Olivia: You’re waiting for a friend at a coffee shop, when you decide to check Facebook to pass the time. So you whip out your phone, connect to the Wi-Fi network with the shop’s name, and log in. Then, you order a new phone case and start scrolling through your email.

But then you overhear someone ask an employee if the coffee shop has any free Wi-Fi. And the person behind the counter says that they don’t. A bunch of people start looking really confused, and then the network you were using just... disappears. A laptop shuts, and you see someone slowly walk away -- only to have your friend hold the door for them on the way out. Yikes!

Free wireless internet is getting so common that we’re starting to expect it pretty much everywhere we go, from coffee shops to airports to entire cities. And while that’s great in a lot of ways, it also means there are more opportunities to fool people. Because anyone can sit down somewhere, set up a mobile hotspot or wireless network of their own, and give it a name like “Free Airport WiFi.” And if you use their network, they can watch and record anything you send through it -- including any usernames, password, and credit card details you may have entered in.

But avoiding imposters is only the first step to keeping yourself safe, because a lot of public Wi-Fi networks don’t have a password. And everything sent over a password-free network is unencrypted, meaning that anyone who wants to can just sit and read whatever gets sent through them without a problem.

One way to avoid these sorts of attacks is to use what’s known as a Virtual Private Network, or VPN, where you just use the public connection to access a private connection that encrypts everything you send. If you use a VPN, hackers can’t see your info, but if you don’t have access to one, the best way to stay safe is to pay attention to whether the URL of the site you’re on starts “http” or “https.” If it’s https, you should see a little lock next to the URL.

Sites get those locks after your browser basically sends them an encrypted message that only the true company knows how to decrypt. Anything sent to or from these websites is secure -- even just about any of those password-free hacker networks. Anyone trying to peek at what you’re doing just sees gibberish.

And once you’re on a secure website, make sure the little lock stays there the whole time. Hackers might try to send you pop-ups asking you to log in, or they might bring you to a website that looks exactly like Gmail, but actually sends your login details to the hacker’s computer. And if a site just uses plain old http, don’t type anything in there you wouldn’t want a hacker to see.

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