Windows Vista includes some new software called Bitlocker that promises to lock up your disks - not just files, but entire disks - so that they can't be accessed without a password. That's great news for some businesses, who need to make sure that, should a notebook computer get lost, the data still can't be accessed. In fact, the government could probably do with a bulk order.

But here's the thing - it's not quite as secure as we thought. A group of computer scientists from Princeton University has found a way to get around the encryption technology with something as simple as a can of compressed air.

Essentially, the way it works is to rely on the fact that memory chips, although they lose information when they're switched off, they don't do so instantly. It takes a few seconds, and if you cool the chips down (which is where the cold compressed air comes in) you can slow the process further. Because the drive password is stored in memory you can then remove the chips and read the password.

It's not just Windows, either. Both Macos and Linux implement drive encryption in the same way, so the same hack applies to them. You can read the paper on their research, or take a look at a video they've posted that summarises the process, with handy pictures.