In a nutshell: Not very. With portable computers being more and more popular, and wireless access in public places being found more and more often, this becomes a problem.
Let’s take a look. Public wireless networks (hotspots) like those found at airports, cafes, libraries, hotels, supermarkets, etc. lack encryption. What is encryption? basically the transforming of information using a special formula that is only decipherable by having a certain piece of information – a key. So your hotspot with no encryption looks like this:
laptop –> wireless receiver –> Internet
Nothing wrong with that, except the information is traveling from your laptop in the form of radio airwaves spreading in all directions in plain form and it’s therefore possible for a “sniffer” to intercept the data – an activity that has been given the name of “sidejacking”. And since there is no encryption, your data is open to view.
Let’s look at the same setup, but with encryption enabled:
laptop –> (encryption) –> wireless receiver –> (decryption) –> Internet
Now the wireless aspect of the data transmission is protected by encryption, and is no longer available to sniffers who might want to access it. Of course strictly talking any encryption can be broken, but the difficulty to do it when using good encryption discourages most cyber-criminals as long as the target (you) doesn’t look too attractive, as I’ve explained in this earlier article.
So, what rules emerge from the above data? when using a public, non-encrypted hotspot to access the internet:
1) Do not enter passwords or supply other credentials in a website, unless the webpage itself is protected with encryption (in browsers like Internet Explorer or Mozilla Firefox you’ll see a lock in the lower right corner to symbolize encryption is being used in that web page, and typically the website address starts with “https://” instead of “http://” , signifying the page is secure). Even then and for reasons beyond the level and scope of this article this is not particularly recommended.
2) Avoid banking or doing online transactions, even in a secure webpage.
3) Basically, don’t do anything on your computer related to an internet connection you wouldn’t mind doing if you had a bunch of strangers right behind you looking at your screen and taking notes!
Wait until you get home (or to a secure wireless network) to do any of that. And I surely hope you have encryption enabled at home if you connect wirelessly to the internet!
Hope this data helps.