Free Secure (Destructive) File and Disk Deletion Tools

Free Secure (Destructive) File and Disk Deletion Tools
The utilities on this page allow you to destructively wipe / delete / erase a file, a disk (floppy disks, hard disks, etc), or a partition. This is usually accomplished by overwriting the existing data on the disk or file with either random numbers or a series of zeros and ones (or some such bit patterns). The tools are useful if you want to make it difficult for people to recover deleted data from your disk. You could say that these tools are the computer equivalent of a file shredder, an electronic or digital file shredder for files, hard disks, etc.
Note that if you are concerned about the security of your data or simply wish to protect your privacy, you should also look at the Free Data Encryption Utilities, On the Fly Encryption, Steganography, Public Key Encryption page. Your data will be less easily recoverable if it is encrypted from the start.
This page does not list commercial file shredders and secure disk erasers like East-Tec Eraser (wipes files, has a trial download), and East-Tec DisposeSecure (wipes hard disks, has a trial download).
Free Secure Delete / Wipe Files / Wipe Disk / Destructive Delete
Freeraser: Free Shredder
This is a Windows file shredding utility that wipes your files in one of three ways (at your option): a quick 1 round of filling the erased space with random data, a 3 round erasure using the DoD 5220.22M standard (one of the US Department of Defense standards), or wiping your erased file with 35 rounds of data using the Gutmann algorithm.
Eraser Secure Data Removal Tool
Eraser is a Windows utility that allows you to securely erase files, file slack space or cluster tips (the space that is not occupied by the data in a file, but nonetheless allocated to that file by the operating system), Windows virtual memory swap file, unused space on a hard disk, or an entire hard disk or floppy disk or Zip disk or the like. It is able to wipe data using pseudo-random data (or any combination of data that you specify), any number of times you wish (eg, once, or using the US Department of Defense (DOD) recommendations of either 3 times or 7 times, or the Gutmann recommendation of 35 times, etc). It is also able to erase the filenames in the directories for files you delete. The program is open source and works under Windows.
SysInternals SDelete
SDelete is a secure delete application that can overwrite a disk's unused or unallocated space, or securely delete existing files. It implements the US Department of Defense clearing standard DOD 5220.22-M, and you can specify the number of overwrite passes it makes. It can also wipe Windows NT/2K compressed, encrypted and sparse files (it uses Windows defragmentation API to accomplish this), and clears the NTFS Master File Table (MFT). (It does not delete the filenames of your files in the free disk space though - apparently it is not possible to do this in NT/2K.) This program comes with source code and works under Windows 95, 98, NT 4.0 and Windows 2000. It is a command line utility.
Darik's Boot and Nuke
Darik's Boot and Nuke is a utility that you use when you want to completely obliterate all your data in all your hard disks and their partitions. It comes in the form of a bootable floppy disk or a bootable CDROM image (you download whichever you prefer), complete with an operating system (Linux) and the Boot and Nuke utility. Once you boot up that floppy (or CDROM), the utility will proceed to destroy all your data in every partition of every hard disk. The site says that it is designed for bulk or emergency data destruction. (It is probably also useful in less dramatic cases, such as when you want to wipe your disks prior to giving your computer away to someone.)
OverWrite
OverWrite is a Unix utility that overwrites files with random patterns and deterministic patterns. It comes with source code and is released under the GNU General Public License.
Wipe Secure File Deletion
Wipe, a secure file wiping tool for Linux, destructively deletes files by overwriting its data using a pseudorandom data. It is open source.
Secure Delete
Secure Delete is a Windows program that erases files or directories after filling them with random data. It comes with source code. Their site warns that the utility does not meet the requirements of the US DoD or the UK Ministry of Defense.
Active@ Kill Disk Free Version
This DOS program allows you to wipe all data on a physical drive (hard disk, zip drives, floppy drives). You can display information about the drive, including data present in any sector on the drive before wiping. The program only writes zeros to the drive.
Autoclave
Autoclave is an open source drive sterilization utility that wipes a hard disk multiple times. You run it from a bootable floppy disk, which you create after downloading the file. It requires an x86 PC. Note that this software is no longer supported nor maintained