CryptoFS is a encrypted filesystem for Filesystem in Userspace (FUSE) and
the Linux Userland FileSystem (LUFS). Visit http://fuse.sourceforge.net/
for more information on FUSE or http://lufs.sourceforge.net/lufs/  for more
information on LUFS.

CryptoFS will use a normal directory to store files encrypted. The
mountpoint will contain the decrypted files. Every file stored in this
mountpoint will be written encrypted (data and filename) to the directory
that was mounted. If you unmount the directory the encrypted data can only
be access by mounting the directory with the correct key again. Like other
FUSE/LUFS filesystems it does not need root access or any complicated setup
like creating a filesystem on a encrypted disk using the loop device.

CryptoFS can be build for FUSE and LUFS. When you build for FUSE you get a
program to mount the filesystem. For LUFS a shared library will be built
that can be used by LUFS's lufsd. Both methods can use the same encrypted
directory.

WWW: http://reboot.animeirc.de/cryptofs/