Method Of Constructing Digital Chaotic Systems On Finite Automaton And Its Applications

Chaotic systems are widely used in cryptographic design because of their highly consistent dynamics and cryptographic design criteria.However,most chaotic systems are implemented on finite automata.It is precisely because of the limitation of accuracy that the output sequence of the chaotic system will present the problem of dynamic degradation,and the excellent characteristics of the original chaos will no longer exist,thus constituting a considerable hidden danger to the chaotic-based cryptosystem.In this paper,a method of constructing digital chaotic system based on external feedback chaotic anti-control is proposed to overcome the degradation of chaotic system dynamics.Based on this method,a pseudo-random number generator and an image encryption algorithm are proposed.Most of the existing methods to overcome the dynamic degradation of digital chaotic systems are to improve the statistical characteristics of their output sequences,and only to improve the statistical characteristics of their output sequences can not achieve the desired dynamic performance of sequence signals in cryptography.By introducing a continuous chaotic system,a digital chaotic system based on external feedback chaotic anti-control is designed.The numerical simulation of the established system is carried out to verify that the chaotic sequence has good dynamic characteristics and high complexity.A new chaotic pseudo-random number generator is designed by using the digital chaotic system.The output sequence generated by the chaotic pseudo-random number generator is analyzed comprehensively by NIST-SP800 statistical test.The numerical simulation results show that the output sequence of the chaotic pseudo-random number generator has good performance in randomness,correlation and security.It can be used as the key stream encrypted in the cryptosystem and applied to the sequence cryptosystem and other related information security.In the field.Based on the previous theoretical knowledge and research results,the key stream generated by chaotic pseudo-random number generator is further used to encrypt digital images.The numerical simulation results show that the random sequence of the pseudo-random number generator can be used as a good key source and can effectively encrypt the image.