To reduce the risk of losing files we, therefore, write several copies of each inode and data block. If we overwrite some of the copies, we hopefully have others left to use instead. However, if all copies are overwritten then that data is lost. This is one of the prices to pay for the steganography. Because we write multiple copies of blocks you should also remember that this takes up more space.
Key management uses a number of security levels accessed via a number of security contexts.
Each context is accessed using a passphrase and contains keys for one or more of the security levels. StegFS is distributed as a tarball with a name like stegfs-a.b.c.tar.gz. This contains both the kernel module and the utilities. The StegFS filesystem module can either be built against a vanilla kernel, or a kernel with the kernel crypto patch applied. This is probably the simplest method.