Now that we covered most features of the Torah browser I want to spend one more lecture talking about
the security settings.
What do they change and how these changes affect our privacy and anonymity we can access the security
settings from the shield icon and here beside the Onion.
That we were using in the previous lecture.
If this shield is empty it means the security settings are set to the standard settings.
Clicking on it again will show you the security level that you have right now.
And as you can see I'm at standard.
If you want to change this you can click on advanced security settings in here you can also access this
from the options menu like I showed you in the previous lecture.
So you just go here you go to options and then go to privacy and scroll down to the security levels.
So as you can see we have three main very simple security levels right now.
We're set to standard which is the default.
This option will make tor browser as usable as any other browser.
Just a little bit slower but it'll allow you to access everything all content is available.
Scripts will not be blocked.
So it'll make all Web sites very nice and usable but it is not the most secure setting especially if
you're using Tor browser on Windows which is not a very secure operating system by default so cranking
this up to safer will disable javascript on hash TTP pages.
It will also disable some fonts and other hasty e-mail content.
So it might make web sites function slightly different than normal.
They might look slightly different than normal but it'll be a little bit safer and more private.
And then if you crack this up all the way to the safest it'll disable javascript on all pages even ETP
pages.
Obviously all traffic will be forest over hash TTP s because tor comes with his TTP everywhere videos
will not play by default.
A lot of other hasty e-mail content will be blogged to make sure that you get the highest levels of
security and anonymity out of this browser.
Note how change in the security level and here changes the icon on the top right.
So in the future when you're using Tor and you're not sure what level you're in you can simply look
at the icon if it's false that means you're in safest if it's half full.
That means you're in safer.
And if it's empty it means you're on standard.
You can also just click it to see exactly what security level you're on.
So now that I'm happy with my level I'm going to keep it that the safest and we're going to close this
and I actually want to show you the results of some tests that I did for the three different security
levels.
So with the basic or standard security level I use this Web site right here and I'm going to include
its link in the resources of this lecture.
Basically this Web site runs a number of tests to see how much information your browser is given about
you.
So as you can see with the standard the browser is blocking ads.
It's not like an invisible trackers it's like parties that honor the Do Not Track promise.
This is fine.
This is good.
And finally it does not protect from fingerprinting.
So it's telling us that the browser has a unique fingerprint.
And at the bottom here if you read this statistic it's telling you that among the more than 200000 browsers
that were tested on this Web site our browser appears to be unique so that it can be used to basically
identify us and in here it's telling us that there are at least seventeen point eight four bits of identifying
information that can be gathered by literally analyzing our browser.
Now I've also run the same test after changing my security level to medium.
And if you come here you'll see that my browser is blocking traffic in ads.
It also has partial protection against blocking invisible trackers which is again very similar to what
we had with the standard.
We can also see that our browser blocks Acceptable Ads.
It still blocks parties that honor the Do Not Track.
Like I said this is fine.
And finally our browser still has a unique fingerprint.
Now again if we click on the show the full details we can get the statistics.
Again it's saying that our browser can is still unique and the browser is given seventeen point eight
four bits of identifying information.
Again it's actually identical to what we got with the standard.
Now finally I cranked my security all the way to the highest similar to what I have right now and I
run the same test in here and as you can see the results are much better.
So again browser is blocking all tracking us.
This is fine.
It was happening with both standard and medium.
Then it's also a block in invisible trackers.
It's not except in the Do Not Try commitment.
Like I said this is fine.
This is good.
And finally when it's CNN does your browser protect you from fingerprinting.
This is yes.
So this is the main thing that's different here.
If you look here and it says no.
And in the standard again it was saying no so our browser had a unique fingerprint whereas right now
it has less unique fingerprint if you want to think of it that way.
So looking at the statistic here it's saying that only one in one hundred and fourteen browsers have
the same fingerprint whereas before we had one unique fingerprint among more than 200000 browsers.
Not only that but our browser now only gives six point eighty four bits of identifying information whereas
as shown before here and here with the two medium and low security settings it was given seventeen point
eight four.
So with the high security settings you're given much less information about your browser and about yourself
in general now you can actually scroll down here after clicking on more information to see where exactly
these bits of information are coming from so you can see the user agent of the browser is revealing
three point seventy four bits of information about you.
You can see the history teepee header here revealing the language used along with more information.
Again this is accounting for one point five eight bits of info going down we can see the browser plugins
are revealing information the time zone even the screen size and the color depth.
And that's why I said don't maximize the screen because if you maximize it.
This will give the true size of your monitor.
Again given even more information.
If you keep scrolling down here you'll see exactly where each bit of information is coming from.
And given us the total of seventeen point four eight in this example when we had the security at medium
now you might think big deal.
So what if my browser is given seventeen point eight four 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 plugins 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 plug in this value
into this equation right here.
We can see that in order to identify a person on earth.
All we need is thirty two point eight.
So nearly thirty three 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 thirty three bits of information identifying this person will become relatively easy
so going back to what we had here you can see the browser in the medium security settings is already
revealing seventeen point eight bits of information about you.
So all that's left is only 15 bits of information and locating you will be relatively easy.
Now granted some of the information that we see here is incorrect such as the screen size because we
don't have the screen in full screen but you get the idea the more bits that your browser is given about
you the worst 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 eighty four 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.