[Winpt-users] File wipe options

[Timo Schulz]

On Wed May 03 2006; 12:53, Roger Carr wrote:

> I wasn't able to find any documentation on the file wipe option 
> "Simple".  Can anyone tell me what is done when using this default option?  

Overwrite file with 2 random passes.

  
> I saw some old release notes that listed the wipe options as 
> "experimental"..  Are they still considered experimental?  

I'm not sure where you read this. But it is a well known problem
to delete data securely from hard disks. The file is overwritten
with random data but due to disk caches and other (technical issues)
there is still a risk that some portions of the file remain in
unscrambled on the hard disk.
(Peter Gutmann published an excellent paper about this problem)

> One final question.  When selecting the "Wipe Free Space" option, does 
> a dialog box come up asking you which drive to perform the operation on?
> I didn't want to try this until I knew what it was going to do.

The command does exactly what the description is saying. It wipes
out the free space of the selected hard disk. 

The current code uses a simple "trick" to achieve this. It creates
a temporary file and the size of this file is equal to the free disk
space(*). Then this file is overwritten with random pattern and at the
end the file is deleted. The only risk _could be_ that the temp file
remains on the disk and there is no free disk space. But WinPT tries
to delete the file whenever the procedure is cancelled.


   Timo
   

p.s.
The code has a major problem on XP/NTFS. In general a user can't wipe
out the free space due to restrctions (quotas, privileges). The new
0.12.0 version (not yet released) provides code to check the
privileges of  the current user.