I have long time been a fan of
Truecrypt and used it very successfully, but I've been looking about for a replacement
that kept within FOSS guidelines of being 'free', free as in speech not as in free beer! FOSS being
http://www.gnu.org/philosophy/free-sw.html at free and open source software.
And I've found
Cryptkeeper, whose home page is at http://tom.noflag.org.uk/cryptkeeper.html and its in the Debian
repos with these requirements - gconf-service, libatk1.0-0 (>= 1.12.4), libc6 (>= 2.4), libcairo2 (>= 1.2.4),
libfontconfig1 (>= 2.9.0), libfreetype6 (>= 2.2.1), libgcc1 (>= 1:4.1.1), libgconf-2-4 (>= 2.31.1), libgdk-pixbuf2.0-0
(>= 2.22.0), libglib2.0-0 (>= 2.16.0), libgtk2.0-0 (>= 2.10.0), libpango1.0-0 (>= 1.14.0), libstdc++6 (>= 4.1.1),
libx11-6, zenity, fuse, encfs. The version in Wheezy is 0.9.5-5.1.
It installs nicely and then can be opened from the menu at System > Cryptkeeper, which opens a padlock icon in your system tray. If you right-click it your options are 'Preferences, About or Quit'. But the left click is the interesting one as it gives you 'Encrypted Folders, foobar [your encrypted folder with a tick beside it showing that its active], Import encFS Folder, New encrypted folder'. If you click on 'New Encrypted folder' it guides you through creating a new encrypted folder, very smoothly and easily too.
This new encrypted folder and file can be opened with the password you assigned to it during the creation. In my case I have my directory as /home/boudiccas/casket and with 'coffin' being the encrypted file.
The git repository is at https://github.com/tomm/cryptkeeper and there have been no updates to it since August 2010, so it may be dropped from the debian repositories before too long. But this is just my own thoughts on it.
And in the five years since it was last updated things have moved on, so I would question its security and accuracy.