LONDON — Are you on the go and looking for an internet connection to check your email or post a video on TikTok? It’s tempting to use the free Wi-Fi at the cafe or mall. But don’t do that if you’re not protected.

Using an unsecured internet connection can be risky. Hackers can secretly put themselves between you and the internet and see everything you do online, inject malware into your device, or even set up a rogue hotspot that looks authentic. In such cases, it’s best to use a virtual private network, or VPN.

VPNs should be part of most people’s internet security toolbox. For inexperienced users, they can seem technically confusing at first.

What is a VPN?

A virtual private network is a service that hides your online activity from everyone else on the Internet. A VPN encrypts your traffic so no one else can read it and routes it through private tunnels to secure servers around the world.

If normal Internet use is like a city bus driving by, then using a VPN is like riding in a limousine with tinted windows. Everyone can see the bus’s passengers and the destination sign. The limousine, on the other hand, reveals little to people on the street about what it is carrying or where it is going.

Why do I need to use a VPN?

Privacy is one of the main reasons. If you connect to a free public Wi-Fi network, such as in a hotel lobby or coffee shop, using a VPN will prevent anyone from eavesdropping on you electronically.

You can also use it at home if you don’t want your ISP to know what you’re doing. But if that’s not a problem, you probably don’t need to, as long as your network is password protected.

Another big reason to use a VPN is to “spoof” your location and make it look like your phone or computer is somewhere else. Choose from a list of countries where your VPN provider has servers, and you’ll have a different IP address that will trick a website into thinking you’re in Singapore or Germany, for example, instead of at your desk in New York or using your phone in London. Now you can access localized versions of websites or stream videos that are only available in a specific country.

VPNs also help people evade censorship in countries with strict internet controls.

Remember that a VPN doesn’t hide everything. For example, when you log into your Gmail account, Google still knows who you’re emailing.

Aren’t VPNs illegal?

VPNs are perfectly legal in most countries, but they are banned or restricted in countries like North Korea and China, where authorities control internet access or engage in online surveillance and censorship.

How do I choose a VPN?

There are dozens, if not hundreds, of VPN services, but not all of them are trustworthy. Experts warn that some may be run by shady operators.

Start with technical review sites that have tested and analyzed their privacy policies, encryption practices, ease of use, speed, price, and other categories. Some review sites rate VPNs based on specific uses, such as streaming.

The more well-known or established providers include NordVPN, Mullvad, Proton, Surfshark, ExpressVPN and Private Internet Access.

There are some important features you should look for.