Scientists at the Georgia Institute of Technology (Atlanta), working with L-3 Communications Corp. (New York), said they have developed a technique for quickly erasing hard-disk drives. The team reports development of a prototype fast-erasure system to prevent sensitive information from reaching enemy eyes.

The researchers concluded that permanent magnets are the best solution. Other methods, including burning disks with heat-generating thermite, crushing drives in presses, chemically destroying the media or frying them with microwaves all proved susceptible to sensitive, patient, recovery efforts.

Permanent magnets for erasing magnetic media have been available since the dawn of disk drives, but the team found that commercial systems were either magnetically too weak, too large and heavy or could not meet air-safety standards. Instead, the team crafted a new generation of super-powerful magnets to penetrate hard disk enclosures to quickly erase magnetic media. Special high-strength magnets as powerful as those in medical imaging equipment proved sufficient for permanently erasing all information on a disk drive in a single pass.

To create a magnetic field strong enough to penetrate the metal housing around a disk drive and erase the magnetic media inside, the researchers designed a neodymium iron-boron magnet with special pole pieces made of esoteric cobalt alloys. A motorized mechanism pushed disk drives past the magnets; a back up twist-knob allows operators to manually pull drives through the magnetic field.