[mdlug] Disk encryption - once copied its vunerable

[Raymond McLaughlin]

gib at juno.com wrote:
>  
> Okay, I understand that having the key makes it a lot easier
> to decrypt the data. But isn't it possible to decrypt the data
> by brute force too?   So, encryption is not completely safe, right?
> I was watching the new Knight Rider (talking car) on TV. The
> inventor's laptop was stolen by the bad guys.  But then a statement
> was made that they recovered the laptop and the encryption was not
> broken.  I think that once the bad guys have a laptop they can make
> a copy of the data and then they can allow the laptop to be returned.
> They can take their time cracking the data.

The questions become: How much time? and How much resources (computing
power). Remember that every bit added to a key's length *doubles* the
number of possible values of the key, hence doubling the difficulty of
brute recovery. I've seen estimates putting the power required to break
a 256 bit key at something like "all the computers in the world running
nonstop for the rest of the age of the universe." But I'm not sure how
good the starting numbers were.