Research On Financial Image Information Encryption Based On Hyperchaos

In the process of information society,information security has been paid more and more attention.Information security is not only related to personal privacy,the interests of enterprises,but also closely related to national security.In the financial field related to the development of national economy and people's livelihood,information security is particularly important.The frequency of financial information being attacked is much higher than other information,and the security of financial information is seriously threatened.It is important and urgent to protect the security of financial information.Encryption is one of the important ways to protect the security of financial information,which can improve the security of financial image information in the process of storage and transmission.In this paper,hyperchaos system with higher security is introduced into the field of financial information security,and two different encryption algorithms are designed to encrypt financial images,aiming at designing encryption algorithms with high security and efficiency.The first algorithm uses the pixel value of plaintext to set the control parameters of hyperchaotic system.Four chaotic sequences are generated by fractional Chen hyperchaos.The plaintext is scrambled by two chaotic sequences in DWT domain,and then transformed by S-box which is processed by chaotic sequence.Finally,the ciphertext is obtained by two-way exclusive or cyclic left shift diffusion between the ciphertext and chaotic sequence.In algorithm 2,a set of 256 bit hash values of plaintext are obtained by sha256 function.After being processed,they are brought into the formula designed by ourselves to obtain the initial value of Hyperchaotic Lorenz system,and then four chaotic sequences are generated.Firstly,three-dimensional Arnold bidirectional variable parameter scrambling is used for plaintext,and then the S-box after being processed by chaotic sequence is used for substitution.Finally,two chaotic sequences are used to select cellular automata We get the ciphertext image after diffusion.Through experimental simulation and performance analysis,it can be proved that the two algorithms have achieved good encryption effect,not only strong sensitivity,large key space,but also can effectively resist attacks,ensure the security of financial image information,and improve thesecurity and efficiency.Both algorithms abandon the scrambling diffusion method commonly used in image encryption,but use the scrambling substitution diffusion method,which increases the complexity of the algorithm,so that the algorithm can achieve the same security level as the common algorithm with only three iterations,and improve the encryption efficiency.The initial value of hyperchaotic system in the two algorithms is determined by the quantization and decomposition of plaintext pixel value,which is more flexible and changeable than the commonly used self-set initial value.It can achieve one density at a time and improve the difficulty of decoding.The two algorithms use different hyperchaos,and the chaotic sequences are used in scrambling,substitution and diffusion,which makes every part of the algorithm chaotic,the results are more random and the security is higher.Compared with algorithm one,algorithm two is more complex,and the performance analysis result is slightly better than algorithm one.However,because of its difficulty,algorithm one is better in running time.In practice,the algorithm can be selected according to the security level of financial information to achieve the optimal choice of security and running time.