Justin A. Parr - Technologist

Windows XP and above includes a free, secure disk wipe capability.

Background

When files are deleted, the directory entry is removed, leaving the data in-tact.  Commercial and open source software is available to recover deleted files, by finding the disk cluster chain, and restoring the original directory entry.

“Secure delete” means overwriting the cluster chains for a given file.  Likewise, a “secure wipe” overwrites all unused clusters on the drive.

Solution

Windows XP and above has the “cipher” command, that includes a built-in disk wipe feature.  Cipher ONLY deletes unused clusters, meaning that the file must be deleted, followed by a cipher “disk wipe” to ensure that the data can’t be recovered.

Likewise, a quick format followed by a cipher disk wipe effectively securely wipes the entire drive.

Procedure:  Securely Erase Deleted Files

1. Delete the files / folders in question.  Use SHIFT+DEL instead of DEL to do a permanent delete, bypassing the recycle bin.
2. Empty the recycle bin (just to be sure)
3. Run the following commands at an Admin Command Prompt (Right-click “Command Prompt”, select “Run As Administrator”):
   cd /d d:\
   (where d: is the drive to wipe)
   cipher /w:.

Procedure:  Securely Erase an  Entire Drive

1. Format the partition using quick format
   1. Right-click the drive in “My Computer”, select “Format”
   2. In “Format Options”, select “Quick Format”
   3. OK
2. Run the following commands at an Admin Command Prompt (Right-click “Command Prompt”, select “Run As Administrator”)
   cd /d d:\
   (where d: is the drive to wipe)
   cipher /w:.

Summary

The command:

cipher /w:somepath

…will write “0x00” to every free byte on the drive, followed by “0xFF” (all 1’s), followed by random bytes.

By deleting files, then running a secure wipe, you ensure that deleted files (such as history, temporary internet files) can’t be recovered.

Cipher only overwrites free space, so there are no sharp edges – you can’t accidentally delete files that way.