Star letter
Over the last few months, a local charity I volunteeer with has been refurbishing donated laptops for use by disadvantaged schoolkids. We’ve fitted each device with an SSD, upgraded it to 4GB RAM where it came with less and installed a fresh copy of Windows 10 or CloudReady for the less capable devices, making them into very useful machines. But this left us with numerous hard disks that possibly contained the personal data of previous owners.
So I was interested to read Lee Grant’s reminder last month ( seeissue321,p114) of a 3,000-year-old technology that can be effectively applied to the problem of secure data destruction.. However, I would like to report to Lee that I’ve recently refined that technology in important ways.
The National Cyber Security Centre (NCSC) recommends that the platters of a hard disk be broken into pieces, none larger than around a quarter of the disk. The trouble with using a hammer on the unopened case is that you can’t be sure that this has been achieved. Even if you can hear shards of a broken platter rattling about inside, there could be a second platter still intact. You can take the lid off, but then you risk spilling a lot of very nasty shards of glass or ceramic.
My improved technique is to drive a masonry nail through the drive, to be sure, at two points roughly diametrically opposite on the disk. The result is a photo opportunity ( seeimage) that should reassure the most risk-averse donors and would dismay even the Russian FSB, if they had hopes of recovering details of the nation’s nuclear arsenal or the recipe for Coca-Cola from the device.
In practice, a smaller nail than the one shown in the photo is more practical. I find a 25 x 2.5mm masonry nail works well and is easily extracted with a claw hammer for use on another disk, or indeed for subsequently fixing something to a wall. It leaves a small hole, limiting the possible escape of shards, but it’s highly recommended to cover the hole on both sides of the disk with sticky tape. In fact, if you’re feeling bad about committing such violence against a device that’s faithfully stored your data for a number of years, you can use a plaster as some kind of apology. You’ll then feel you’ve at least done your best for the device before consigning it to the tender care of the local council’s electrical waste collection.
Having attained such dizzy heights of destructive skill, I wondered what could be done for SSDs, which are notoriously difficult to wipe with a high degree of assurance. Of course, what you should have done was to encrypt it before writing any data to it. You then simply change and destroy any copy of the key. But if you didn’t have that measure of foresight, my experiments with a couple of dead memory sticks show that a hammer and cold chisel applied to each of the large memory chips causes it to neatly break in two. You can then thumb your nose at the FSB!