Digital Secure Communications Research Based On Chaos

Chaos is a phenomenon deterministically and random-like of non-linear dynamic system. Chaos signal has the properties of very sensitivity to chaos system's initial conditions, wide frequency spectrum and noise-like, chaos signal can be regenerated exactly and freely, so it is broadly used in secure communications. In this paper, several kinds of technologies of chaos communications are studied based on analogical chaos signal. By using the knowledge of cryptology and by tracking recent research tendency of chaos communications, this paper put much energy into the researching of digital secure communications. Much computer simulations are done, and show that the new method can generate key sequences which match the requirements of secure communications, key sequences have the property of resisting attacking, key space is considerable large. Two ideas are presented to enhance the key sequences, compound attractor is introduced and be pilot studied. This paper concentrates on the following:1. Analogical chaos communications are studied. Information can be transported safely by adding to chaos signal. Enhanced methods of chaos communications have bright future of being used in real life because noise and aberrance of channel have little influence on them.2. Based on the research of digital chaos communications, a new method that generates key sequences by using more chaotic equations is presented. Based on attractor. characteristics of chaotic signal and the m sequences are involved to generate new key sequences. The key space is considerable large because of chaotic signal's high sensitivity to initial values. Results of computer emulation show that even very small difference can bring about great errors.3. Sequences must meet some requirements before they are used to encrypt digital information. In this paper, by testing the random and complexity properties of the new key sequences, large number of graphs and pictures are obtained, which prove that the new sequences have the ability of resisting attacking.4. In order to robust the key sequences, ideas of inserting and discarding are employed, this make the encrypted digital information cannot be picked-up easily, the random properties and the effective digital data transport efficiency are also clearly analyzed. Research shows that key information can be transported more safely.5. Compound attractor is presented and is piloted studied so as to enlarge key space, then giving out the ideas of how to expand the new method of generating key sequences. Types of pseudo-random sequences, attractor can be chosen more freely, which can bring lots of choices when generating key sequences.