Research On Image Encryption Techniques Based On Hyperchaos System

With the rapid development of the network and the information technology, the information security and confidentiality of network becomes more significant and prominent. The characteristics of the chaotic system such a well pseudorandom,long inscrutability, high sensibility to the initial value, and a large number of non-periodic, and the chaos system high complexity and easy to realize, applies the chaos theory in the cryptology has become present domestic and foreign receives the attention the academic hot spot.Firstly, we introduced the chaotic theory and the principle of modern cryptography, and propose some new ideas in the application of chaotic sequences in cryptography.Secondly, based on the original hyperchaos system, a new four-dimension hyperchaotic system is proposed, and properties of the new hyperchaotic system is studied in detail,including the chaotic attractor phase diagram,the equilibrium ponit, Lyapunov exponents and nonlinear dynamics characteristics is proved that the new system is hyperchaotic. And the chaotic sequences of the correlation and the complexity is analyzed.Finally,using the chaotic sequence of the new hyperchaos produced, the image encryption scheme is researched.Based on the existing image encryption algorithm of the chaos theory, in view of the fact that th traditionl image encryption technology and the low dimension chaos encryption technology respectively had its limitation, compared with chaotic system the hyperchaos system have more positive lyapunov exponent and more complicated and thedynamical characterisics is hard to predict.based on the hyperchaos a new image encryption scheme is proposed,analyzing the detail description.The experiments are simiulated, and the various performance(inculding the key space and initial value sensitivity and statistual properties ane so on) is analyzed.The experiment results and security analysis shows that the algorithm can achieve cryptography required in confusion and spread of the purpose and the new scheme has stronger resistance for the exhaustion attack, count attack and known-plaintext attack, and it is of high security.