Wikipedia
StegFS
StegFS is a free file system for Linux. It is licensed under the GPL. It was principally developed by Andrew D. McDonald and Markus G. Kuhn. It is a steganographic file system based on the ext2 filesystem.
The last version of StegFS is 1.1.4, released February 14, 2001. This is a development release, with known bugs, such as a file corruption bug. There is no stable release. The last website activity was in 2004. In 2003, Andreas C. Petter and Sebastian Urbach intended to continue development of StegFS, and created a site for it on SourceForge.net. The development has further moved to using FUSE library, and working releases are available from the development homepage.