exHide: Hiding Data within the exFAT File System

Abstract

Recently, steganographic techniques for hiding data in file system metadata gained focus. Tools for commonly used file systems were published but the exFAT file system did not get much attention – probably because its structure provides only few suitable locations to hide data. In this work we present two approaches to hide data in the exFAT file system. While the first approach is more flexible regarding embedding locations, it is rather fragile and provides a lower embedding rate. The second approach, called exHide, has stricter requirements for embedding, but is rather robust and provides a reasonable embedding rate. We describe the design of both approaches, evaluate them, and discuss their weaknesses and advantages.