Tuesday, July 26, 2005 10:53 AM bart

Basic disk wiping in Windows - cipher /w

If you want to perform basic disk wiping to clean free space on your harddrive, you can use the cipher tool which is included in the Windows OS installation (as from Windows 2000 SP3 on; for earlier Windows 2000 pre-SP3, download it over here or better install SP4). It's not supported on Windows XP Home however. Output looks as follows:

C:\>cipher /w:c
To remove as much data as possible, please close all other applications while
running CIPHER /W.
Writing 0x00
................................................................................
.....................
Writing 0xFF
................................................................................
....................
Writing Random Numbers
................................................................................
....................

As you can see, the syntax includes a /W flag to turn on the wiping mode. As an argument you do specify the volume drive letter or a specific directory. I'm using cipher /w:c to clean all free space on the harddrive. Notice that during executing you can get "Low Disk Space" messages (information -> warning -> critical) because of the wipe data that's being written temporarily to the disk.

The wiping mode of cipher works in three stages: first it writes 0x00 (all zeros), then 0xFF (all ones) and finally random numbers. Use this too to make sure deleted data is really deleted and unavailable, which is important when you want to sell (or throw away) your computer (or the harddisk in it), or when your machine is stolen some day. Use it when you have misused EFS as well. With misuse I mean using EFS to encrypt individual files instead of folders, because EFS creates plaintext copies (for recovery purposes) in that case (thus, when encrypting individual files).

For more complex (and secure) wiping algoritms and support for non-NTFS volumes, you can use other tools instead (e.g. R-Wipe & Clean which includes Department-of-Defense approved algorithms, that take longer but are more secure too). Search results for "disk wipe" can be found here.

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# re: Basic disk wiping in Windows - cipher /w

Thursday, April 20, 2006 3:32 AM by tony

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