42,000
+hybrid cryptography okay.
+
+120
+00:06:42,000 --> 00:06:47,000
+So you may want to watch that process again understand the pros and cons of it and the process.
+
+121
+00:06:47,000 --> 00:06:53,000
+Don't worry too much about the algorithm, but just remember all practical implementations of asymmetric
+
+122
+00:06:53,000 --> 00:06:55,000
+utilizes hybrid cryptography.
+

07 - Cryptography/011 Hashing OB 1.4_en.srt

@@ -0,0 +1,1600 @@
+1
+00:00:00,000 --> 00:00:05,000
+In this video, we're going to get started in the beautiful world of cryptographic hashes.
+
+2
+00:00:05,000 --> 00:00:11,000
+Now we covered asymmetric and symmetric asymmetric and a asymmetric and symmetric works directly on
+
+3
+00:00:11,000 --> 00:00:13,000
+data and produces things like ciphertext.
+
+4
+00:00:13,000 --> 00:00:15,000
+In this one we're going to do something different.
+
+5
+00:00:15,000 --> 00:00:20,000
+What we're going to be doing is we're going to be taking data of any length and turn it into a fixed
+
+6
+00:00:20,000 --> 00:00:21,000
+length hash.
+
+7
+00:00:21,000 --> 00:00:24,000
+This doesn't actually encrypt the data at all.
+
+8
+00:00:24,000 --> 00:00:26,000
+This is just a cryptographic number.
+
+9
+00:00:26,000 --> 00:00:31,000
+It's basically a value that represents the data.
+
+10
+00:00:31,000 --> 00:00:35,000
+It's not used to replace the data and it's not used to be decrypted.
+
+11
+00:00:35,000 --> 00:00:38,000
+This is something that's best shown than me trying to explain it.
+
+12
+00:00:38,000 --> 00:00:39,000
+Let me show it to you.
+
+13
+00:00:39,000 --> 00:00:42,000
+And then we're going to get into the nitty gritty detail.
+
+14
+00:00:42,000 --> 00:00:44,000
+I'm going to be showing you a hash function.
+
+15
+00:00:44,000 --> 00:00:49,000
+The most used hash function on the planet basically is going to be Sha 256.
+
+16
+00:00:49,000 --> 00:00:52,000
+We're going to get more into this function later on in the in these lessons.
+
+17
+00:00:52,000 --> 00:00:55,000
+But let's take a look.
+
+18
+00:00:55,000 --> 00:00:57,000
+So here I am at uh, this website.
+
+19
+00:00:57,000 --> 00:01:02,000
+And this is going to be a live view of a cryptographic hash functions getting done.
+
+20
+00:01:02,000 --> 00:01:05,000
+Now the link to this website is in the slides.
+
+21
+00:01:05,000 --> 00:01:06,000
+So I want to show you guys something.
+
+22
+00:01:07,000 --> 00:01:12,000
+I'm going to be entering my text at the bottom and at the bottom, at the top and at the bottom you're
+
+23
+00:01:12,000 --> 00:01:15,000
+going to get your cryptographic hash output.
+
+24
+00:01:15,000 --> 00:01:15,000
+Let's see.
+
+25
+00:01:15,000 --> 00:01:25,000
+So I'm going to say did you guys know I have many certifications.
+
+26
+00:01:25,000 --> 00:01:32,000
+Now I want you guys to watch something every single time I touch that keyboard.
+
+27
+00:01:33,000 --> 00:01:35,000
+The whole hash function chain.
+
+28
+00:01:35,000 --> 00:01:38,000
+You see this function, right.
+
+29
+00:01:38,000 --> 00:01:41,000
+This particular output, this string.
+
+30
+00:01:42,000 --> 00:01:43,000
+Represents this data.
+
+31
+00:01:44,000 --> 00:01:51,000
+If this data is modified in its slightest, this entire string will change.
+
+32
+00:01:52,000 --> 00:01:55,000
+For example, I want you guys to select on the screen.
+
+33
+00:01:55,000 --> 00:01:56,000
+We make this bigger so we can all see.
+
+34
+00:01:58,000 --> 00:01:58,000
+Okay.
+
+35
+00:01:59,000 --> 00:02:00,000
+Select any value here.
+
+36
+00:02:00,000 --> 00:02:04,000
+It doesn't matter what this any value, any one of these.
+
+37
+00:02:04,000 --> 00:02:06,000
+Maybe you got this one or maybe this eight here.
+
+38
+00:02:06,000 --> 00:02:08,000
+And I'm just going to click in the data.
+
+39
+00:02:08,000 --> 00:02:09,000
+And I'm just going to add a period.
+
+40
+00:02:09,000 --> 00:02:10,000
+That's it.
+
+41
+00:02:10,000 --> 00:02:11,000
+I'm just going to add a period.
+
+42
+00:02:12,000 --> 00:02:13,000
+Did it change.
+
+43
+00:02:13,000 --> 00:02:14,000
+More than likely it changed.
+
+44
+00:02:14,000 --> 00:02:15,000
+All right.
+
+45
+00:02:15,000 --> 00:02:17,000
+This whole thing basically changes.
+
+46
+00:02:17,000 --> 00:02:19,000
+Almost all those values will change.
+
+47
+00:02:20,000 --> 00:02:20,000
+Let me continue.
+
+48
+00:02:20,000 --> 00:02:27,000
+Notice that there's two main properties I need you guys to know every single time I type something.
+
+49
+00:02:28,000 --> 00:02:29,000
+Uh, watch it change.
+
+50
+00:02:29,000 --> 00:02:31,000
+But there's something else that's not changing.
+
+51
+00:02:31,000 --> 00:02:33,000
+Let's let me see if you detect it.
+
+52
+00:02:33,000 --> 00:02:41,000
+So I hope you will get more certs than I have.
+
+53
+00:02:42,000 --> 00:02:43,000
+Okay.
+
+54
+00:02:43,000 --> 00:02:43,000
+Nope.
+
+55
+00:02:43,000 --> 00:02:44,000
+I put an extra space.
+
+56
+00:02:44,000 --> 00:02:45,000
+Let me remove it.
+
+57
+00:02:45,000 --> 00:02:51,000
+Notice every single time I type the hash is changing.
+
+58
+00:02:51,000 --> 00:02:53,000
+But there's something not changing.
+
+59
+00:02:53,000 --> 00:02:56,000
+And what's not changing is the size of this.
+
+60
+00:02:56,000 --> 00:02:58,000
+This thing stays the same.
+
+61
+00:02:58,000 --> 00:03:00,000
+Doesn't matter how much text I put.
+
+62
+00:03:00,000 --> 00:03:02,000
+You see, if I copy this here.
+
+63
+00:03:04,000 --> 00:03:06,000
+I paste it into that box.
+
+64
+00:03:06,000 --> 00:03:12,000
+Once again, the hash changes, but the size of the hash is not changing.
+
+65
+00:03:12,000 --> 00:03:16,000
+No matter what I put in here, the hash size of the hash will not change.
+
+66
+00:03:16,000 --> 00:03:22,000
+See, if I go in here and I put and I keep doing, it doesn't matter how many times I copy paste it,
+
+67
+00:03:22,000 --> 00:03:23,000
+it will not change.
+
+68
+00:03:24,000 --> 00:03:26,000
+This is a very unique characteristics of this hash.
+
+69
+00:03:26,000 --> 00:03:32,000
+You see this particular value represents all this data.
+
+70
+00:03:33,000 --> 00:03:39,000
+So if anybody manipulates this data in any which way and you have this hash value.
+
+71
+00:03:39,000 --> 00:03:43,000
+So let's say I send you the data all of this and I send you this hash.
+
+72
+00:03:44,000 --> 00:03:45,000
+Okay.
+
+73
+00:03:45,000 --> 00:03:49,000
+You'll be able to tell if anybody manipulated it, because if somebody manipulates this data, maybe
+
+74
+00:03:49,000 --> 00:03:52,000
+they went in here after this morning, they put a space.
+
+75
+00:03:52,000 --> 00:03:53,000
+Then of course, the hash will change.
+
+76
+00:03:53,000 --> 00:03:55,000
+You would know somebody modified that somehow.
+
+77
+00:03:56,000 --> 00:03:57,000
+And that's what hashing is.
+
+78
+00:03:57,000 --> 00:04:04,000
+Hashing is about detecting modification of the data, the hash value, the string of characters that
+
+79
+00:04:04,000 --> 00:04:05,000
+we saw.
+
+80
+00:04:05,000 --> 00:04:07,000
+That was a 256 bit hash.
+
+81
+00:04:07,000 --> 00:04:10,000
+What we saw here, this is 256 bit.
+
+82
+00:04:10,000 --> 00:04:12,000
+It's just written.
+
+83
+00:04:13,000 --> 00:04:16,000
+It's written in a different format than you would know in in binary.
+
+84
+00:04:16,000 --> 00:04:17,000
+Okay.
+
+85
+00:04:17,000 --> 00:04:21,000
+So in this particular one it's, uh, hexadecimal.
+
+86
+00:04:21,000 --> 00:04:23,000
+So it's 0298F.
+
+87
+00:04:23,000 --> 00:04:26,000
+Now it's a base 16.
+
+88
+00:04:26,000 --> 00:04:28,000
+So don't worry too much about the specific math.
+
+89
+00:04:28,000 --> 00:04:29,000
+Just know that this is 200.
+
+90
+00:04:29,000 --> 00:04:31,000
+This is 256 bit hash.
+
+91
+00:04:31,000 --> 00:04:37,000
+And any kind of changes in here will result in a change here.
+
+92
+00:04:37,000 --> 00:04:40,000
+Now let's talk about these characteristics of this.
+
+93
+00:04:42,000 --> 00:04:45,000
+Because there's a lot of things here we should be able to understand.
+
+94
+00:04:45,000 --> 00:04:49,000
+Number one is that when it comes to hashing what are we doing.
+
+95
+00:04:49,000 --> 00:04:52,000
+Well we're converting an input of any length.
+
+96
+00:04:52,000 --> 00:04:54,000
+Like I mentioned any length.
+
+97
+00:04:54,000 --> 00:04:59,000
+It could be something as small as one bit all the way to terabytes of data.
+
+98
+00:04:59,000 --> 00:05:06,000
+Doesn't matter into a fixed size string of text using a mathematical function.
+
+99
+00:05:06,000 --> 00:05:07,000
+That's the hash function.
+
+100
+00:05:07,000 --> 00:05:08,000
+That's what we just saw.
+
+101
+00:05:09,000 --> 00:05:14,000
+Now a hash function takes data input data, like a message produces that fixed length hash.
+
+102
+00:05:14,000 --> 00:05:17,000
+Now the thing to know is that it's you can't go back.
+
+103
+00:05:17,000 --> 00:05:18,000
+And we'll talk about that in a minute.
+
+104
+00:05:20,000 --> 00:05:24,000
+A good hash function produces a unique and distinct value for every single input.
+
+105
+00:05:24,000 --> 00:05:27,000
+Even a small change results in a significant one.
+
+106
+00:05:27,000 --> 00:05:31,000
+So that means that every time you type text in, you're going to get a different output.
+
+107
+00:05:31,000 --> 00:05:34,000
+Every time the text changes, the output changed.
+
+108
+00:05:34,000 --> 00:05:35,000
+Now we saw that.
+
+109
+00:05:35,000 --> 00:05:39,000
+Now, just in case you don't have your following, just the slides, I give you a few examples.
+
+110
+00:05:39,000 --> 00:05:42,000
+But you saw that here where that was this website I gave you.
+
+111
+00:05:42,000 --> 00:05:43,000
+This is a link I was at.
+
+112
+00:05:43,000 --> 00:05:49,000
+So you would just type in the value type in your text, the hash function, and then it would give you
+
+113
+00:05:49,000 --> 00:05:51,000
+the different hashes.
+
+114
+00:05:51,000 --> 00:05:54,000
+Now this particular website has more than just Sha 256.
+
+115
+00:05:54,000 --> 00:06:03,000
+I think it has MD5 three shot 253 356 or I'm sorry 384 512 this is a variety of different ones there.
+
+116
+00:06:03,000 --> 00:06:10,000
+Now there are some things that I want to talk about in terms of hashing, right.
+
+117
+00:06:10,000 --> 00:06:13,000
+Some characteristics that we want to be familiar with.
+
+118
+00:06:13,000 --> 00:06:16,000
+Number one is that it's deterministic.
+
+119
+00:06:16,000 --> 00:06:26,000
+The same input always produces the same output every single time you hash that text.
+
+120
+00:06:26,000 --> 00:06:31,000
+It should always give you that exact exact output.
+
+121
+00:06:31,000 --> 00:06:34,000
+If the text is modified, the output is different.
+
+122
+00:06:34,000 --> 00:06:41,000
+And I want to show you guys, uh, I want to show you guys this, uh, in their.
+
+123
+00:06:42,000 --> 00:06:43,000
+So here's what I'm going to do.
+
+124
+00:06:45,000 --> 00:06:47,000
+I'm going to highlight all this and I'm going to.
+
+125
+00:06:49,000 --> 00:06:51,000
+Put I have.
+
+126
+00:06:51,000 --> 00:06:53,000
+I want to show you guys something because this is going to make more sense.
+
+127
+00:06:53,000 --> 00:06:55,000
+Have I have many certs.
+
+128
+00:06:55,000 --> 00:06:55,000
+All right.
+
+129
+00:06:55,000 --> 00:06:56,000
+This is my message.
+
+130
+00:06:56,000 --> 00:07:02,000
+Every time I do this, every time I type this text, it should give me this exact hash.
+
+131
+00:07:02,000 --> 00:07:07,000
+Doesn't matter where any time you run this text it should always give you this hash.
+
+132
+00:07:07,000 --> 00:07:12,000
+So let me just go here and I'm going to say Sha 256 online.
+
+133
+00:07:13,000 --> 00:07:14,000
+I'm just going to go to another website.
+
+134
+00:07:15,000 --> 00:07:16,000
+I'm just going to use theirs okay.
+
+135
+00:07:16,000 --> 00:07:17,000
+This is another website.
+
+136
+00:07:17,000 --> 00:07:19,000
+And let's drag this one here.
+
+137
+00:07:19,000 --> 00:07:22,000
+So we have two inputs on our screen.
+
+138
+00:07:22,000 --> 00:07:27,000
+So let's see if what I do here this this output should be matched in this one.
+
+139
+00:07:27,000 --> 00:07:28,000
+So let's see if we get it right.
+
+140
+00:07:28,000 --> 00:07:32,000
+So I'm going to take this I'm going to copy this I'm going to put it into this screen now.
+
+141
+00:07:32,000 --> 00:07:34,000
+So again it's the same function just a different site.
+
+142
+00:07:35,000 --> 00:07:37,000
+I'm just showing you that the output is going to match watch.
+
+143
+00:07:37,000 --> 00:07:41,000
+So I just put that there and let's see if the output matches.
+
+144
+00:07:41,000 --> 00:07:43,000
+Now I'm not going to go one by one here.
+
+145
+00:07:43,000 --> 00:07:46,000
+But the first couple should be fine e f.
+
+146
+00:07:46,000 --> 00:07:48,000
+Let's see this one.
+
+147
+00:07:48,000 --> 00:07:52,000
+Output F90F90 okay.
+
+148
+00:07:52,000 --> 00:07:55,000
+What is it n with this one ends in 3266.
+
+149
+00:07:55,000 --> 00:07:56,000
+This one ends in three two, six, six.
+
+150
+00:07:56,000 --> 00:07:56,000
+See that?
+
+151
+00:07:57,000 --> 00:07:59,000
+So if I go in here and I say I have.
+
+152
+00:08:01,000 --> 00:08:04,000
+66 shirts.
+
+153
+00:08:04,000 --> 00:08:10,000
+So if I go in here and I say same thing six.
+
+154
+00:08:12,000 --> 00:08:15,000
+66 certs should match.
+
+155
+00:08:15,000 --> 00:08:16,000
+Let's see again.
+
+156
+00:08:16,000 --> 00:08:19,000
+So look at this e f f.
+
+157
+00:08:20,000 --> 00:08:21,000
+E f f.
+
+158
+00:08:21,000 --> 00:08:22,000
+Okay, great.
+
+159
+00:08:22,000 --> 00:08:23,000
+This matches perfectly.
+
+160
+00:08:23,000 --> 00:08:25,000
+It ends in 0303.
+
+161
+00:08:25,000 --> 00:08:26,000
+So this one ends in 0303.
+
+162
+00:08:27,000 --> 00:08:28,000
+Exactly.
+
+163
+00:08:28,000 --> 00:08:34,000
+So any time you type that text using that function, you should always get that output.
+
+164
+00:08:34,000 --> 00:08:36,000
+That's what that's the point I'm trying to make here.
+
+165
+00:08:36,000 --> 00:08:43,000
+Now that's important to understand because when we come to passwords, the world of password management
+
+166
+00:08:43,000 --> 00:08:46,000
+you're going to need to know that, uh, okay.
+
+167
+00:08:46,000 --> 00:08:48,000
+So it's deterministic.
+
+168
+00:08:48,000 --> 00:08:49,000
+It's fast.
+
+169
+00:08:49,000 --> 00:08:52,000
+It should be able it doesn't really matter the size of it.
+
+170
+00:08:52,000 --> 00:08:55,000
+It should be able to compute the hash relatively quickly.
+
+171
+00:08:56,000 --> 00:08:58,000
+It should be preimage resistant.
+
+172
+00:08:58,000 --> 00:09:01,000
+Now this is something you have to understand.
+
+173
+00:09:01,000 --> 00:09:04,000
+It is considered one way.
+
+174
+00:09:04,000 --> 00:09:07,000
+What does that mean if I give you.
+
+175
+00:09:08,000 --> 00:09:16,000
+A hash value, you should not be able to reconstruct the original input.
+
+176
+00:09:16,000 --> 00:09:19,000
+Well, what does that mean?
+
+177
+00:09:19,000 --> 00:09:21,000
+Well let's see.
+
+178
+00:09:21,000 --> 00:09:23,000
+So if I give you.
+
+179
+00:09:25,000 --> 00:09:31,000
+If I give you this value, there is no way you should be going back.
+
+180
+00:09:31,000 --> 00:09:32,000
+It's one way.
+
+181
+00:09:32,000 --> 00:09:32,000
+It's.
+
+182
+00:09:32,000 --> 00:09:35,000
+Take the data, produce a cryptographic hash.
+
+183
+00:09:35,000 --> 00:09:42,000
+You should never be able to turn this the cash value into the text itself.
+
+184
+00:09:43,000 --> 00:09:47,000
+In fact, it's probably not even feasible because when you have large amounts of text, it's not feasible
+
+185
+00:09:48,000 --> 00:09:57,000
+because you can have data that's 20MB, that's 160 bits being brought down to 256 bits.
+
+186
+00:09:58,000 --> 00:09:58,000
+Okay.
+
+187
+00:09:58,000 --> 00:09:59,000
+That's like me.
+
+188
+00:09:59,000 --> 00:10:03,000
+You know, if you take a four megabyte file, that's 32 billion bits.
+
+189
+00:10:03,000 --> 00:10:08,000
+That's like me giving you $256 and say, go make 4 billion, $32 million.
+
+190
+00:10:08,000 --> 00:10:10,000
+Not very hard to do.
+
+191
+00:10:10,000 --> 00:10:15,000
+So it is considered a one way function.
+
+192
+00:10:15,000 --> 00:10:15,000
+Okay.
+
+193
+00:10:15,000 --> 00:10:17,000
+What are some other function of this.
+
+194
+00:10:17,000 --> 00:10:18,000
+Let's see.
+
+195
+00:10:19,000 --> 00:10:19,000
+Okay.
+
+196
+00:10:19,000 --> 00:10:26,000
+So the other thing here we have is going to be small changes leads to large differences.
+
+197
+00:10:26,000 --> 00:10:28,000
+Now that means that we saw this earlier.
+
+198
+00:10:28,000 --> 00:10:32,000
+You make one small change to to the text.
+
+199
+00:10:32,000 --> 00:10:36,000
+Remember when I just added a space or just one letter change or put a period or something.
+
+200
+00:10:36,000 --> 00:10:38,000
+The whole hash will change.
+
+201
+00:10:38,000 --> 00:10:40,000
+This is called the avalanche effect.
+
+202
+00:10:40,000 --> 00:10:44,000
+What that means is that basically it's like a cascading effect.
+
+203
+00:10:44,000 --> 00:10:46,000
+Okay, you change it, then it changes the entire hash.
+
+204
+00:10:47,000 --> 00:10:51,000
+Now, the one I want to spend a couple of minutes on is called collision resistance.
+
+205
+00:10:51,000 --> 00:10:53,000
+What exactly is this?
+
+206
+00:10:53,000 --> 00:10:55,000
+Well, you have to understand how this thing works.
+
+207
+00:10:55,000 --> 00:10:57,000
+It basically takes data.
+
+208
+00:10:58,000 --> 00:11:01,000
+Of any length and it produces this fixed length string of text.
+
+209
+00:11:01,000 --> 00:11:02,000
+This hash.
+
+210
+00:11:03,000 --> 00:11:09,000
+You see, collisions occur when two different messages produces the same hash.
+
+211
+00:11:09,000 --> 00:11:10,000
+That's really bad.
+
+212
+00:11:11,000 --> 00:11:13,000
+You see, you have to understand how it functions.
+
+213
+00:11:13,000 --> 00:11:15,000
+And let's talk about how it functions.
+
+214
+00:11:15,000 --> 00:11:20,000
+So like how do you end up with a collision.
+
+215
+00:11:21,000 --> 00:11:21,000
+We.
+
+216
+00:11:21,000 --> 00:11:24,000
+First of all, you have to understand the hash value.
+
+217
+00:11:24,000 --> 00:11:28,000
+The hash value algorithm a hash algorithm comes in bit string.
+
+218
+00:11:28,000 --> 00:11:32,000
+For example, Sha like we saw was 256.
+
+219
+00:11:32,000 --> 00:11:36,000
+That means that the output that it's giving you is 256 bit.
+
+220
+00:11:37,000 --> 00:11:41,000
+There's another famous one called MD5, although you shouldn't be using it.
+
+221
+00:11:41,000 --> 00:11:44,000
+It was pretty famous that has 128 bit.
+
+222
+00:11:44,000 --> 00:11:52,000
+And if you remember earlier in the video, when we say 128 bit 256 bits, that tells me that's those
+
+223
+00:11:52,000 --> 00:11:53,000
+are the number of digits in the hash.
+
+224
+00:11:53,000 --> 00:11:55,000
+So how many possible hash you can have?
+
+225
+00:11:55,000 --> 00:11:57,000
+Well, the number of bits tell you that.
+
+226
+00:11:57,000 --> 00:12:06,000
+So if it's 128 bit there's 2 to 128 number of hashes available to be used.
+
+227
+00:12:07,000 --> 00:12:12,000
+It's not an unlimited number of hashes out there, it is just a fixed number of hashes.
+
+228
+00:12:12,000 --> 00:12:15,000
+Although it's a big pool, it's still a pool.
+
+229
+00:12:15,000 --> 00:12:16,000
+It's still a fixed number.
+
+230
+00:12:17,000 --> 00:12:22,000
+For example, let's say I'm really, really crazy and I make a hash function.
+
+231
+00:12:22,000 --> 00:12:25,000
+A hash function that's two bits.
+
+232
+00:12:25,000 --> 00:12:28,000
+Two bits only gives me four possible hashes.
+
+233
+00:12:28,000 --> 00:12:38,000
+So if you're using my for my hash function to to do to to hash your data with, it'll be easy to have
+
+234
+00:12:38,000 --> 00:12:43,000
+multiple different data having the exact same hash because only four possible hashes.
+
+235
+00:12:44,000 --> 00:12:45,000
+So.
+
+236
+00:12:45,000 --> 00:12:51,000
+Because the hash functions of today uses like 128, 256, 384, 512.
+
+237
+00:12:52,000 --> 00:12:53,000
+Crazy amount of hashes.
+
+238
+00:12:54,000 --> 00:12:57,000
+Collisions are not very likely, but they're not impossible.
+
+239
+00:12:58,000 --> 00:13:00,000
+And there is a paradox.
+
+240
+00:13:00,000 --> 00:13:04,000
+I want to talk to you guys about today that makes it somewhat possible.
+
+241
+00:13:04,000 --> 00:13:15,000
+So for example MD5, the hash function of MD5, MD5 is 128 bit two to the 128 is a number 38 zeros,
+
+242
+00:13:15,000 --> 00:13:16,000
+37 zeros.
+
+243
+00:13:16,000 --> 00:13:16,000
+I forgot this number.
+
+244
+00:13:16,000 --> 00:13:18,000
+It's a crazy big number.
+
+245
+00:13:18,000 --> 00:13:23,000
+So what is the probability that two different messages produce the same hash?
+
+246
+00:13:23,000 --> 00:13:28,000
+It's not impossible because again there's a fixed number of hashes, but it doesn't seem likely.
+
+247
+00:13:30,000 --> 00:13:32,000
+I want to show you guys a couple of things.
+
+248
+00:13:32,000 --> 00:13:33,000
+First of all I want to show you a collision.
+
+249
+00:13:33,000 --> 00:13:36,000
+So here is a diagram that we have.
+
+250
+00:13:36,000 --> 00:13:39,000
+So this is the normal this is the collision.
+
+251
+00:13:39,000 --> 00:13:47,000
+So in the normal look at the text the red fox runs across the box box and input field hashes it.
+
+252
+00:13:47,000 --> 00:13:53,000
+And he gets this this this uh this output the yellow fox different message hashes to get this.
+
+253
+00:13:53,000 --> 00:13:54,000
+But they're different right.
+
+254
+00:13:54,000 --> 00:13:55,000
+This is normal.
+
+255
+00:13:55,000 --> 00:13:57,000
+Different messages, different hash.
+
+256
+00:13:57,000 --> 00:14:04,000
+The collision occurs when you take the red fox and the yellow fox to different messages, hashes it
+
+257
+00:14:04,000 --> 00:14:05,000
+with the same function.
+
+258
+00:14:05,000 --> 00:14:09,000
+But now all of a sudden you have the exact same hash.
+
+259
+00:14:09,000 --> 00:14:14,000
+This is the collision two different messages producing the same hash function.
+
+260
+00:14:16,000 --> 00:14:19,000
+Now, this is a kind of a weakness.
+
+261
+00:14:19,000 --> 00:14:20,000
+All right.
+
+262
+00:14:20,000 --> 00:14:22,000
+MD5 has multiple collision.
+
+263
+00:14:22,000 --> 00:14:23,000
+That's what you should never use it.
+
+264
+00:14:24,000 --> 00:14:27,000
+Uh, you should be using Sha 256 and above.
+
+265
+00:14:27,000 --> 00:14:32,000
+An example of this I want to mention is something we call a birthday attack against passwords.
+
+266
+00:14:32,000 --> 00:14:34,000
+The birthday attack is like a password thing.
+
+267
+00:14:35,000 --> 00:14:36,000
+Most people know it as a password.
+
+268
+00:14:36,000 --> 00:14:37,000
+I'll explain what this is to you.
+
+269
+00:14:37,000 --> 00:14:40,000
+The what's called the birthday paradox.
+
+270
+00:14:41,000 --> 00:14:46,000
+So I'm going to give you guys and I'm gonna explain why this is related to hashing.
+
+271
+00:14:46,000 --> 00:14:49,000
+I'm going to give you guys something to think about.
+
+272
+00:14:49,000 --> 00:14:50,000
+All right.
+
+273
+00:14:50,000 --> 00:14:52,000
+Here's a type of a math function.
+
+274
+00:14:52,000 --> 00:14:53,000
+You have to do a little bit of math.
+
+275
+00:14:53,000 --> 00:14:55,000
+Don't worry it's not complex.
+
+276
+00:14:55,000 --> 00:14:57,000
+If I put 30 people in a room.
+
+277
+00:14:58,000 --> 00:15:03,000
+What is the probability that any two people have the exact same birthday?
+
+278
+00:15:03,000 --> 00:15:07,000
+In that year there's 365 possible combinations of birthday, right?
+
+279
+00:15:07,000 --> 00:15:11,000
+January 1st, January 2nd, January 3rd, 365 combinations.
+
+280
+00:15:12,000 --> 00:15:14,000
+There's 30 people in the room.
+
+281
+00:15:14,000 --> 00:15:18,000
+If I was to ask you guys if we were to, um.
+
+282
+00:15:20,000 --> 00:15:25,000
+If we were to just grab two people that any two people, what's the probability that if we grab any
+
+283
+00:15:25,000 --> 00:15:27,000
+two people, they have the same birthday?
+
+284
+00:15:27,000 --> 00:15:29,000
+Would you say that number is small?
+
+285
+00:15:29,000 --> 00:15:30,000
+1%, 2%.
+
+286
+00:15:30,000 --> 00:15:31,000
+Would you say it's moderate?
+
+287
+00:15:31,000 --> 00:15:33,000
+30, 40, 50, 60%?
+
+288
+00:15:33,000 --> 00:15:34,000
+Would you say it's high?
+
+289
+00:15:34,000 --> 00:15:34,000
+80?
+
+290
+00:15:34,000 --> 00:15:35,000
+90%.
+
+291
+00:15:37,000 --> 00:15:39,000
+Well without me giving it to you.
+
+292
+00:15:39,000 --> 00:15:40,000
+Let me just show you.
+
+293
+00:15:40,000 --> 00:15:42,000
+So here I have.
+
+294
+00:15:42,000 --> 00:15:45,000
+I went to Wikipedia and I looked up birthday attack.
+
+295
+00:15:45,000 --> 00:15:48,000
+You see, the birthday attack is a brute force.
+
+296
+00:15:48,000 --> 00:15:49,000
+Is a brute force collision.
+
+297
+00:15:49,000 --> 00:15:50,000
+Attack?
+
+298
+00:15:51,000 --> 00:15:54,000
+It works on something we call the birthday paradox.
+
+299
+00:15:54,000 --> 00:15:55,000
+Now what?
+
+300
+00:15:55,000 --> 00:15:56,000
+This is.
+
+301
+00:15:56,000 --> 00:15:57,000
+This is what I was just explaining.
+
+302
+00:16:00,000 --> 00:16:05,000
+A scenario where a teacher with a class of 30 students actually everyone's birthday to determine whether
+
+303
+00:16:05,000 --> 00:16:08,000
+any two students have the same birthday.
+
+304
+00:16:08,000 --> 00:16:14,000
+Although this may seem small, the probability of one student having the same birthday as any other
+
+305
+00:16:14,000 --> 00:16:16,000
+is actually 70%.
+
+306
+00:16:16,000 --> 00:16:23,000
+Now, most of my students generally say 1% or 2%, but in actuality it's actually 70%.
+
+307
+00:16:23,000 --> 00:16:24,000
+It's not a small number.
+
+308
+00:16:25,000 --> 00:16:31,000
+In fact, if you put, I believe it's 60 people in a room, there's a 90 or 99% people percentage that
+
+309
+00:16:31,000 --> 00:16:34,000
+they're going to have two, two people are going to have the same birthday.
+
+310
+00:16:35,000 --> 00:16:40,000
+And if you're wondering, what the hell does that have to do with passwords or hashing collision.
+
+311
+00:16:40,000 --> 00:16:47,000
+You see, the birthday paradox teaches us a very important thing about the laws of probability.
+
+312
+00:16:47,000 --> 00:16:50,000
+What seems improbable is actually more probable than we believe.
+
+313
+00:16:50,000 --> 00:16:57,000
+Although it seems like 30 people with 365 combinations seems like a very small likelihood, it's actually
+
+314
+00:16:57,000 --> 00:16:58,000
+very likely.
+
+315
+00:16:58,000 --> 00:17:00,000
+You see, how does this relate to hashing?
+
+316
+00:17:00,000 --> 00:17:01,000
+Is this.
+
+317
+00:17:02,000 --> 00:17:08,000
+There's two to the 128 bit number of hashes when you use an MD5 hash.
+
+318
+00:17:08,000 --> 00:17:10,000
+There's an unlimited number of messages.
+
+319
+00:17:10,000 --> 00:17:16,000
+The probability of two messages having the same hash seems very unlikely because there's so many hashes.
+
+320
+00:17:16,000 --> 00:17:19,000
+But the birthday paradox says actually there is.
+
+321
+00:17:19,000 --> 00:17:22,000
+There is no way to defeat the birthday paradox.
+
+322
+00:17:22,000 --> 00:17:23,000
+There's no way to stop it.
+
+323
+00:17:23,000 --> 00:17:27,000
+It's just the laws of math, except if you increase the number of birthdays.
+
+324
+00:17:27,000 --> 00:17:32,000
+So instead of having 365 put 1000 combinations, then that percentage drops, that 70 goes down.
+
+325
+00:17:32,000 --> 00:17:37,000
+So the way to break it is to increase the pool of possible hashes.
+
+326
+00:17:37,000 --> 00:17:40,000
+Or in this come in this one pool of possible birthdays.
+
+327
+00:17:41,000 --> 00:17:42,000
+Now.
+
+328
+00:17:43,000 --> 00:17:45,000
+How does a birthday attack relate to passwords?
+
+329
+00:17:45,000 --> 00:17:47,000
+Well, first of all, just what a heads up.
+
+330
+00:17:47,000 --> 00:17:52,000
+When we get to the password section, I'm going to tell you guys remember hashing all passwords are
+
+331
+00:17:52,000 --> 00:17:52,000
+hash.
+
+332
+00:17:52,000 --> 00:17:55,000
+Computers don't store your passwords.
+
+333
+00:17:56,000 --> 00:17:59,000
+As password as a plaintext, it stores it as hashes.
+
+334
+00:17:59,000 --> 00:18:00,000
+Let me show you guys something.
+
+335
+00:18:02,000 --> 00:18:06,000
+So a computer if your password is password one.
+
+336
+00:18:06,000 --> 00:18:09,000
+This is what the computer stores this.
+
+337
+00:18:11,000 --> 00:18:11,000
+Okay.
+
+338
+00:18:11,000 --> 00:18:14,000
+It does not store your plaintext password.
+
+339
+00:18:14,000 --> 00:18:20,000
+All computers, all computing systems doesn't store this plaintext.
+
+340
+00:18:20,000 --> 00:18:21,000
+It stores this.
+
+341
+00:18:22,000 --> 00:18:28,000
+So when you type in your password as password one, it then rehashes this and matches it to what it
+
+342
+00:18:28,000 --> 00:18:29,000
+has on file.
+
+343
+00:18:30,000 --> 00:18:35,000
+Remember, it's one way even if people compromise your system and steal your steal the hash, they should
+
+344
+00:18:35,000 --> 00:18:36,000
+never be able to work it backwards.
+
+345
+00:18:36,000 --> 00:18:37,000
+Because remember what I said?
+
+346
+00:18:37,000 --> 00:18:43,000
+Hashing is one way where the birthday paradox comes into play, or the birthday attack comes into play
+
+347
+00:18:43,000 --> 00:18:44,000
+is like this.
+
+348
+00:18:45,000 --> 00:18:49,000
+It comes into play when your password is car, car.
+
+349
+00:18:49,000 --> 00:18:53,000
+And then I come to you and it says, hey man, I guess your password.
+
+350
+00:18:53,000 --> 00:18:54,000
+And you're like, okay, what is it?
+
+351
+00:18:54,000 --> 00:18:56,000
+And I say, it's van, van.
+
+352
+00:18:56,000 --> 00:18:59,000
+And you're like, no, it's car.
+
+353
+00:18:59,000 --> 00:19:00,000
+And I said, nope, it's van.
+
+354
+00:19:00,000 --> 00:19:01,000
+So you say prove it.
+
+355
+00:19:01,000 --> 00:19:03,000
+So I go to the machine.
+
+356
+00:19:03,000 --> 00:19:08,000
+And I type in your username and I type the word van and boom, it logs me in.
+
+357
+00:19:08,000 --> 00:19:09,000
+You like me.
+
+358
+00:19:09,000 --> 00:19:11,000
+I change my password so I log out.
+
+359
+00:19:11,000 --> 00:19:15,000
+Then you come, you type your same username, you type the word car and you press enter and boom.
+
+360
+00:19:15,000 --> 00:19:16,000
+It logs you in too.
+
+361
+00:19:16,000 --> 00:19:17,000
+It's odd.
+
+362
+00:19:17,000 --> 00:19:20,000
+It's two different words logging into the same account.
+
+363
+00:19:20,000 --> 00:19:23,000
+It's like this one account has two different password.
+
+364
+00:19:23,000 --> 00:19:24,000
+Know what's happening?
+
+365
+00:19:24,000 --> 00:19:26,000
+There is the collision of where.
+
+366
+00:19:27,000 --> 00:19:28,000
+Password.
+
+367
+00:19:28,000 --> 00:19:34,000
+One is producing this hash and another text is producing the same hash as password one.
+
+368
+00:19:34,000 --> 00:19:39,000
+The computer thinks car and van is the same thing because it's the same hash.
+
+369
+00:19:40,000 --> 00:19:41,000
+That's a birthday attack.
+
+370
+00:19:41,000 --> 00:19:42,000
+How do you defeat it?
+
+371
+00:19:42,000 --> 00:19:43,000
+Use a big hash.
+
+372
+00:19:43,000 --> 00:19:45,000
+Don't use a 128 bit hash.
+
+373
+00:19:45,000 --> 00:19:49,000
+Remember I said you can only beat the birthday attack if you increase the number of birthdays.
+
+374
+00:19:49,000 --> 00:19:50,000
+How do you beat it?
+
+375
+00:19:50,000 --> 00:19:52,000
+Don't use the same number.
+
+376
+00:19:52,000 --> 00:19:54,000
+Don't use small birthdays.
+
+377
+00:19:54,000 --> 00:19:56,000
+Don't use a pool with a small amount of birthdays.
+
+378
+00:19:56,000 --> 00:19:56,000
+Use a big one.
+
+379
+00:19:56,000 --> 00:19:57,000
+Don't use 128.
+
+380
+00:19:57,000 --> 00:19:58,000
+Use 256.
+
+381
+00:19:58,000 --> 00:20:00,000
+That's the one we should be using today.
+
+382
+00:20:00,000 --> 00:20:05,000
+Sha 256 all right, a lot of stuff in hashing.
+
+383
+00:20:05,000 --> 00:20:07,000
+But before I go, let's do a quick recap of hashing.
+
+384
+00:20:07,000 --> 00:20:09,000
+So hash is a cryptographic function.
+
+385
+00:20:09,000 --> 00:20:13,000
+It takes data of any length, produces a fixed length hash.
+
+386
+00:20:13,000 --> 00:20:14,000
+It's a one way thing.
+
+387
+00:20:14,000 --> 00:20:18,000
+You cannot take the the hash function and turn it back into the plaintext.
+
+388
+00:20:18,000 --> 00:20:20,000
+It should be quick.
+
+389
+00:20:20,000 --> 00:20:23,000
+In other words, the computation should be very, very fast.
+
+390
+00:20:23,000 --> 00:20:28,000
+Any change to the data results in a change to the cryptographic hash.
+
+391
+00:20:28,000 --> 00:20:29,000
+Why are we doing this?
+
+392
+00:20:29,000 --> 00:20:30,000
+The big word is integrity.
+
+393
+00:20:30,000 --> 00:20:34,000
+We're able to detect modification on the data and determine integrity.
+
+394
+00:20:34,000 --> 00:20:37,000
+And remember what collisions are the.
+
+395
+00:20:37,000 --> 00:20:39,000
+We should be able to resist collisions.
+
+396
+00:20:39,000 --> 00:20:41,000
+And the way we do that is by using bigger hashes.
+
+397
+00:20:41,000 --> 00:20:46,000
+Collision is when two messages produce the same, the exact same hash.
+
+398
+00:20:47,000 --> 00:20:51,000
+An example of this is the birthday attack, which we just which we just spoke about.
+
+399
+00:20:51,000 --> 00:20:55,000
+So so remember what the characteristics of hashes.
+
+400
+00:20:55,000 --> 00:20:59,000
+And now let's take a look at the different functions in the in the next video.
+

