Computer and Electronic Data Destruction
Computers are often the repository of an astounding amount of information. Even in a stand-alone computer that is not linked to the Internet, millions of conventional pages of text and images can be stored in the hard drive and on peripherals, such as a floppy disk or on a compact disk (CD).
For sensitive operations, the security of computer data must be ensured. This is particularly true when data is erased. The convention version of data removal involves the deletion of a file, by the movement of the file to a "garbage can" (i.e., the "Recycling Bin" in the various Windows operating systems). This form of deletion instructs the computer to use the slice of hard or floppy disk space for something else. Eventually, the file will be over-written. But, until that occurs, the information is recoverable.
The true cleaning of a hard or floppy disk involves overwriting the actual data. Computer data is recorded as a series of 0s and 1s. Irrevocable erasure of data can be achieved by rewriting the relevant sector of a drive with 0's. Others advocate for a hexadecimal pattern (i.e., 110000001) followed by a "second pass", which over-writes the hexadecimal pattern as 00111110. In this way, every unit of information has been changed at least once.
True cleaning of a CD is also possible. The data layer that was previously "burned" onto the CDs surface can be removed and ground into fine powder. The original polycarbonate disk that remains contains no trace of the original data. The CD, which is rendered unusable, can be conventionally disposed of.
Destruction can also be a brute force physical process. For example, a hard drive can be physically damaged so that it cannot be read, even if installed into another computer. Floppy disks can be cut apart. Thus, while information may still reside on the drive, that information is essentially destroyed. Disks and CDs can even be melted down.
A number of vendors offer data destruction services to those having concerns about the sensitivity and vulnerability of their data. Government agencies usually have in-house staff and facilities, so that sensitive information does not pass into unauthorized hands, even during the destruction process.
█ FURTHER READING:
Bosworth, Seymour and Michael E. Kabay. Computer Security Handbook. New York: John Wiley & Sons, 2002.
Eoghan, Casey. Digital Evidence and Computer Crime. New York: Academic Press, 2000.
Kruse, Warren G., II., and Jay G. Heiser. Computer Forensics: Incident Response Essentials. Boston: Addison Wesley Professional, 2001.