WEBVTT 0 00:01.640 --> 00:03.200 Hello and welcome back! 1 00:04.010 --> 00:11.150 We'll start a few lectures on anonymity and we'll take a closer look at the onion routing and Tor. 2 00:12.260 --> 00:20.060 Onion Routing, Tor, Tor Hidden Services, Dark Web and Deep web are related concepts and we’ll 3 00:20.060 --> 00:21.440 take them one by one 4 00:21.680 --> 00:29.170 through this section. In this lecture will start discussing onion routing, which was developed in the mid-90s 5 00:29.170 --> 00:34.840 by US Naval Research to protect U.S. intelligence communications online. 6 00:36.490 --> 00:43.630 Tor, which is an acronym f The Onion Router is a particular implementation of Onion Routing 7 00:43.870 --> 00:48.210 and is an OpenSource, Free and privacy-focused network 8 00:48.380 --> 00:55.360 that hides your traffic, by routing it through multiple random servers also called relays on the Tor 9 00:55.360 --> 00:55.930 Network. 10 00:56.800 --> 01:04.900 This way you can browse privately and explore freely by defending yourself against tracking and surveillance 11 01:04.990 --> 01:10.240 and circumventing censorship. In an Onion network like Tor 12 01:10.540 --> 01:16.750 messages are encapsulated in more layers of encryption, analogous to layers of an onion. 13 01:17.440 --> 01:24.280 The encrypted data is transmitted through a series of network nodes called onion routers or 14 01:24.290 --> 01:30.400 Tor Relays, each of which "peels" away a single layer, uncovering the data's 15 01:30.430 --> 01:38.320 next destination. The sender remains anonymous because each Tor really only knows the location 16 01:38.530 --> 01:40.960 of the preceding and following nodes. 17 01:42.380 --> 01:49.140 Tor is a network of virtual tunnels that guarantee your privacy on the Internet. Tor works by 18 01:49.140 --> 01:55.950 sending your traffic through a virtual circuit composed of three random servers (also known as Tor 19 01:56.010 --> 01:58.720 relays or Onion Routers) in the Tor network. 20 01:59.430 --> 02:07.830 These relays are run by volunteers around the world, and the millions of people rely on them for privacy 21 02:07.950 --> 02:09.930 and freedom online every day. 22 02:11.130 --> 02:16.810 At the moment, when I'm recording this, there are approximately 6000 relays. 23 02:17.970 --> 02:24.870 We can see a lot of statistics about the Tor network, anytime we want, at metrics.torproject.org 24 02:24.900 --> 02:25.500 For 25 02:27.070 --> 02:30.280 example, let's see the relays by platform. 26 02:31.830 --> 02:32.860 And we notice that 27 02:33.000 --> 02:35.510 the vast majority run Linux. 28 02:37.080 --> 02:40.480 Let's take a look at the traffic over a period of time, 29 02:42.310 --> 02:45.100 for example, for the last 10 years. 30 02:53.070 --> 02:58.950 And we see that the total relay bandwidth has increased continuously over the years. 31 03:00.740 --> 03:02.540 Let me show you something else, 32 03:02.870 --> 03:04.520 that's also quite interesting. 33 03:12.060 --> 03:15.280 This is a live representation of Tor traffic. 34 03:16.520 --> 03:23.940 If we take a closer look, we see that most of the Tor relays operate in Central Europe and in the 35 03:23.950 --> 03:24.410 U.S., 36 03:27.080 --> 03:29.780 especially on East and West coasts. 37 03:31.660 --> 03:38.680 Tor is often used by journalists and activists, particularly when they are working in hostile states. 38 03:39.560 --> 03:43.000 Tor is both a network and a piece of software. 39 03:43.450 --> 03:50.830 The software known as the Tor browser allows us to access the Tor network and they are both referred 40 03:50.830 --> 03:51.700 as Tor. 41 03:52.760 --> 03:57.710 Note that this is different from confidentiality, which is done using encryption. 42 03:58.190 --> 04:04.360 When we sent an encrypted message, no one can see the content of the message, but they can see that 43 04:04.370 --> 04:10.880 we are transmitting it and they can also see our real identity, which is the public IP address, 44 04:11.120 --> 04:13.100 we are connected to the Internet. 45 04:14.390 --> 04:18.900 Tor prevents anyone to see that we are sending a message at all. 46 04:19.760 --> 04:27.510 Let's see what are the main features of Tor. The Tor browser blocks trackers and isolates each 47 04:27.510 --> 04:28.890 website you visit 48 04:28.950 --> 04:32.760 so third-party trackers and ads can't follow you. 49 04:33.570 --> 04:40.440 Any cookies are automatically cleared when you are done browsing or a new identity is required. 50 04:41.070 --> 04:43.080 So we'll be your browsing history. 51 04:43.680 --> 04:50.190 Tor browser prevents someone watching your connection from knowing what websites you visit. 52 04:51.090 --> 04:58.470 I have one remark here: although no one is able to see what Web sites you visit sniff the traffic, 53 04:58.740 --> 05:02.490 someone that’s monitoring your traffic can see that you're using Tor. 54 05:03.210 --> 05:04.860 This is not good at all 55 05:05.130 --> 05:12.180 if the oppressive regime considers Tor as being illegal. What you can do to hide that you are using 56 05:12.210 --> 05:19.410 Tor is to use a Bridge which is essentially an entry point into the Tor network that helps you hide 57 05:19.440 --> 05:21.390 the fact that you are using it. 58 05:22.260 --> 05:29.100 We'll talk about Tor Bridges in the installation section, where I'll show you how to set up such a 59 05:29.100 --> 05:29.520 Bridge. 60 05:30.530 --> 05:34.500 Tor browser aims to make all users look the same, 61 05:34.770 --> 05:42.360 making it difficult for you to be fingerprinted based on your browser and device information. Your 62 05:42.360 --> 05:48.540 traffic is relayed and encrypted three times as it passes over the Tor network. 63 05:48.870 --> 05:55.740 The network is composed of thousands of volunteer run servers known as Tor Relays. 64 05:57.170 --> 06:03.980 Note that like any other amazing tool, Tor can be used by people that need to remain anonymous due 65 06:03.980 --> 06:11.360 to hostile regimes and people that want to remain anonymous due to the illegal activities they perform. 66 06:11.720 --> 06:18.410 I discourage anyone from using Tor or hidden Tor services to hide his identity while breaking the 67 06:18.410 --> 06:18.730 law. 68 06:19.400 --> 06:26.540 Even when using Tor the law enforcement entities might be able to link different areas of your activity 69 06:26.540 --> 06:27.110 together. 70 06:27.560 --> 06:30.920 What you do online is only your own responsibility! 71 06:31.460 --> 06:37.070 That was a short overview of Tor and onion routing. In the next lecture 72 06:37.310 --> 06:39.720 we'll dive deeper into how they really work.