\section{Conclusion}
This work has reviewed the evolution of chaos based data hiding schemes.
The whole class of  algorithms has been formally presented and implemented.
Two watermarking processes ($\mathcal{CIW}_1$ and $\mathcal{CIS}_2$) have been
recalled; the former is a one-bit approach whereas the latter allows to 
embed any message of reasonable size. 
The two schemes have been 
theoretically evaluated: both are stego-secure and verify the 
topological expansiveness property.
These two scheme has been practically evaluated: they have been proven to be
robust against a large class of attacks.
Finally, $\mathcal{DI}_3$ which  adapts the $\mathcal{CIS}_2$ scheme to 
the steganography field. It capacity to resists to steganalysis has been 
evaluated and has shown promissing results. 

To summarize, this works has presented three 
chaos based data hiding schemes and has study their security.
In a future work we plan to combine these approaches to other data hiding 
schemes to take benefit of their best behaviors: 
for instance the pixel selection may be achieved by state of the art 
distortion function and modifications may be delayed to chaos 
based schemes.
  