Maintaining privacy in the era of digital information requires work on a number of fronts, whether fending off spyware, protecting important files with encryption or configuring a Wi-Fi hot spot to keep interlopers off a wireless network.

One basic privacy measure, however, is easily overlooked: proper data destruction.

Deleting confidential data completely is essential when donating or selling old computers, and it can also help maintain privacy on computers that may end up lost or stolen. And for businesses looking for ways to comply with the security requirements of laws like the Sarbanes-Oxley Act, a sound policy on data control and destruction is crucial.

When normal deletion methods like the Recycle Bin or the delete command are used, the computer's operating system, for the sake of speed, creates an illusion that data has been deleted. In fact, it merely earmarks that region of a disk or drive as being available for new data to overwrite the old data. Until that overwriting occurs, the old data can be retrieved with undelete programs and tools used by data recovery labs and law enforcement agencies.

There are, however, several options for securely eliminating data from hard disks, U.S.B. flash drives and other storage media. These programs overwrite data with meaningless characters to render it unrecoverable with today's data recovery techniques. Some of the programs can overwrite entire drives, while others can single out individual files or other information saved by a computer's operating system or programs like Web browsers. Shredding machines that can destroy diskettes, CD's and DVD's are also available.