On 1052687897 seconds since the Beginning of the UNIX epoch
Bill Studenmund wrote:
>

>No, cgd is a cryptographic device, not a file system. A cryptographic file
>system would encrypt the data in the files, but not necessarily the meta
>data. Also, a cryptographic file system could use different keys for
>different users.
>
>A file system would be more for a case where physical security isn't a
>strong issue but protecting one user from another is. cgd is best for a
>case where protecting one user from another isn't a big deal, but phsyical
>security is.

It warrants pointing out that an encrypting file system does not
really protect users from each other on a single host much more
than chmod 600 does, though.  If you can circumvent the kernel then
you can read the other user's key.  The best you get in this case
from an encrypting file system is temporal protection, i.e. you
have to compromise the box when the target user is logged in rather
than at any point in time.

>cgd is great for your laptop in case it gets stollen. A cryptographic file
>system is great for a file server that needs to protect data from
>different users. Say a computing center that performes service work
>(computations, simulations) for competing companies.

Exactly, in the case of a distributed file system if the encryption
is performed on secure clients then an encrypting file system has
significant value---although it does leak much of the meta-data to
other people who have access to the file system.

--
    Roland Dowdeswell                      http://www.Imrryr.ORG/~elric/