Design And Application Research Of Four-dimensional Discrete Chaotic System Based On FPGA

In recent years,with the rapid development of semiconductor technology,the highspeed chip designed has extremely powerful computing power,and can gradually crack some encryption systems.Therefore,in the digital age,people are increasingly worried about the security of digital information.Chaotic system is widely used in the field of information encryption because of its good nonlinear dynamic characteristics.When using digital hardware equipment to realize chaotic system,it will lead to the degradation of some characteristics of chaotic system,so that there are some security problems in the application of chaotic pseudo-random sequence in the field of information encryption,which hinders the development of digital chaotic hardware encryption.Therefore,the research of digital chaotic system and its hardware encryption is of great significance in the field of information encryption.Firstly,a four-dimensional discrete chaotic system is designed according to the inverse Jacobi matrix method.A new four-dimensional discrete hyperchaotic system with four positive Lyapunov exponents is designed based on the improvement of Sine chaotic map,and a number of simulation analysis are carried out for the chaotic system.It is found that Cosine map can also be applied to improve the chaotic system,so a new design method of high-dimensional discrete chaotic system is proposed.Then,based on the improved four-dimensional discrete hyperchaotic system,a chaotic sequence generator based on FPGA is designed,and a chaotic image encryption system is further realized.The system mainly includes key transmission module,chaotic sequence generator module,chaotic image encryption module and LCD display module.In this paper,the chaotic pseudo-random sequence generated by the hyperchaotic system is tested by fifteen NISTSP800 standards.It is proved that it has good randomness and is suitable for the field of information encryption.The chaotic image encryption algorithm uses the key sequence composed of different chaotic pseudo-random sequences to perform XOR operation with the plaintext image sequence,and adds the ciphertext feedback operation.This algorithm not only simplifies the encryption steps,saves hardware resources,but also obtains a good encryption effect.Finally,a number of security comparative analysis are carried out.The average value of ciphertext image information entropy in this paper is 7.9971 and the average value of adjacent pixel correlation coefficient is 0.0011.It can be clearly seen that the chaotic image encryption system designed has high security in this paper.