Extreme measures

For those occasions when simply encrypting, hiding, or wiping a few files are insufficient, a person — or more likely, a country — with something important to hide might resort to one of the following methods. All but the first of these are the extreme of the extreme methods, not only making the data completely irretrievable but also destroying the media used.

Encrypting hard drive

Toshiba is beginning to produce drives whose control hardware includes the ability to encrypt and decrypt data during I/O. Since this occurs at the hardware level of the drive itself, the process should be much faster than whole-disc encryption software (e.g. TrueCrypt). The drive can also automatically destroy its data (by securely deleting its encryption key, leaving behind a disc full of random bits) if removed and accessed by an unauthorized computer.

Degaussing

Degaussing magnetic media scrambles the data on the drive, but will also destroy whatever low-level formatting the drive had. While a floppy disc may be reused by formatting it, a hard drive would need to be sent to the manufacturer to use it again.

Crushing, shredding, disintegrating

Companies such as [SE1] market devices that damage media ranging from making a drive unusable to turning it into small pieces of unidentifiable matter. Their web site makes for amusing reading.

Heating

According to NIST, “physical destruction can be accomplished using a variety of methods, including disintegration, incineration, pulverizing, shredding and melting” [RK1]. But even extreme conditions do not guarantee complete data destruction, as was proved by the recovery of data from an older hard drive that was on board the space shuttle Columbia when it burned up on re-entry [BF1]. To utterly destroy a drive takes the temperatures of a foundry, as in [DB1] (and in roughly 1.7 million other hits on a Google search for “melt hard drive,” many of which make for more amusing reading).