07 - Cryptography/012 Hashing Algorithms OB 1.4_en.srt

@@ -0,0 +1,240 @@
+1
+00:00:00,000 --> 00:00:05,000
+Okay, before I get into this, I want you guys to remember I have a table at the end of this section
+
+2
+00:00:05,000 --> 00:00:09,000
+that's going to summarize everything that I'm about to cover with you guys.
+
+3
+00:00:09,000 --> 00:00:13,000
+So this video we're going to be taking a look at all the different hash functions that are out there.
+
+4
+00:00:13,000 --> 00:00:15,000
+Once again, don't memorize all of this.
+
+5
+00:00:15,000 --> 00:00:20,000
+I just need you to know which ones are hash functions, which one are symmetric functions, and which
+
+6
+00:00:20,000 --> 00:00:22,000
+ones are asymmetric functions or algorithms.
+
+7
+00:00:22,000 --> 00:00:23,000
+Let's take a look.
+
+8
+00:00:23,000 --> 00:00:32,000
+So when it comes to hashing algorithm uh Sha or the secure hash algorithm, those series is going to
+
+9
+00:00:32,000 --> 00:00:34,000
+be the most famous one.
+
+10
+00:00:34,000 --> 00:00:41,000
+In fact Sha two, which comes the 256 bit version of it, is one of the most popular hashing function
+
+11
+00:00:41,000 --> 00:00:42,000
+on the planet.
+
+12
+00:00:43,000 --> 00:00:48,000
+So the secure hash algorithm is a series of government hash functions.
+
+13
+00:00:48,000 --> 00:00:49,000
+This is promoted by NIST.
+
+14
+00:00:49,000 --> 00:00:53,000
+And if you know one thing in the world of security, if it's good enough for the government, it's generally
+
+15
+00:00:53,000 --> 00:00:54,000
+good enough for us.
+
+16
+00:00:54,000 --> 00:00:59,000
+The original Sha one was 160 bit hash.
+
+17
+00:00:59,000 --> 00:01:04,000
+This one here should no longer be used because it is subject to collisions.
+
+18
+00:01:04,000 --> 00:01:07,000
+Remember, how you beat collisions is by having a bigger hash function.
+
+19
+00:01:08,000 --> 00:01:11,000
+Sha two came in a variety of sizes.
+
+20
+00:01:11,000 --> 00:01:13,000
+Uh 256 bit.
+
+21
+00:01:13,000 --> 00:01:17,000
+It came in 512 and it also was 384.
+
+22
+00:01:17,000 --> 00:01:18,000
+I think this one came in.
+
+23
+00:01:18,000 --> 00:01:22,000
+So it did came in multiple sizes.
+
+24
+00:01:22,000 --> 00:01:24,000
+Now I don't need you guys to worry about the blocks.
+
+25
+00:01:24,000 --> 00:01:27,000
+I just need you guys to know basically the bit sizes on that.
+
+26
+00:01:27,000 --> 00:01:32,000
+There was a Sha three that came out that uh, is a newer version of that.
+
+27
+00:01:34,000 --> 00:01:37,000
+One of the most famous old school one was MD5.
+
+28
+00:01:37,000 --> 00:01:40,000
+Now MD5 should not be used.
+
+29
+00:01:40,000 --> 00:01:48,000
+MD5 has a lot of collisions because it doesn't have a very large, um, output at 128 bit.
+
+30
+00:01:48,000 --> 00:01:51,000
+Although it's big in today's world, it's not big anymore.
+
+31
+00:01:51,000 --> 00:01:53,000
+It is subject to collisions.
+
+32
+00:01:54,000 --> 00:02:03,000
+Now, the other one here is a ripe re and ripe MD uh or message digest.
+
+33
+00:02:03,000 --> 00:02:07,000
+This is an alternative to the Sha algorithms that are out there.
+
+34
+00:02:07,000 --> 00:02:10,000
+And these have a variety of different block sizes.
+
+35
+00:02:10,000 --> 00:02:14,000
+Now I did put it on the text here, but I do summarize it for you guys right here.
+
+36
+00:02:15,000 --> 00:02:21,000
+Realistically, I don't need you guys to know all this last column.
+
+37
+00:02:21,000 --> 00:02:23,000
+What I do need you guys to know is to know this column.
+
+38
+00:02:23,000 --> 00:02:26,000
+Know that these are basically.
+
+39
+00:02:28,000 --> 00:02:29,000
+Uh, hash functions.
+
+40
+00:02:29,000 --> 00:02:35,000
+So on the exam, if they give you something, a scenario that you have to use this particular algorithm
+
+41
+00:02:35,000 --> 00:02:40,000
+for, like for example, if they send your encrypted data across a network, don't select any of these
+
+42
+00:02:40,000 --> 00:02:42,000
+because these are hash functions.
+
+43
+00:02:42,000 --> 00:02:44,000
+They don't encrypt data, right.
+
+44
+00:02:44,000 --> 00:02:45,000
+They produce hash functions.
+
+45
+00:02:45,000 --> 00:02:46,000
+They're used for integrity.
+
+46
+00:02:46,000 --> 00:02:48,000
+So that's what you should know.
+
+47
+00:02:48,000 --> 00:02:53,000
+But if you want to see what what algorithm can change, data can detect if data has been modified.
+
+48
+00:02:53,000 --> 00:02:56,000
+Those hash functions, that's what they're there for.
+
+49
+00:02:56,000 --> 00:02:56,000
+All right.
+
+50
+00:02:56,000 --> 00:02:59,000
+So don't you know don't go crazy.
+
+51
+00:02:59,000 --> 00:02:59,000
+Oh my God.
+
+52
+00:02:59,000 --> 00:03:03,000
+And you know, you just maybe this column here you should know.
+
+53
+00:03:03,000 --> 00:03:04,000
+And it's pretty easy right.
+
+54
+00:03:04,000 --> 00:03:05,000
+Because.
+
+55
+00:03:05,000 --> 00:03:10,000
+Ripemd sha md5, just the ones you're probably going to see.
+
+56
+00:03:10,000 --> 00:03:13,000
+So it's basically only three of them you really should keep in mind.
+
+57
+00:03:14,000 --> 00:03:14,000
+Okay.
+
+58
+00:03:14,000 --> 00:03:20,000
+Make sure you know these, um, as a real life security person, just remember, Sha256 should be your
+
+59
+00:03:20,000 --> 00:03:21,000
+minimum.
+
+60
+00:03:21,000 --> 00:03:28,000
+Don't use hash functions that are generally under 256 bit in the world of security.
+

