Secure Data Deletion
https://ssd.eff.org/tech/deletion
How to electronically eradicate, expunge, extirpate, obliterate digital data
Partitions
All data on drive X may be
permanently destroyed
by using the following command (warning - this may take a very long time):
dd if=/dev/zero of=/dev/sdX
Confirmation of whether or not any non-zero bytes exist:
dd if=/dev/sdX | hexdump -C | grep [^00]
Confirmation of whether or not any files exist (
photorec)
:
photorec
http://www.murga-linux.com/puppy/viewtopic.php?t=65509
Individual files
Individual files may be made permanently inaccessible by:
encrypting
them first
then, deleting them in the usual way, e.g.:
shred -uvz <file>
How to physically eradicate, expunge, extirpate, obliterate digital data
https://www.youtube.com/watch?v=hqyc37aOqT0
TUTORIALS