Securely wipe laptop hard drive

[jedenfalco]

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, September 24, 2021 1:40 PM, Eric Blake <eblake@redhat.com> wrote:

> On Fri, Sep 24, 2021 at 12:30:48PM +0000, Evan Greenup wrote:
>
> > +1 Here,
> > If shred can support shredding directory tree recursively, it would be 
> > awesome.
>
> It can't, because that's not how shred works. Recursively shredding
> files within a larger filesystem does NOT guarantee that the old file
> is wiped out, because modern file systems tend to write the new file
> to a different part of the block storage while leaving the old storage
> unchanged other than marked as unused; with the right software, it's
> fairly trivial to read the contents of those areas of the disk. On an
> even more fundamental level, SSD disks tend to use wear-leveling
> technology, where the hardware itself will dynamically reroute writes
> to the same logical address to different portions of the storage over
> time, again leading to hardware still containing old data that was not
> overwritten. If you are not shredding an entire disk, chances are you
> are not actually shredding the old data from the storage. Adding a
> recursive option to shred to visit a series of files (rather than an
> entire block device) would give users a false sense of security, so we
> are unlikely to do it.

Could it work on a specific partition?


> > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> > On Friday, September 24th, 2021 at 9:06 PM, jedenfalco via GNU coreutils 
> > General Discussion coreutils@gnu.org wrote:
> >
> > > I have a laptop and want to securely wipe the hard drive. It would be 
> > > good to be able to wipe out an directory tree (e.g. /home) but it seems 
> > > that dd can only wipe an entire drive.
> > > This means that I have to remove the hard drive and connect it externally 
> > > to another PC to wipe it.
>
> No need to unplug the hard drive, when you could instead boot your
> computer from a live USB stick with a minimal operating system that
> contains enough software to perform the shredding of your unmounted
> hard drive. You may have to tweak BIOS/UEFI settings to be able to
> boot from live media instead of from the hard drive, but that's still
> easier than moving the hard drive to a different PC.
>

You are right. Wanted to avoid moving the hard drive to a different PC to do 
this thing.