Tip: How to secure your laptop data

— -- Question of the week: Considering that laptops are sometimes lost or stolen, do you have any recommendations for securing confidential data on them?

Answer: The easiest way to keep your data safe is not to put it on a machine that somebody could easily walk away with.

Before everybody says "duh" all at once, think about all of the schools, businesses and government agencies that saved sensitive data on employee laptops that then got stolen. If those offices had stored that data securely on their own servers, accessible only via an encrypted online connection, the major cost of a stolen laptop would have been the price to buy a replacement computer.

On a personal level, this means using cloud-based apps instead of traditional, disk-bound programs — for example, using a Web-mail service instead of an application like Microsoft Outlook, or employing a Web personal-finance tool like Intuit's Mint.com in place of a program like Quicken.

You should use secure passwords at these sites — see my column of two weeks ago for some advice on that point.

Your browser will offer to save passwords for many of those sites, but unless you have a separate password that must be entered before your browser logs you in anywhere — for example, Mozilla Firefox's master-password option— a thief could take advantage of that feature.

Separate password-management programs like the free LastPass offer one way around that. Another option, contrary to many password myths, is to write down those passwords on a piece of paper — which you then stuff in your wallet, something you already know to keep safe.

Having a strong password for your computer should block access to it (the reader who asked this question mentioned that he had a 12-character password, which is good enough). But even then, you can use widely available software to copy files off a computer without logging into it.

And unless you're running a Google Chromebook, you'll need to store some data on the machine.

In Windows, I suggest using the free, open-source TrueCrypt. ("Open-source" means that other programmers have had a chance to inspect and improve its code, so you don't have to trust the developers when they say they did their job). It's not the prettiest or the simplest app, but it will let you create a special folder that turns into gibberish once locked. You can even create a TrueCrypt "container" on a cloud-based storage service like Dropbox, then open its contents on any PC — or Mac — running TrueCrypt.

On a Mac, use the FileVault encryption built into Mac OS X— it's under the "Security & Privacy" heading in System Preferences— which automatically secures all of your data from anybody who doesn't have your computer's password.

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Tip: Backup DNS can keep you online

The Domain Name System— the invisible switchboard your Internet provider runs to translate addresses like http://www.usatoday.com/ into numeric Internet Protocol identifiers like 159.54.238.69 — is usually the least-dramatic part of Internet access. It works so well that you never know it's there, in the same way that you don't stop to think how calls reach your phone from any other phone in the world.