EncFS
EncFS provides an encrypted filesystem in user-space. It runs without any special permissions and uses the FUSE library and Linux kernel module to provide the filesystem interface. You can find links to source and binary releases below. As with most encrypted filesystems, Encfs is meant to provide security against off-line attacks; ie your notebook is stolen, your backups are stolen, etc. The way Encfs works is different from the loopback encrypted filesystem support built into the Linux kernel because it works on files at a time, not an entire block device. This is a big advantage in some ways, but does not come without a cost. http://arg0.net/users/vgough/encfs.html
Off-the-Record Messaging
Nikita Borisov and Ian Goldberg have released Off-the-Record Messaging
("http://www.xelerance.com/mirror/otr/";),
an IM plugin for private communication providing not only
the usual encryption and authentication, but also deniability and
perfect forward secrecy. Deniability avoids digital signatures on
messages (while preserving authenticity and integrity), so there is no
hard-to-deny proof you wrote anything in particular; in fact, there is a
toolkit to help people forge messages, making it extra-hard to pin
things on you. Perfect forward secrecy means that your past messages
and conversations remain protected even if your keys are compromised.
