ecryptfs:

        
    eCryptfs (the Enterprise Cryptographic Filesystem) is a POSIX-compliant encrypted filesystem that has been part of the mainline Linux Kernel since version 2.6.19. It has been implemented as a stackable file system and provides filesystem-level encryption. eCryptfs has been derived from Erez Zadok's Cryptfs. More information and related tools can be obtained from https://launchpad.net/ecryptfs