Research On Anti-Degenerate Chaotic Stream Cipher

With the rapid development of Internet technology,computer technology and information technology,our way of life and work has changed a lot.Therefore,the importance of information security is more and more known.Cryptography is one of the main ways to ensure information security,so it has gradually become the focus of many scholars.The main characteristics of chaos are determinacy,unpredictability and initial value sensitivity,which coincide with lots of requirements of cryptography.Chaos Cryptography has been developed for 30 years since it was first proposed in 1989.Chaos Cryptography has the advantages of simplicity,high efficiency and security,so it has become a hot spot of many scholars since it was proposed.Many excellent research results of Chaos Cryptography have been proposed,but there are still some problems to be solved.Among many problems,the degradation of dynamic characteristics caused by the limited precision effect of digital chaotic system has the most serious harm,which directly affects the security of chaotic system in cryptography.The research goal of this paper is to propose a method that can configure the continuous chaotic system without degradation,and the corresponding chaos quantization method.Finally,the obtained chaotic binary sequence is applied to the sequence cipher algorithm,and good results are achieved.The main work and innovation of this paper are as follows(1)Firstly,this paper introduces the research background and development status of cryptography,explains the main analysis attack methods of cryptography and the security of cryptography,describes the basic definition and development process of chaos theory in detail,and introduces several common chaotic maps.In addition,analyzed and studied the degradation of dynamic characteristics caused by the limited precision effect of digital chaotic system,and the common methods to overcome the degradation of chaotic system are briefly described.(2)In this paper,a new method based on matrix eigenvalue assignment is proposed to construct a continuous time chaotic system with multiple positive Lyapunov exponents.By designing a linear feedback controller,any system can be configured as an asymptotically stable linear system with the stable focus as the origin,and then multiple positive Lyapunov exponents can be configured by designing a nonlinear feedback controller.Compared with the existing algorithm,for any controlled system,this method can systematically configure the Lyapunov exponents of the controlled system to make it a non-degenerate chaotic system.(3)In this paper,the quantization scheme of chaos system is studied and analyzed,several commonly used quantization methods are introduced,and a set of quantization scheme is designed by introducing two irreversible functions,based on multi value quantization and threshold quantization.The scheme has good discrete effect and good quantization speed.The output sequence of the non-degenerate chaotic system configured in this paper is transformed into the chaotic binary sequence by this scheme.The randomness of the obtained sequence is tested and compared with the general chaotic sequence.It is proved that this sequence has better randomness than the general chaotic sequence,which shows that this quantization scheme has good quantization effect.(4)At the end of this paper,a chaotic sequence cipher algorithm based on non-degenerate chaotic system is proposed.In Matlab,the algorithm is verified by simulation,and the encrypted ciphertext is compared with the unencrypted plaintext,this algorithm has good 0-1 balance,discreteness and initial value sensitivity,which proves that the sequence cipher algorithm based on non-degenerate chaotic system has good encryption performance.