Research On Image Information Encryption And Hiding Algorithm Based On RSA And DCT

Digital image has a very intuitive visual effect,which is one of the most widely used digital data formats.It can be transmitted to any corner of the world at high speed.In addition,digital images also have great potential and additional information,and there will be risks in the process of storage or transmission.Therefore,the protection of image information becomes particularly important.Based on the chaotic system and asymmetric encryption system,this paper studies three image encryption schemes.The main contents are as follows:Based on the generalized Arnold map,a new image encryption scheme is proposed.First,RSA algorithm is used to generate a pair of public and private keys.Then,four randomly selected positive integers are encrypted with the public key,and the parameters of the generalized Arnold map are calculated and generated.Secondly,the key stream is used to perform XOR diffusion on the plain image,and then the scrambling operation is used to reduce the correlation between pixels.Finally,perform the diffusion operation again to enhance the randomness.The difficulty of factoring large integers at present ensures the safety of this scheme.At the same time,two generalized Arnold maps are used to generate the key stream,which expands the key space to resist brute force attacks.A new image encryption algorithm is designed by combining quantum logistic map with cellular automata.Quantum chaotic map is used to generate the key stream with strong randomness,and the scrambled sequence is processed by cellular automata.In the encryption process,the key stream is used to shift the pixel of the image,and then the diffusion operation is performed after scrambling.In order to increase the security,the final encryption effect is realized through multiple rounds of encryption of the encryption process.Among them,the generation of initial value of chaotic system is related to the plain image,which can resist plaintext attack.According to the experimental results,the cipher image has evenly distributed pixel values,which is suitable for the confidential communication of the image.An asymmetric image encryption scheme based on RSA and DCT is designed.The initial values of the chaotic system are calculated by using the eigenvalues of the plain image and the values of the public information.The key stream generated by the chaotic system is involved in the encryption process.First,the image pixel position is scrambled.Then,the discrete cosine transform is used to transform the spatial image information into the frequency domain,and the discrete cosine transform coefficients are scrambled.Finally,the diffusion operation is used to enhance sensitivity.The test results show that the algorithm is sensitive to both plain and key,and has the ability to resist attacks such as cropping and statistical analysis.