If you've been putting off backing up your important computer files, now may be a good time to do so. One of the latest Trojans making the rounds is a pretty nasty version of ransomware that encrypts files on your computer then deletes the original files. In order to get your data back, you have to contact the malware's authors to buy the decrypting tool. The malware targets 143 different file types including digital pictures, office documents and backup files. This type of ransomware first appeared a couple of years ago, but wasn't deemed a severe threat due to its poor implementation of the 660-bit encryption routine which security researchers were able to crack. This time around things are different as the authors are using a RSA-1204 bit algorithm that security firm Kaspersky Lab estimated would take 15 million PCs working in parallel to crack. While the threat is not widespread yet, that's no excuse to put off making sure your important files are backed up and any external backup media disconnected from the host computer to prevent the backup files from being targeted as well.