Secure deletion (file shredding)
Also known as: file shredding, secure erase, wipe data, permanently delete
Secure deletion permanently erases data so it cannot be recovered, unlike a normal delete that only removes the file’s entry and leaves the contents on disk until overwritten. On modern phones this is done instantly by wiping the encryption key.
- Normal delete leaves recoverable data on disk
- Overwriting destroys data on traditional drives
- Phones crypto-erase by wiping the encryption key
Why a normal delete is not enough
Deleting a file usually just removes its directory entry and marks the space as free. The actual bytes stay on the drive until something else happens to write over them, which is why recovery tools can often bring "deleted" files back.
Trash and Recently Deleted folders add another delay — items sit there for days before the space is even released. Until then, nothing is truly gone.
How secure deletion actually works
Traditional file shredding overwrites the data with random patterns one or more times so the original cannot be reconstructed. This makes sense on older spinning hard drives.
Modern phones and SSDs take a faster route: because the whole device is encrypted, erasing or rotating the encryption key instantly makes all the data unreadable, with no need to overwrite every byte. This is what an iPhone’s Erase All Content and Settings does — a "crypto-erase." For privacy, also remember that sharing a file can leak its embedded metadata even after you "clean up" the visible content.