File Shredder

Wipe free space by overwriting it!

The contents of a file are not cleared when normally deleting a file. Forensic tools and file recovery tools can be used to recover files which have not been securely deleted.

File Shredder is a simple, handy app that makes deleted files on your internal storage unrecoverable by overwriting all available space with zeros or random data (see modes below). This means recoverable data from deleted files such as images, videos, databases, is replaced with useless bytes.

A large file is created on the selected storage device which will fill remaining space on the device. This app does NOT delete any existing files.

Any storage device that is visible to Android's Storage Access Framework can be shredded.

You can choose between different shredding modes:

- Zeros - overwrites free space with zeros (fastest)

- Random - overwrites free space with random data

- Secure Random - overwrites free space with cryptographically secure random data (slowest)

File Shredder can also shred individual files and directories. This involves overwriting the files with data from the chosen mode, overwriting the file's name with a random name (longer than the original name), and finally deleting the file normally.

File Shredder has been tested with a handful of file recovery apps available for Android (including root ones that directly read from block storage devices) and all were unable to recover any deleted files after using this app.

NOTE: flash memory used in phones has limited durability - it is recommended that File Shredder is not used as a habit, but rather only when it's needed. Additionally, flash memory usually comes with 'wear levelling' features, which means that writing to the same 'file' twice does not necessarily mean that the same physical location on the flash memory will be written to. This means it is possible (but rather unlikely) that very sophisticated recovery methods that look at wear levelling blocks of the device's flash memory could pick up fragments of deleted files. Running File Shredder multiple times may reduce this chance (although it is quite low to begin with).