Digital World Tokyo -
[Cached Version]
Published on: 3/15/2005
Last Visited: 7/17/2006
Michael Knotts (above, seated), a senior research scientist at the Georgia Tech Research Institute, dealt with this question after a U.S. plane collided with a Chinese fighter jet and was forced to land near what he called "China's premiere signals intelligence department" four years ago.At the request of defense contractor L3 Communications, he and other researchers developed a method for quickly erasing hard drives by cranking them through a mechanism with a powerful magnet inside.
Knotts explains that the device, dubbed the "Guard Dog" by the researchers, requires no electricity and is powerful enough to overcome the magnetic shielding effect of steel casings.
"The [National Security Agency] has to destroy about 30,000 hard drives a year," Knotts says."Presently they do it by grinding them into powder or magnetically degaussing them" with a large electromagnet.These methods don't work when there's little time, power, and space.
He adds that although software-based "shredders" such as Norton WipeInfo can delete and overwrite files several times to ensure that they cannot be read again, they are not powerful or fast enough for some military applications.These programs can take hours to erase a drive, he says, and they might leave some data behind."A lot of approaches to erasing disks do only a partial job," Knotts says.
He explains that when a portion of a hard drive is found to be unstable, the drive automatically disables access to that region.All programs, including "shredder" software, are unable to write or read from these "sequestered sectors" and so cannot remove data that might be left in them.Theoretically, he says, a determined investigator with knowledge of how the drive works could find these sectors and read them, revealing a few important pieces of data.
"For the average person, software approaches are completely fine," Knotts says, but a leak of even a few words of NSA information could be dangerous.
The Guard Dog destroys all the data on a drive, even in parts that computers cannot access, and it can erase any magnetic media , VHS tapes, DAT tapes, ZIP disks and the like , in the same way that it erases hard drives.While CDs are beyond its reach, Knotts says that those can be easily destroyed using a sander-like tool that grinds off the bottom plastic layer and cuts into the underlying aluminum plate.
Although this system will probably be too expensive for individual users, Knotts says that L3 may produce hundreds or thousands of the devices to sell to government agencies and perhaps to private companies that deal with social security numbers or other sensitive data.The latter is important, he says, because "not just government targets are potential targets [for terrorists]," and even small amounts of important data could be dangerous in the wrong hands.