Overwriting/Clearing. Overwrite utilities can only be used on working devices. Overwriting is appropriate only for devices designed for multiple reads and writes. The EIEP should overwrite disk drives, magnetic tapes, floppy disks, USB flash drives, and other rewriteable media. The overwrite utility must completely overwrite the media. SSA recommends the use of purging media sanitization to make the data irretrievable, protecting data against laboratory attacks or forensics. Reformatting the media does not overwrite the data.
Overwriting/Clearing. This type of media sanitization is adequate for protecting information from a robust keyboard attack. Clearing must prevent retrieval of information by data, disk, or file recovery utilities. Clearing must be resistant to keystroke recovery attempts executed from standard input devices and from data scavenging tools. For example, overwriting is an acceptable method for clearing media. Deleting items, however, is not sufficient for clearing. This process may include overwriting all addressable locations of the data, as well as its logical storage location (e.g., its file allocation table). The aim of the overwriting process is to replace or obfuscate existing information with random data. Most rewriteable media may be cleared by a single overwrite. This method of sanitization is not possible on un- writeable or damaged media.
