Yesterday I published an article entitled How to Get Your Identity Stolen in One Easy Step that describes the risk of data theft from discarded computers. The threat is real and the article gave links to other articles showing how to destroy the data before discarding a computer. However, I will also suggest there is a better way: encrypt your hard drive(s) NOW, long before you discard the computer. If the data is encrypted, nobody will be able to access your data without knowing the encryption key.
Encrypting the entire hard drive now will prevent anyone from accessing your hard drive's data on the computer you use today as well as on any discarded computer. I am especially sensitive to this as I had a laptop stolen from the trunk of my automobile some years ago. I wrote about it at the time. You can read I Wuz Robbed!" at http://blog.eogn.com/eastmans_online_genealogy/2006/11/i_wuz_robbed.html.
The thief probably turned the computer on and then was able to see everything stored within it. When I later received a replacement computer, I immediately encrypted its hard drive and I then did the same on my desktop computers at home and at the office as well. If those computers are stolen, I am confident the thief will not have access to anything stored in the computer.
When booting up any of these computers, I am first asked to enter the encryption key. That looks like a password but technically is different. If the correct encryption key is not entered, the computer and all its data remains locked. Encrypting an entire hard drive is rather easy to do.
You can learn more about entire disk encryption on Wikipedia at http://en.wikipedia.org/wiki/Disk_encryption.
Apple includes a hard drive encryption program on every Macintosh, called FileVault. The latest version is called FileVault 2. When FileVault has been enabled, it encrypts everything stored on the computer's hard drive(s) and actively encrypts and decrypts any new data being added. It’s fast and incredibly secure, using XTS-AES 128 encryption to keep things far out of the reaches of prying eyes.
When OS X is installed at the factory, FileVault is turned off by default. You have to turn it on to protect your data. You can find step-by-step instructions for using FileVault 2 on Apple's support site at http://support.apple.com/kb/ht4790.
Microsoft includes a hard drive encryption program with every version of Windows Pro, Ultimate, or Enterprise editions, but not with Home Editions. If you have Windows Pro, Ultimate, or Enterprise editions, look for a program in your computer called BitLocker. Of course, BitLocker only works if you enable it. When Windows is installed at the computer factory, BitLocker is turned off by default. You have to turn it on to protect your data. Instructions may be found on Microsoft's support site at http://windows.microsoft.com/en-us/windows7/products/features/bitlocker.
Sadly, Microsoft does not include BitLocker on the Home Editions that are normally included on computers sold for in-home use. Windows Home computers are vulnerable to data theft unless the owner takes steps to obtain and install a third-party disk encryption program. Luckily, there are several to choose from.
By far, TrueCrypt is the most popular disk encryption program. It works well on Windows Home Edition and is available for Windows 7/Vista/XP, Mac OS X, and Linux. Best of all, it is open source and is available free of charge. All the encryption experts also claim that it is very effective. You can learn more about TrueCrypt or download the FREE program at http://www.truecrypt.org/.
You can find several other disk encryption programs by starting at https://www.google.com/#q=+drive+encryption. You can also find a side-by-side comparison of many disk encryption software products at http://en.wikipedia.org/wiki/Comparison_of_disk_encryption_software.
While any of these disk encryption programs will protect your data when it is stored on your computer's hard drive(s), data copied from your hard drive to a flash drive, CD, or sent online will not be protected. The data is unencrypted during the file copy process, then stored as an unencrypted file. You can find other programs to protect removable media.
Now, let's go lock up your valuable personal information.