What is a virtual private network (VPN)?

Not long ago, like many other high schoolers, I used virtual private networks, or VPNs, to bypass the school content filter to scroll Instagram or play games. While I knew how to use one, I didn’t understand exactly how they work and have recently started getting curious about them.
While VPNs are an increasingly popular way to establish secure connections, they are difficult to describe without learning how the internet works! In this answer, I try to break down what VPNs are and how they work. If you want to learn more about VPNs, let us know at hello@datacurious.org.

What is a VPN?

Essentially, a VPN is a tunnel that prevents your web traffic from being seen. It allows you to do things like hide personal information you are sending, along with other metadata like IP addresses; access services that might not be available in your region; or prevent some websites from tracking information about you.

VPNs create a secure connection between a device and a computer network by encrypting the data that is transmitted. Similar to how end-to-end encryption (E2EE) is used when sending messages, VPNs use a set of keys to scramble and encrypt the data, hiding it from outside viewers. The process of creating a secure connection is called “tunneling.”

The information goes from your device to a server through a VPN. It is called VPN because

It is virtual, meaning there is no dedicated hardware needed.
It is private, meaning the information sent via VPN is only seen by you and the recipient.
It is a network, meaning it can involve multiple devices.

For home use, personal VPNs are the most common, such as Brave VPN, Nord VPN or Express VPN.

How does a VPN work?

Imagine you want to read a Data Curious article from your website using a VPN. Before entering the Data Curious site, you first enable the VPN. This tells your computer to establish a secure connection with the VPN server, which is like other servers, except it provides VPN services. (More on servers in another post!)

Then the VPN service creates a encrypted connection called a “tunnel,” This is accomplished by the secure exchanging of keys to protect any data that travels between the VPN server and your computer.

Your computer sends the encrypted request of accessing the Data Curious site to the VPN server. The VPN server then accesses the Data Curious site and routes back to your device through the encrypted tunnel.

We can see how this process is similar to accessing the site without a VPN, with the only difference being that the VPN server becomes a middleman between your computer and the target service. This hides your identity because the server you access sees the VPN server as the only connection.

Should you use a VPN?

VPNs are generally very secure from unwanted or unknown eyes. They can be a good alternative to protecting your data when using public Wi-Fi networks. This is because when using public Wi-Fi networks, your data may be visible by other people on the network, and VPNs can shield your private data from other people. VPNs can also allow you to mask or even change your location. If you want to stream movies or TV shows not available in your geographic location, VPNs can allow you to access these.

Next time on Data Curious

Do you want to know more about how the internet works?

Now that you know what VPNs are, you might be curious to know how the internet works. This is a big topic! Here’s a very brief introduction.

A computer network refers to devices including computers, phones, servers, etc. that can share data.1 The internet is a connection of those interconnected computer networks that is the backbone behind web browsers and all the services you would associate with being online.2

When you enter a web address, or URL, into your browser, the URL gets translated into an IP address through a process called Domain Name System (DNS) resolution. IP addresses are like home addresses, however instead of a physical address, IP addresses refer to the server or device of where the data for the URL can be found.

Your computer then sends a Hypertext Transfer Protocol (HTTP) request to this IP address and the target server then sends the data back in the form of data packets which your browser then reassembles.3 For more information on the various standards and rules governing how data is sent can be found here.

The website article and all its contents can be thought of as data that your computer receives and loads through the internet. This data is held in data centers that are in remote areas and are operated by large technology companies or other commercial organizations supporting smaller websites like Data Curious.

In order to travel through through the internet to your computer, this data travels from the data centers on long distance fiber optic cables to the towers near where you may live.2 When traveling from these towers to your computer this infrastructure of the internet is called the last mile, and includes typical service providers such as Comcast and AT&T.3, 4

This is just a brief, simplified explanation. We’ll answer more questions about the inner workings of the internet in later posts!

Sources

What do you want to know about data, privacy, or technology?

Data Curious is a public resource supported by Good Research LLC in collaboration with the Center for Digital Civil Society at University of San Diego.

To contact us, send us an email at hello@datacurious.org.

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