Rook is a covert communication system that works by hiding information in altered network data. It was designed with first-person shooters in mind, but can theoretically work on other applications.
Rook is modular, the code here is the basic client and server framework. Both of these depend on a packet parsing module (a mock example is provided in DummyParsers and the Parser class is described in StegoEngine.py). The parsing module takes a packet from the application and parses it to find mutable fields, which are selections of bits that can be altered by Rook without creating invalid application packets. Thus, to run Rook on a given protocol, you must create a packet parsing module to do this so that Rook will not accidentally overwrite structural data and create invalid packets.