A discreetly tucked-away folder that contains your résumé, your tax returns, and other important files may be convenient for you, but it's also a gold mine for online crooks who steal and sell digital data on a thriving black market.

Even though encrypting data unquestionably helps protect it from thieves, many users in the past felt that using encryption programs wasn't worth the trouble. But times change: In the second half of 2007, thefts of laptops, hard drives, and computer accounted for 57 percent of sensitive data losses reported by companies, according to Symantec.

Luckily, as data theft has be­­come more common, encryption has gotten easier to use. An array of options today--both free and paid--can keep your information safe even if someone walks off with your laptop or breaks into your PC.

Encrypting Everything

Full-disk encryption protects everything on a hard drive--even if the drive departs in someone else's pocket.

BitLocker, a utility built in to Vista Enterprise and Vista Ultimate, provides such protection. You'll find it in the Windows Security Control Panel.

Other Windows users--and Mac and Linux aficionados--have options as well. TrueCrypt is a free, easy-to-use open-source encryption product maintained by an active development community. If you feel more comfortable working with commercially supported, full-featured software, consider PGP Desktop (US$99).For encrypting USB thumb drives, Windows users can nab the free Rohos Mini Drive download.

File encryption protects only the files and folders you specify, of course. Typically you'll set up a folder or virtual drive to encrypt any files saved inside it automatically; as long as you haven't left the relevant folder or files open,the person won't be able to access the protected data. In contrast, if you set up your PC with full disk encryption enabled, you have no protection once you log in and unlock the drive.

File encryption can also protect against doh! moments such as accidentally sharing more than you meant to with a misconfigured file-sharing program, for example. The drawback, compared with full-disk protection, is that if you un­­thinkingly save a sensitive file outside an en­­crypted folder, it's fair game. If you want maximum protection, you can use both full-disk and file encryption on the same drive.

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