Design and Efficient Implementation of a Chaos-based Stream Cipher
Résumé
We designed and implemented a stream cipher cryptosystem based on an
ecient chaotic generator of nite computing precision (N = 32). The proposed structure
of the chaotic generator is formed by a Key-Setup, an IV-Setup, a non-Volatile memory,
an output and an internal state function. The chaotic generator uses internal feedback
mode and the generated keystream is used for secure stream ciphers. The cryptographic
complexity mainly lies in the internal state containing two recursive lters, with one,
two or three delays. Each recursive lter includes a perturbation technique using a linear
feedback shift register (LFSR). The rst recursive lter includes a discrete skew tent
map, and the second one includes a discrete piecewise linear chaotic map (PWLCM). The
chaotic generator is implemented in sequential and parallel versions using Pthread library.
The proposed Stream ciphers have a very good performance in terms of security and
execution time. The parallel version of the proposed chaos-based stream cipher is faster
than the eSTREAMS project, and other known chaos-based stream cipher when size of
data is big. Security performance of chaos-based stream cipher is analyzed, cryptanalytic
analysis and statistical tests such as Histogram with Chi-square test, correlation and NIST
test are applied. Experimental results highlight the robustness of proposed system. The
security of the implemented stream ciphers is investigated by applying several software
security tools.