Date Added: Jan 2010
Linear cryptanalysis methods are rarely used to improve the security of chaotic stream ciphers. In this paper, the authors apply linear cryptanalysis to a chaotic stream cipher which was designed by strictly using the basic design criterion of cryptosystem - confusion and diffusion. They show that this well-designed chaos-based stream cipher is still insecure against distinguishing attack. This distinguishing attack promotes the further improvement of the cipher. In recent years, chaos has been used to design ciphers. Chaotic systems are defined on real numbers and characterized by sensitive dependence on initial conditions and parameters, random-like behavior, which are desirable to ciphers. The early chaotic ciphers were designed by directly using the chaotic maps. These ciphers often suffer from security weakness.