WEBVTT 00:00.780 --> 00:06.360 Now so far we have David, who wants to send a secret message to John to do this. 00:06.360 --> 00:07.860 John generated a key. 00:08.790 --> 00:12.330 John also sent the public key to David. 00:12.360 --> 00:17.860 David has downloaded the public key and imported it into his key ring. 00:17.880 --> 00:23.790 So if we go to David's computer right here, we can see he has John's public key. 00:24.210 --> 00:30.690 So right now, David can encrypt data with John's public key, send it to John. 00:30.690 --> 00:37.380 And that way, John will be the only person who can decrypt this data because he is the only person 00:37.380 --> 00:39.780 that has his own private key. 00:40.500 --> 00:43.980 Now you'll also notice an extra entry in here. 00:43.980 --> 00:50.190 I've actually created a key pair for David in this section right here for the sake of completion. 00:50.370 --> 00:56.460 You don't have to do this because, like I said, all we need is John's public key to send data to John. 00:56.460 --> 01:01.500 And according to the example we're doing, David will be sending data to John. 01:01.500 --> 01:04.110 So all we need is John's public key. 01:04.860 --> 01:11.130 I just created a key pair here for David, just for the sake of completion so that you can see how this 01:11.130 --> 01:13.140 will work in a real life scenario. 01:13.770 --> 01:19.380 So we actually don't need to use this anymore because David already has the public key of John. 01:19.470 --> 01:24.750 So all you have to do is literally start typing the message that you want to send. 01:25.170 --> 01:28.080 To do this, I'm just going to open a text editor. 01:28.140 --> 01:30.660 So again, we're going to go to accessories. 01:30.660 --> 01:35.550 We're going to open my text editor and I'm just going to start composing the message. 01:35.820 --> 01:38.430 So for this, we're just going to say hello. 01:38.460 --> 01:44.310 This is a secret message sent from David to John. 01:45.180 --> 01:49.320 Now, before sending this, we're going to select all of this text. 01:49.350 --> 01:50.820 We're going to copy it. 01:51.860 --> 01:59.240 And then we're going to go to the clipboard applet and we're going to click on Sign in Clipboard with 01:59.240 --> 02:00.200 Public Key. 02:00.860 --> 02:02.480 We're going to click on this. 02:03.020 --> 02:09.080 And as you can see, you get a list of all of the public key that you have on your computer. 02:09.350 --> 02:14.900 Now, like I said, all of the ones that start with tails are default public keys added. 02:14.900 --> 02:20.150 In order to verify the integrity of packages downloaded from tails. 02:20.180 --> 02:22.210 You don't want to select any of these. 02:22.220 --> 02:26.460 You want to make sure you select the contact that you want to send the message to. 02:26.480 --> 02:30.200 And in our example, we want to send the message to John Wake. 02:31.170 --> 02:33.180 Now this is perfectly fine. 02:33.180 --> 02:37.830 You can just select it like this and click on okay to encrypt the message. 02:38.220 --> 02:42.110 But in this case, even you, even David. 02:42.120 --> 02:46.800 So even the sender won't be able to see the contents of the message. 02:46.830 --> 02:53.520 If you want to be able to decrypt the contents of the message yourself as well, then you should take 02:53.520 --> 02:55.540 the entry for your own key. 02:55.560 --> 03:01.680 So this is David's computer, and if David wants to still be able to see the contents of the message 03:01.680 --> 03:04.710 that he is going to send, he should take this box. 03:04.980 --> 03:07.260 Otherwise, we can just take John. 03:07.260 --> 03:13.500 And the only person in the world that will be able to read the content of this message will be John 03:13.500 --> 03:15.590 or anyone who has the private key. 03:15.600 --> 03:21.120 But if John is using PGP properly, he should never share the private key with anybody. 03:21.120 --> 03:27.660 And therefore, when we encrypt a message with his private key, we can be sure that John will be the 03:27.660 --> 03:30.990 only person that can read the content of this message. 03:31.470 --> 03:34.320 So we're going to click on okay. 03:35.040 --> 03:37.520 It's going to ask us if we trust this key. 03:37.530 --> 03:39.720 We're going to say, yes, we do trust it. 03:40.350 --> 03:47.550 And as you can see in here, you can see the icon of the clipboard has changed to indicate that the 03:47.550 --> 03:54.840 clipboard right now contains an encrypted text that represents the text that we copied already. 