07 - Cryptography/013 Digital Signatures OB 1.4_en.srt

@@ -0,0 +1,636 @@
+1
+00:00:00,000 --> 00:00:07,000
+So far we have covered a lot symmetric asymmetric hashing hybrid cryptography.
+
+2
+00:00:07,000 --> 00:00:10,000
+So far we covered a lot in this topic.
+
+3
+00:00:10,000 --> 00:00:14,000
+We're going to be combining a lot of what we learned to produce a particular function that I need you
+
+4
+00:00:14,000 --> 00:00:16,000
+guys to know, because we use it a lot.
+
+5
+00:00:16,000 --> 00:00:19,000
+And that's called a digital signature.
+
+6
+00:00:19,000 --> 00:00:23,000
+Now a digital signature is not a not a way to encrypt data.
+
+7
+00:00:23,000 --> 00:00:28,000
+So it doesn't provide confidentiality, but it's a way that when you send data to someone, they know
+
+8
+00:00:28,000 --> 00:00:33,000
+it came from you, you can prove it came from you and it wasn't modified.
+
+9
+00:00:33,000 --> 00:00:39,000
+And a digital signature is going to utilize some of the things we learned in in asymmetric and hashing
+
+10
+00:00:39,000 --> 00:00:40,000
+in order to get it done.
+
+11
+00:00:40,000 --> 00:00:46,000
+So in this video, I want to go through what exactly is a digital signature and what is the process?
+
+12
+00:00:46,000 --> 00:00:50,000
+What is the process to make a signature and to verify a signature?
+
+13
+00:00:50,000 --> 00:00:51,000
+Let's get into it.
+
+14
+00:00:52,000 --> 00:00:55,000
+So what exactly is a digital signature?
+
+15
+00:00:55,000 --> 00:01:02,000
+Well, it's a cryptographic technique used to validate the authentic unity and integrity of a message
+
+16
+00:01:02,000 --> 00:01:03,000
+software digital document.
+
+17
+00:01:03,000 --> 00:01:09,000
+Now a lot of times we digitally sign things like digital certificates and even PDF files.
+
+18
+00:01:09,000 --> 00:01:11,000
+Word documents can all be digitally signed.
+
+19
+00:01:11,000 --> 00:01:14,000
+Emails very famous to be digitally signed.
+
+20
+00:01:14,000 --> 00:01:18,000
+Also, when you're doing a digital signature, you must remember.
+
+21
+00:01:19,000 --> 00:01:25,000
+A digital signature is authenticity or authentication, its integrity and non-repudiation.
+
+22
+00:01:25,000 --> 00:01:27,000
+It is not confidentiality.
+
+23
+00:01:27,000 --> 00:01:30,000
+The data goes in plain text.
+
+24
+00:01:30,000 --> 00:01:31,000
+You have to remember this.
+
+25
+00:01:31,000 --> 00:01:40,000
+So if I have an email that I digitally sign and I send you that email, the email goes in plain text.
+
+26
+00:01:40,000 --> 00:01:43,000
+That means if if all I did was digitally sign it.
+
+27
+00:01:44,000 --> 00:01:46,000
+And I sent it to you.
+
+28
+00:01:46,000 --> 00:01:47,000
+And a hacker sniffs the line.
+
+29
+00:01:47,000 --> 00:01:50,000
+The hacker would be able to read the email because the email is not encrypted.
+
+30
+00:01:50,000 --> 00:01:56,000
+But when you receive it, you'll know that it came from me.
+
+31
+00:01:57,000 --> 00:02:01,000
+I wouldn't be able to deny that it came from me.
+
+32
+00:02:01,000 --> 00:02:02,000
+Non-repudiation.
+
+33
+00:02:02,000 --> 00:02:06,000
+And you're going to be 100% sure it was never modified.
+
+34
+00:02:06,000 --> 00:02:07,000
+All right.
+
+35
+00:02:07,000 --> 00:02:09,000
+So that's these three things.
+
+36
+00:02:09,000 --> 00:02:11,000
+Confirms the signature was created by a sender.
+
+37
+00:02:11,000 --> 00:02:14,000
+So you'll know it came from me.
+
+38
+00:02:14,000 --> 00:02:17,000
+And I can't deny that it came from me.
+
+39
+00:02:17,000 --> 00:02:17,000
+All right.
+
+40
+00:02:17,000 --> 00:02:22,000
+So the authenticity, the non-repudiation, and then you'll know it was never modified.
+
+41
+00:02:22,000 --> 00:02:24,000
+That's the point that you guys need to get.
+
+42
+00:02:25,000 --> 00:02:29,000
+Once again, digital signatures does not encrypt the data.
+
+43
+00:02:29,000 --> 00:02:31,000
+The data is actually transferred in plain text.
+
+44
+00:02:31,000 --> 00:02:34,000
+Now, if you want to encrypt the data, well, that's a whole different thing.
+
+45
+00:02:34,000 --> 00:02:41,000
+Maybe then you can combine with SSL, IPsec or other types of secure, secure algorithms.
+
+46
+00:02:41,000 --> 00:02:45,000
+But if you're just using digital signatures, you're not going to get that.
+
+47
+00:02:46,000 --> 00:02:52,000
+Now in this video, I want to talk to you guys about the creation and the verification of it.
+
+48
+00:02:52,000 --> 00:03:00,000
+I do have all the texts listed here, but I have the, uh, I have a process that I drew out that I
+
+49
+00:03:00,000 --> 00:03:02,000
+want to go over with you that covers all of this.
+
+50
+00:03:02,000 --> 00:03:07,000
+So if you're watching, if you're reading this instead of watching it, well, you guys can read this,
+
+51
+00:03:07,000 --> 00:03:12,000
+but since you're with me, I'm going to explain it to you in this particular.
+
+52
+00:03:14,000 --> 00:03:15,000
+In this.
+
+53
+00:03:15,000 --> 00:03:16,000
+Uh, where is my.
+
+54
+00:03:16,000 --> 00:03:17,000
+Here we go.
+
+55
+00:03:17,000 --> 00:03:18,000
+In this process.
+
+56
+00:03:18,000 --> 00:03:20,000
+So I watch you guys watch this.
+
+57
+00:03:20,000 --> 00:03:25,000
+So I'm going to show you how we are going to generate a signature.
+
+58
+00:03:26,000 --> 00:03:26,000
+Okay.
+
+59
+00:03:26,000 --> 00:03:28,000
+We're going to generate a digital signature.
+
+60
+00:03:28,000 --> 00:03:30,000
+We're going to attach it to a document send it to the receiver.
+
+61
+00:03:30,000 --> 00:03:31,000
+Let's see how this is done.
+
+62
+00:03:31,000 --> 00:03:33,000
+So here we have the sender and the.
+
+63
+00:03:35,000 --> 00:03:37,000
+And the receiver.
+
+64
+00:03:37,000 --> 00:03:42,000
+Mary I'm always sending Mary things because okay, so here's how it's done okay.
+
+65
+00:03:43,000 --> 00:03:46,000
+You take a plain text message?
+
+66
+00:03:46,000 --> 00:03:48,000
+This is the message.
+
+67
+00:03:48,000 --> 00:03:53,000
+And then what you're going to do is you're going to hash it, hash the entire message.
+
+68
+00:03:53,000 --> 00:03:58,000
+And this produces that cryptographic hash that, remember, if you remember in the hashing video was
+
+69
+00:03:58,000 --> 00:03:59,000
+just a string of characters.
+
+70
+00:03:59,000 --> 00:04:01,000
+Basically it produces the digest.
+
+71
+00:04:01,000 --> 00:04:03,000
+Remember the digest hash.
+
+72
+00:04:03,000 --> 00:04:03,000
+Same thing.
+
+73
+00:04:04,000 --> 00:04:15,000
+Then what the sender does is the sender encrypts this digest with the sender's private key.
+
+74
+00:04:16,000 --> 00:04:18,000
+That is.
+
+75
+00:04:18,000 --> 00:04:18,000
+All right.
+
+76
+00:04:18,000 --> 00:04:20,000
+Then they're using an RSA key here.
+
+77
+00:04:20,000 --> 00:04:22,000
+That is the digital signature.
+
+78
+00:04:23,000 --> 00:04:24,000
+So let's get this straight.
+
+79
+00:04:25,000 --> 00:04:26,000
+If I'm the sender.
+
+80
+00:04:26,000 --> 00:04:27,000
+I took the message.
+
+81
+00:04:28,000 --> 00:04:30,000
+I hashed it.
+
+82
+00:04:30,000 --> 00:04:34,000
+I did encrypt the hash with my private key.
+
+83
+00:04:34,000 --> 00:04:35,000
+Not my public key.
+
+84
+00:04:36,000 --> 00:04:37,000
+My private key.
+
+85
+00:04:37,000 --> 00:04:38,000
+Why the private key?
+
+86
+00:04:38,000 --> 00:04:44,000
+Because the only person in the world that has my private key is me.
+
+87
+00:04:44,000 --> 00:04:46,000
+No one else.
+
+88
+00:04:46,000 --> 00:04:52,000
+So a digital signature in its purest form is an encrypted hash.
+
+89
+00:04:52,000 --> 00:04:53,000
+Really all it is?
+
+90
+00:04:53,000 --> 00:04:56,000
+It's encrypted with an asymmetric algorithm.
+
+91
+00:04:56,000 --> 00:04:58,000
+In this one they're using RSA.
+
+92
+00:04:58,000 --> 00:05:00,000
+You can also use ECC here.
+
+93
+00:05:00,000 --> 00:05:08,000
+So what I do is I take this digital signature and I attach it to the document and I send it to the receiver.
+
+94
+00:05:10,000 --> 00:05:13,000
+Mary has the document okay.
+
+95
+00:05:14,000 --> 00:05:15,000
+And the digital signature.
+
+96
+00:05:15,000 --> 00:05:18,000
+But remember it's all going in plain text signatures.
+
+97
+00:05:18,000 --> 00:05:20,000
+Everything is in plain text.
+
+98
+00:05:20,000 --> 00:05:21,000
+What does Mary do?
+
+99
+00:05:21,000 --> 00:05:23,000
+So Mary is like, okay, I got this signature.
+
+100
+00:05:23,000 --> 00:05:27,000
+Mary is like, okay, I need to verify, you know, that this actually came from Andy.
+
+101
+00:05:27,000 --> 00:05:28,000
+How is she going to do it?
+
+102
+00:05:28,000 --> 00:05:29,000
+Next slide.
+
+103
+00:05:30,000 --> 00:05:31,000
+How does she do it?
+
+104
+00:05:31,000 --> 00:05:31,000
+Well.
+
+105
+00:05:32,000 --> 00:05:33,000
+Here's what she's going to do.
+
+106
+00:05:34,000 --> 00:05:37,000
+So receiver again.
+
+107
+00:05:37,000 --> 00:05:37,000
+Mary.
+
+108
+00:05:40,000 --> 00:05:46,000
+Mary has to go through a couple of things, but Mary does is she takes this digitally signed message.
+
+109
+00:05:46,000 --> 00:05:49,000
+She removes the digital signature from it.
+
+110
+00:05:49,000 --> 00:05:51,000
+So now she has the plain text message.
+
+111
+00:05:51,000 --> 00:05:58,000
+She then hashes it with the same algorithm that I used to hash the original message, and she ends up
+
+112
+00:05:58,000 --> 00:05:58,000
+with a digest.
+
+113
+00:05:59,000 --> 00:06:02,000
+She then takes the digital signature right?
+
+114
+00:06:02,000 --> 00:06:09,000
+And she decrypts it with my the sender's.
+
+115
+00:06:09,000 --> 00:06:11,000
+Public key.
+
+116
+00:06:11,000 --> 00:06:12,000
+Why the sender's public key?
+
+117
+00:06:12,000 --> 00:06:19,000
+Because, remember, in the generation, it was the sender's private key that was used to.
+
+118
+00:06:20,000 --> 00:06:23,000
+Encrypt the actual hash.
+
+119
+00:06:23,000 --> 00:06:28,000
+So what she's doing here is she's decrypting the signature with the public key.
+
+120
+00:06:29,000 --> 00:06:32,000
+If the private encrypts, the public has to decrypt that.
+
+121
+00:06:33,000 --> 00:06:36,000
+Provides the message digest.
+
+122
+00:06:36,000 --> 00:06:41,000
+So what she's going to do now is she's going to compare the hash that she generated from the message,
+
+123
+00:06:41,000 --> 00:06:45,000
+and she's going to compare the hash that was generated from the signature she just decrypted.
+
+124
+00:06:45,000 --> 00:06:53,000
+And she's going to see do they compare if the message is from the digital signatures matches.
+
+125
+00:06:54,000 --> 00:06:54,000
+Right.
+
+126
+00:06:54,000 --> 00:06:58,000
+If the if this digest matches this digest, then it could be trusted by.
+
+127
+00:06:59,000 --> 00:07:00,000
+Well.
+
+128
+00:07:01,000 --> 00:07:05,000
+If the two digests are matching, it shows that the message was never modified.
+
+129
+00:07:06,000 --> 00:07:06,000
+Right.
+
+130
+00:07:06,000 --> 00:07:08,000
+Because if there's any modification to digest would change.
+
+131
+00:07:08,000 --> 00:07:13,000
+And she knows 100% that it came from me.
+
+132
+00:07:13,000 --> 00:07:13,000
+Why?
+
+133
+00:07:13,000 --> 00:07:17,000
+Because she used my public key to decrypt that.
+
+134
+00:07:17,000 --> 00:07:20,000
+If she had used somebody else public key, it would never match.
+
+135
+00:07:20,000 --> 00:07:23,000
+It would look like more garbage or more ciphertext.
+
+136
+00:07:24,000 --> 00:07:27,000
+So that is the process of a digital signature.
+
+137
+00:07:28,000 --> 00:07:31,000
+Now digital signatures are widely used.
+
+138
+00:07:31,000 --> 00:07:34,000
+Now, if you by the way, if you don't understand this process and you want to do it, you know, watch
+
+139
+00:07:34,000 --> 00:07:35,000
+this video a couple of times.
+
+140
+00:07:35,000 --> 00:07:38,000
+But digital signatures are widely used.
+
+141
+00:07:38,000 --> 00:07:41,000
+In fact, there's a whole standard on it.
+
+142
+00:07:41,000 --> 00:07:46,000
+So one time that you may want to be familiar with is something we call the DSS or the digital signature
+
+143
+00:07:46,000 --> 00:07:52,000
+standard, because when you produce a signature, the person has to know what algorithm you use, right?
+
+144
+00:07:52,000 --> 00:07:55,000
+They have to know, did he use Sha256?
+
+145
+00:07:55,000 --> 00:07:55,000
+512.
+
+146
+00:07:55,000 --> 00:08:03,000
+Sha Sha two Sha three uh, you could use ECC as the asymmetric or RSA.
+
+147
+00:08:04,000 --> 00:08:07,000
+So there is a standard for this, right?
+
+148
+00:08:07,000 --> 00:08:13,000
+So NSA created the digital digital signature algorithm.
+
+149
+00:08:13,000 --> 00:08:16,000
+The digital signature algorithm utilizes either.
+
+150
+00:08:16,000 --> 00:08:20,000
+So the DSA is either it's shot 2 or 3.
+
+151
+00:08:20,000 --> 00:08:28,000
+With RSA there's another one called Ecdsa which is instead of using RSA they use elliptic curve.
+
+152
+00:08:28,000 --> 00:08:28,000
+All right.
+
+153
+00:08:28,000 --> 00:08:32,000
+So just be familiar that there is a signature standard for this.
+
+154
+00:08:33,000 --> 00:08:36,000
+Digital signatures are really important digital signatures.
+
+155
+00:08:36,000 --> 00:08:43,000
+When somebody signs a document you are 100% sure it came from that person and it was never modified.
+
+156
+00:08:43,000 --> 00:08:47,000
+You have to remember that because I'm about to bring everything together when we talk about public key
+
+157
+00:08:47,000 --> 00:08:48,000
+infrastructure.
+
+158
+00:08:48,000 --> 00:08:51,000
+So remember that once a digital signature is done.
+
+159
+00:08:52,000 --> 00:08:59,000
+You're 100% sure that it came from that person and it was never modified.
+

07 - Cryptography/014 Intro to PKI OB 1.4_en.srt

@@ -0,0 +1,124 @@
+1
+00:00:00,000 --> 00:00:04,000
+In this video, I want to start the discussion of the public key infrastructure.
+
+2
+00:00:04,000 --> 00:00:10,000
+But before we get into that, I want to go to Amazon and I want to clear up some things about Amazon
+
+3
+00:00:10,000 --> 00:00:11,000
+that we should know.
+
+4
+00:00:11,000 --> 00:00:13,000
+Before we get into this topic, let's take a look.
+
+5
+00:00:13,000 --> 00:00:16,000
+So here I am at Amazon.com.
+
+6
+00:00:16,000 --> 00:00:19,000
+Now the question is going to be how do I know?
+
+7
+00:00:19,000 --> 00:00:24,000
+How does this computer know that this is Amazon.
+
+8
+00:00:24,000 --> 00:00:27,000
+Like do you trust the browser?
+
+9
+00:00:27,000 --> 00:00:34,000
+Okay, it says Amazon.com on it, but how does this computer know that this is Amazon.com?
+
+10
+00:00:34,000 --> 00:00:36,000
+Is there a trust factor?
+
+11
+00:00:36,000 --> 00:00:41,000
+Did Amazon tell this computer something that says, hey, I'm Amazon.com and the computer is like,
+
+12
+00:00:41,000 --> 00:00:45,000
+okay, well, I guess you are, but how can the machine verify that?
+
+13
+00:00:46,000 --> 00:00:51,000
+Well, you guys probably already know the answer to this is because it has a certificate.
+
+14
+00:00:51,000 --> 00:00:55,000
+This connection is secured using TLS.
+
+15
+00:00:55,000 --> 00:00:58,000
+And how do we know connections are secured?
+
+16
+00:00:58,000 --> 00:01:00,000
+Well, on most browsers, if not all.
+
+17
+00:01:00,000 --> 00:01:08,000
+When you look at a connection like on Amazon, you'll notice that we have a little lock icon.
+
+18
+00:01:08,000 --> 00:01:10,000
+If I go to this icon, I click on it.
+
+19
+00:01:10,000 --> 00:01:12,000
+It says the connection is secure.
+
+20
+00:01:12,000 --> 00:01:15,000
+I click here and it says the certificate is valid.
+
+21
+00:01:15,000 --> 00:01:19,000
+But what exactly is this particular certificate?
+
+22
+00:01:19,000 --> 00:01:23,000
+What is the purpose of this certificate and what you know?
+
+23
+00:01:23,000 --> 00:01:30,000
+What exactly is it doing that makes this computer trust that this is Amazon.com?
+
+24
+00:01:31,000 --> 00:01:39,000
+A certificate is basically nothing more than a document that contains Amazon's public key and a signature
+
+25
+00:01:39,000 --> 00:01:43,000
+from a certificate authority saying that that's actually Amazon in a nutshell.
+
+26
+00:01:43,000 --> 00:01:44,000
+That's what it is.
+
+27
+00:01:44,000 --> 00:01:51,000
+But in this section of the course, I'm going to go in depth into more into all the fields on that certificate.
+
+28
+00:01:51,000 --> 00:01:57,000
+What exactly is a certificate authority and why is, you know, why do we need it?
+
+29
+00:01:57,000 --> 00:02:01,000
+Why is it so important that your connection be trusted or secure?
+
+30
+00:02:01,000 --> 00:02:02,000
+Okay.
+
+31
+00:02:02,000 --> 00:02:05,000
+So let's go ahead and get started in this section.
+

