Barrapunto

Tercer parrafo y cuarto: The loop device driver can also be used to "hide" a file system in a disk partition, floppy, or regular file, either using encryption (scrambling the data) or steganography (hiding the data in the low bits of, say, a sound file). This is also safe if the file resides on a remote file server. If you want to do this, you will first have to acquire and install a kernel patch from < ftp://ftp.kerneli.org/pub/kerneli/ > [kerneli.org], and then you need to say Y to this option.

Note that alternative ways to use encrypted file systems are provided by the cfs package, which can be gotten from < ftp://ftp.kerneli.org/pub/kerneli/net-source/ > [kerneli.org], and the newer tcfs package, available at < http://tcfs.dia.unisa.it/ > [unisa.it]. You do not need to say Y here if you want to use one of these. However, using cfs requires saying Y to "NFS file system support" below while using tcfs requires applying a kernel patch. An alternative steganography solution is provided by StegFS, also available from < ftp://ftp.kerneli.org/pub/kerneli/net-source/ > [kerneli.org]."

También tienes Encryption-HOWTO.html [sourceforge.net]. En lo personal nunca lo he probado, pero me lo recomendaron bastante para emplearlo.