Which method of data sanitization involves the use of an electromagnetic field?

Degaussing is the method of data sanitization that involves the use of an electromagnetic field. This process works by exposing storage media, such as hard drives or magnetic tapes, to a strong magnetic field, which disrupts the magnetic domains on the medium. This disruption renders the data stored on the device unrecoverable by normal means, effectively purging it of any usable data.

In contrast, other methods like purging, shredding, and wiping utilize different techniques for sanitization. Purging may involve overwriting data with new data multiple times to prevent recovery, while shredding physically destroys storage media by cutting it into small pieces. Wiping, on the other hand, typically entails overwriting existing data with zeros or random patterns. However, these methods do not utilize electromagnetic fields, which distinguishes degaussing as the unique choice in this context.