Unknown to many, deleting files on their devices does not mean that these files cannot be recovered. According to security researchers, data does not disappear when users delete a piece of data from their device. Instead, the device in question designates that space as available to be overwritten by new information.
According to Alfred Demirjian, founder and CEO of TechFusion, once a user has sent it, this information is likely to exist forever, especially if the government wants whatever you have sent.
“My theory — and I believe I am right — anything digital gets recorded; you text anything, it gets recorded somewhere. If it’s for national security, they will open it up, if they want it, they will find it. When you delete something, it doesn’t erase it, it basically makes it available for the system to copy on top of it,” Demirjian said.
The fact that mobile devices now have larger storage makes it even easier for an investigator to retrieve certain data.
Demirijian pointed out that people who want to delete their device can have it professionally removed, even though the procedure is expensive.
While there are other extreme measures, such bashing the phone with a hammer or throwing laptops into the ocean, they are not enough to prevent digital forensics from recovering the data they need.
The best way to get rid of data effectively is to burn a device into a molten pile of plastic.
The sources for this piece include an article in NPR.