Research On Medical Image Encryption Based On Multi-chaotic Sequences And Steganography

In recent years,with the development of telemedicine technology,the issue of confidentiality of medical images has been particularly prominent.Therefore,the research based on medical image encryption algorithm is very important.In order to ensure the safe storeage and reliable transmission of information,researchers have proposed various types of security methods,of which cryptography and information hiding technology are the two most important technologies.Cryptography is to encrypt plaintext to hide information content,and information hiding technology is to hide the existence of information.In real applications,it is usually required to combine these two technologies to improve the security of the data.The combination of the technologies can not only provide confidentiality protection but also provide integrity protection.The contribution of the thesis are as follows:1)In order to ensure the security of medical images,this thesis proposes an image encryption algorithm based on Logistic chaotic image and hyperchaotic sequences.Firstly,a chaotic image with the same size as the orginal image is generated by using a Logistic chaotic map.Then the image are partitioned into different blocks and hyper-chaos sequencesare generated based on the image blocks obtained by partitioning the orignal image.Finally,the appropriate hyperchao weightsare selected for each image block based on the values of the corresponding blocks obtained by partitioning the Logistic chaotic image.The appropriate hyper-chao weightsare used in the operation of XORs to encrypte the image.2)In order to ensure the security of the above-mentioned encryption algorithm,RSA encryption algorithm is adopted to encrypt the initial values and the parameters of Logistic chaotic map and hyperchaotic map,and a PBE mechanism is proposed to manage the key of RSA so as to achieve more users friendly and more convenient effect.3)In order to facilitate the decryption,this thesis proposes an F5 information hiding algorithm.The RSA-encrypted ciphertext is embedded and hidden in the encrypted ciphertext image so that the decryption key is integrated with the ciphertext image and no additional transmission is required.4)This thesis also studies the security of medical images for mobile medicine and designs a secure scheme to ensure the security of the storage and transmission of medical images.We also descibe the implemention of the scheme on Andriod mobile phones.