Digital File Shredding: Can We Recover Shredded Files

We have talked about recovering data from accidental deletion, formatted disks, and deleted partitions. Today let’s focus on file shredding.

What Is File Shredding?

A file shredding program uses algorithms to overwrite certain files over and over again with other data till the trace or data remanence can no longer be recognized or recovered. 

Studies have shown that most of today’s media can be effectively cleared by one overwrite. However, more overwrites are required for data with high-security level. It is like writing on a paper with a pen over and over till you can’t read the original texts anymore.

File shredding doesn’t actually shred anything. It is in essence wiping or erasing. We call it shredding in an analogy with traditional paper shredding machines, which are used for disposing of sensitive documents.

Is File Shredding Necessary?

When we delete a file and empty the recycle bin, your computer doesn’t actually delete the data. It is the pointer in the address table that’s been deleted. The file is now latent to your computer system and the space it takes is viewed as free and can be overwritten anytime when needed. This is how the file system handles deletion because to erase each deleted file would take tremendous time.

Because of the fact that the data are still there, it is possible to recover deleted files with some special programs like Hdata Recovery Software.  If you are disposing of sensitive data, leave it to the chance of being overwritten by new files is not secure.

Can Shredded Files Be Recovered?

Mostly no. The overwrite algorithm is designed to blur the residual pattern. With one-pass overwrite, it is impossible to recover for most consumer level software. It is still possible, though, with forensic analysis and advanced labs but it is far beyond the means of an ordinary user. Even with this immense resources, only negligible fragments of data can be recovered.

Regarding SSD

Individual file shredding does not apply well enough to SSDs (Solid State Drives). Traditional hard disk drives store data in small units on the magnetic surface. SSDs store data in flash memories and tend to move files around to avoid wearing out a certain area. This means that if you overwrite a file, it may not actually put that file in the same location. To secure an SSD, you should utilize some encryption software and be sure to enable TRIM.