He was able to scan the phone's memory card (SD card) and display a list of all non-hidden files on it.

CNN: 'No permission' Android apps can see and share your data

But, said Mr Pearson, this "save as" culture could lay firms open to all kinds of problems because hidden information inside files reveals the document's true genesis.

BBC: NEWS | Technology | Document deluge threatens firms

But it turns out that, behind the scenes, Sony may also be installing invisible services in the form of a hidden directory containing cloaked files, which run when you use that media player.

ENGADGET: Sony DRM hacks your PC

When the thrill of being unplugged outweighs the danger of losing essential data, there are a number of technologies that make it easier to back up those files, keep them hidden and even track down the missing computer itself.

CNN: Mobile PCs can be risky on the road

It also makes it easier to find the files that have been created, accessed and modified during an attack, and it is able to reconstruct deleted files from raw data found in various hidden parts of a computer's hard disk, such as unallocated space and file slack.

ECONOMIST: Forensic computing studies the anatomy of computer crime