Chaotic bit sequences for stream cipher cryptography and their correlation functions
Tohru Kohda, Akio Tsuneda · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1995
Two types of balanced binary sequence have recently been defined, referred to as a chaotic threshold sequence and a chaotic bit sequence, each of which is obtained from chaotic real- valued orbits generated by nonlinear maps. This paper presents a stream cipher system whose running-key sequences are threshold and bit sequences generated by Chebyshev polynomials. Such a system has the following characteristics: (1) Chebyshev threshold and bit sequences can easily generate unpredictable i.i.d. binary random variables; (2) The correlation properties of ciphertexts are at least as good as those of the standard block ciphers, DES and FEAL. Since portable ANSI C permits us to implement such a cipher system in the floating-point environment, Chebyshev threshold and bit sequences are excellent choices for running-key sequences in stream cipher cryptography.