Vault is like TrueCrypt: it creates a file-backed encrypted dev where you can store all your files. This is just a thin wrapper around cryptsetup with some niceness to make managing the vault easier.

1. Add deb http://deb.stoney.io/ testing/ to your sources.list.
2. Install the archive keys: sudo apt-get install stoney.io-archive-keyring
3. sudo aptitude install vault