"Simple file encryption is useful, but sometimes it's more
useful to encrypt a complete filesystem or disk, such as when you
need to protect a large set of files. Or you may need not only to
protect, but to completely hide the presence of sensitive data from
prying eyes. For these cases, here are several options for securing
your systems.
"If you have a dedicated encrypted partition or disk, you need
to keep only one passphrase or key to unlock all your protected
files. Some solutions allow you to go as far as encrypting the swap
and the root partition. The drawbacks include sometimes a loss of
performance (unfortunately, a necessary trade-off for security),
and the fact that if an attacker gets ahold of your key (or you
just happen to lose it), you can say goodbye to all your protected
files..."
