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Do “File Shredder” Programs Really Work?

July 19, 2022

You’ve got sensitive data that you want to destroy, and you want to be extremely thorough. You want to make sure that no one — not even’s engineering team — can restore the target files. What do you do?

Physical media destruction is always an option, but if you’re not willing to disassemble your hard drive and drill holes through the platters, file deletion software (or “file shredders”) are the next-best option. They’re effective, easy to use, and much safer than the aforementioned drilling method (to be clear, we’d put down the drill, since hard drive platters can break into sharp fragments). 

On many operating systems, deleted files are fully recoverable

Of course, every operating system has “file deletion” software; on Windows, for example, you’ve got the Recycle Bin. Unfortunately — or fortunately, depending on your perspective — OS tools don’t always overwrite data. 

Hard drives store data on platters, which are coated with a thin magnetic material. To actually delete a file, you’d need to change all of the magnetic charges associated with that file. 

But in most cases, that’s unnecessary. Writing data (i.e., changing the magnetic charges) consumes energy and takes time. The hard drive’s actuator heads must visit every sector of the file, which causes mechanical stress and limits the computer’s processing power until the operation is complete.

If you’re deleting a 2-gigabyte application, it doesn’t make sense to spend resources overwriting every bit of data — instead, the operating system will simply mark the space that the data occupied as “deleted,” then use that space when it needs to execute another write operation.

To put that another way, deleting a file doesn’t actually delete anything. You’re simply putting a “VACANT” sign on the file’s address. Note that this is only true for magnetic media — solid state drives (SSDs) don’t use magnetic charges to store data, and deleting a file from an SSD will immediately destroy the target file.

How File Deletion Software Works

File deletion software actually goes through the process of changing the magnetic charges on the hard drive’s platters. It’s an intensive process, and it works — provided you’ve selected a decent application for the task. 

Many “file shredder” tools go even further, writing random 1s and 0s to the space occupied by the target file. Some tools follow the Department of Defense’s (DoD) standards, overwriting the target area up to 7 times to completely annihilate the data.

But do they work? Yes — data recovery technicians have theorized that a single overwrite (or one pass deletion) could be recovered, but multiple overwrites eliminate any magnetic artifacts that would allow file recovery. Even with a single pass, data recovery is extremely unlikely, especially for larger files.

Even so, we do not officially recommend any file shredder applications, and we don’t use them frequently in our laboratories. Why? Put simply, software (and users) aren’t perfect. When we need to eliminate sensitive data, we usually degauss the hard drive by using powerful electromagnetic fields. 

If we need to destroy a single file while keeping the media intact, we use proprietary tools built to meet DoD/NIST standards. We don’t use commercial software for secure file deletion.

With that said, several free file shredders are ideal for private use. We’re listing them below, but this isn’t an official endorsement; research data security applications carefully before using them.

  • Eraser – This simple application supports 10 data sanitization protocols, and it’s available for most Windows operating systems.
  • WipeFile – WipeFile works similarly to Eraser, but it has several features that may appeal to power users, including options for creating log files.
  • Secure Eraser – Secure Suite is a data sanitization tool and registry cleaner. It supports several sanitization protocols, including DoD 52220.22-M.

Before using any file deletion software, read the instructions. Make sure you have a backup of all important files — even if you’re not targeting them with the file shredder — and understand that “shredding” a file is permanent.

If you’ve lost data due to file deletion, can help. 

With no-risk quotes and a no data, no charge guarantee, we provide reliable resources for recovering from any data failure scenario. 

Contact us at 1-800-237-4200 or submit a case online to schedule a free evaluation.