07 - Cryptography/016 SSLTLS Handshake OB 1.4_en.srt

@@ -0,0 +1,1176 @@
+1
+00:00:00,000 --> 00:00:06,000
+In this video, I'm going to be going over the SSL handshake, something that you really have to understand,
+
+2
+00:00:06,000 --> 00:00:10,000
+not just for your exam, but exactly how this cryptography work.
+
+3
+00:00:10,000 --> 00:00:17,000
+When you buy something on Amazon or any website or any website that is secured using TLS or SSL.
+
+4
+00:00:17,000 --> 00:00:22,000
+Now for this course and in particular this section, TLS and SSL is the same thing.
+
+5
+00:00:22,000 --> 00:00:26,000
+So if I ever say SSL, TLS remember something SSL is not used anymore.
+
+6
+00:00:26,000 --> 00:00:31,000
+SSL is replaced by TLS, but a lot of people still reference it.
+
+7
+00:00:31,000 --> 00:00:34,000
+Like if you go online, you Google SSL certificate.
+
+8
+00:00:34,000 --> 00:00:36,000
+They're not really SSL, they're all TLS certificate.
+
+9
+00:00:37,000 --> 00:00:42,000
+So for argument's sake, we'll just say we'll just use the terms SSL for the remainder of the course.
+
+10
+00:00:42,000 --> 00:00:44,000
+Remember it is actually TLS.
+
+11
+00:00:44,000 --> 00:00:46,000
+Now let's get started.
+
+12
+00:00:46,000 --> 00:00:49,000
+So in this video we want to talk about the SSL handshake.
+
+13
+00:00:49,000 --> 00:00:55,000
+Now the presentation that I'm going to be using the diagram I'm going to be using comes from Ibm.com.
+
+14
+00:00:55,000 --> 00:01:01,000
+And that particular link I will be sharing with you guys on the slide.
+
+15
+00:01:01,000 --> 00:01:06,000
+And I want to show you guys what that looks like now, so you can check it out whenever you get a minute.
+
+16
+00:01:06,000 --> 00:01:08,000
+Uh, here's Ibm.com.
+
+17
+00:01:09,000 --> 00:01:12,000
+This was last updated 2021 the SSL handshake.
+
+18
+00:01:12,000 --> 00:01:12,000
+So I took this.
+
+19
+00:01:12,000 --> 00:01:13,000
+I put it on the slide.
+
+20
+00:01:13,000 --> 00:01:18,000
+Of course, I put the link here for you guys to review it also, and I want to go over this with you
+
+21
+00:01:19,000 --> 00:01:21,000
+if you're asking yourself well why?
+
+22
+00:01:21,000 --> 00:01:25,000
+Because this is going to explain to you at a high level overview.
+
+23
+00:01:25,000 --> 00:01:29,000
+Exactly how does a connection work?
+
+24
+00:01:29,000 --> 00:01:36,000
+Like when you go to Amazon.com and you try to purchase something, you go to Yahoo YouTube.
+
+25
+00:01:36,000 --> 00:01:37,000
+It doesn't matter.
+
+26
+00:01:37,000 --> 00:01:39,000
+They're all secure sites.
+
+27
+00:01:39,000 --> 00:01:43,000
+In fact, all sites on the internet right now are secured using SSL.
+
+28
+00:01:43,000 --> 00:01:46,000
+How exactly this whole encryption process work?
+
+29
+00:01:46,000 --> 00:01:47,000
+Now I want to point out something.
+
+30
+00:01:47,000 --> 00:01:52,000
+The SSL handshake presentation that I'm using from IBM is a high level.
+
+31
+00:01:52,000 --> 00:01:55,000
+It's not very detailed and it's not very technical.
+
+32
+00:01:55,000 --> 00:01:56,000
+For your exam.
+
+33
+00:01:56,000 --> 00:01:58,000
+You don't need to be detailed and technical.
+
+34
+00:01:59,000 --> 00:02:02,000
+If you take my course, I'll get more in depth into it.
+
+35
+00:02:02,000 --> 00:02:04,000
+But for this course you don't need that.
+
+36
+00:02:04,000 --> 00:02:08,000
+You just need to have a good understanding or a high level overview understanding.
+
+37
+00:02:08,000 --> 00:02:09,000
+Let's get started on it.
+
+38
+00:02:09,000 --> 00:02:18,000
+So I go to Amazon.com and here I am at Amazon and I can see that my connection is secure.
+
+39
+00:02:18,000 --> 00:02:21,000
+And if you notice is it secure.
+
+40
+00:02:21,000 --> 00:02:22,000
+Yeah, it's fully secured.
+
+41
+00:02:22,000 --> 00:02:25,000
+Because if you notice I have an Https right here.
+
+42
+00:02:25,000 --> 00:02:28,000
+So this is utilizing SSL.
+
+43
+00:02:28,000 --> 00:02:31,000
+Now the question is going to be how do I know.
+
+44
+00:02:31,000 --> 00:02:32,000
+Like it's actually working.
+
+45
+00:02:32,000 --> 00:02:34,000
+And you know what's happening in the background.
+
+46
+00:02:34,000 --> 00:02:40,000
+Well one of the things is that every single website you go to that is secure is going to have this little
+
+47
+00:02:40,000 --> 00:02:41,000
+lock icon.
+
+48
+00:02:41,000 --> 00:02:42,000
+So I'm going to click on this little lock icon.
+
+49
+00:02:42,000 --> 00:02:46,000
+This lock icon tells me the connection is secure.
+
+50
+00:02:46,000 --> 00:02:49,000
+And you can't have a secure connection without a certificate.
+
+51
+00:02:49,000 --> 00:02:52,000
+So I'm going to go to connection to secure certificate is valid.
+
+52
+00:02:52,000 --> 00:02:53,000
+I'm just going to click on this.
+
+53
+00:02:53,000 --> 00:02:56,000
+This is Amazon certificate.
+
+54
+00:02:56,000 --> 00:02:58,000
+Now what exactly is a certificate.
+
+55
+00:02:58,000 --> 00:03:04,000
+Well a certificate really serves two main purpose in the world of encryption.
+
+56
+00:03:04,000 --> 00:03:09,000
+Number one, it serves as a trusted as an external validation of trust.
+
+57
+00:03:09,000 --> 00:03:15,000
+So right now Amazon is not saying that I'm Amazon because I'm Amazon.
+
+58
+00:03:16,000 --> 00:03:20,000
+Amazon is telling your computer that it's Amazon.
+
+59
+00:03:20,000 --> 00:03:24,000
+Not because I said it's Amazon or because Amazon said it's Amazon.
+
+60
+00:03:24,000 --> 00:03:31,000
+It's saying that because this authority Digicert says that this is Amazon.com and this is important.
+
+61
+00:03:31,000 --> 00:03:35,000
+External validation creates trust.
+
+62
+00:03:35,000 --> 00:03:36,000
+Let me explain this to you.
+
+63
+00:03:37,000 --> 00:03:40,000
+So I'm Andrew Ramsdale okay.
+
+64
+00:03:40,000 --> 00:03:44,000
+I'm the guy with the 66 certifications, the world's best selling book.
+
+65
+00:03:45,000 --> 00:03:47,000
+But do you know that for sure?
+
+66
+00:03:47,000 --> 00:03:49,000
+Do you know if I'm that person?
+
+67
+00:03:49,000 --> 00:03:54,000
+There is a guy that wrote the world's best selling book on Amazon for project management.
+
+68
+00:03:54,000 --> 00:03:58,000
+There is a guy that made a, you know, a lot of different videos and has helped hundreds of thousands
+
+69
+00:03:58,000 --> 00:04:02,000
+of people pass exams, but am I that person?
+
+70
+00:04:02,000 --> 00:04:03,000
+Do you trust me?
+
+71
+00:04:03,000 --> 00:04:05,000
+If I told you I'm Andrew, do you?
+
+72
+00:04:05,000 --> 00:04:06,000
+How do you know?
+
+73
+00:04:06,000 --> 00:04:09,000
+How do you know I am that person?
+
+74
+00:04:09,000 --> 00:04:10,000
+How do you.
+
+75
+00:04:10,000 --> 00:04:12,000
+You know I am that entity.
+
+76
+00:04:13,000 --> 00:04:15,000
+Well, I'm just telling you I am.
+
+77
+00:04:15,000 --> 00:04:16,000
+Is that okay if I tell you?
+
+78
+00:04:16,000 --> 00:04:19,000
+Or would you like for me to produce my driver's license?
+
+79
+00:04:19,000 --> 00:04:20,000
+Like if I told you.
+
+80
+00:04:20,000 --> 00:04:21,000
+Okay.
+
+81
+00:04:21,000 --> 00:04:23,000
+Here's my driver's license.
+
+82
+00:04:23,000 --> 00:04:24,000
+Would you believe me then?
+
+83
+00:04:25,000 --> 00:04:27,000
+So if you say yes, okay.
+
+84
+00:04:27,000 --> 00:04:34,000
+If you show me your license, that shows me that your Andrew and that picture matches you, then you,
+
+85
+00:04:34,000 --> 00:04:36,000
+then you're more likely or you will believe it.
+
+86
+00:04:36,000 --> 00:04:41,000
+That tells me something that tells me that you don't trust me.
+
+87
+00:04:41,000 --> 00:04:44,000
+You trust the DMV.
+
+88
+00:04:44,000 --> 00:04:46,000
+You have a trust with the DMV.
+
+89
+00:04:46,000 --> 00:04:53,000
+And if the DMV says that this guy is Andrew, then you trust that you're like, okay, that that guy
+
+90
+00:04:53,000 --> 00:04:54,000
+must be Andrew.
+
+91
+00:04:54,000 --> 00:04:56,000
+Do you understand what I'm saying here?
+
+92
+00:04:56,000 --> 00:05:00,000
+What I'm trying to tell you is you don't have a trust with me.
+
+93
+00:05:00,000 --> 00:05:02,000
+You have a trust with the DMV.
+
+94
+00:05:02,000 --> 00:05:08,000
+And because the DMV is saying that I'm Andrew now, you believe, okay, he's Andrew, but you don't
+
+95
+00:05:08,000 --> 00:05:10,000
+believe a word that comes out of my mouth.
+
+96
+00:05:10,000 --> 00:05:13,000
+You believe what the DMV is saying?
+
+97
+00:05:13,000 --> 00:05:15,000
+And why do you believe the DMV?
+
+98
+00:05:15,000 --> 00:05:16,000
+That's the question.
+
+99
+00:05:16,000 --> 00:05:18,000
+Why do you believe the DMV?
+
+100
+00:05:18,000 --> 00:05:25,000
+Well, because I couldn't get the license if I didn't show my passport.
+
+101
+00:05:25,000 --> 00:05:27,000
+Bank statements.
+
+102
+00:05:27,000 --> 00:05:29,000
+Uh, I forgot all the documents.
+
+103
+00:05:29,000 --> 00:05:29,000
+Right?
+
+104
+00:05:29,000 --> 00:05:30,000
+You got to get in New York.
+
+105
+00:05:30,000 --> 00:05:31,000
+You got to get all these points.
+
+106
+00:05:31,000 --> 00:05:32,000
+Right.
+
+107
+00:05:32,000 --> 00:05:34,000
+So I had to show all these identity documents.
+
+108
+00:05:34,000 --> 00:05:37,000
+And that's the reason why you trust the DMV.
+
+109
+00:05:37,000 --> 00:05:40,000
+Well, you see, in computers, it's the same thing.
+
+110
+00:05:41,000 --> 00:05:42,000
+Computers.
+
+111
+00:05:42,000 --> 00:05:45,000
+Don't trust a website to say it's a web.
+
+112
+00:05:45,000 --> 00:05:48,000
+It doesn't trust the website to say it's that website.
+
+113
+00:05:49,000 --> 00:05:50,000
+It trusses.
+
+114
+00:05:50,000 --> 00:05:55,000
+Your computer has a pre list of authorities that it trusts.
+
+115
+00:05:55,000 --> 00:05:57,000
+Quote unquote DMVs.
+
+116
+00:05:57,000 --> 00:05:59,000
+These are going to be called certificate authorities.
+
+117
+00:05:59,000 --> 00:06:02,000
+Your computer has a pre list of certificate authorities that it trusts.
+
+118
+00:06:02,000 --> 00:06:07,000
+Similarly to how your mind has a list of people that it trusts like DMVs.
+
+119
+00:06:08,000 --> 00:06:14,000
+So when these authorities give out, quote unquote, driver's license, we'll call them certificates,
+
+120
+00:06:14,000 --> 00:06:16,000
+two different websites.
+
+121
+00:06:16,000 --> 00:06:21,000
+When your computer go to them, your computer is like, hey, how do I know this is Amazon?
+
+122
+00:06:21,000 --> 00:06:26,000
+And then you look at your computer, looks at the certificate and say, well, how do I know this is
+
+123
+00:06:26,000 --> 00:06:26,000
+Amazon?
+
+124
+00:06:26,000 --> 00:06:31,000
+Well, it's coming from somebody I trust Digicert in particular.
+
+125
+00:06:31,000 --> 00:06:33,000
+And how do I know this is Amazon?
+
+126
+00:06:33,000 --> 00:06:43,000
+Because Digicert is saying that this is Amazon and because your computer is able to trust.
+
+127
+00:06:43,000 --> 00:06:46,000
+Uh digicert you now trust that this is Amazon.
+
+128
+00:06:46,000 --> 00:06:48,000
+That's how this game works.
+
+129
+00:06:49,000 --> 00:06:54,000
+There are certain websites where there's something called a self-signed certificate.
+
+130
+00:06:54,000 --> 00:06:55,000
+We'll talk more about this later.
+
+131
+00:06:55,000 --> 00:07:00,000
+But self-signed certificates is when the company it's trust it's issued by Amazon to Amazon to Amazon
+
+132
+00:07:00,000 --> 00:07:01,000
+is saying I'm Amazon.
+
+133
+00:07:01,000 --> 00:07:04,000
+You don't trust that a lot of people don't trust self-signed certificates.
+
+134
+00:07:04,000 --> 00:07:08,000
+In fact, when internal organizations do it internally, it's not considered external trust because
+
+135
+00:07:08,000 --> 00:07:10,000
+nobody trusts it externally.
+
+136
+00:07:10,000 --> 00:07:11,000
+Self-signed.
+
+137
+00:07:11,000 --> 00:07:15,000
+That's like me making my own ID it's like, hey, you trust I'm Andrew when I here is an ID that I made
+
+138
+00:07:15,000 --> 00:07:16,000
+on my computer last time.
+
+139
+00:07:16,000 --> 00:07:17,000
+It says I'm Andrew.
+
+140
+00:07:17,000 --> 00:07:18,000
+Do you trust that?
+
+141
+00:07:18,000 --> 00:07:18,000
+No.
+
+142
+00:07:18,000 --> 00:07:22,000
+You trust the driver's license because it comes from the DMV.
+
+143
+00:07:23,000 --> 00:07:25,000
+So that's this concept of trust.
+
+144
+00:07:25,000 --> 00:07:27,000
+That's why trust is important.
+
+145
+00:07:27,000 --> 00:07:34,000
+Your computer needs to have some kind of external validation that this is Amazon.
+
+146
+00:07:34,000 --> 00:07:35,000
+And what's doing that.
+
+147
+00:07:35,000 --> 00:07:39,000
+The certificate is doing that now a certificate I mentioned.
+
+148
+00:07:39,000 --> 00:07:39,000
+It's two things.
+
+149
+00:07:39,000 --> 00:07:46,000
+Not just establishing that trust, but the certificate is a way to give the public key.
+
+150
+00:07:46,000 --> 00:07:49,000
+And that's important because that's going to become part of this handshake.
+
+151
+00:07:49,000 --> 00:07:50,000
+And I want to show you guys that.
+
+152
+00:07:51,000 --> 00:07:57,000
+So by looking if I go to details on this certificate on here.
+
+153
+00:07:57,000 --> 00:07:59,000
+So this is the Amazon certificate that we have.
+
+154
+00:07:59,000 --> 00:08:02,000
+And you notice I have a variety of fields here.
+
+155
+00:08:02,000 --> 00:08:11,000
+So if I go down and I look into all of these fields that is listed here notice subject public key info.
+
+156
+00:08:12,000 --> 00:08:14,000
+Subjects public key algorithm.
+
+157
+00:08:14,000 --> 00:08:17,000
+It's an RSA key that they're using.
+
+158
+00:08:17,000 --> 00:08:19,000
+Remember RSA is asymmetric.
+
+159
+00:08:19,000 --> 00:08:22,000
+But here is Amazon's actual public key.
+
+160
+00:08:22,000 --> 00:08:25,000
+This is a it's written it looks weird.
+
+161
+00:08:25,000 --> 00:08:29,000
+It's written in a hex but it's a 2048 bit RSA key.
+
+162
+00:08:29,000 --> 00:08:32,000
+This is Amazon's actual public key.
+
+163
+00:08:33,000 --> 00:08:35,000
+Remember there is a public and a private key.
+
+164
+00:08:35,000 --> 00:08:41,000
+So Amazon is allowing the transport of their public key to the world.
+
+165
+00:08:41,000 --> 00:08:47,000
+Now if you remember how asymmetric works in the world of asymmetric cryptography your public key is
+
+166
+00:08:47,000 --> 00:08:47,000
+given to the world.
+
+167
+00:08:47,000 --> 00:08:52,000
+The question is how is Amazon distributing the public key to the rest of the world?
+
+168
+00:08:52,000 --> 00:08:54,000
+Well, that's done using a certificate.
+
+169
+00:08:54,000 --> 00:08:58,000
+So certificates are ways to pass the public key around.
+
+170
+00:08:58,000 --> 00:09:00,000
+And that brings me to the SSL handshake.
+
+171
+00:09:00,000 --> 00:09:06,000
+So exactly when I go to Amazon, what exactly happens in the background.
+
+172
+00:09:06,000 --> 00:09:09,000
+How am I getting this secure trust between them?
+
+173
+00:09:09,000 --> 00:09:15,000
+How am I security transferring data and that brings me to the SSL handshake that I have right here.
+
+174
+00:09:15,000 --> 00:09:18,000
+And again I took this from the IBM website.
+
+175
+00:09:19,000 --> 00:09:20,000
+Uh.
+
+176
+00:09:20,000 --> 00:09:25,000
+And the link is provided at the top of me.
+
+177
+00:09:25,000 --> 00:09:25,000
+All right.
+
+178
+00:09:25,000 --> 00:09:26,000
+Somewhere around there.
+
+179
+00:09:27,000 --> 00:09:28,000
+Uh, so let's get into it.
+
+180
+00:09:28,000 --> 00:09:32,000
+So now the steps are going to be listed on the left side of the screen.
+
+181
+00:09:32,000 --> 00:09:34,000
+And I want to go over the diagram.
+
+182
+00:09:34,000 --> 00:09:40,000
+So let's say in this diagram the client is you will put Andy.
+
+183
+00:09:42,000 --> 00:09:43,000
+And the server is Amazon.
+
+184
+00:09:46,000 --> 00:09:50,000
+Now I go to Amazon.com and I press enter.
+
+185
+00:09:50,000 --> 00:09:50,000
+I type.
+
+186
+00:09:51,000 --> 00:09:51,000
+Well, I don't go.
+
+187
+00:09:51,000 --> 00:09:54,000
+I type Amazon.com and I press enter.
+
+188
+00:09:54,000 --> 00:09:55,000
+What happens?
+
+189
+00:09:55,000 --> 00:09:58,000
+The client issues a secure request session.
+
+190
+00:09:58,000 --> 00:10:03,000
+So it's me going to Amazon and says, Hey Amazon, I need to set up a secure session with you.
+
+191
+00:10:03,000 --> 00:10:09,000
+Amazon sends back an X509 certificate.
+
+192
+00:10:09,000 --> 00:10:11,000
+That's the type of certificate that they're using.
+
+193
+00:10:11,000 --> 00:10:11,000
+Now.
+
+194
+00:10:11,000 --> 00:10:14,000
+In reality, almost all certificates are x509.
+
+195
+00:10:14,000 --> 00:10:16,000
+They send back.
+
+196
+00:10:16,000 --> 00:10:21,000
+The certificate that I showed you containing their public key.
+
+197
+00:10:21,000 --> 00:10:24,000
+Now that we spoke about that, I showed you you.
+
+198
+00:10:24,000 --> 00:10:31,000
+When you receive it, you're going to authenticate that certificate against a list of known certificate
+
+199
+00:10:31,000 --> 00:10:32,000
+authorities.
+
+200
+00:10:32,000 --> 00:10:33,000
+This is important.
+
+201
+00:10:33,000 --> 00:10:35,000
+This is the part of the trust.
+
+202
+00:10:35,000 --> 00:10:39,000
+So when you receive Amazon Cert, you're like, well, who gave him this cert?
+
+203
+00:10:39,000 --> 00:10:39,000
+Okay.
+
+204
+00:10:39,000 --> 00:10:41,000
+It was given by Digicert.
+
+205
+00:10:41,000 --> 00:10:45,000
+Do you trust Digicert yes I do again your computer does all this.
+
+206
+00:10:45,000 --> 00:10:49,000
+Your computer trusts Digicert now.
+
+207
+00:10:49,000 --> 00:10:50,000
+What happened?
+
+208
+00:10:50,000 --> 00:10:57,000
+You, the client on your computer, generate a symmetric key.
+
+209
+00:10:58,000 --> 00:11:05,000
+Once you generate the symmetric key, you then encrypt it with the server's public key and you send
+
+210
+00:11:05,000 --> 00:11:06,000
+it back.
+
+211
+00:11:06,000 --> 00:11:08,000
+Notice the arrow to Amazon.
+
+212
+00:11:08,000 --> 00:11:09,000
+So here's what you're doing.
+
+213
+00:11:09,000 --> 00:11:18,000
+You're going to generate, for example, an AES 120 beta 128 bit or 256 bit AES key.
+
+214
+00:11:18,000 --> 00:11:21,000
+You're then going to send it to Amazon.com.
+
+215
+00:11:21,000 --> 00:11:23,000
+Amazon.
+
+216
+00:11:23,000 --> 00:11:27,000
+Remember it was encrypted with their what public key.
+
+217
+00:11:27,000 --> 00:11:28,000
+So what does Amazon do.
+
+218
+00:11:29,000 --> 00:11:32,000
+Amazon once they receive.
+
+219
+00:11:33,000 --> 00:11:36,000
+Uh, your symmetric key encrypted with their public key.
+
+220
+00:11:36,000 --> 00:11:38,000
+They decrypt it with their corresponding.
+
+221
+00:11:38,000 --> 00:11:39,000
+What?
+
+222
+00:11:39,000 --> 00:11:39,000
+Private key.
+
+223
+00:11:39,000 --> 00:11:44,000
+Remember, if you encrypt something with Amazon's public key, only Amazon's private key can decrypt
+
+224
+00:11:44,000 --> 00:11:44,000
+it.
+
+225
+00:11:45,000 --> 00:11:52,000
+Now Amazon has that public has that symmetric key or that session key that you make.
+
+226
+00:11:52,000 --> 00:11:55,000
+Now the client and the server knows both.
+
+227
+00:11:55,000 --> 00:12:02,000
+Now the client and server now both know that symmetric key and the what happens to the rest of it.
+
+228
+00:12:02,000 --> 00:12:10,000
+Well you Amazon and you and Amazon will now use that symmetric key to encrypt data.
+
+229
+00:12:10,000 --> 00:12:11,000
+So what happens is this.
+
+230
+00:12:12,000 --> 00:12:16,000
+You generate a symmetric key, you encrypt it with Amazon's public key.
+
+231
+00:12:16,000 --> 00:12:19,000
+Remember I showed you the actual public key there.
+
+232
+00:12:20,000 --> 00:12:22,000
+You encrypt it with that public key.
+
+233
+00:12:22,000 --> 00:12:23,000
+You send it to Amazon.
+
+234
+00:12:23,000 --> 00:12:25,000
+Amazon then decrypts it with their private key.
+
+235
+00:12:26,000 --> 00:12:27,000
+Now they have the symmetric key.
+
+236
+00:12:27,000 --> 00:12:28,000
+You have the symmetric key.
+
+237
+00:12:28,000 --> 00:12:36,000
+Anything that you send to Amazon username passwords credit cards address products you want to buy,
+
+238
+00:12:36,000 --> 00:12:39,000
+search queries, anything that you want to send to Amazon.
+
+239
+00:12:39,000 --> 00:12:41,000
+You encrypt it with that symmetric key.
+
+240
+00:12:41,000 --> 00:12:41,000
+Send it to Amazon.
+
+241
+00:12:41,000 --> 00:12:43,000
+Amazon already has the symmetric key.
+
+242
+00:12:44,000 --> 00:12:46,000
+Amazon wants to send you back web pages.
+
+243
+00:12:46,000 --> 00:12:51,000
+They want to send you back product listing confirmations and whatever they encrypt it with that symmetric
+
+244
+00:12:51,000 --> 00:12:51,000
+key.
+
+245
+00:12:51,000 --> 00:12:56,000
+Remember symmetric the same key used to encrypt is the same key used to decrypt.
+
+246
+00:12:56,000 --> 00:13:04,000
+So all of this is happening in the background when you go and when when you go to Amazon and you purchase
+
+247
+00:13:04,000 --> 00:13:04,000
+anything.
+
+248
+00:13:05,000 --> 00:13:05,000
+All right.
+
+249
+00:13:05,000 --> 00:13:08,000
+So that's something that you guys want to keep in mind as you use this.
+
+250
+00:13:08,000 --> 00:13:15,000
+So if I go back here, if I go back to Amazon, all of what I just mentioned.
+
+251
+00:13:16,000 --> 00:13:17,000
+Happens.
+
+252
+00:13:17,000 --> 00:13:21,000
+So what if you go to another website?
+
+253
+00:13:21,000 --> 00:13:21,000
+All right.
+
+254
+00:13:21,000 --> 00:13:24,000
+What if you go to another, uh.
+
+255
+00:13:26,000 --> 00:13:26,000
+Website?
+
+256
+00:13:26,000 --> 00:13:27,000
+Google.com.
+
+257
+00:13:27,000 --> 00:13:28,000
+Let's go to google.com.
+
+258
+00:13:29,000 --> 00:13:31,000
+Google.com.
+
+259
+00:13:31,000 --> 00:13:33,000
+Everything I just happened just happened.
+
+260
+00:13:33,000 --> 00:13:35,000
+Everything I just went through just happened.
+
+261
+00:13:35,000 --> 00:13:36,000
+So let's do a quick review.
+
+262
+00:13:36,000 --> 00:13:37,000
+What happened?
+
+263
+00:13:37,000 --> 00:13:40,000
+When I went to Google, I sent the request to Google.
+
+264
+00:13:41,000 --> 00:13:43,000
+Google sent me back their certificate.
+
+265
+00:13:43,000 --> 00:13:44,000
+Where is it?
+
+266
+00:13:44,000 --> 00:13:49,000
+Well, if I click on the lock icon and I go to connection to secure and I say certificate, this is
+
+267
+00:13:49,000 --> 00:13:50,000
+Google certificate.
+
+268
+00:13:50,000 --> 00:13:55,000
+By acquiring Google certificate, I acquire Google's public key.
+
+269
+00:13:56,000 --> 00:13:58,000
+This is the fingerprint if I go here.
+
+270
+00:13:59,000 --> 00:14:00,000
+Whereas Google here we go.
+
+271
+00:14:00,000 --> 00:14:01,000
+Google's public key.
+
+272
+00:14:01,000 --> 00:14:03,000
+So I acquired a public key.
+
+273
+00:14:03,000 --> 00:14:05,000
+What do I do with the public key?
+
+274
+00:14:05,000 --> 00:14:08,000
+I generate a symmetric key on my computer.
+
+275
+00:14:09,000 --> 00:14:15,000
+I then encrypt that symmetric key with Google's public key send it to Google.
+
+276
+00:14:15,000 --> 00:14:17,000
+Google then decrypts it with their private key.
+
+277
+00:14:17,000 --> 00:14:19,000
+Now they have the symmetric key.
+
+278
+00:14:19,000 --> 00:14:20,000
+I have the symmetric key.
+
+279
+00:14:20,000 --> 00:14:26,000
+What Google does is Google then encrypts the web page that I just saw on my screen and sends it to my
+
+280
+00:14:26,000 --> 00:14:26,000
+machine.
+
+281
+00:14:26,000 --> 00:14:31,000
+When my machine gets it, it decrypts it with symmetric key, all the search queries and all the pages
+
+282
+00:14:31,000 --> 00:14:36,000
+that goes back and forth between me and Google is now encrypted with that symmetric key.
+
+283
+00:14:36,000 --> 00:14:41,000
+What I just explained to you is the easiest way to understand SSL.
+
+284
+00:14:41,000 --> 00:14:44,000
+This is the simplest explanation of it.
+
+285
+00:14:44,000 --> 00:14:49,000
+Now it does get technical verification of signatures and all that, but you don't need to know that
+
+286
+00:14:49,000 --> 00:14:50,000
+for your exam.
+
+287
+00:14:50,000 --> 00:14:51,000
+Understand the SSL handshake.
+
+288
+00:14:51,000 --> 00:14:55,000
+And now you see why it's so important to have certificates.
+
+289
+00:14:55,000 --> 00:15:00,000
+Because without those certificates, the whole connection wouldn't be able to start.
+
+290
+00:15:00,000 --> 00:15:01,000
+There'd be no way of passing that public key.
+
+291
+00:15:01,000 --> 00:15:06,000
+There'll be no way to verify that that's Google's public key or Amazon's public key.
+
+292
+00:15:06,000 --> 00:15:08,000
+But how do we get a certificate?
+
+293
+00:15:08,000 --> 00:15:09,000
+How do we set this thing up?
+
+294
+00:15:10,000 --> 00:15:12,000
+Well that we'll cover next.
+

