I carry a small, laminated card indicating my subscription to the IUSP (International Union of the Super Paranoid, tin hat division). Well, you can’t be too careful. After all, we live in a dangerous world and computers are just an extension of that. After you’ve installed the right operating system—GNU/Linux, of course—secure browsers, rootkit and virus scanners, you might just start to feel secure—and smug. Don’t be. Until you have understood and mastered some of these GNU core utilities to securely delete, shred and wipe files, directories, partitions and whole disks you’re not in the clear. Why not?

In the last year or so the British press has been full of stories about Government departments and individual employees who have lost laptops and flash sticks. Lost in the post, left on train seats, you name it. Not password protected, not encrypted. Nothing, and you can bet they were all running Windows. A wet dream for anyone trading in identity theft or blackmail. This cavalier approach to computer security should come as no surprise. Most people just want to switch computers them on and use them. Security is usually an afterthought—if at all.