Stegfs
From Just Solve the File Format Problem
StegFS (previously vstegfs - Virtual Steganographic File System) by Andrew D. McDonald and Markus G. Kuhn is an open source steganographic filesystem with the plausible deniability feature that works with FUSE.
Version 2015.08 is incompatible with file systems created by previous versions.
A typical stegfs partition of 1GB will support approximately 123MB of files.
Unlike the previous version, the 2015.08 releases are not yet multi-threaded; this is (hopefully) enforced by the FUSE driver. This makes stegfs slow!