07 - Cryptography/017 PKI Process OB 1.4_en.srt

@@ -0,0 +1,664 @@
+1
+00:00:00,000 --> 00:00:00,000
+Okay.
+
+2
+00:00:00,000 --> 00:00:05,000
+You have just been assigned the job of installing a certificate on a computer.
+
+3
+00:00:05,000 --> 00:00:09,000
+Your new your the new system administrator for a company.
+
+4
+00:00:09,000 --> 00:00:13,000
+And they said, well, we have a web server that we want to put a certificate on.
+
+5
+00:00:13,000 --> 00:00:16,000
+What is the process and exactly how is this done?
+
+6
+00:00:16,000 --> 00:00:21,000
+So in this video I'm going to walk you guys through the process of how you can get a certificate, a
+
+7
+00:00:21,000 --> 00:00:24,000
+trusted certificate on a computer.
+
+8
+00:00:24,000 --> 00:00:26,000
+Let's get started in this one.
+
+9
+00:00:26,000 --> 00:00:32,000
+Now, in order to do this, there are basically four components that I need you to know for your exam.
+
+10
+00:00:32,000 --> 00:00:37,000
+When it comes to getting a certificate, the first thing is that digital certificate.
+
+11
+00:00:37,000 --> 00:00:40,000
+This is what you want to install on your computer.
+
+12
+00:00:40,000 --> 00:00:42,000
+If you remember I went over the SSL handshake.
+
+13
+00:00:43,000 --> 00:00:48,000
+And the SSL handshake begins with the passing of that digital certificate.
+
+14
+00:00:48,000 --> 00:00:51,000
+So this is a digital document that provides the public key.
+
+15
+00:00:51,000 --> 00:00:55,000
+It also has a digital signature that provides the trust to the organization.
+
+16
+00:00:55,000 --> 00:00:58,000
+Where are we going to get the certificates from?
+
+17
+00:00:58,000 --> 00:01:01,000
+You're going to get that from a certificate authority.
+
+18
+00:01:01,000 --> 00:01:07,000
+This is a trusted entity that manages certificates and digitally signs the certificate.
+
+19
+00:01:07,000 --> 00:01:08,000
+This is the entity.
+
+20
+00:01:08,000 --> 00:01:15,000
+This is the DMV, I should say that verifies you are who you say you are.
+
+21
+00:01:15,000 --> 00:01:23,000
+Now, before the CA can give you a certificate, the CA needs to verify that you're you, that you're
+
+22
+00:01:23,000 --> 00:01:25,000
+actually that company.
+
+23
+00:01:25,000 --> 00:01:28,000
+You're not trying to steal someone's identity, that you are Bob Jones.
+
+24
+00:01:28,000 --> 00:01:30,000
+That's the registration authority.
+
+25
+00:01:30,000 --> 00:01:31,000
+That's their job.
+
+26
+00:01:31,000 --> 00:01:38,000
+They're going to verify that the person is who they say they are for the CA before the CA can issue
+
+27
+00:01:38,000 --> 00:01:38,000
+them a cert.
+
+28
+00:01:38,000 --> 00:01:45,000
+And when you start to give out your certificate on the internet, you're going to have to get it validated.
+
+29
+00:01:45,000 --> 00:01:48,000
+People that receive it is going to validate, hey, this certificate is still good.
+
+30
+00:01:48,000 --> 00:01:51,000
+It's kind of like me giving you my driver's license.
+
+31
+00:01:51,000 --> 00:01:54,000
+And you're like, well, I don't know.
+
+32
+00:01:54,000 --> 00:01:57,000
+It's this driver's license actually came from the DMV that's still valid.
+
+33
+00:01:57,000 --> 00:02:02,000
+So you call up a number to check if the license is valid.
+
+34
+00:02:02,000 --> 00:02:04,000
+That's the validation authority.
+
+35
+00:02:04,000 --> 00:02:07,000
+Now, I went to Wikipedia and I took their diagram.
+
+36
+00:02:07,000 --> 00:02:10,000
+I should say I borrowed it the diagram.
+
+37
+00:02:10,000 --> 00:02:12,000
+But I do have the link right here to it.
+
+38
+00:02:12,000 --> 00:02:17,000
+So here is the uh all of the information that we need.
+
+39
+00:02:17,000 --> 00:02:21,000
+Now I'm going to go through it, uh, at a high level right now.
+
+40
+00:02:21,000 --> 00:02:25,000
+And then we'll take a look at the slides in order to, to go more details into it.
+
+41
+00:02:25,000 --> 00:02:29,000
+So this is you right here.
+
+42
+00:02:29,000 --> 00:02:29,000
+This is you.
+
+43
+00:02:29,000 --> 00:02:35,000
+So the way you start this process is you what what you're going to do.
+
+44
+00:02:35,000 --> 00:02:36,000
+Let's put you on this.
+
+45
+00:02:37,000 --> 00:02:42,000
+What you're going to do is you're going to generate the public private key on your machine.
+
+46
+00:02:42,000 --> 00:02:49,000
+So you have a web server and you're going to create what's called a certificate request certificate,
+
+47
+00:02:49,000 --> 00:02:52,000
+sign in requests or CSR on your machine.
+
+48
+00:02:52,000 --> 00:02:56,000
+What this does is that this is going to generate a public and a private key.
+
+49
+00:02:57,000 --> 00:02:58,000
+On your computer.
+
+50
+00:02:58,000 --> 00:03:02,000
+The certificate authority does not generate the public private keys.
+
+51
+00:03:02,000 --> 00:03:04,000
+It signs your public private key.
+
+52
+00:03:04,000 --> 00:03:08,000
+You generate that public private key pair on your machine.
+
+53
+00:03:08,000 --> 00:03:09,000
+So you generate.
+
+54
+00:03:09,000 --> 00:03:12,000
+This is going to be your private key.
+
+55
+00:03:13,000 --> 00:03:15,000
+And you generate your public key.
+
+56
+00:03:15,000 --> 00:03:21,000
+What you do now is you then take this and you submit it to a registration authority.
+
+57
+00:03:21,000 --> 00:03:29,000
+Now, the registration authority is the entity that verifies that you are who you say you are.
+
+58
+00:03:29,000 --> 00:03:36,000
+For example, let's say you are a hacker and you want to reproduce Amazon.com.
+
+59
+00:03:36,000 --> 00:03:41,000
+Well, you just can't go and get a certificate with the name Amazon.com because you're going to have
+
+60
+00:03:41,000 --> 00:03:43,000
+to prove that you are Amazon.
+
+61
+00:03:43,000 --> 00:03:50,000
+If you are organization A or B or C, and you want to get a certificate for that organization, you're
+
+62
+00:03:50,000 --> 00:03:54,000
+going to have to verify that you are that company and depend how it's done.
+
+63
+00:03:54,000 --> 00:03:58,000
+It may just be checking the domain actually belongs to you, or it may be that they're going to check
+
+64
+00:03:58,000 --> 00:04:00,000
+that the company actually exists.
+
+65
+00:04:00,000 --> 00:04:03,000
+That's the registration authority.
+
+66
+00:04:03,000 --> 00:04:06,000
+So the registration authority stamps that OKC okay.
+
+67
+00:04:06,000 --> 00:04:08,000
+This is Bob.
+
+68
+00:04:08,000 --> 00:04:10,000
+This is company A this is what.
+
+69
+00:04:10,000 --> 00:04:12,000
+And you can trust them.
+
+70
+00:04:12,000 --> 00:04:16,000
+The registration authority then sends your public key.
+
+71
+00:04:16,000 --> 00:04:17,000
+To the CA.
+
+72
+00:04:17,000 --> 00:04:26,000
+The CA then takes all of your company information, all this great stuff that was given to them, including
+
+73
+00:04:26,000 --> 00:04:32,000
+your public key and what the CA does is it then sends you back a certificate.
+
+74
+00:04:32,000 --> 00:04:39,000
+Now on the certificate it contains your public key, but it also contains a digital signature from the
+
+75
+00:04:39,000 --> 00:04:39,000
+CA.
+
+76
+00:04:40,000 --> 00:04:45,000
+Now if you remember what a digital signature is, a digital signature verifies that something actually
+
+77
+00:04:45,000 --> 00:04:48,000
+came from that entity and it was never modified.
+
+78
+00:04:48,000 --> 00:04:58,000
+So when you receive this certificate and you install it on your web server, this certificate was never
+
+79
+00:04:58,000 --> 00:05:00,000
+actually issued by you, was it?
+
+80
+00:05:00,000 --> 00:05:01,000
+It came from who?
+
+81
+00:05:01,000 --> 00:05:02,000
+The certificate authority.
+
+82
+00:05:02,000 --> 00:05:06,000
+The only thing it has that you really gave it was basically a public key.
+
+83
+00:05:06,000 --> 00:05:08,000
+But the certificate has more information.
+
+84
+00:05:08,000 --> 00:05:12,000
+I have a video coming up later on all the other data that the certificate contains.
+
+85
+00:05:12,000 --> 00:05:18,000
+So what you do is you install that certificate on your machine.
+
+86
+00:05:18,000 --> 00:05:20,000
+Now you're done with these entities.
+
+87
+00:05:20,000 --> 00:05:27,000
+Now somebody comes to Shop.com or whatever your website is, and the first thing you're going to do,
+
+88
+00:05:27,000 --> 00:05:32,000
+if you remember the SSL handshake is you're going to do what you're going to send them that certificate
+
+89
+00:05:32,000 --> 00:05:35,000
+so you can start the SSL connection.
+
+90
+00:05:35,000 --> 00:05:36,000
+You send them the certificate.
+
+91
+00:05:36,000 --> 00:05:38,000
+Well, how do they know the certificate is still valid?
+
+92
+00:05:38,000 --> 00:05:42,000
+How do they know your website hasn't been hacked or something went wrong?
+
+93
+00:05:42,000 --> 00:05:47,000
+You didn't renew the certificate, you became malicious and your company is stealing data now.
+
+94
+00:05:48,000 --> 00:05:52,000
+Well, what they do is they send their certificate to a validation authority.
+
+95
+00:05:52,000 --> 00:05:57,000
+Now notice the CA also sent information to the validation authority.
+
+96
+00:05:57,000 --> 00:05:59,000
+To day I issue this cert.
+
+97
+00:05:59,000 --> 00:06:05,000
+And if anybody ever wants to check if it's good just let them know it's okay because we did issue that.
+
+98
+00:06:06,000 --> 00:06:12,000
+The validation authority when they when the user gets it, checks it and says okay it's good.
+
+99
+00:06:12,000 --> 00:06:14,000
+Tells back to use a yeah, this is good.
+
+100
+00:06:14,000 --> 00:06:14,000
+You can use it.
+
+101
+00:06:14,000 --> 00:06:17,000
+And this starts the entire SSL connection.
+
+102
+00:06:18,000 --> 00:06:24,000
+So this is the PKI process in a nutshell with a CA, an RA and a VA.
+
+103
+00:06:24,000 --> 00:06:33,000
+Now I just want to point out something that even though in this particular diagram it looks like it's
+
+104
+00:06:33,000 --> 00:06:34,000
+different entities.
+
+105
+00:06:34,000 --> 00:06:37,000
+RA it's all the same entity.
+
+106
+00:06:37,000 --> 00:06:39,000
+Generally this like Digicert.
+
+107
+00:06:40,000 --> 00:06:44,000
+Uh, GoDaddy or whoever you're using as your public key.
+
+108
+00:06:44,000 --> 00:06:45,000
+It's always the same entity.
+
+109
+00:06:45,000 --> 00:06:48,000
+It's not going to be like it's three different businesses.
+
+110
+00:06:48,000 --> 00:06:56,000
+But in organizations that utilizes internal certs, they can have different machines to do this particular
+
+111
+00:06:56,000 --> 00:06:57,000
+job.
+
+112
+00:06:57,000 --> 00:07:00,000
+Now let's take a look at some things here.
+
+113
+00:07:00,000 --> 00:07:04,000
+Now everything I covered is in detail on these two sections.
+
+114
+00:07:04,000 --> 00:07:06,000
+So I'm going to go over them quickly since we covered it already.
+
+115
+00:07:06,000 --> 00:07:09,000
+So the certificate signing request.
+
+116
+00:07:09,000 --> 00:07:13,000
+So this is the part of it where we had to.
+
+117
+00:07:14,000 --> 00:07:15,000
+Obtain.
+
+118
+00:07:15,000 --> 00:07:19,000
+This is the request we're going to send to the CA to get that digital certificate.
+
+119
+00:07:19,000 --> 00:07:19,000
+All right.
+
+120
+00:07:19,000 --> 00:07:24,000
+So the first thing we're going to be doing is in order to do this, we're going to have to include things
+
+121
+00:07:24,000 --> 00:07:29,000
+like our organization name, our domain name, what country we're in, and of course our public key.
+
+122
+00:07:29,000 --> 00:07:31,000
+So this is what we're sending.
+
+123
+00:07:31,000 --> 00:07:35,000
+Now the first thing you want to do is you want to start this process.
+
+124
+00:07:35,000 --> 00:07:41,000
+When you want to get a certificate is you have to go to your machine and you have to create a key pair,
+
+125
+00:07:41,000 --> 00:07:43,000
+that public private key pair.
+
+126
+00:07:43,000 --> 00:07:44,000
+Remember the private key is kept secret.
+
+127
+00:07:44,000 --> 00:07:46,000
+The public key is given to anyone.
+
+128
+00:07:46,000 --> 00:07:48,000
+You want to fill in the details.
+
+129
+00:07:48,000 --> 00:07:49,000
+All right.
+
+130
+00:07:49,000 --> 00:07:52,000
+The certificate is going to have a is going to need a lot of information.
+
+131
+00:07:52,000 --> 00:07:55,000
+All this information the name of your company where it's located state.
+
+132
+00:07:55,000 --> 00:07:58,000
+And I'm going to show you certificate details in the next video.
+
+133
+00:07:58,000 --> 00:08:01,000
+And you're going to see a certificate has all this information.
+
+134
+00:08:02,000 --> 00:08:08,000
+So you create this, uh, you create it using a software.
+
+135
+00:08:08,000 --> 00:08:14,000
+And this is going to be submitted in a format that the CAS can understand that format.
+
+136
+00:08:14,000 --> 00:08:18,000
+But I get into technical is called PK, CS number ten.
+
+137
+00:08:18,000 --> 00:08:21,000
+This is the format that it's submitted into.
+
+138
+00:08:21,000 --> 00:08:27,000
+This is just a file format, if you think about it like an Excel file as dot xls x.
+
+139
+00:08:27,000 --> 00:08:28,000
+That's the file format.
+
+140
+00:08:28,000 --> 00:08:29,000
+This is just the file format.
+
+141
+00:08:29,000 --> 00:08:30,000
+What does it contain?
+
+142
+00:08:30,000 --> 00:08:33,000
+Well, the public key and all the corresponding information.
+
+143
+00:08:34,000 --> 00:08:38,000
+Now you submit the CSR to the RA to the CA.
+
+144
+00:08:38,000 --> 00:08:39,000
+What happens here?
+
+145
+00:08:40,000 --> 00:08:43,000
+Uh, they will validate your identity.
+
+146
+00:08:43,000 --> 00:08:44,000
+They'll validate that you're good.
+
+147
+00:08:45,000 --> 00:08:50,000
+And once they can validate all that information, we'll talk more about validations coming up a little
+
+148
+00:08:50,000 --> 00:08:51,000
+bit later.
+
+149
+00:08:51,000 --> 00:08:53,000
+But they're going to validate that you're good.
+
+150
+00:08:53,000 --> 00:08:58,000
+Sometimes they may validate your just your domain name or sometimes they'll do an extended validation.
+
+151
+00:08:58,000 --> 00:09:03,000
+We're going to do more than a domain name that you actually own that domain, but you actually own that
+
+152
+00:09:03,000 --> 00:09:04,000
+business.
+
+153
+00:09:04,000 --> 00:09:06,000
+Then the certificate is issued to you.
+
+154
+00:09:06,000 --> 00:09:12,000
+You install it on your web server, and you're ready to rock and roll with the SSL connection.
+
+155
+00:09:12,000 --> 00:09:12,000
+Okay.
+
+156
+00:09:12,000 --> 00:09:16,000
+So that's the process of how to get a certificate.
+
+157
+00:09:17,000 --> 00:09:24,000
+Now I want you guys to keep in mind that this is a very easy and simple process.
+
+158
+00:09:24,000 --> 00:09:28,000
+It's if you've ever installed a certificate on a web server, it's a very simple thing.
+
+159
+00:09:28,000 --> 00:09:33,000
+You go to the web server, you do a few clicks that give you doing an IIs server, and you create that
+
+160
+00:09:33,000 --> 00:09:34,000
+certificate request.
+
+161
+00:09:34,000 --> 00:09:38,000
+You go to your CA, you basically install it there and they give you a certificate.
+
+162
+00:09:38,000 --> 00:09:39,000
+You put it back on your web server.
+
+163
+00:09:39,000 --> 00:09:44,000
+There's something that's done actually doesn't take very long, a few minutes if you know the skills
+
+164
+00:09:44,000 --> 00:09:44,000
+to do it.
+
+165
+00:09:44,000 --> 00:09:46,000
+So it's not complex to do.
+
+166
+00:09:46,000 --> 00:09:50,000
+But for your exam you want to be able to understand the process, which is what we just went over.
+

07 - Cryptography/018 Certificates OB 1.4_en.srt

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+In this video we're going to be talking about certificates.
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+What exactly is on a certificate?
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+Now, I already went over that.
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+It has the signature from the, uh, certificate authority.
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+It also has your public key.
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+But what else does it contain?
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+Let's get into that.
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+I want to talk about the format.
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+Self-signed certificates versus third party certificates.
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+Let's knock it out.
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+The first thing I want to do is I want to show you guys when you have a certificate.
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+Now, a certificate has a variety of different fields.
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+It's not just the couple things.
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+In fact, it has a couple different things on it, from a version number to the subject's name, the
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+company's name, your public key.
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+Who gave you the certificate, how long it's valid for, what digital signature algorithm you're using,
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+and a unique serial number to identify the certificate.
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+You know the certificate types.
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+Now, I do want to mention this, that all certificates that are coming out today is going to be the
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+X509 certificate.
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+It's going to be a certificate format.
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+Now the certificate types are going to be either it's going to be self-signed or it's going to be third
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+party issue, which we'll take a look at in a few minutes.
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+So I want to show you all of these fields on an actual certificate so you can better understand what
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+I'm talking about.
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+So let's go to Amazon.com.
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+Here we are back again.
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+Connection is secure.
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+Let's take a look at some of the things I mentioned.
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+So we're going to go to detail.
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+So we have all the data.
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+So right now I'm just going to expand some of these boxes so you can see them.
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+Uh first of all what version is it.
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+Well this is version three certificate.
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+Here is a serial number.
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+Now this is a unique number that is unique to this certificate.
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+No certificate should have this.
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+The signature algorithm.
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+Now, I mentioned that a digital signature using the DSS standards is generally some kind of asymmetric
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+algorithm and a hashing algorithm.
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+In this one, we're going to be using Sha 256 with RSA.
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+Pretty pretty standard.
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+Who gave us the certificate.
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+Now Digicert is one of the biggest provider of certificate.
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+Digicert took over from Symantec's who took over VeriSign.
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+VeriSign being one of the most popular names out there.
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+But Digicert is now them, and there's a lot of big names in this space.
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+Uh, such as?
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+I know GoDaddy gives out a lot of certificates, you can get Google search and so on.
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+How long is it valid?
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+What?
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+A certificate is not valid forever.
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+In fact, you have to renew certificates generally every 1 to 3 years.
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+You notice, uh, this particular certificate is valid basically from 1127 23 to 11 1124.
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+So this is about a one year, a little less than a one year certificate.
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+The subject, well, the chronological or the key name, this certificate is only for WW dot amazon.com.
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+So this is certificate can only be used at WW dot.
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+So this is going to be a certificate only for this website.
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+But who exactly.
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+I'm.
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+So where is the public key on this.
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+So the subject's public key.
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+So we have.
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+The the public key algorithm.
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+It's an RSA key.
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+Here is the public key.
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+Now in here there are some additional things I don't.
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+You don't need to go into all of these things such as certificate policies and all that.
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+But what I do need you guys to know is there is something we call a CRL distribution point, certificate
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+revocation list distribution point, which you can find on the certificate itself to check if the certificate
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+has been revoked.
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+That is something we're going to cover a little bit later.
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+If I just take a look at the general part of the certificate, you can see it's just giving me some
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+of the basic information that I had their start on expires on.
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+So this is going to be some of the main fields that you should understand about a certificate.
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+Now when you get a certificate let's go back to slides here.
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+Oops.
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+Uh, there's a couple of things here.
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+When you get a certificate, there's what's called an entity certificate, what's called a domain validation
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+certificate and extended validation.
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+When you go out and you purchase a certificate from somebody like Digicert, a domain validation just
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+checks if you actually own the domain Amazon.com, but it doesn't verify if that business is associated
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+with that domain.
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+That's going to be called an extended validation.
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+Sometimes if you go to a website and the the bar at the top turns green, that's an extended validation
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+certificate.
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+Another type of certificate you can get is what's called a wild card certificate.
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+So wild card certificates if you notice it has a wild card.
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+If you remember the one on Amazon was just WW dot amazon.com.
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+That can't be used for anything but that w w dot.
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+If you go and you get a wildcard certificate with a wildcard, you notice how I have this wildcard at
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+Tidcombe.
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+So we could use it for t w w dot t edu comm.
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+You can use it for mail at tidcombe.
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+We can use it maybe for if you had a subdomain called vpn at t com ftp at tidcombe.
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+So you can use it for multiple subdomains.
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+Now I do want to talk about when you get a certificate, you can get them either from yourself or you
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+can get them from a certificate authority like Digicert.
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+And there are many, like I said, Digicert GoDaddy.
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+I use a site called cheap SSL.
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+Uh, so there is a ton of them.
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+I'm not going to get into all the different names.
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+It's out of the scope here.
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+But if you just go to Google and you type, uh, SSL certificates or purchase certificates, you know
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+what I'll do that when I get here so I can show you some of the names here.
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+Okay.
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+But let's go.
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+Self-signed certificates A self-signed certificate is a certificate that you make internally in your
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+organization.
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+The problem with a self-signed certificate is the trust level.
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+Okay, so this is something that you make internally, and it has no independence of trust.
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+In other words, only you trust it.
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+Only your organization trusts it.
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+Now, you're probably saying yourself, well, is it useful?
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+Well, it's it's useful as much, externally speaking, as an ID that you make inside.
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+Okay.
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+Think about this.
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+If you are a company and you create badges for all your employees.
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+Those employees can't use your company badges or IDs to externally validate anything externally.
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+They can't give it to highway patrol and says, this is me, right?
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+Nobody's going to know what kind of stupid ID is this?
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+We don't trust this.
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+But people in your organization will.
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+So if you want to set up SSL connection within your organization, that is okay because it's all trusted
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+internally, but you need that SSL connection.
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+Then I recommend a self-signed certificate.
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+The cost is free.
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+That's what makes it good.
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+It's actually free versus Digicert can cost a couple GS a year.
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+A couple of thousand dollars.
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+So the use case here is going to be for internal networks applications.
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+If you need to issue certificates for smart cards, people log in internal SSL on web servers, internally
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+speaking, where it never touches the external world.
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+This is a good solution.
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+It's free and you should be doing this.
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+I.
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+In fact at TI we have a ton of self-signed certificates on all of our internal servers now.
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+If what you're doing is going to be external facing and you need that external validation, you need
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+that DMV, I should say to validate your request, then you can go and get a third party certificate.
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+And before I get into this, you know what?
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+Let me just show it to you.
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+Uh, all the different.
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+So I'm going to go to Google and I am going to say.
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+Where is my, uh.
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+Here we go.
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+Oh.
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+147
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+Let's stop.
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+148
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+Here we go.
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+149
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+So I'm going to go to Google, and here we go with all kinds of certificates.
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+All these names here are going to start popping up.
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+Uh, and notice I have uh, Comodo certificates are popular, GoDaddy certificates are popular.
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+There's one that says cheap SSL.
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+I use this one on a private web server.
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+Uh, you can get them from Digicert.
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+GoDaddy and Digicert is going to be your big player in the game.
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+156
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+So if you want a certificate, this is going to be where you're going to get the the biggest, uh,
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+157
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+certificates from like the highest name I would say comes from Digicert, but Digicert certificates
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+are not cheap.
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+They're pretty expensive and they do have extended validation certificates and so on.
+
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+Okay.
+
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+So you guys can check that if you want a certificate.
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+162
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+There's tons of certificate external parties that you can get a third party cert from.
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+163
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+But the question is why would you want a third party cert.
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+And the reason is a third party certificate.
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+It's all about trust.
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+You see, the difference between a self-signed certificate and a third party certificate is just here.
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+It's not the level of encryption strength.
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+It's just a trust.
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+For example, let's say I create an ID in my house that has my name, my picture, my wait, no, my
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+height and my eye color and my address.
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+It has the exact same information as my driver's license.
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+Then what is the difference between my ID and internal ID and the driver's license?
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+Nothing except the trust.
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+People are more likely to trust the DMV stamp than they are to trust me, saying I'm me.
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+That is the only difference.
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+So when you get a third party certificate, you're not going to get any more IT security.
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+I'm going to get a higher level encryption, for example.
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+In fact, if you generate an internally, you can select to use bigger RSA keys, or you can select
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+a type of uh, RSA key or the type of hashing you want to use.
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+So you can actually even make it more secure.
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+For example, if I internally, if I put the weight on my ID versus the DMV doesn't have that, then
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+technically my internal ID has more unique identifying factors than the DMV does, but the DMV comes
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+with that trust factor.
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+All right.
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+185
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+This trust factor.
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+So the CA the external CA like Digicert they're going to give you that certificate.
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+They're going to sign digitally signed with a digital signature on the certificate to verify that it
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+came from them.
+
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+This is going to be.
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+The trust is most central to most secure communication.
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+If you're doing Https, where are you going to use this?
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+You should be using third party certificates for anything that is public facing websites.
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+Anything that faces the public that public users come to.
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+The cost?
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+It will be a cost and it can vary.
+
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+You can get a certificate for a few bucks a year to a few thousand dollars a year, depending on the
+
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+entity.
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+I'm not going to get into the exact why it depends on warranty and how much you trust them, and if
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+they can get hacked and how secure they are.
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+200
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+I'm not going to get into all that.
+
+201
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+It's not needed for your course, but it does.
+
+202
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+There is a cost associated with this.
+
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+Bottom line goes like this.
+
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+If you're going to get a certificate for internal access, and you will never have any kind of external
+
+205
+00:11:42,000 --> 00:11:49,000
+access into that machine, self-signed certificates may be just fine, but if any external access is
+
+206
+00:11:49,000 --> 00:11:56,000
+required to that machine, for example, like a public website, make sure to get a third party certificate.
+

