Hmm, there are some types of real-time encrypted filing systems available, but IMO they are not trivial (for a casual user) to impliment or get going. In certain situations or power-loss scenarios they can even be dangerous, becoming undecryptable (ever!) or unusable.
IMO the easiest, quickest way to reliably encrypt or decrypt sensitive data is to simply use the p7zip archiver. It was a quite powerful encryption feature you can use, and is reasonably user friendly.
I. e. what I'd do is to simply tar the directory, then 7zip it up, encrypting with a password. For casual use, that should be more then secure. Note, this is of course a MANUAL way to do it. However, it is very simple to do it this way, and safer, than doing it on the fly on an encrypted filing system. If you, for example, forget to tar/7zip encrypt the folder, it will be "in the clear" and thus a security risk. If you absolutely must have on the fly encryption, you -will- need a real encrypted filing system though.
Last edited by rylan76; 05-18-2009 at 08:36 AM.