When is a Wi-Fi network secure?

If you send documents directly via a public Wi-Fi network, that is just what any hacker targeting you has been waiting for. You might just as well use a projector to display the contents of your laptop on a screen.

Hackers can also quickly lure their victims into a trap using a trustworthy sounding Wi-Fi network. Anyone setting up a Wi-Fi network can choose its name freely. Just because it is called “O2 Hotspot” does not guarantee that O2 is behind it.

Use encryption

An open Wi-Fi network enables everybody within range to read all your data. Even a password-protected Wi-Fi network is not secure. Anyone logged into the same Wi-Fi network can still read your data.

You should therefore only ever transfer encrypted data.

There are two methods for doing this:

1. VPN

In addition to the actual Internet connection, a second encrypted connection is established to the company network via a so-called VPN (Virtual Private Network), before data can be transmitted. This enables you to use any Wi-Fi network securely.

ATTENTION: A VPN only protects your data en route from your cell phone or computer to the company. This is usually sufficient for in-house communication.

2. SSL encryption

More and more websites – including all major US Internet services – are now encrypting the data they exchange with you via SSL. If you see a small, often green, closed padlock in your browser window, this means that all data you input to this website is not visible to outsiders.

ATTENTION: Unfortunately, cell phone apps or computer programs are often not encrypted via SSL. So, when you use your cell phone to log in to a public Wi-Fi network, it may be that everyone can read the name and password of your email account. Unfortunately, you cannot see that yourself.

If you want to avoid a cyber attack we warn you from this and other stuff in our online course ”IT-Security for employees”.