07 - Cryptography/019 PKI Root of Trust OB 1.4_en.srt

@@ -0,0 +1,220 @@
+1
+00:00:00,000 --> 00:00:00,000
+Okay.
+
+2
+00:00:00,000 --> 00:00:06,000
+When you're building a PKI, especially internally, you're going to want to understand how the structure
+
+3
+00:00:06,000 --> 00:00:08,000
+of the PKI is laid out.
+
+4
+00:00:08,000 --> 00:00:14,000
+So in this video, we want to take a look at that particular structure, uh, of a PKI.
+
+5
+00:00:14,000 --> 00:00:18,000
+Now, this this topic in particular is called the root of trust.
+
+6
+00:00:18,000 --> 00:00:20,000
+And it's how the PKI are managed.
+
+7
+00:00:20,000 --> 00:00:21,000
+It's basically how you structure it.
+
+8
+00:00:22,000 --> 00:00:27,000
+So when you set up a PKI, you have a root CA.
+
+9
+00:00:27,000 --> 00:00:30,000
+Underneath that you have what's called subordinate CAS.
+
+10
+00:00:30,000 --> 00:00:30,000
+All right.
+
+11
+00:00:30,000 --> 00:00:32,000
+Now why do we have this?
+
+12
+00:00:32,000 --> 00:00:34,000
+Well you see this root CA.
+
+13
+00:00:34,000 --> 00:00:37,000
+This root CA technically doesn't issue certificates.
+
+14
+00:00:37,000 --> 00:00:39,000
+Let's go back to the process of getting a certificate.
+
+15
+00:00:39,000 --> 00:00:44,000
+If you remember in that process the CA digitally signs your certificate.
+
+16
+00:00:45,000 --> 00:00:52,000
+If you remember how a digital signature works is that the CA utilizes its private key, it hashes all
+
+17
+00:00:52,000 --> 00:00:53,000
+the information on your.
+
+18
+00:00:53,000 --> 00:00:58,000
+The way it's done is that it will hash all the information on a certificate to company.
+
+19
+00:00:58,000 --> 00:01:04,000
+Name your domain name, uh, the certificate start and end dates.
+
+20
+00:01:04,000 --> 00:01:10,000
+It then hashes all this information and then it encrypts it with its private key.
+
+21
+00:01:10,000 --> 00:01:11,000
+Remember how signatures are done.
+
+22
+00:01:12,000 --> 00:01:18,000
+So if that certificate like for example, let's say Digicert.
+
+23
+00:01:18,000 --> 00:01:19,000
+If Digicert.
+
+24
+00:01:20,000 --> 00:01:26,000
+Ever gets compromised and their private key is compromised.
+
+25
+00:01:26,000 --> 00:01:33,000
+Every single certificate, the millions and millions of certificate that Digicert has ever given out,
+
+26
+00:01:33,000 --> 00:01:35,000
+becomes invalid instantly.
+
+27
+00:01:35,000 --> 00:01:38,000
+Because then anybody could remake the certificate because they have the private key.
+
+28
+00:01:38,000 --> 00:01:40,000
+And of course, everybody had the public key.
+
+29
+00:01:40,000 --> 00:01:41,000
+It was always public.
+
+30
+00:01:41,000 --> 00:01:51,000
+So in order to help minimize this kind of impact, what we do is we set up a root CA and then subordinate
+
+31
+00:01:51,000 --> 00:01:51,000
+CAS.
+
+32
+00:01:51,000 --> 00:01:55,000
+Now the reason why you have this is because of this.
+
+33
+00:01:55,000 --> 00:01:57,000
+You you set up a root CA.
+
+34
+00:01:58,000 --> 00:02:05,000
+And this root CA will then issue a certificate to the subordinate CAS which can then issue it to even
+
+35
+00:02:05,000 --> 00:02:06,000
+lower CAS.
+
+36
+00:02:06,000 --> 00:02:11,000
+The reason you do this is because then you can take the root CA offline when I mean offline.
+
+37
+00:02:11,000 --> 00:02:17,000
+This is a computer that is literally unplugged, shut off, and put into a vault a couple thousand feet
+
+38
+00:02:17,000 --> 00:02:23,000
+in the air because this is certify and this and this is certifying this.
+
+39
+00:02:23,000 --> 00:02:31,000
+So technically speaking, if somebody hacks the company and they hack this lower CA right here at the
+
+40
+00:02:31,000 --> 00:02:34,000
+bottom, then you know what?
+
+41
+00:02:34,000 --> 00:02:39,000
+All the certificate that's issued by this cert by DCA is invalidated.
+
+42
+00:02:39,000 --> 00:02:42,000
+Not everything in the entire organization.
+
+43
+00:02:42,000 --> 00:02:48,000
+So what this does is this helps to minimize the impact of the data breach or the attack.
+
+44
+00:02:48,000 --> 00:02:49,000
+That's what you would want.
+
+45
+00:02:49,000 --> 00:02:55,000
+This you don't you never want to just start issuing certificate from your root CA because if that root
+
+46
+00:02:55,000 --> 00:02:56,000
+CA.
+
+47
+00:02:57,000 --> 00:02:58,000
+Is.
+
+48
+00:02:59,000 --> 00:03:03,000
+If that route C is ever compromised, every search you've ever given is invalidated.
+
+49
+00:03:03,000 --> 00:03:06,000
+But if you branch it off into four subordinates.
+
+50
+00:03:07,000 --> 00:03:11,000
+Then if one of those is compromised, there's just those certs are compromised, not the other three.
+
+51
+00:03:11,000 --> 00:03:16,000
+So that's why you would want to use this kind of structure.
+
+52
+00:03:16,000 --> 00:03:19,000
+Now this kind of structure is only done well.
+
+53
+00:03:19,000 --> 00:03:20,000
+It's done basically for two reasons.
+
+54
+00:03:20,000 --> 00:03:25,000
+Number one easier to administer and of course for the data protection.
+
+55
+00:03:25,000 --> 00:03:29,000
+That way if something happens, not everything becomes invalidated.
+

07 - Cryptography/020 PKI Verification and Revocation OB 1.4_en.srt

@@ -0,0 +1,372 @@
+1
+00:00:00,000 --> 00:00:00,000
+Okay.
+
+2
+00:00:00,000 --> 00:00:05,000
+When you receive a certificate from someone, you have to verify that it actually came from them.
+
+3
+00:00:05,000 --> 00:00:11,000
+There's a couple of things here that we need to know for our exam when it comes to this process of verification.
+
+4
+00:00:11,000 --> 00:00:14,000
+And again, this is when a user wants to validate your certificate.
+
+5
+00:00:14,000 --> 00:00:19,000
+So somebody comes to an app, maybe like a web app that you made or a device that you're using.
+
+6
+00:00:19,000 --> 00:00:23,000
+Maybe you have certificates installed on your on your firewall for VPN and so on.
+
+7
+00:00:23,000 --> 00:00:25,000
+Somebody comes there and they get a certificate.
+
+8
+00:00:25,000 --> 00:00:27,000
+They want to verify that it's coming from you.
+
+9
+00:00:27,000 --> 00:00:31,000
+If I get into that, do I want to talk about a firm that you may see appear on your exam?
+
+10
+00:00:31,000 --> 00:00:32,000
+It's called certificate pinning.
+
+11
+00:00:32,000 --> 00:00:35,000
+This is a techniques that helps to prevent man in the middle attacks.
+
+12
+00:00:35,000 --> 00:00:39,000
+What it does is that it hard codes the SSL public key into an app.
+
+13
+00:00:40,000 --> 00:00:44,000
+This means that when the output device communicates with the server to compare the SSL certificates
+
+14
+00:00:44,000 --> 00:00:46,000
+public key with the one in the app.
+
+15
+00:00:46,000 --> 00:00:48,000
+Now let me give you an example how this works.
+
+16
+00:00:48,000 --> 00:00:48,000
+So.
+
+17
+00:00:49,000 --> 00:00:54,000
+Let's say you have an application, and every time people come, they get your certificate and then
+
+18
+00:00:54,000 --> 00:00:55,000
+they check the certificate.
+
+19
+00:00:55,000 --> 00:01:00,000
+Now, what you can do in order to prevent people from intercepting or changing anything, you can hardcode
+
+20
+00:01:00,000 --> 00:01:02,000
+the public key in the application itself.
+
+21
+00:01:02,000 --> 00:01:07,000
+So then the certificate that's given to them by the SSL process, they can then compare it to the application's
+
+22
+00:01:07,000 --> 00:01:08,000
+public key.
+
+23
+00:01:08,000 --> 00:01:16,000
+That way no one can intercept the certificate or change it and say that this is their certificate of
+
+24
+00:01:16,000 --> 00:01:19,000
+any kind, because you have a hardcoded the public key in the app.
+
+25
+00:01:20,000 --> 00:01:21,000
+Okay.
+
+26
+00:01:21,000 --> 00:01:24,000
+Let's move on here quickly to the verification process.
+
+27
+00:01:24,000 --> 00:01:28,000
+So when you get a certificate all right a couple of things here.
+
+28
+00:01:28,000 --> 00:01:33,000
+The certificate verification process includes verifying the digital signature of the CA is authentic.
+
+29
+00:01:33,000 --> 00:01:35,000
+And they trust the CA.
+
+30
+00:01:35,000 --> 00:01:39,000
+So when you receive a certificate you're going to check okay.
+
+31
+00:01:39,000 --> 00:01:41,000
+Who the certificate came from.
+
+32
+00:01:41,000 --> 00:01:42,000
+Digicert.
+
+33
+00:01:42,000 --> 00:01:49,000
+I want you guys to keep in mind that your computer has a list of already pre-approved certificate authorities
+
+34
+00:01:49,000 --> 00:01:50,000
+that it trusts.
+
+35
+00:01:50,000 --> 00:01:55,000
+You're then going to check that a signature on it to make sure it's good.
+
+36
+00:01:56,000 --> 00:02:02,000
+One of the things that you guys will check is what's called a CRL, the certificate revocation list.
+
+37
+00:02:02,000 --> 00:02:06,000
+This is a published list of certificates that have been revoked.
+
+38
+00:02:06,000 --> 00:02:08,000
+Let's talk about this revocation process.
+
+39
+00:02:08,000 --> 00:02:16,000
+Sometimes when you get a certificate, you yourself may want to revoke the certificate for reasons such
+
+40
+00:02:16,000 --> 00:02:19,000
+as you're changing the server and the server is not valid anymore.
+
+41
+00:02:19,000 --> 00:02:23,000
+The server crashed, your server was hacked, and you lost the private key.
+
+42
+00:02:23,000 --> 00:02:27,000
+Something happened internally and you don't want to use that certificate anymore.
+
+43
+00:02:27,000 --> 00:02:33,000
+So you call your certificate provider like Digicert and say, well, can you reissue this cert?
+
+44
+00:02:33,000 --> 00:02:34,000
+Desert we have is no good.
+
+45
+00:02:35,000 --> 00:02:37,000
+So maybe your server got hacked.
+
+46
+00:02:37,000 --> 00:02:40,000
+So you call Digicert and say, well, my server got hacked.
+
+47
+00:02:40,000 --> 00:02:42,000
+I need a brand new certificate.
+
+48
+00:02:42,000 --> 00:02:43,000
+So Digicert says, no problem.
+
+49
+00:02:43,000 --> 00:02:48,000
+Here's a brand new certificate with a and you generate a new public private key pair.
+
+50
+00:02:48,000 --> 00:02:50,000
+Now what happens to that old certificate?
+
+51
+00:02:50,000 --> 00:02:53,000
+You see the old certificate that Digicert issued?
+
+52
+00:02:53,000 --> 00:02:56,000
+It's still technically valid.
+
+53
+00:02:56,000 --> 00:02:56,000
+Here's why.
+
+54
+00:02:56,000 --> 00:03:00,000
+Because the public the the expiration date hasn't occurred yet.
+
+55
+00:03:00,000 --> 00:03:01,000
+So it's not expired.
+
+56
+00:03:02,000 --> 00:03:04,000
+The signature is still valid.
+
+57
+00:03:04,000 --> 00:03:10,000
+Remember, signature is the hash of the certificate encrypted with the CA's private key.
+
+58
+00:03:11,000 --> 00:03:13,000
+That's still valid.
+
+59
+00:03:13,000 --> 00:03:16,000
+So anybody that receives that certificate is going to think it's valid.
+
+60
+00:03:16,000 --> 00:03:24,000
+So what we do is we will publish a list of certificates that's revoked.
+
+61
+00:03:24,000 --> 00:03:27,000
+So when people come to the website, they're going to check the CRL list.
+
+62
+00:03:27,000 --> 00:03:32,000
+Or they check this thing called Ocsp, an online certificate status protocol.
+
+63
+00:03:32,000 --> 00:03:35,000
+This is a real time validation with the CA.
+
+64
+00:03:35,000 --> 00:03:36,000
+This is a is this valid?
+
+65
+00:03:36,000 --> 00:03:37,000
+The CA is like yeah that's good.
+
+66
+00:03:38,000 --> 00:03:43,000
+Now the certificate usually contains the data that you're going to be trusting such as that public key.
+
+67
+00:03:43,000 --> 00:03:46,000
+So this is the revocation that I was mentioning.
+
+68
+00:03:46,000 --> 00:03:51,000
+So when it's compromised it gets added to the certificate revocation list.
+
+69
+00:03:51,000 --> 00:03:57,000
+If you want a real time validation that the certificate is actually good.
+
+70
+00:03:57,000 --> 00:04:00,000
+Then you use all CSP.
+
+71
+00:04:00,000 --> 00:04:01,000
+Know that for your exam.
+
+72
+00:04:01,000 --> 00:04:02,000
+There's a real time.
+
+73
+00:04:02,000 --> 00:04:07,000
+So right now, almost all of us, every time we go to Amazon or we get the certificate, we use this
+
+74
+00:04:07,000 --> 00:04:10,000
+protocol to check if that certificate is still valid.
+
+75
+00:04:11,000 --> 00:04:15,000
+Another time you may see on your exam is something we call certificate stapling.
+
+76
+00:04:15,000 --> 00:04:16,000
+All right.
+
+77
+00:04:16,000 --> 00:04:20,000
+And what this does is that it avoids the client from sending the Ocsp request.
+
+78
+00:04:20,000 --> 00:04:27,000
+Instead, the web server itself checks the validation with the CA now certificate stapling is this.
+
+79
+00:04:27,000 --> 00:04:34,000
+Every time you get, uh, the certificate, you have to check with the ocsp.
+
+80
+00:04:34,000 --> 00:04:35,000
+Is it good?
+
+81
+00:04:35,000 --> 00:04:35,000
+Okay, great.
+
+82
+00:04:35,000 --> 00:04:36,000
+Let me use it.
+
+83
+00:04:36,000 --> 00:04:44,000
+How about if I just the actual web server gets the validation, and then when you receive the certificate,
+
+84
+00:04:44,000 --> 00:04:48,000
+you're receiving the validation that you're looking for and the certificate.
+
+85
+00:04:48,000 --> 00:04:48,000
+So that's what this does.
+
+86
+00:04:48,000 --> 00:04:51,000
+It makes it a lot easier so you don't have to waste time.
+
+87
+00:04:51,000 --> 00:04:52,000
+Keep going here.
+
+88
+00:04:53,000 --> 00:04:54,000
+Okay.
+
+89
+00:04:54,000 --> 00:04:56,000
+Revocation is a is a pretty important thing.
+
+90
+00:04:56,000 --> 00:05:01,000
+At some point, if in your history of managing web servers or managing this kind of technology like
+
+91
+00:05:01,000 --> 00:05:06,000
+SSL, you're probably going to have to revoke a cert when a cert is revoked.
+
+92
+00:05:06,000 --> 00:05:11,000
+It has to be a way for other users in the public internet, or in turn, your organization to note that
+
+93
+00:05:11,000 --> 00:05:15,000
+certificate is no good and these are the ways that it's done.
+

