[Nottingham] Secure deletion of files

[Duncan John Fyfe]

On Wed, 2005-05-25 at 17:59 +0100, David Aldred wrote:
> A question arising from a discussion at work: how secure is deletion of files 
> in Linux?  
> 

If you are using a non-journaling filesystem (eg ext2 or FAT)  it can be
very secure.  If your using a journalling filesystem (eg ext3  reiserfs)
then it isn't guaranteed (see shred(1) for more details).
At least if you are using ext3 you can re-mount it ext2 then shred the
files.

> And is there any way of doing it retrospectively, if I were to forget at the 
> time and simply delete the file in the usual way?
> 
> (The video about security which triggered the discussion suggested a way of 
> securely deleting your files under Windows, which would be better than 
> nothing but still not particularly secure - and illustrated it with a video 
> of someone working on a Mac!).

I don't know about hfs (the mac filesystem) but it works for windows
(FAT) because the filesystem is simple not because windows is clever.

> 
Have fun,
Duncan