In the previous lecture, I showed you how to modify the settings for the Tor browser for maximum privacy,
anonymity, and security.
But when we got to this security section in here, I actually skipped it and I told you that I will
cover it in the next lecture.
I did that because the settings in here are very, very important and they can drastically affect your
privacy, anonymity and security online.
That's why I want to spend a full lecture talking about the three options that we have in here, and
how they compare once we actually test them against real online trackers.
Now, just a quick reminder.
In order to access this window, you have to go to the options.
Click on settings, click the security settings and scroll down to the settings section that we have
in here.
Now as you can see, the default option is standard.
And this is basically the normal default settings that you get on any web browser or specifically a
Firefox web browser because the Tor browser is based on Firefox.
The safer option in here.
As you can see, it's going to disable JavaScript on Non-https websites.
It's going to disable some fonts and math symbols, and the audio and video are click to play.
If you crank it all the way up to the safest.
It's going to disable JavaScript on all websites, so Http and https.
It's also going to disable more fonts, icons, math symbols and images and videos and audio are going
to be click to play.
Now if you look here on the top right this shield icon here, this indicates the security settings that
you are at.
So as you can see, if you are on the safest it's set to full.
If we are on the safer the middle it's set to half full.
And if you are on the standard it is set to empty.
Now, an important thing to keep in mind is that the higher the security setting, the more browser
features that will be disabled.
So again on the safest.
As you can see, JavaScript is disabled on everything and more symbols and more images are disabled.
Therefore, some website features are not going to work, but you will be more secure, more private
and more anonymous.
So this is up to you.
You can go ahead and modify this as you're browsing, but it is best to keep it on the safest.
And I'm not just saying this.
I actually ran three different tests, one with each security level.
And I'm going to show you now the results, and you'll see how the safest security level is actually
so much better than the other two.
So I'm going to share this website for you.
And basically this website runs a number of tests against your browser to see how easy it is to track
it and to fingerprint it.
So the first test run in here with the lowest security settings.
And as you can see it's saying we have some protection but we also have some gaps.
If we look at the details in here, you can see that we have partial protection against tracking ads.
We have partial protection against invisible trackers, and we have partial protection against fingerprinting.
What we mean by fingerprinting is how unique our browser is.
The more unique it is, the worst for us because that means we can be identified easier.
So we actually want to be less unique.
And we want to be mixed up with all of the other browsers around the world.
Now, if we scroll down, we'll get even more information.
So you can see that our browser is one in over 100,000 browsers, again meaning that it is very, very
unique.
And you can see that our browser is leaking 13.42 bits of identifying information.
We will talk more about these identifying information at the end of the lecture.
But let's see how these results in here compare to the second to the moderate security level.
Now if you look up again, you can see we have partial protection against tracking ads and invisible
trackers, very similar to what we had in the low security setting, believe it or not.
And in the fingerprinting we actually have more of a unique fingerprint.
So as a result, the safer option, the middle option is actually less safe than the low option.
So even if we scroll down you can see that we are more unique.
So our browser is one in over 200,000 instead of 100,000 in here.
And you can see that the browser is leaking 14.49 bits of identifying information compared to what we
have in here, which was 13.42.
Now, if we compare this to the safest, you can actually see that it's telling you in the title that
we have strong protection against web tracking.
And as you can see, it's not partial anymore.
We are blocking tracking ads.
We're blocking invisible trackers.
And it is protecting us from fingerprinting.
So as you can see, this table is already much safer than the results that we had in here and in here.
Now, going back to the details of the highest security, you can see that our browser is 1 in 96 browsers.
So that means it is not unique.
It's actually mixed up with a lot of other browsers around the world around the internet.
Whereas again, in here we were one in over 200,000, and in here we were one in over 100,000.
You can also see it's only leaking 6.59 bits of identifying information.
Again, this is much less than what we had in the two options in here.
Therefore, as you can see, the safest option is actually going with the safest in here.
The only thing is, like I said, some website features are not going to work.
In that case, if you trust that website, you can come here and change the setting when you're loading
that website.
Now.
Also, if you scroll down in here in this website, it's actually going to show you each browser feature
and the amount of identifying information it is leaking.
So you can see the user agent in here is leaking 4.39 of identifying information.
If you scroll down, the Http accept header is leaking 4.6 bits of identifying information, and as
you scroll down, you'll get more information on how this number is being calculated in here.
Now you might think, big deal.
So what if my browser is given 17.84 bits of information?
What does that mean?
Well.
According to information theory, this information can be added together in order to identify you in
information theory.
Information is measured in bits and according to this formula right here we can calculate the amount
of information a certain fact, such as your browser plug ins can reveal about your identity.
Like I said, this is measured in bits and adding all these bits together can be used to identify you.
So at the time of recording this lecture, the population of Earth is around 77 billion.
Plugging this value into this equation right here, we can see that in order to identify a person on
Earth, all we need is 32.8.
So nearly 33 bits of information.
So when searching for someone, we start adding the bits of information that we discover about them
one by one, such as their language, their location, the browser they use, and so on.
Once we get about 33 bits of information, identifying this person will become relatively easy.
So going back to what we had here, you get the idea.
The more bits that your browser is given about you, the worse, because these bits can be used to locate
and identify you.
So if we look at the high security, we can see we're only revealing six point bits of information.
And as I said before, some of this information is incorrect.
So it's a pretty good start.
And again, as we go through the course, we're going to talk about more advanced methods of protecting
our security and anonymity.