Hi Charles, I am a forensics teacher.
There is another point to be considered: the RAM memory. The data, commonly, pass across RAM and is easy get the key from a memory dump (even if the computer was turned off). So, after take care of the SDD, you need to wipe the RAM. An 'apt-get install secure-delete' wil provide sdmem command, that will wipe the RAM. I suggest to use a live-CD or flash drive with Debian to boot in shell only mode and run sdmem. You can install Debian in a flash drive and use it. It is easy to do. Regards, Eriberto
