Hello and welcome back!
We'll start a few lectures on anonymity and we'll take a closer look at the onion routing and Tor.
Onion Routing, Tor, Tor Hidden Services, Dark Web and Deep web are related concepts and we’ll
take them one by one
through this section. In this lecture will start discussing onion routing, which was developed in the mid-90s
by US Naval Research to protect U.S. intelligence communications online.
Tor, which is an acronym f The Onion Router is a particular implementation of Onion Routing
and is an OpenSource, Free and privacy-focused network
that hides your traffic, by routing it through multiple random servers also called relays on the Tor
Network.
This way you can browse privately and explore freely by defending yourself against tracking and surveillance
and circumventing censorship. In an Onion network like Tor
messages are encapsulated in more layers of encryption, analogous to layers of an onion.
The encrypted data is transmitted through a series of network nodes called onion routers or
Tor Relays, each of which "peels" away a single layer, uncovering the data's
next destination. The sender remains anonymous because each Tor really only knows the location
of the preceding and following nodes.
Tor is a network of virtual tunnels that guarantee your privacy on the Internet. Tor works by
sending your traffic through a virtual circuit composed of three random servers (also known as Tor
relays or Onion Routers) in the Tor network.
These relays are run by volunteers around the world, and the millions of people rely on them for privacy
and freedom online every day.
At the moment, when I'm recording this, there are approximately 6000 relays.
We can see a lot of statistics about the Tor network, anytime we want, at metrics.torproject.org
For
example, let's see the relays by platform.
And we notice that
the vast majority run Linux.
Let's take a look at the traffic over a period of time,
for example, for the last 10 years.
And we see that the total relay bandwidth has increased continuously over the years.
Let me show you something else,
that's also quite interesting.
This is a live representation of Tor traffic.
If we take a closer look, we see that most of the Tor relays operate in Central Europe and in the
U.S.,
especially on East and West coasts.
Tor is often used by journalists and activists, particularly when they are working in hostile states.
Tor is both a network and a piece of software.
The software known as the Tor browser allows us to access the Tor network and they are both referred
as Tor.
Note that this is different from confidentiality, which is done using encryption.
When we sent an encrypted message, no one can see the content of the message, but they can see that
we are transmitting it and they can also see our real identity, which is the public IP address,
we are connected to the Internet.
Tor prevents anyone to see that we are sending a message at all.
Let's see what are the main features of Tor. The Tor browser blocks trackers and isolates each
website you visit
so third-party trackers and ads can't follow you.
Any cookies are automatically cleared when you are done browsing or a new identity is required.
So we'll be your browsing history.
Tor browser prevents someone watching your connection from knowing what websites you visit.
I have one remark here: although no one is able to see what Web sites you visit sniff the traffic,
someone that’s monitoring your traffic can see that you're using Tor.
This is not good at all
if the oppressive regime considers Tor as being illegal. What you can do to hide that you are using
Tor is to use a Bridge which is essentially an entry point into the Tor network that helps you hide
the fact that you are using it.
We'll talk about Tor Bridges in the installation section, where I'll show you how to set up such a
Bridge.
Tor browser aims to make all users look the same,
making it difficult for you to be fingerprinted based on your browser and device information. Your
traffic is relayed and encrypted three times as it passes over the Tor network.
The network is composed of thousands of volunteer run servers known as Tor Relays.
Note that like any other amazing tool, Tor can be used by people that need to remain anonymous due
to hostile regimes and people that want to remain anonymous due to the illegal activities they perform.
I discourage anyone from using Tor or hidden Tor services to hide his identity while breaking the
law.
Even when using Tor the law enforcement entities might be able to link different areas of your activity
together.
What you do online is only your own responsibility!
That was a short overview of Tor and onion routing. In the next lecture
we'll dive deeper into how they really work.