New method developed to hide data on computer hard drive

New Scientist : Data on a hard drive can now be hidden without the use of encryption, writes Paul Marks for New Scientist. Instead of using a cipher to scramble text, the technique exploits the way hard drives store file data in numerous small chunks, called clusters. Normally the operating system stores the clusters all over the disk, wherever there is free space between fragments of other files. Hassan Khan, at UCLA, and his colleagues have written software that ensures clusters of a file are positioned according to a code rather than being positioned at the whim of the disk drive controller chip. “An investigator can’t tell the cluster fragmentation pattern is intentional—it looks like what you’d get after addition and deletion of files over time,” said Khan. Such “steganography” avoids the problem experienced with encryption, which can be a “dead giveaway” that someone has something to hide, according to Khan.