This article was taken from the October 2011 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
You've deleted a file. Hell, you've emptied the recycle bin, just to make sure. But don't for a minute think the information is gone for good. That process only erases the file's entry in the computer's central index, which is the list of file locations that the operating system uses to find the physical data on the hard drive. The file itself is still at large -- and could be rediscovered with a bit of technical know-how. Here's how to completely erase all traces of that time when you rolled with LulzSec.
1. USE FORENSIC TOOLS
A file exists until it is overwritten with new information, and
forensic software is able to locate an unindexed file. PC owners can use a program such as Evidence Eliminator to replace the data with innocuous zeroes. "Its name may conjure up images of wrongdoing," says Daryl Hamilton-Wallis of Fields Associates, a computer-forensics service, "but it is very effective. I know, because we've been on the receiving end of it."
2. BUY A MAC
"Apple Macs are very security-friendly because they have a facility for permanently deleting files built into their operating systems," says Hamilton-Wallis. Macs can overwrite unindexed space up to 35 times per scrub (you know, just to be absolutely sure). Simply open the Disk Utility tool from Applications > Utilities. Select the drive, go to the "erase" tab, and follow the instructions.
3. WIPE THE DRIVE
Even high-calibre deletion software won't erase file fragments."Think of it as an old video tape," says Hamilton-Wallis. "If you record a one-hour show over a two-hour film, the second half still remains." That's the equivalent of the "file slack", created by saving new files over old, that the third-party software does not address. And you still have the nuclear option: back up your files and overwrite the entire disk with zeroes using a downloadable tool.
This article was originally published by WIRED UK
