Why can't privacy be protected on a public computer?

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January 21st, 2010 - Posted by Kent

The following post in our Reader Question series is an actual user submitted question:

Q: I have a question becaue I have been using a public computer which i know isn't safe but I am wondering why your privacy cannot be protected.

A: There are two big reasons why public computers aren't secure and could be used to expose your personal information, but they both stem from the same thing: if a computer is public, anyone has access to it.

Public computers are physically open to hackers who can install keyloggers or other info-snooping software or hardware. There's just no way for the average user to defend against this. We can hope that the computer's owner has security software installed, but there's never a guarantee.

The other problem with public computers is one you can actually do something about: keeping your browsing private. Web browsers store your browsing history by default. If you've ever hit the "back" button on your browser, you know that it's possible to virtually go back in time and see pages you've already visited. Just look at your web browser's "History" tab and you'll see what we mean. Web browsers can also store cookies that tell certain websites that you've already logged in, allowing someone else to revisit a site as if they were you.

Now if you need to use a public computer, there are things you can do to help keep protect your privacy:

1) Always choose "Private Browsing" when possible. Both Firefox and Microsoft Internet Explorer allow you to select this option. Do this  before you start your web surfing (in Explorer this is found under the "Safety" menu, in Firefox it's under "Tools"). This will prevent the computer from remembering your cookies, temporary Internet files, history, and other data. When you're done, shut down the browser or close the browser window you were using.

2) Whenever possible, avoid sites that require you to enter any personal information such as credit card numbers, PINs, or passwords. Also, don't let it store any "auto-fill" data.

3) If you do decide to log in to a website, never let a website "remember" your login information.

4) Logged in? Make sure to log out. This will end your session and disallow anyone from going back into your account.

5) Clear the web browser's cookies, history, and cache when you're done. In Explorer, this is done using the "Delete Browsing History" function under the "Safety Tab"; in Firefox, look under the "Tools" menu for "Clear Recent History" and make sure to use the details sub menu and select everything. This is a little redundant if you're using the "Private Browsing" function, but it's not a bad habit to get into.

6) Watch out for people reading over your shoulder. Evesdropping is another risk of using a public computer. People or well-placed cameras can scope out your data, or watch the keys you type when you enter a password.

Ultimately, if you must use a public computer for your private browsing needs, you'll have to use your best judgment about how safe the computer is. If there's an administrator or other personnel responsible for the computers, ask them if there's Internet security software running.