[Cryptography] Shredding a file on a flash-based file system?

[Bear]

On Thu, 2014-06-19 at 16:32 -0400, Darren Lasko wrote:
> On Thu, Jun 19, 2014 at 3:52 PM, Bear <bear at sonic.net> wrote:

>         Under what circumstances would an attacker have the drive
>         platters in hand, but not have access to the key which is
>         stored in the drive hardware?


> When the encryption key isn't just "stored" in the drive hardware.
> Any implementation worth its salt will only store the key wrapped with
> the authentication credentials required for unlocking the drive.

Could you please explain what you mean, in hardware-oriented 
terms, what you mean when you use the words "wrapped with"
in this context?  

Because clearly the key is stored unsecured if the machine can 
boot up the operating system without me entering a key.  To boot
the operating system requires reading the supposedly encrypted 
drive.  If the key doesn't come from outside, then it is stored 
in the same machine the attacker would presumably be stealing. 
If it doesn't require someone to demonstrate their credentials 
by entering a secret, then it is stored unsecured.  

So if there's meaningful protection attached to the words "wrapped 
with" I don't understand how it can possibly work.

			Bear