The Enhanced File Crypt/eXtended File Stealth System (EFC/XFSS) makes your uploaded files safe on the server so that no one can read them without knowing a few details to decipher the files. It generates different obfuscated names and encrypted files so no one will know what the original format or name was.
fakedbfs is a suite of tools and a library for cataloguing files. Anything that is a file can be catalogued along with metadata. The metadata is then searchable through various querying facilities. It runs entirely in userland and was inspired by BFS, which doesn't do content indexing, only metadata.