07 - Cryptography/021 Steganography OB 1.4_en.srt

@@ -0,0 +1,392 @@
+1
+00:00:00,000 --> 00:00:05,000
+Okay, let's talk of a pretty cool technology called steganography.
+
+2
+00:00:05,000 --> 00:00:11,000
+Now, steganography is basically a technique where you're able to encode a hidden message into different
+
+3
+00:00:11,000 --> 00:00:17,000
+things, such as pictures, audio files, video files, or text files.
+
+4
+00:00:17,000 --> 00:00:20,000
+And I have a link here that I want you guys to try.
+
+5
+00:00:20,000 --> 00:00:25,000
+I'm going to show you guys how to use that, and I'm going to show you guys how we can take an image
+
+6
+00:00:25,000 --> 00:00:27,000
+and encode a secret message into it.
+
+7
+00:00:27,000 --> 00:00:31,000
+Why is this bad and somewhat good?
+
+8
+00:00:31,000 --> 00:00:38,000
+So let's say you're working in an organization and you are a bad person, and you want to get secret
+
+9
+00:00:38,000 --> 00:00:44,000
+data out of that organization right in front of their faces, and they would never know.
+
+10
+00:00:44,000 --> 00:00:46,000
+So here's what you do.
+
+11
+00:00:46,000 --> 00:00:51,000
+You go to the office and you take a group picture with all your bosses and everyone, and then you take
+
+12
+00:00:51,000 --> 00:00:53,000
+that picture and you put it on your computer.
+
+13
+00:00:53,000 --> 00:01:00,000
+What you do then is you take the company's secret information, secret data, and you encode it into
+
+14
+00:01:00,000 --> 00:01:00,000
+the picture.
+
+15
+00:01:01,000 --> 00:01:07,000
+Then what you do is you email the picture out outside to your personal private email.
+
+16
+00:01:07,000 --> 00:01:12,000
+And then what happens is when you get home, you decode the picture and you take the message out the
+
+17
+00:01:12,000 --> 00:01:13,000
+picture.
+
+18
+00:01:13,000 --> 00:01:19,000
+So this picture is flying around the internet, but the picture is actually just a front for the secret
+
+19
+00:01:19,000 --> 00:01:21,000
+message that lies behind it.
+
+20
+00:01:21,000 --> 00:01:24,000
+It's actually really easy to do, and you can even do a website that does it.
+
+21
+00:01:24,000 --> 00:01:26,000
+And I'll show you guys how easy it is.
+
+22
+00:01:26,000 --> 00:01:31,000
+Now, what I'm describing to you here is called image steganography.
+
+23
+00:01:31,000 --> 00:01:37,000
+And this what they do is they modify LSB the least significant bit in the image.
+
+24
+00:01:37,000 --> 00:01:42,000
+Basically, they're going to modify the image to the point where the human eyes can notice that the
+
+25
+00:01:42,000 --> 00:01:44,000
+image has actually been modified.
+
+26
+00:01:44,000 --> 00:01:50,000
+You could also do this with audio file concealing the information within audio files, or particularly
+
+27
+00:01:50,000 --> 00:01:54,000
+all kinds of video files like MP4 video files are famous for this.
+
+28
+00:01:54,000 --> 00:01:59,000
+You can even embed it into white spaces into certain text document.
+
+29
+00:01:59,000 --> 00:02:06,000
+Now for this I want to show you guys how it's done, and I'll give you guys some ways of how to detect
+
+30
+00:02:06,000 --> 00:02:06,000
+it.
+
+31
+00:02:06,000 --> 00:02:07,000
+So let's take a look here.
+
+32
+00:02:07,000 --> 00:02:11,000
+Here I am at that particular website that I just showed you.
+
+33
+00:02:11,000 --> 00:02:14,000
+Now on my desktop.
+
+34
+00:02:14,000 --> 00:02:15,000
+Let me pull up my desktop here.
+
+35
+00:02:17,000 --> 00:02:19,000
+On my desktop, I have an image.
+
+36
+00:02:21,000 --> 00:02:24,000
+I have this image that I just downloaded, royalty free image.
+
+37
+00:02:24,000 --> 00:02:26,000
+And let's see what it looks like.
+
+38
+00:02:26,000 --> 00:02:28,000
+This image of a laptop that I have.
+
+39
+00:02:28,000 --> 00:02:33,000
+So what I'm going to do is I'm going to encode select file.
+
+40
+00:02:33,000 --> 00:02:34,000
+I'm going to choose my image.
+
+41
+00:02:36,000 --> 00:02:37,000
+There is my desktop.
+
+42
+00:02:37,000 --> 00:02:38,000
+Here we go.
+
+43
+00:02:38,000 --> 00:02:39,000
+Image image image.
+
+44
+00:02:39,000 --> 00:02:47,000
+So I select the image and I'm going to put a message that says Andrew has many certifications.
+
+45
+00:02:47,000 --> 00:02:48,000
+That's my message.
+
+46
+00:02:48,000 --> 00:02:50,000
+And this is your original image.
+
+47
+00:02:50,000 --> 00:02:53,000
+Now you're not going to notice a difference when it encodes it.
+
+48
+00:02:54,000 --> 00:02:55,000
+Okay.
+
+49
+00:02:55,000 --> 00:03:00,000
+So here's the binary representation of the actual image that it's that it's encoding it into.
+
+50
+00:03:00,000 --> 00:03:05,000
+And here is the actual stick node image.
+
+51
+00:03:06,000 --> 00:03:07,000
+It says message hidden in the image.
+
+52
+00:03:07,000 --> 00:03:10,000
+You can't tell the difference between that and this.
+
+53
+00:03:11,000 --> 00:03:16,000
+Now, when you try it on your computer, try to see the human eyes cannot tell.
+
+54
+00:03:16,000 --> 00:03:19,000
+Now what I'm going to do is I'm going to right click and I'm going to save this one.
+
+55
+00:03:21,000 --> 00:03:24,000
+And uh, we're going to call it now, I already tried this.
+
+56
+00:03:24,000 --> 00:03:27,000
+I wanted to try it before it before showing to you.
+
+57
+00:03:27,000 --> 00:03:34,000
+So we're going to call S I stick node image for now dot png.
+
+58
+00:03:34,000 --> 00:03:34,000
+All right.
+
+59
+00:03:34,000 --> 00:03:36,000
+So we're going to save this.
+
+60
+00:03:37,000 --> 00:03:38,000
+All right, that's it.
+
+61
+00:03:38,000 --> 00:03:39,000
+It's saved.
+
+62
+00:03:39,000 --> 00:03:43,000
+Now, if I open up the image, you notice it pretty much is the same thing.
+
+63
+00:03:43,000 --> 00:03:49,000
+Now, let's say I can give this image to a lot of people around the internet.
+
+64
+00:03:49,000 --> 00:03:53,000
+Uh, no one would know unless you actually know there is an image.
+
+65
+00:03:53,000 --> 00:03:55,000
+So let's close out this site.
+
+66
+00:03:55,000 --> 00:03:57,000
+I'm going to reopen it.
+
+67
+00:03:59,000 --> 00:04:00,000
+So you can see it's all brand new.
+
+68
+00:04:00,000 --> 00:04:02,000
+So I'm going to go to decode this time.
+
+69
+00:04:02,000 --> 00:04:04,000
+I'm going to select the file.
+
+70
+00:04:05,000 --> 00:04:07,000
+Including the downloads folder.
+
+71
+00:04:07,000 --> 00:04:07,000
+We had it.
+
+72
+00:04:08,000 --> 00:04:09,000
+Here we go.
+
+73
+00:04:10,000 --> 00:04:12,000
+So this is the image the input I'm just going to click on decode.
+
+74
+00:04:13,000 --> 00:04:15,000
+And notice my message has just popped up.
+
+75
+00:04:16,000 --> 00:04:18,000
+You can see the message right there at the top.
+
+76
+00:04:19,000 --> 00:04:19,000
+All right.
+
+77
+00:04:19,000 --> 00:04:20,000
+Very good.
+
+78
+00:04:20,000 --> 00:04:22,000
+So that is steganography.
+
+79
+00:04:22,000 --> 00:04:29,000
+Steganography is just the way of embedding a message into an image, or a text file, or a movie file
+
+80
+00:04:29,000 --> 00:04:29,000
+or audio file.
+
+81
+00:04:29,000 --> 00:04:35,000
+Now, the way you can tell is the file size.
+
+82
+00:04:35,000 --> 00:04:35,000
+All right.
+
+83
+00:04:35,000 --> 00:04:40,000
+The way you can tell if an image has signal, you would need to have that original file.
+
+84
+00:04:40,000 --> 00:04:46,000
+And if you believe that an image has some kind of steganography behind it, look at the file size.
+
+85
+00:04:46,000 --> 00:04:49,000
+Another thing you can do is run it against a hash checker.
+
+86
+00:04:49,000 --> 00:04:53,000
+The hash of the images would be different because one of them just has more information than the other.
+
+87
+00:04:53,000 --> 00:04:55,000
+There are some ways of checking.
+
+88
+00:04:55,000 --> 00:04:58,000
+Other than that, there's not many different ways of stopping this thing.
+
+89
+00:04:58,000 --> 00:05:04,000
+Steganography is difficult to detect, but it's as difficult to detect.
+
+90
+00:05:05,000 --> 00:05:14,000
+But this is why you should limit the output in or send in of things like, uh, images and audio files
+
+91
+00:05:14,000 --> 00:05:15,000
+outside your organization.
+
+92
+00:05:15,000 --> 00:05:20,000
+Because now that you know that this exists, maybe you shouldn't allow images to go out.
+
+93
+00:05:20,000 --> 00:05:25,000
+In fact, one of the dumbest things I see organizations do sometimes.
+
+94
+00:05:25,000 --> 00:05:32,000
+I got an email from a bank, like legitimate email from a representative of a bank, and in it they
+
+95
+00:05:32,000 --> 00:05:35,000
+have the logo of the bank and the email signature of the person.
+
+96
+00:05:35,000 --> 00:05:42,000
+That's smart, because if the head of the bank realizes that they can embed messages into that little
+
+97
+00:05:42,000 --> 00:05:44,000
+logo, I don't think they would have allowed it.
+
+98
+00:05:44,000 --> 00:05:49,000
+So it's important to know what this thing is and realize it's difficult to detect.
+

07 - Cryptography/022 Blockchain OB 1.4_en.srt

@@ -0,0 +1,476 @@
+1
+00:00:00,000 --> 00:00:03,000
+In this video, we're going to talk of a pretty famous technology.
+
+2
+00:00:03,000 --> 00:00:06,000
+And that technology is called blockchain.
+
+3
+00:00:06,000 --> 00:00:09,000
+Now blockchain I'm going to show you guys how a blockchain is built.
+
+4
+00:00:09,000 --> 00:00:15,000
+But this particular technology is famous in cryptocurrencies where most people hears it from.
+
+5
+00:00:15,000 --> 00:00:21,000
+But blockchain can be applied to many different applications, whether it's an accounting application,
+
+6
+00:00:21,000 --> 00:00:24,000
+banking transactions or all different kinds of financial transactions.
+
+7
+00:00:24,000 --> 00:00:25,000
+You can use a blockchain.
+
+8
+00:00:25,000 --> 00:00:27,000
+So it's not just for cryptocurrency.
+
+9
+00:00:27,000 --> 00:00:30,000
+In fact, this video has nothing to do with cryptocurrency.
+
+10
+00:00:30,000 --> 00:00:31,000
+Let's get started.
+
+11
+00:00:31,000 --> 00:00:38,000
+So blockchain let's take a look at some definitions before I show you exactly how a blockchain is built.
+
+12
+00:00:38,000 --> 00:00:46,000
+So a blockchain is known as a decentralized and distributed ledger technology known for its role in
+
+13
+00:00:46,000 --> 00:00:47,000
+underpinning cryptocurrency.
+
+14
+00:00:47,000 --> 00:00:53,000
+Like I mentioned now a blockchain is just a chain of blocks where each block represents a list of transaction.
+
+15
+00:00:53,000 --> 00:00:58,000
+Each transaction in the blockchain is secured through a cryptographic principle known as hashing, which
+
+16
+00:00:58,000 --> 00:01:00,000
+we covered earlier in the course.
+
+17
+00:01:00,000 --> 00:01:05,000
+The blockchain is decentralized and maintain across a network of computers across all of the nodes in
+
+18
+00:01:05,000 --> 00:01:07,000
+that particular system.
+
+19
+00:01:07,000 --> 00:01:10,000
+It does utilize a hash function.
+
+20
+00:01:10,000 --> 00:01:15,000
+Each block contains a cryptographic hash of the previous block, chaining them together.
+
+21
+00:01:15,000 --> 00:01:17,000
+This ensures that each block is added to.
+
+22
+00:01:17,000 --> 00:01:21,000
+Jim cannot be altered without messing up all the blocks that comes after it.
+
+23
+00:01:22,000 --> 00:01:24,000
+Lots of information here.
+
+24
+00:01:24,000 --> 00:01:27,000
+Let me show you it and it'll make more sense.
+
+25
+00:01:27,000 --> 00:01:29,000
+So I have an image.
+
+26
+00:01:30,000 --> 00:01:33,000
+Uh, from Money.com.
+
+27
+00:01:33,000 --> 00:01:38,000
+And I want to show you guys what is, you know, what exactly is how how a blockchain works.
+
+28
+00:01:38,000 --> 00:01:43,000
+So first of all, when they say the word decentralized ledger, let's take the word ledger.
+
+29
+00:01:43,000 --> 00:01:48,000
+Ledger literally means list when they say a list of transactions.
+
+30
+00:01:48,000 --> 00:01:54,000
+When you design a blockchain, you design how many of these transactions are going to be stored on every
+
+31
+00:01:54,000 --> 00:01:55,000
+single block.
+
+32
+00:01:55,000 --> 00:01:58,000
+So every block can hold a list of transactions.
+
+33
+00:01:58,000 --> 00:02:02,000
+Let's say you're a reseller and you're selling books.
+
+34
+00:02:03,000 --> 00:02:04,000
+Okay.
+
+35
+00:02:04,000 --> 00:02:07,000
+Each block for you holds three transactions.
+
+36
+00:02:07,000 --> 00:02:12,000
+It holds who bought the book when they bought the book, and how much money they spent buying the book.
+
+37
+00:02:12,000 --> 00:02:13,000
+And again, this is a list.
+
+38
+00:02:13,000 --> 00:02:18,000
+Anything that you can, anything that you can put a make a list out of, you can make a blockchain out
+
+39
+00:02:18,000 --> 00:02:18,000
+of.
+
+40
+00:02:18,000 --> 00:02:21,000
+So let's say each block holds three transactions.
+
+41
+00:02:21,000 --> 00:02:26,000
+And I'll show you why the blockchain is so powerful and why people like using it.
+
+42
+00:02:26,000 --> 00:02:28,000
+So each block is three transactions.
+
+43
+00:02:28,000 --> 00:02:32,000
+So in the first block you put transaction number one.
+
+44
+00:02:32,000 --> 00:02:38,000
+Let's say Bob bought a book for $10 and the book was, uh, Excel.
+
+45
+00:02:38,000 --> 00:02:45,000
+Then the second book was bought by Mary for 20 bucks, and she bought a word book.
+
+46
+00:02:45,000 --> 00:02:49,000
+And, uh, number three was Peter.
+
+47
+00:02:49,000 --> 00:02:54,000
+He bought a CISSP book for a $30 CISSP book.
+
+48
+00:02:54,000 --> 00:02:55,000
+It doesn't matter what it is.
+
+49
+00:02:55,000 --> 00:02:58,000
+Just know it's three transaction.
+
+50
+00:02:58,000 --> 00:03:06,000
+What you do is you take your entire three transaction, all three of them, everything about them,
+
+51
+00:03:06,000 --> 00:03:07,000
+and you hash it.
+
+52
+00:03:07,000 --> 00:03:14,000
+Now, the most famous hash they use is a crypto is a, uh, Sha 256 is the most famous hash they use.
+
+53
+00:03:14,000 --> 00:03:19,000
+If you remember the hash in videos, how I was able to type text in the box and they generate a hash,
+
+54
+00:03:19,000 --> 00:03:20,000
+the same thing here.
+
+55
+00:03:20,000 --> 00:03:23,000
+They're just going to put all the transaction in and boom, generate a hash.
+
+56
+00:03:23,000 --> 00:03:26,000
+This is the hash that comes out of this block.
+
+57
+00:03:27,000 --> 00:03:29,000
+There is no previous hash or zero.
+
+58
+00:03:30,000 --> 00:03:31,000
+Then what they do?
+
+59
+00:03:32,000 --> 00:03:40,000
+Is they go to the next block and they put another one, two, three transaction.
+
+60
+00:03:40,000 --> 00:03:41,000
+Whatever they are, it doesn't matter for now.
+
+61
+00:03:42,000 --> 00:03:45,000
+And then they hash it.
+
+62
+00:03:45,000 --> 00:03:46,000
+But here's what they do.
+
+63
+00:03:46,000 --> 00:03:50,000
+This block starts out with the this previous hash.
+
+64
+00:03:50,000 --> 00:03:55,000
+This hash comes right here 6UP2.
+
+65
+00:03:55,000 --> 00:04:02,000
+So it takes the three transaction plus this hash to produce this hash.
+
+66
+00:04:02,000 --> 00:04:11,000
+Then it takes this hash puts it here I'm talking the hash value itself 8Y5C9.
+
+67
+00:04:11,000 --> 00:04:14,000
+And then it does 123 transaction.
+
+68
+00:04:15,000 --> 00:04:16,000
+And it.
+
+69
+00:04:17,000 --> 00:04:18,000
+And it gets a hash.
+
+70
+00:04:18,000 --> 00:04:20,000
+Now this is great.
+
+71
+00:04:20,000 --> 00:04:21,000
+Why is this good?
+
+72
+00:04:21,000 --> 00:04:22,000
+This is a blockchain.
+
+73
+00:04:22,000 --> 00:04:25,000
+If you ever wanted to know what exactly is a blockchain, this is how it works.
+
+74
+00:04:25,000 --> 00:04:26,000
+Why is this good?
+
+75
+00:04:26,000 --> 00:04:32,000
+Because remember in the world of hashing, if anything changes, it changes all of the files within
+
+76
+00:04:32,000 --> 00:04:33,000
+it, right?
+
+77
+00:04:33,000 --> 00:04:37,000
+If anything changes, if if anything changes in the transaction, the hash will change.
+
+78
+00:04:37,000 --> 00:04:39,000
+This is a this is a great technology.
+
+79
+00:04:39,000 --> 00:04:46,000
+And the reason we do this is because if anyone ever manipulates a transaction, let's say any one of
+
+80
+00:04:46,000 --> 00:04:48,000
+these first transaction.
+
+81
+00:04:49,000 --> 00:04:55,000
+Then this hash will change, which will then invalidate this hash, which will then invalidate this
+
+82
+00:04:55,000 --> 00:04:56,000
+hash.
+
+83
+00:04:56,000 --> 00:05:01,000
+In other words, any time you manipulate a block, all the block that goes forward after that becomes
+
+84
+00:05:01,000 --> 00:05:02,000
+invalidated.
+
+85
+00:05:03,000 --> 00:05:04,000
+And here's a pretty cool part.
+
+86
+00:05:05,000 --> 00:05:12,000
+This ledger, this block chain, these lists of blocks or all these blocks are stored across thousands
+
+87
+00:05:12,000 --> 00:05:14,000
+of machines across your network.
+
+88
+00:05:14,000 --> 00:05:16,000
+They all have the exact same ledger.
+
+89
+00:05:16,000 --> 00:05:19,000
+So when somebody manipulates this one, they'll be able to tell, hey, you know what?
+
+90
+00:05:19,000 --> 00:05:21,000
+That ledger is different than my ledger.
+
+91
+00:05:21,000 --> 00:05:22,000
+What's the difference here?
+
+92
+00:05:22,000 --> 00:05:24,000
+So it's decentralized.
+
+93
+00:05:24,000 --> 00:05:27,000
+Decentralized means it's not stored on a single machine.
+
+94
+00:05:27,000 --> 00:05:29,000
+In fact, it's stored on tons of machines.
+
+95
+00:05:29,000 --> 00:05:33,000
+If anybody ever does a manipulation, it updates all the ledgers, and people are going to see.
+
+96
+00:05:33,000 --> 00:05:39,000
+Well, technically, the only blocks that should ever be manipulated is this block four.
+
+97
+00:05:39,000 --> 00:05:40,000
+Then block five.
+
+98
+00:05:40,000 --> 00:05:43,000
+If anybody is changing blocks 2 or 3, that's a problem.
+
+99
+00:05:43,000 --> 00:05:45,000
+So that's the concept of a blockchain.
+
+100
+00:05:45,000 --> 00:05:51,000
+Now one thing that you may see pop up on your exam is a firm we call an open public ledger.
+
+101
+00:05:52,000 --> 00:05:54,000
+This is a decentralized and transparent record.
+
+102
+00:05:54,000 --> 00:05:58,000
+Keeping the ledger is accessible to anyone provides a permanent record of all transactions.
+
+103
+00:05:58,000 --> 00:06:05,000
+Now, there are websites out there that has all of the crypto currency transaction.
+
+104
+00:06:05,000 --> 00:06:09,000
+So if you ever find somebody who's cryptocurrency number.
+
+105
+00:06:11,000 --> 00:06:16,000
+Uh, you can actually put it into the public ledger, and the ledger is going to show you all the transactions
+
+106
+00:06:16,000 --> 00:06:17,000
+against that.
+
+107
+00:06:17,000 --> 00:06:25,000
+So all the transactions that you take, utilize in a particular cryptocurrency is public to everyone.
+
+108
+00:06:25,000 --> 00:06:29,000
+So they could see that this was used to purchase this, this and this was used in these transactions,
+
+109
+00:06:29,000 --> 00:06:30,000
+but they don't know who owns it.
+
+110
+00:06:31,000 --> 00:06:34,000
+So that is what a public ledger is.
+
+111
+00:06:35,000 --> 00:06:42,000
+Once again, keep in mind that, uh, blockchains is not something unique only to cryptocurrency.
+
+112
+00:06:42,000 --> 00:06:46,000
+Although it was pretty much invented with crypto, the creation of Bitcoin, it's not being utilized
+
+113
+00:06:46,000 --> 00:06:50,000
+in tons of applications, so make sure you're familiar with it.
+
+114
+00:06:50,000 --> 00:06:51,000
+It's all about integrity.
+
+115
+00:06:51,000 --> 00:06:58,000
+Public ledgers, especially blockchains, is not about confidentiality because technically in a public
+
+116
+00:06:58,000 --> 00:06:59,000
+ledger, it's all available.
+
+117
+00:06:59,000 --> 00:07:01,000
+The big key word there is integrity.
+
+118
+00:07:01,000 --> 00:07:06,000
+That means that if anybody manipulates any transaction on the blockchain, you're going to be able to
+
+119
+00:07:06,000 --> 00:07:12,000
+detect it, making it one of the best technologies, best in upcoming technologies going forward.
+

