Topological Study and Lyapunov Exponent of a Secure Steganographic Scheme
CI S2 is a steganographic scheme proposed in the information hiding literature, belonging into the small category of algorithms being both stego and topologically secure. Due to its stego-security, this scheme is able to face attacks that take place into the "Watermark only attack" framework. Its topological security reinforces its capability to face attacks in other frameworks as "Known message attack" or "Known original attack", in the Simmons' prisoner problem. In this research paper, the study of topological properties of CI S2 is enlarged by describing this scheme as iterations over the real line, and investigating other security properties of topological nature as the Lyapunov exponent. Results show that this scheme is able to withdraw a malicious attacker in the "Estimated original attack" context too.