There has long existed a basic need for rendering old, expired, or sensitive data unreadable by forensic methodologies. Businesses routinely reformat and/or carry out other actions, such that externally attached disk drives and other storage media such that sensitive data can not be read by persons who should not have access to that data. Over the years several schemes have been designed to thwart attempts to recover data from storage devices where the files have been deleted and in some cases where the storage device itself has been reformatted. However, it is believed that it is still possible to recover sensitive classified and business data from such a hard drive.
Typical methods of rendering data residing on storage devices unreadable involve writing different patterns over the old data. While this would seem to render the older data unrecoverable, it often is not the case. Different physical media types often do not completely switch the magnetic state of bits of the old data when written over. Sophisticated recovery techniques, therefore, can still obtain the data that has been “deleted” in this way.
Generally the types of utilities that attempt to render data unrecoverable require the user to explicitly execute the program and to name the file to be security wiped or erased. Other utilities are launched on a scheduled basis and are driven by script files. Still other methodologies are in place to allow IT departments and administrators to decide when and what behavior the security erase programs are to exhibit.