Explanation/Reference:
Explanation:
Degaussing is the most effective method out of all the provided choices to erase sensitive data on magnetic media.
A device that performs degaussing generates a coercive magnetic force that reduces the magnetic flux density of the storage media to zero. This magnetic force is what properly erases data from media. Data are stored on magnetic media by the representation of the polarization of the atoms. Degaussing changes this polarization (magnetic alignment) by using a type of large magnet to bring it back to its original flux (magnetic alignment).
Simply deleting files or formatting the media does not actually remove the information. File deletion and media formatting often simply remove the pointers to the information.
Specialized hardware devices known as degaussers can be used to erase data saved to magnetic media.
The measure of the amount of energy needed to reduce the magnetic field on the media to zero is known as coercivity. It is important to make sure that the coercivity of the degausser is of sufficient strength to meet object reuse requirements when erasing data. If a degausser is used with insufficient coercivity, then a remanence of the data will exist.
Remanence is the measure of the existing magnetic field on the media; it is the residue that remains after an object is degaussed or written over. Data is still recoverable even when the remanence is small. While data remanence exists, there is no assurance of safe object reuse. Some degaussers can destroy drives.
The security professional should exercise caution when recommending or using degaussers on media for reuse.
Incorrect Answers:
B: Software tools also exist that can provide object reuse assurance. These tools overwrite every sector of magnetic media with a random or predetermined bit pattern. Overwrite methods are effective for all forms of electronic media with the exception of read-only optical media. There is a drawback to using overwrite software. During normal write operations with magnetic media, the head of the drive moves back-and-forth across the media as data is written. The track of the head does not usually follow the exact path each time.
The result is a miniscule amount of data remanence with each pass. With specialized equipment, it is possible to read data that has been overwritten. Degaussing is more effective than overwriting the sectors.
C: Simply deleting files or formatting the media does not actually remove the information. File deletion and media formatting often simply removes the pointers to the information.
D: Deleting the File allocation table will not erase all data. The data can be recoverable using software tools.