Database Encryption (now required by law in Italy)

The new italian law about personal data protection (aka "privacy") requires
the use of cryptography _both_ for protecting the network traffic _and_ for
protecting the (personal) data stored on the hard disk.

While I can see how to protect a PGSQL connection using SSH tunneling or a
VPN, I cannot see any way to encrypt a PGSQL database stored on a hard disk,
put aside the possibility to encrypt the hosting file system with LoopAES.

Is there any (native/third party) tool for encrypting a PGSQL database on the
disk? Is there any PGSQL option for encrypting data on the fly?

Many thanks in advance for your attention.

NOTE: the italian law on privacy ("Decreto Legge 196/03", Dicembre 2003) is
available on the net:

http://www.garanteprivacy.it
http://www.interlex.it

Of course, just in italian...
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Alessandro Bottoni and Silvana Di Martino
alessandrobottoni(at)interfree(dot)it
silvanadimartino(at)tin(dot)it