Research On Stream Cipher Algorithm Based On Piecewise Chaotic Map

With the advent of the era of big data,information security has attracted more and more attention.Because the security of traditional encryption algorithm is threatened by various novel attack methods,it is urgent to design new secure and efficient encryption algorithms.Chaos is a disorder phenomenon in nonlinear dynamic system.Due to its characteristics of nonlinearity and pseudo-randomness,chaos has attracted the interest of cryptography researchers,and it has been widely used in various fields of cryptography and achieved fruitful results.In chaos-based cryptography,chaos-based stream cipher is an important branch of it.The performance of the chaos-based stream cipher algorithm depends heavily on the performance of the chaotic system used.In the current research,a common problem is that the security and the availability of stream cipher algorithm can not reach a good balance.Therefore,how to construct a chaotic system with good chaotic performance and high computational efficiency,and design a safe and efficient stream cipher algorithm on this basis has become a research hotspot.To this end,this thesis conducts further research on this issue.The main work and research contents are as follows:1.To overcome the shortcomings of Piecewise Logistic map(PLM),this thesis proposes a new chaotic map which is called Parameter Coupled Piecewise Logistic map(PCPLM).Then,using it as the basic unit,a novel four dimensional chaotic model,4D PCPLM,is constructed.The experimental results show that the 4D PCPLM has good chaotic cryptographic performance.2.Based on 4D PCPLM,this thesis proposes a novel chaotic stream cipher algorithm.Theoretical analysis and simulation tests show that the algorithm has excellent randomness and high computational efficiency.3.In order to improve the chaotic performance of Cubic map.In this thesis,a new chaotic map,Piecewise Cubic map(PCM),is proposed.The simulation results show that PCM has very complex chaotic behavior.4.According to the mathematical derivation of Lyapunov exponent,this thesis theoretically proved that the chaotic performance of PCM is better than that of Cubic map.5.A stream cipher algorithm based on PCM is proposed.Theoretical analysis and numerical experiments show that the algorithm is safe and efficient.