Research On Chaotic Image Encryption Algorithm Based On Improved RSA

The rapid development of the Internet plays an important role in today’s era,and it brings people a simple and fast way of life.However,the development of information has two sides.While bringing convenience to people,the problem of information leakage is becoming more and more serious.The high redundancy of image data and the strong correlation between adjacent pixels make traditional text cryptography systems inefficient and insecure when applied to digital images.Therefore,more effective and secure image encryption algorithms are particularly important.important.Based on the study of common chaotic systems,this paper proposes a new chaotic map,and combines the asymmetric encryption system in the text cryptography system to design a new image encryption scheme.The specific content is as follows:(1)Aiming at the limitation of one-dimensional Chebyshev chaotic map,an improved two-dimensional Chebyshev chaotic map is proposed.This map makes its structure more complex by extending the original one-dimensional map to a highdimensional map and adding system parameters.Second,the introduction of the sine function further increases the computational complexity of the mapping.Then,aiming at the periodic shortcoming of traditional Arnold scrambling,the non-linear improvement of its scrambling equation is carried out to make it have better scrambling characteristics.Based on the improved Chebyshev map and the improved Arnold scrambling equation,a digital image encryption scheme is proposed.The scheme first uses the RSA algorithm to generate a pair of public and private keys,then randomly selects six parameters as the key stream,and uses the public key to encrypt the key stream.Then,an improved Arnold scrambling is performed on the plaintext using keystream parameters to reduce the correlation between pixels.Then the key stream parameters are input into the improved chaotic map to generate a chaotic sequence,which is used to perform XOR diffusion on the scrambled image.Finally,the image is scrambled again to enhance randomness.Experimental results show that the proposed encryption scheme can effectively resist plaintext attack,differential attack,statistical analysis and other attacks.(2)Aiming at the efficiency problem of RSA algorithm,an improved random incremental search algorithm and a method of replacing traditional high-order twoprime numbers with low-order four-prime numbers are proposed to optimize the efficiency of RSA algorithm.Combining the improved RSA algorithm with the improved two-dimensional Chebyshev map in(1)above,an image encryption scheme is proposed.The scheme first extracts the plaintext pixel value from the plaintext image to calculate and generate the key stream,and then encrypts the key stream through the improved RSA algorithm.Compared with the random key stream encrypted by the traditional RSA algorithm,the key stream has better Security and plaintext dependencies.Then the key stream is brought into the improved Chebyshev map to generate chaotic sequence.Use the chaotic sequence to scramble the row and column cyclic displacement of the plaintext image,and then perform XOR diffusion on the scrambled image to change its pixel value,and finally perform the bit crossexchange position on the pixel value of the diffused image in turn chaos.Experimental results prove that the encryption scheme performs well in resisting plaintext attack,differential attack and noise attack.