If you use public WiFi, you may wonder if it is safe. Mainstream tech news seems to always be reporting on stories about exploits, along with admonitions to keep wireless access points locked. The short answer on whether public WiFi like coffee shop access points are safe depends heavily on how you use them, and whether you are aware of and responsible about the risks.
Public WiFi access points introduce concerns not found on wired networks or locked hotspots. Secured networks, via wired networks or locked hotspots, have more guarantees that your internet surfing is secure from outside observation. With a public WiFi, all of your data is being broadcast to the room or neighborhood at large without any security measures being taken. Imagine having a private conversation where everything you say can be heard by the entire room. While this doesn't seem like a very secure way to exchange confidential information, there are ways to work around this issue.
For example, imagine having that same conversation in another language known only to you and your listener. This would mean your communication is secure even if everyone in the area knew what was happening. This is exactly what happens when your specific website connection is encrypted. Your data is sent in small blocks of information called “packets,” and while anyone in range of your computer's wifi signal can intercept those packets, they cannot know what the packets contain if they are encrypted.
So, when using coffee shop WiFi (or other public internet connections), a good rule of thumb is whenever you send confidential information such as user names or passwords make sure that your connection is secure. You can easily see whether your connection is secure by looking for an icon of a lock in your browser's address bar and a URL beginning with "https."
Also, when you access an important site (such as checking your bank account online), ensure that the lock you see in your browser address bar remains active for the entire time you are logged in – not just during the time when you enter your user name and password. For instance, if you've logged into a social network, and the connection becomes unsecure, an attacker can start using your login credentials to access the site as if they were you.
Put another way, if you have to type in a password, the site should have an https connection...at least if you plan to access that site in public.
Another option is to use some special software on your laptop that will create your own Virtual Private Network (VPN) connection over any public WiFi network. This VPN will encrypt your traffic, sending it directly to your network provider who in turn forwards it to your destination. This method does not offer total security, as information is still in the clear between the network provider and the destination, but it securely moves your data through the public WiFi connection...sort of like whispering in a crowded room.
While there are definitely some risks that come with using public WiFi, awareness of your activity and adopting a few simple practices will go a long way to making sure your information is safe and secure. If you're smart, you don't need to sweat the details.