“ext2hide is a proof-of-concept program that seeks to magically
hide confidential data and files where nobody will look for them.
It accomplishes its magic by making use of otherwise abandoned
space in the superblocks in ext2/ext3 filesystems. Even though
Jason McManus, the author of the code, has been testing and using
ext2hide on his own machines without catastrophic results, I urge
you to use the utmost caution both in testing and using it. If you
don’t grok superblocks and filesystems, you probably should not
experiment with ext2hide, at least until it’s out of beta
testing.“Grab the latest tarball, decompress it, and enter the resulting
ext2hide-version subdirectory…”