Some tools for attacking secure communication systems employing chaotic carriers

We present a review of methods which can be used to uncover the information signal hidden using one of so-called chaos communication methodologies. All of the known secure communication methods employing chaotic carriers are shown to be of very low security. Hidden messages can be found using extremely simple reasoning and straightforward computational methods. We point out also that none of the methodologies proposed so far uses the properties of the chaotic signal. The only property exploited is the sensitivity (instability) of the transmitter/receiver pair to parameter and initial condition changes.