03:55.170 --> 04:02.400 So if in the same text editor in here, if I just paste whatever that is in my clipboard, you will 04:02.400 --> 04:04.860 see I'll get an encrypted message. 04:04.860 --> 04:11.880 And this is basically the content in here, encrypted using John's public key. 04:12.570 --> 04:21.840 So right now you can just copy all of this and send it to John using any method of communication so 04:21.840 --> 04:24.120 you can send it as an instant message. 04:24.120 --> 04:30.930 You can send it in a chat room, you can send it as an email, you can even put it in a pastebin publicly 04:30.930 --> 04:35.380 where anybody can see your message or anybody can see your secret message. 04:35.400 --> 04:37.440 This is the beauty of PGP. 04:37.470 --> 04:44.460 You can put this anywhere and nobody will be able to see or read the content of this unless they have 04:44.460 --> 04:46.020 the private key of John. 04:46.020 --> 04:52.470 And like I said, if John is using PGP properly and he knows what he's doing, he should never share 04:52.470 --> 04:53.550 his private key. 04:53.550 --> 04:59.790 Therefore, he will be the only person in the world that is able to read the content of this message. 05:00.420 --> 05:06.870 Now, for this example, to make things easy, I'm going to go back to my email client and I'm just 05:06.870 --> 05:08.760 going to reply to this email. 05:10.940 --> 05:13.880 And we'll put our encrypted message in here. 05:13.910 --> 05:17.780 Keep in mind, I'm copying it from the start to the end. 05:17.930 --> 05:22.310 I'm going to click on Send and that's it sent to John. 05:22.340 --> 05:24.980 So let's go to John's computer. 05:25.910 --> 05:28.500 We're going to go to his email account. 05:28.520 --> 05:33.980 We're going to refresh the inbox and we're going to click on the message that we just got. 05:34.580 --> 05:37.870 And as you can see, this message is encrypted. 05:37.880 --> 05:38.920 It's gibberish. 05:38.930 --> 05:43.220 We can't really see what David is trying to tell us. 05:43.220 --> 05:47.240 So we're going to right click and copy this message. 05:47.240 --> 05:54.110 And as soon as we copy it, you'll notice the clipboard icon in here again, changes to indicate a lock 05:54.110 --> 05:58.280 to indicate that the clipboard contains encrypted text. 05:59.000 --> 06:04.910 We're going to click on this and we're going to say, I want to decrypt or verify my clipboard. 06:05.930 --> 06:11.810 It's going to ask me for the passphrase, for my key, for John Wick's key. 06:11.840 --> 06:18.470 Remember when we created this key, we had to select a passphrase and that passphrase will always be 06:18.470 --> 06:21.710 required before you can use this private key. 06:21.800 --> 06:26.120 So I'm going to put the passphrase that I set when I created this key. 06:28.000 --> 06:29.800 I'm going to click on OC. 06:30.800 --> 06:31.610 And perfect. 06:31.610 --> 06:36.350 As you can see, we can see the contents of the message saying Hello. 06:36.380 --> 06:40.610 This is a secret message sent from David to John. 06:41.390 --> 06:42.950 So that's pretty much it. 06:42.980 --> 06:46.970 As you can see, the receiver shares their public key with the sender. 06:47.000 --> 06:52.370 The sender uses this public key to encrypt the message, and then they can put the message anywhere 06:52.400 --> 06:54.030 or even share it publicly. 06:54.050 --> 06:59.120 It doesn't really matter, because the only person that can read this message is the person who has 06:59.120 --> 07:00.110 the private key. 07:00.140 --> 07:02.380 The private key never gets shared. 07:02.390 --> 07:06.770 Therefore, this is a very, very good and secure implementation. 07:07.490 --> 07:11.450 So now in this example, John created the key pair. 07:11.480 --> 07:17.240 He shared his public key with David, and David was the one encrypting the message and sending it back 07:17.240 --> 07:17.960 to John. 07:18.770 --> 07:25.120 Now, if John wants to send something back to David, we just have to do the reverse of the process. 07:25.130 --> 07:31.190 So David will just have to create his own key pair, share the public key with John, and then John 07:31.190 --> 07:34.610 will be able to encrypt messages and share them with David. 07:34.610 --> 07:42.020 And now that David would be the only one able to read the contents of the messages sent to him.