Chaos-based cryptosystem on DSP

We present a numeric chaos-based cryptosystem, implemented on a Digital Signal Processor (DSP), which resists all the attacks we have thought of. The encryption scheme is a synchronous stream cipher. Its security arises from the properties of the trajectories in a chaotic attractor, reinforced by the use of a nonlinear non-invertible two-dimensional map, the introduction of jumps between successive points of the orbits and the retaining of only one bit of the representation of real values. We describe the results obtained through a cryptanalytic study, we detail how to adjust the different parameters of the cryptosystem in order to ensure security, and we apply the NIST (National Institute of Standards and Technology) standard tests for pseudo-randomness to our construction. The originality of this work lies in the end in the way we were able to improve the security of our system, so that it is from now on possible to envisage the use, in more general cryptographic purposes, of other recurrences than those classically employed.