StegFS: A steganographic file system for linux

Abstract

Cryptographic file systems provide little protection against legal or illegal instruments that force the owner of data to release decryption keys for stored data once the presence of encrypted data on an inspected computer has been established. We are interested in how cryptographic file systems can be extended to provide additional protection for such a scenario and we have extended the standard Linux file system (Ext2fs) with a plausible-deniability encryption function. Even though it is obvious that our computer has harddisk encryption software installed and might contain some encrypted data, an inspector will not be able to determine whether we have revealed the access keys to all security levels or only those to a few selected ones. We describe the design of our freely available implementation of this steganographic file system and discuss its security and performance characteristics.