DiskWiper

DiskWiper overwrites the free space on a drive so that files deleted earlier cannot be recovered, and it never touches existing files. It is written in Rust with zero external crates: the random generator (a ChaCha8 keystream), the terminal UI, argument parsing and the Win32 bindings are all written in-tree, and the whole tool ships as a single executable of about 550 KB.

It fills temporary files inside its own scratch folder instead of writing to the raw device, using multi-threaded unbuffered I/O tuned to the medium. It then floods free NTFS MFT records so that small deleted files stored inside the MFT are overwritten too, and finishes with a TRIM on SSDs. A shred command securely deletes individual files and folders.

Most of the work went into safety. Every run shows a plan and asks for confirmation, with a stricter typed phrase for the system drive. The volume always keeps some headroom, Ctrl+C cancels cleanly, and temporary files are removed even after a crash. The tool is also honest about its limits: on SSDs a free-space wipe is best-effort, and it says so before it starts.