In the connected world we live in
it becomes harder and harder to remain anonymous.
When we connect to the Internet,
to browse a website, send an e-mail
or use another service
our identity and online activity could be tracked by governments and private companies, mainly to serve
us targeted ads.
I think that anyone has searched on Google at least once for something ordinary like sports shoes,
and was later bumped by tens of related.
adds on third party websites.
There is nothing wrong with being anonymous and controlling your own personal privacy
if you are doing a legitimate business. In this lecture, we'll discuss how online tracking really works.
But what is actually web tracking? It is the practice by which websites identify and collect information
about users; without tracking e-commerce and advertising businesses would treat every user is a stranger
and would be unable to show him personalized content.
Whenever you use the Internet, you leave a record of the websites you have visited, along with each
and everything you've clicked. To track this information
many websites save a small piece of data, embed invisible objects or use your user accounts and
hardware configuration to uniquely identify you.
Say, for example, you visit the website and read the review about a pair of shoes you'd like to buy.
The website you visit knows what you are interested in,
shoes in this case, and it is referred to as a first-party.
At this moment, you won't find anything strange as you don't actually care that the website knows
you are interested in shoes because you are the person who willingly visited the website and clicked
on the link of the review page.
But what happens next is troublesome.
The website you are visiting has embedded a 3rd party-tracker like AddRoll.com
or doubleclick.com - that logs all of the information about you and your visit as well.
So a third party tracker is an entity, other than the website directly visited by the user, that tracks
their users visit to the website.
Using sophisticated techniques and by collecting and correlating your data on different occasions in
the past, the tracker could uniquely identify you and know everything about you, such as your
age, your gender, your location or address, your income, your medical status, your habits, your
favorite websites and so on.
So just imagine if you are reading a review about a pair of shoes you want to buy on a random website
and that website already knows everything about you, just like your best friend or your spouse.
Maybe you think that Web tracking is anonymous since only habits are connected, not your real identity,
like your name, address or government I.D. But when a website like Facebook acts as a third party tracker,
then your identity is exposed
since you've created a Facebook account and you are logged in. Or even if you aren't logged in; this
is really creepy!
Let’s see what are the tracking mechanism!
The most commonly used ways to track a user are by using cookies, browser fingerprinting and invisible
pixels or beacons. Let's take them one by one!
A cookie is a small text file saved locally on your machine, in your browser storage by a web server.
When you visit the website for the first time, a cookie file with a unique identifier is stored on
your computer.
Subsequently, when you revisit the website, the web server will read the cookie to find your unique
ID so that it can uniquely identify you; and then eat to retrieve all information about you from its
database.
Modern websites used cookies for two main purposes: keeping you locked in and tracking your behavior.
I'm sure you've noticed that websites like Google.com or Facebook.com do not require you to
log in each time you visit the website and that's because your details will be remembered by the browser
through a cookie stored during your first log in.
If you want to view the cookies saved in your browser, it depends on your browser you use.
But on Chrome, go to Chrome menu in the top right corner select settings
and under privacy and security, click on a site settings.
And then click on cookies and cite data.
Here you can block all third party cookies or view all cookies that were saved in your browser.
Let's all cookies and side data.
These are all cookies saved in my browser.
On this page, you can also remove one or all cookies.
Another technique used for tracking is called browser fingerprinting.
This is another incredibly accurate method of identifying users uniquely and tracking their online activity.
When you connect to the Internet, your device will hand over a bunch of specific data to the receiving
server, which includes the browser type and version operating system and version, screen resolution,
supported fonts, plugins, time zone, language and phone preferences
and even harder configurations.
These data points might seem generic at first and don't necessarily look tailored to identify one
specific person.
However, there's a significantly smal chance for another user to have 100%
matching browsing information.
A service called Panopticlick found that only 1 in 286,000 other
browsers will share the same fingerprint as another user.
Take a look at this paper,
if you want to go deeper into it.
You'll also find it as an attachment to this lecture.
The uniqueness of browser information is closely related to the investigation method of the police
who identifies suspects and criminals based on fingerprints at the crime scene; browser fingerprinting
works the same.
Websites collect a large set of data from visitors in order to later use it to match against the browser
fingerprints of known users.
Or in other words, they will try to uniquely identify you using these generic information your browser
will hand over to the server.
You can test if your browser is safe against tracking at this address. Let's test
The latest version of Chrome on Windows 10.
It's testing my browser.
And the results
don't look so good.
We see that it doesn't protect us too much against tracking.
From my tests with all known browsers, I've noticed that Brave browser offers the best tracking
protection using the default settings.
This is the Brave browser; let's test it .
And it looks much better compared to Krumm.
This is brave, and this is Krumm.
And the last common way to track users is by using a so-called tracking pixel or the web beacon.
This is an invisible object embedded in a Web page or an e-mail,
most of the time as a transparent image with the size of one pixel that is loaded by the browser
when a Web page is loaded or a link in the e-mail clicked. This way
they know that their advertisment
e-mail has just been opened or their web page visited.
This is, by the way, another reason why you should not display images in the e-mails received from
senders
you do not trust.
Because it is so small, the tracking pixel can hardly be seen by visitors of a Web site or e-mail recipients.
When connecting to the server to download the tracking pixel
some JavaScript code is run on the client and tracking information like operating systems, screen resolution,
the ip address, activities on the website during the session are acquired.
OK.
These were the most common tracking mechanisms in the next lecture
we'll see how to protect us against tracking.