No, I don’t mean go back the way you came. Backup means one thing when you’re driving a fork-lift, but it’s quite something else to those hunched-over, sweater-wearing techies in the server room. You’ve probably heard “BACKUP!” since the first day you put your hands on a computer keyboard, but these days it’s becoming even more important—not just for businesses, but for home users as well.

Now, in this post we’re going to talk about viruses. I know I started by nagging you about backups, but you’ll see why in a minute.

This past summer Kaspersky Lab, a research firm that deals with computer security, sent out an SOS for security and cryptography experts to help them find a solution for a new trojan based on a three year old virus called Gpcode. This nasty little bug infiltrates your computer through unpatched browsers (another good reason to keep your automatic updates turned on) and makes an encrypted copy of all the .doc, .txt, .pdf, .xls, .mp3, .jpg and .png files before deleting the originals. When it’s done, nothing is left on your computer but the encrypted copy. But that’s not the best part—or rather the worst. It then demands money in exchange for the decryption key.

Three years ago, Kaspersky Lab broke the 660-bit encryption of the original Gpcode, effectively rendering it useless to its author. So, what caused them to send out a plea for help with this version? The new one uses an unbreakable 1024-bit encryption key. Kaspersky has estimated that it would take around 15 million modern computers running for about a year to crack a 1024-bit encryption key. The author of the virus is also using several variants of the code, each responding to a different public and private key, which rules out using “brute force” to crack the encryption. And, so far, the experts have found no implementation errors in the virus’s coding that they could exploit to crack it.

No one knows how wide-spread this new virus is, but Roel Schouwenberg, a senior anti-virus researcher at Kaspersky says, "The reason we are making such a big fuss about this is because if you don't have any recent backups, you basically can consider your files lost.” Unless you want to pay the 100 USD blackmail—and even then you can’t be sure your files will be intact.

Ah-ha! That brings us back to why I started this article the way I did. In business, IT backs-up anything that’s on a server, but your local hard drive may be in danger, as well as your home computer. So, keep your virus files up-to-date. Don’t open email attachments if you don’t know what you’ve received. Unless it’s an emergency, don’t cancel that virus scan no matter how irritating it may seem. Keep your Windows updates running automatically and apply all critical patches as soon as possible. And make frequent backups of any files you deem important. Don’t count on those extensions listed above to remain the only files this trojan might encrypt. There are new versions coming out all the time.

Just remember one thing: Backup! Backup! Backup!