07 - Cryptography/023 Salting OB 1.4_en.srt

@@ -0,0 +1,352 @@
+1
+00:00:00,000 --> 00:00:06,000
+One of the worst technologies that still exists today that secures almost all the data on the planet
+
+2
+00:00:06,000 --> 00:00:07,000
+is passwords.
+
+3
+00:00:07,000 --> 00:00:08,000
+Oh, I hate passwords.
+
+4
+00:00:08,000 --> 00:00:10,000
+There's so many passwords to remember.
+
+5
+00:00:10,000 --> 00:00:16,000
+You always got to remember a complex password, and then it's easily hacked unless we salt it.
+
+6
+00:00:16,000 --> 00:00:20,000
+In this video, I want to talk about a topic called Sultan.
+
+7
+00:00:20,000 --> 00:00:24,000
+And Sultan is predominantly used to secure passwords.
+
+8
+00:00:24,000 --> 00:00:29,000
+Now, I do have a link in an article we're going to look at on Wikipedia that really shows in depth
+
+9
+00:00:29,000 --> 00:00:30,000
+salt.
+
+10
+00:00:30,000 --> 00:00:33,000
+And I want to explain this to you guys, but what exactly is it?
+
+11
+00:00:33,000 --> 00:00:37,000
+So Sultan is used to enhance the security of stored passwords.
+
+12
+00:00:37,000 --> 00:00:38,000
+It involves listen carefully.
+
+13
+00:00:38,000 --> 00:00:47,000
+Add in a unique random string of characters known as a salt to each password before it's hashed.
+
+14
+00:00:47,000 --> 00:00:50,000
+Now, in order to move on, you got to understand something.
+
+15
+00:00:50,000 --> 00:00:54,000
+When you store a password, a computer does not store the plaintext.
+
+16
+00:00:54,000 --> 00:00:58,000
+So if your password is password one, two, three, it doesn't store password 123.
+
+17
+00:00:58,000 --> 00:01:00,000
+It stores the hash of that.
+
+18
+00:01:01,000 --> 00:01:02,000
+Now remember I showed you guys hashing.
+
+19
+00:01:03,000 --> 00:01:05,000
+So it will store just the hash value.
+
+20
+00:01:05,000 --> 00:01:12,000
+When you come back to type in your password, it just you type in password one, two, three then hashes
+
+21
+00:01:12,000 --> 00:01:14,000
+it and compare it to the hash it has.
+
+22
+00:01:14,000 --> 00:01:16,000
+If it matches up boom, it logs you in.
+
+23
+00:01:16,000 --> 00:01:17,000
+That's the normal operation.
+
+24
+00:01:17,000 --> 00:01:20,000
+But how does Sultan work?
+
+25
+00:01:20,000 --> 00:01:23,000
+Well, I have the process listed here.
+
+26
+00:01:24,000 --> 00:01:26,000
+Okay, in case you're reading this at a later time.
+
+27
+00:01:27,000 --> 00:01:32,000
+Uh, but I want to go to this article, uh, on Wikipedia, and I want to show it to you, actually,
+
+28
+00:01:32,000 --> 00:01:34,000
+uh, more and more in practice.
+
+29
+00:01:34,000 --> 00:01:39,000
+So let's go to that link that you see on the slide.
+
+30
+00:01:39,000 --> 00:01:40,000
+Um.
+
+31
+00:01:41,000 --> 00:01:43,000
+And here we go.
+
+32
+00:01:44,000 --> 00:01:47,000
+Okay, so here's the link I just put on the slide there.
+
+33
+00:01:47,000 --> 00:01:48,000
+And this is going to be Sultan.
+
+34
+00:01:48,000 --> 00:01:50,000
+Now I want to show you guys a couple of things.
+
+35
+00:01:50,000 --> 00:01:51,000
+First of all.
+
+36
+00:01:53,000 --> 00:01:55,000
+So here is user one.
+
+37
+00:01:55,000 --> 00:01:57,000
+This is their password.
+
+38
+00:01:57,000 --> 00:01:59,000
+This is the hash of their password.
+
+39
+00:02:00,000 --> 00:02:00,000
+Okay.
+
+40
+00:02:00,000 --> 00:02:01,000
+That's the.
+
+41
+00:02:01,000 --> 00:02:05,000
+This is the 256 bit hash that's generated by Sha 256.
+
+42
+00:02:06,000 --> 00:02:15,000
+What the computer does with Sultan is that instead of just having the hash of just this password, what
+
+43
+00:02:15,000 --> 00:02:17,000
+the computer does is that it generates a salt.
+
+44
+00:02:17,000 --> 00:02:22,000
+This thing, it's a random set of a string of characters.
+
+45
+00:02:22,000 --> 00:02:28,000
+What it does now is that it will append this to your password.
+
+46
+00:02:29,000 --> 00:02:31,000
+Notice this is your password 123.
+
+47
+00:02:32,000 --> 00:02:36,000
+And then it appends all this random stuff to it and then hashes this.
+
+48
+00:02:38,000 --> 00:02:41,000
+Ash is all the things I just highlighted to form this.
+
+49
+00:02:41,000 --> 00:02:46,000
+So what's stored in the computer's password file is not this hash of password one, two, three.
+
+50
+00:02:46,000 --> 00:02:47,000
+It's this thing.
+
+51
+00:02:47,000 --> 00:02:51,000
+And this is incredibly difficult to crack.
+
+52
+00:02:51,000 --> 00:02:54,000
+Very few brute force in modern time will ever crack this.
+
+53
+00:02:54,000 --> 00:02:57,000
+Look how long this is, and look how complex it is.
+
+54
+00:02:58,000 --> 00:03:05,000
+So what it does is that it will take your password, append the salt, then hash it and then store it.
+
+55
+00:03:06,000 --> 00:03:11,000
+When you come to log in, the verification process would be you type in password one, two, three.
+
+56
+00:03:11,000 --> 00:03:12,000
+You never know assault.
+
+57
+00:03:12,000 --> 00:03:13,000
+You type in password 123.
+
+58
+00:03:13,000 --> 00:03:19,000
+It then re appends the salt, rehashes it and see oh okay.
+
+59
+00:03:19,000 --> 00:03:20,000
+Does it match what they have?
+
+60
+00:03:20,000 --> 00:03:21,000
+Yes okay.
+
+61
+00:03:21,000 --> 00:03:22,000
+It's correct.
+
+62
+00:03:22,000 --> 00:03:27,000
+Now if you're wondering does this really increase the security?
+
+63
+00:03:27,000 --> 00:03:29,000
+The answer is absolutely.
+
+64
+00:03:31,000 --> 00:03:36,000
+You see, one of the things here we have to remember, some people say, well, if I come to the prompt
+
+65
+00:03:36,000 --> 00:03:38,000
+and I keep typing in the past one, it might crack it.
+
+66
+00:03:38,000 --> 00:03:44,000
+You see, the way they crack password is they steal the hash, and then they run a brute force attack
+
+67
+00:03:44,000 --> 00:03:45,000
+against the hash.
+
+68
+00:03:45,000 --> 00:03:49,000
+No one knows your password except your head, except your brain.
+
+69
+00:03:49,000 --> 00:03:51,000
+But they know the hash.
+
+70
+00:03:51,000 --> 00:03:54,000
+The hash is technically not that difficult to get.
+
+71
+00:03:54,000 --> 00:03:58,000
+And if they get a hash that has a whole bunch of random string of character, what they're going to
+
+72
+00:03:58,000 --> 00:04:00,000
+do is they're going to brute force that hash.
+
+73
+00:04:00,000 --> 00:04:04,000
+And even if they guess the hash, that's technically not your password because your password is one,
+
+74
+00:04:04,000 --> 00:04:05,000
+two, three.
+
+75
+00:04:05,000 --> 00:04:13,000
+So if they use a massive super alien machine to crack that hash and find out your password with the
+
+76
+00:04:13,000 --> 00:04:15,000
+salt, it's not your password.
+
+77
+00:04:15,000 --> 00:04:16,000
+Because you know what?
+
+78
+00:04:16,000 --> 00:04:21,000
+When they type in your password, which they believe is your password, one, two, three plus the salt
+
+79
+00:04:21,000 --> 00:04:24,000
+is then going to re append the old salt.
+
+80
+00:04:25,000 --> 00:04:26,000
+And it's never going to work.
+
+81
+00:04:26,000 --> 00:04:35,000
+Sultan, remember, drastically improves your passwords, drastically improves the password.
+
+82
+00:04:35,000 --> 00:04:37,000
+Now you have to set this up.
+
+83
+00:04:37,000 --> 00:04:43,000
+Sultan is done in many applications and web applications especially will utilize Sultan.
+
+84
+00:04:43,000 --> 00:04:47,000
+So Sultan is an important topic in the world of IT security.
+
+85
+00:04:47,000 --> 00:04:53,000
+Anytime you hear someone do or build in a web application, ask them will the password be salted?
+
+86
+00:04:53,000 --> 00:04:56,000
+If not as an IT security security professional?
+
+87
+00:04:56,000 --> 00:05:01,000
+Tell them, I would highly recommend you salt the password.
+
+88
+00:05:01,000 --> 00:05:04,000
+That way the system is super secure.
+

07 - Cryptography/024 TPM OB 1.4_en.srt

@@ -0,0 +1,284 @@
+1
+00:00:00,000 --> 00:00:05,000
+One of the most dangerous things that can ever happen in the world of it is when you're a security administrator
+
+2
+00:00:05,000 --> 00:00:12,000
+and you get a call that one of your employee has lost their laptop, because on this laptop contains
+
+3
+00:00:12,000 --> 00:00:18,000
+all the company's data, all that person's email, it doesn't matter how secure their password is.
+
+4
+00:00:18,000 --> 00:00:23,000
+You see, if I want the data off of this laptop, I don't need to know your password.
+
+5
+00:00:23,000 --> 00:00:31,000
+All I got to do unscrew the bottom, take out the bottom, take out the hard drive, take that hard
+
+6
+00:00:31,000 --> 00:00:33,000
+drive and mount it to my computer.
+
+7
+00:00:33,000 --> 00:00:36,000
+Whether it's a Sata drive Mdot, it doesn't matter.
+
+8
+00:00:36,000 --> 00:00:38,000
+I'm just going to plug the drive into my machine.
+
+9
+00:00:38,000 --> 00:00:44,000
+And there's a lot of external Mdot two and Sata connectors and whatever I can use to externally mount
+
+10
+00:00:44,000 --> 00:00:47,000
+your hard drive onto my desktop.
+
+11
+00:00:47,000 --> 00:00:51,000
+And now I can open all the files on your hard drive.
+
+12
+00:00:51,000 --> 00:00:53,000
+I don't care about logging into your windows.
+
+13
+00:00:53,000 --> 00:00:55,000
+All I want to do is steal your data.
+
+14
+00:00:55,000 --> 00:01:00,000
+This is a nightmare scenario for any it department.
+
+15
+00:01:00,000 --> 00:01:03,000
+So what do we do with devices like this?
+
+16
+00:01:03,000 --> 00:01:05,000
+Or god forbid, even more devices like this?
+
+17
+00:01:05,000 --> 00:01:11,000
+You see, especially when it comes to computers like this, we need to do what is called hard drive
+
+18
+00:01:11,000 --> 00:01:12,000
+encryption.
+
+19
+00:01:13,000 --> 00:01:16,000
+We need to encrypt the hard drive.
+
+20
+00:01:16,000 --> 00:01:21,000
+That way, if anybody does what I just say, I've taken the hard drive out, mounted it to a machine,
+
+21
+00:01:21,000 --> 00:01:24,000
+and seeing all the files in it, they won't be able to see anything.
+
+22
+00:01:24,000 --> 00:01:26,000
+Because the drive is encrypted.
+
+23
+00:01:26,000 --> 00:01:28,000
+The drive has to be encrypted.
+
+24
+00:01:28,000 --> 00:01:30,000
+This is called disk encryption.
+
+25
+00:01:30,000 --> 00:01:38,000
+And one of the ways of doing that is by utilizing oops, a TPM or a TPM chip.
+
+26
+00:01:38,000 --> 00:01:44,000
+A lot of these corporate laptops comes built with something we call a TPM chip.
+
+27
+00:01:45,000 --> 00:01:52,000
+TPM Trusted Platform module is a hardware component designed to secure hardware by integrating cryptographic
+
+28
+00:01:52,000 --> 00:01:53,000
+keys.
+
+29
+00:01:53,000 --> 00:01:59,000
+It's basically a device, okay that allows the generation of storage of cryptographic keys.
+
+30
+00:01:59,000 --> 00:02:04,000
+TPMs can generate encryption keys, keeping them private, keeping the private portion of these keys
+
+31
+00:02:04,000 --> 00:02:06,000
+safe within a TPM chip itself.
+
+32
+00:02:07,000 --> 00:02:10,000
+Now it's used for multiple purposes.
+
+33
+00:02:10,000 --> 00:02:14,000
+Number one, it's used to do things like disk encryption.
+
+34
+00:02:14,000 --> 00:02:16,000
+Now if you have windows.
+
+35
+00:02:17,000 --> 00:02:19,000
+Windows 11, and so on.
+
+36
+00:02:19,000 --> 00:02:24,000
+Windows 10 11, the higher versions of it, the business editions of it, you can have BitLocker, like
+
+37
+00:02:24,000 --> 00:02:26,000
+I have BitLocker on this machine.
+
+38
+00:02:26,000 --> 00:02:28,000
+I also have BitLocker on this machine.
+
+39
+00:02:28,000 --> 00:02:31,000
+You turn on BitLocker encryption.
+
+40
+00:02:31,000 --> 00:02:37,000
+And what BitLocker does if the machine has a TPM chip, is that it will encrypt the hard drive and it'll
+
+41
+00:02:37,000 --> 00:02:40,000
+store the cryptographic keys on the TPM chip.
+
+42
+00:02:40,000 --> 00:02:46,000
+If you remove the hard drive, you wouldn't be able to see anything because you'll need to decrypt it.
+
+43
+00:02:46,000 --> 00:02:50,000
+But the cryptographic keys is on the TPM chip.
+
+44
+00:02:50,000 --> 00:02:53,000
+Now, the TPM chip will be like something that's sorted into the motherboard.
+
+45
+00:02:53,000 --> 00:02:56,000
+It wouldn't be able something you could just rip off.
+
+46
+00:02:57,000 --> 00:03:02,000
+The TPM can also store and manage keys using the process of verifying the boot process.
+
+47
+00:03:02,000 --> 00:03:06,000
+That way no malware can try to load up in the boot process.
+
+48
+00:03:06,000 --> 00:03:10,000
+So TPM is super important right now.
+
+49
+00:03:10,000 --> 00:03:13,000
+If you're managing an IT department, you must.
+
+50
+00:03:13,000 --> 00:03:21,000
+And I say you must ensure that all your laptops especially have TPM, anything that's mobile.
+
+51
+00:03:22,000 --> 00:03:25,000
+So exactly what is it?
+
+52
+00:03:25,000 --> 00:03:30,000
+Well, it's basically it's a secure it has what's called a crypto processor that's designed to carry
+
+53
+00:03:30,000 --> 00:03:32,000
+out cryptographic operations.
+
+54
+00:03:32,000 --> 00:03:39,000
+The primary purpose of it, once again, is to ensure that we create cryptographic keys to keep our
+
+55
+00:03:39,000 --> 00:03:40,000
+disk secure.
+
+56
+00:03:40,000 --> 00:03:45,000
+This is going to be the two main beneficial aspects of a TPM chip.
+
+57
+00:03:45,000 --> 00:03:47,000
+I can't emphasize this enough.
+
+58
+00:03:47,000 --> 00:03:48,000
+One time.
+
+59
+00:03:49,000 --> 00:03:55,000
+Now this actually, this laptop actually has, uh, a TPM chip.
+
+60
+00:03:55,000 --> 00:03:56,000
+It is fully encrypted.
+
+61
+00:03:56,000 --> 00:04:01,000
+It does have the data of the business on it because it has my email and I am the CEO of the business.
+
+62
+00:04:01,000 --> 00:04:03,000
+It has my email, it has work I'm working on.
+
+63
+00:04:04,000 --> 00:04:06,000
+And one time I left it in the back of an Uber.
+
+64
+00:04:07,000 --> 00:04:09,000
+And you know, it didn't bother me much.
+
+65
+00:04:09,000 --> 00:04:12,000
+I called the Uber like the moment I figured out I left it.
+
+66
+00:04:12,000 --> 00:04:17,000
+It didn't like my heart didn't sink because I realized, well, even if somebody steals this laptop.
+
+67
+00:04:18,000 --> 00:04:20,000
+My password is super secure.
+
+68
+00:04:20,000 --> 00:04:23,000
+They probably not be able to get in, but if they do take the hard drive out.
+
+69
+00:04:24,000 --> 00:04:28,000
+They'll never get anything out of it, because the TPM in which obviously the laptop is back with me,
+
+70
+00:04:28,000 --> 00:04:30,000
+I called Uber and the driver dropped it back.
+
+71
+00:04:30,000 --> 00:04:35,000
+So make sure you use TPM chips, especially on all mobile devices.
+

07 - Cryptography/025 Secure Enclave OB 1.4_en.srt

@@ -0,0 +1,124 @@
+1
+00:00:00,000 --> 00:00:05,000
+When a computer is processing data, one of the things that the computer must be able to do, especially
+
+2
+00:00:05,000 --> 00:00:09,000
+secure processing, is that it has to be able to like segment that off.
+
+3
+00:00:09,000 --> 00:00:16,000
+You don't want things like processing of thumbprints or passwords to just be in any place of memory.
+
+4
+00:00:16,000 --> 00:00:21,000
+We have this concept called a secure enclave.
+
+5
+00:00:21,000 --> 00:00:25,000
+This provides a highly secure space within a device.
+
+6
+00:00:25,000 --> 00:00:29,000
+Memory, where sensitive data can be stored in cryptographic operations is done on.
+
+7
+00:00:29,000 --> 00:00:33,000
+And this basically isolates it from the other operating systems and processes.
+
+8
+00:00:33,000 --> 00:00:35,000
+Why would you do this?
+
+9
+00:00:35,000 --> 00:00:43,000
+Well, cryptographic processes generally in things does things like encrypt and decrypt sensitive data.
+
+10
+00:00:43,000 --> 00:00:48,000
+It checks things like passwords or facial recognition or biometrics.
+
+11
+00:00:48,000 --> 00:00:51,000
+You don't want this to just be in any part of a computer memory.
+
+12
+00:00:51,000 --> 00:00:51,000
+Why?
+
+13
+00:00:51,000 --> 00:00:55,000
+Because then other programs can read it and steal that data.
+
+14
+00:00:55,000 --> 00:01:01,000
+So what we do is we set up secure enclaves, and this is going to be done within the actual software
+
+15
+00:01:01,000 --> 00:01:02,000
+and hardware.
+
+16
+00:01:03,000 --> 00:01:04,000
+So what does it do?
+
+17
+00:01:04,000 --> 00:01:10,000
+Well, it ensures that sensitive data, like fingerprints, is stored in an environment that is separated,
+
+18
+00:01:10,000 --> 00:01:12,000
+segregated from the rest of the operating system.
+
+19
+00:01:12,000 --> 00:01:14,000
+This protects it from any malware.
+
+20
+00:01:14,000 --> 00:01:19,000
+So let's say you don't even know you have malicious software in your machine.
+
+21
+00:01:20,000 --> 00:01:25,000
+So you try to decode a file or log in with something, let's say a thumbprint.
+
+22
+00:01:26,000 --> 00:01:30,000
+Well, you don't really have to worry too much about the malware getting it, because you're using this
+
+23
+00:01:30,000 --> 00:01:33,000
+concept on your operating system and on your hardware.
+
+24
+00:01:34,000 --> 00:01:39,000
+Some of the key features, basically hardware isolation, the data and operations with data are isolated
+
+25
+00:01:39,000 --> 00:01:42,000
+at the hardware level, so software can't break it.
+
+26
+00:01:42,000 --> 00:01:47,000
+It limits access and is generally considered tamper resistant, making physical attacks very difficult
+
+27
+00:01:47,000 --> 00:01:50,000
+to get it on high secure systems.
+
+28
+00:01:50,000 --> 00:01:56,000
+This is one of the things you're going to have to make sure is built into the system, because you could
+
+29
+00:01:56,000 --> 00:02:02,000
+have malware or malicious software on your machine and not know it, and then secure operations could
+
+30
+00:02:02,000 --> 00:02:04,000
+be taking place in the malware can be stealing it.
+
+31
+00:02:04,000 --> 00:02:08,000
+But if you use a secure enclave, that is much less likely to happen.
+

07 - Cryptography/026 Obfuscation OB 1.4_en.srt

@@ -0,0 +1,252 @@
+1
+00:00:00,000 --> 00:00:06,000
+Sometimes when you are playing around with data or have to have test data, you have to be careful because
+
+2
+00:00:06,000 --> 00:00:09,000
+a lot of data in the business is considered confidential.
+
+3
+00:00:09,000 --> 00:00:13,000
+But sometimes when you're building an application, you need data to work with.
+
+4
+00:00:13,000 --> 00:00:16,000
+You need large data sets to actually work with.
+
+5
+00:00:16,000 --> 00:00:22,000
+Now in this video, I want to show you guys a topic we're going to refer to as data obfuscation.
+
+6
+00:00:22,000 --> 00:00:28,000
+Obfuscation is basically the process of disguising sensitive, confidential or sensitive data protected
+
+7
+00:00:28,000 --> 00:00:30,000
+basically from unauthorized access.
+
+8
+00:00:30,000 --> 00:00:32,000
+Now I'm going to try this.
+
+9
+00:00:32,000 --> 00:00:32,000
+Here.
+
+10
+00:00:32,000 --> 00:00:35,000
+We have another video coming up on tokenization.
+
+11
+00:00:35,000 --> 00:00:38,000
+But I'm going to I want to show you guys what obfuscation is going to do.
+
+12
+00:00:39,000 --> 00:00:42,000
+And I'm going to go to that link and I want to show you guys what it does.
+
+13
+00:00:42,000 --> 00:00:45,000
+So basically it's going to hide the data.
+
+14
+00:00:45,000 --> 00:00:51,000
+Let's say you're writing a program like your source code to the program in order to make it difficult
+
+15
+00:00:51,000 --> 00:00:53,000
+for people to find the original source code.
+
+16
+00:00:53,000 --> 00:00:57,000
+If they see the source code they decompile the program is you can obfuscate it.
+
+17
+00:00:57,000 --> 00:00:58,000
+Let me show you guys what it looks like.
+
+18
+00:00:58,000 --> 00:01:02,000
+So if you follow that link in this slide there, this is what you would have gotten.
+
+19
+00:01:02,000 --> 00:01:07,000
+And here's this is a JavaScript Obfuscator tool.
+
+20
+00:01:07,000 --> 00:01:15,000
+And you notice that this is this is basically just the JavaScript that when ran it just says hello world.
+
+21
+00:01:15,000 --> 00:01:18,000
+It's the first thing you learn when you learn JavaScript or Java in general.
+
+22
+00:01:18,000 --> 00:01:22,000
+This is a comment that says paste your JavaScript code here.
+
+23
+00:01:22,000 --> 00:01:24,000
+Now this is going to obfuscate it.
+
+24
+00:01:24,000 --> 00:01:25,000
+So you can use this.
+
+25
+00:01:25,000 --> 00:01:28,000
+You can actually put your code in here if you write code and obfuscate it.
+
+26
+00:01:28,000 --> 00:01:30,000
+So if I say obfuscate watch what happens.
+
+27
+00:01:30,000 --> 00:01:33,000
+Ooh, that looks kind of crazy doesn't it?
+
+28
+00:01:33,000 --> 00:01:37,000
+Now if you run this code.
+
+29
+00:01:38,000 --> 00:01:38,000
+Okay.
+
+30
+00:01:38,000 --> 00:01:44,000
+If you run this code, it will run the code that we saw here.
+
+31
+00:01:44,000 --> 00:01:49,000
+This output obfuscated code technically is this.
+
+32
+00:01:49,000 --> 00:01:54,000
+Except as you notice, it looks kind of crazy.
+
+33
+00:01:56,000 --> 00:01:56,000
+It's obfuscate that.
+
+34
+00:01:57,000 --> 00:01:59,000
+So it's actually all there.
+
+35
+00:01:59,000 --> 00:02:01,000
+But it is difficult.
+
+36
+00:02:01,000 --> 00:02:04,000
+It basically hides a lot of the code, but it's still usable.
+
+37
+00:02:05,000 --> 00:02:09,000
+Now there are some other ways here that we can do.
+
+38
+00:02:09,000 --> 00:02:10,000
+Obfuscation.
+
+39
+00:02:10,000 --> 00:02:14,000
+What I showed you there is basically like a code code obfuscation, but it tells you the principle that
+
+40
+00:02:14,000 --> 00:02:18,000
+basically you're hiding your sensitive data.
+
+41
+00:02:18,000 --> 00:02:20,000
+There are a couple of things here we want to talk about.
+
+42
+00:02:21,000 --> 00:02:22,000
+First of all.
+
+43
+00:02:22,000 --> 00:02:23,000
+Data masking.
+
+44
+00:02:23,000 --> 00:02:28,000
+Data masking is when you create a substitute version of a data set.
+
+45
+00:02:28,000 --> 00:02:32,000
+The values are changed, but the data but the format remains the same.
+
+46
+00:02:32,000 --> 00:02:36,000
+An organization can run tests or training sessions if they were using real data.
+
+47
+00:02:36,000 --> 00:02:41,000
+So let's say you have a let's say you made a financial application and you got to test how credit cards,
+
+48
+00:02:41,000 --> 00:02:44,000
+you know, how much credit cards it can hold when instead of putting in real credit card numbers, just
+
+49
+00:02:44,000 --> 00:02:49,000
+take the take the actual credit card number and create a different version of it that's not real, and
+
+50
+00:02:49,000 --> 00:02:50,000
+then use that data.
+
+51
+00:02:50,000 --> 00:02:50,000
+Masking.
+
+52
+00:02:51,000 --> 00:02:56,000
+Encryption is something that we have spent an enormous amount of time in the encryption section on.
+
+53
+00:02:56,000 --> 00:03:00,000
+So remember encryption will hide the meaning of information.
+
+54
+00:03:00,000 --> 00:03:01,000
+It's part of what it does.
+
+55
+00:03:02,000 --> 00:03:05,000
+The next thing you're going to want to be familiar with is called tokenization.
+
+56
+00:03:05,000 --> 00:03:09,000
+Tokenization, depending on the exam you're taking, will be covered on your test.
+
+57
+00:03:09,000 --> 00:03:14,000
+Tokenization creates tokens to represent certain data.
+
+58
+00:03:14,000 --> 00:03:16,000
+Keep an eye on that door in the next video when I cover it.
+
+59
+00:03:17,000 --> 00:03:21,000
+But obfuscation is something that is important there.
+
+60
+00:03:21,000 --> 00:03:25,000
+They come up lots of times when you have to use sensitive data.
+
+61
+00:03:25,000 --> 00:03:30,000
+You want to process sensitive data without actually having the sensitive data.
+
+62
+00:03:30,000 --> 00:03:31,000
+You'll see what I mean next.
+
+63
+00:03:31,000 --> 00:03:32,000
+Tokenization.
+