What is a Digital Shredder?

The shredder technology is based on the United States Department of Defense Directive 5220.22-M, which provides baseline standards for the protection of classified information.  It uses multiple levels of deletion so that the file you delete may not be recovered, even by undelete programs.  You can read more on the Defense Technical Information Center PDF : http://www.dtic.mil/whs/directives/corres/pdf/522022m.pdf