Note: SuperScrubber is no longer under development and the developer provides no support for it.SuperScrubber understands the phenomenon of Shadow Data and writes data multiple times over your hard drive to ensure all previous information can never be recovered. SuperScrubber conforms to the Department of Defense standard for disk sanitization when selecting the built-in Military Scrub configuration. And if you're even more paranoid than that, there are additional customizable levels of scrubbing security, too.
When you delete a file, drag it to the trash, or reformat your hard drive, the area it was saved on is not erased, but simply freed up for another layer of data to be written over it. The old files are not completely erased and leave magnetic footprints called "shadow data." Sophisticated data recovery tools are available for retrieving deleted files and information from damaged disks.