Medical treatment has always been an important part of people’s life.With the rapid development of electronic technology,more and more electronic devices are used in hospitals to assist diagnosis.The traditional management mode of patient data is no longer applicable.To this end,PACS(Picture Archiving and Communication Systems)system for electronic management,the patient’s various diagnostic results have been stored in the system in the way of digital images.Because these images contain patients’ personal information,it is easy to cause social problems if people access and view them at will.How to realize the safe storage and safe transmission of patient data has become a hot research field at present.This paper takes Dicom standard medical image as the research object,analyzes the encryption algorithm of this type of image,proposes a medical image encryption algorithm based on AES and chaotic sequence,and designs and implements the medical image encryption system based on this algorithm.The main work includes:First of all,through the systematic analysis of Rijndael algorithm,the characteristics and limitations of the algorithm are summarized:the algorithm is easy to implement,stable performance,strong key flexibility,high security,can effectively resist powerful attacks,differential and linear cryptanalysis,has good security and high efficiency.However,the algorithm is mainly used for one-dimensional data stream encryption,but has some limitations for image encryption.Secondly,Logistic mapping is extremely sensitive to the change of initial values and parameters,and chaos can be generated under certain conditions,Thus,a generator of pseudorandom numbers can be constructed.The real numerical chaotic sequence generated by Logistic mapping is transformed into binary chaotic sequence.The test results show that the binary chaotic sequence is an ideal random sequence and can be used in digital image encryption.Finally,in view of the medical digital image data,high redundancy and the characteristics of the strong correlation between pixels,the key of AES algorithm are exclusive or operation to realize image pixel values of the transform,S-box transform to complete the image instead of pixels,the pseudo random number generator to generate chaos sequence to determine the image pixel replacement of digits,An image scrambling encryption algorithm based on AES and chaotic sequence is proposed,which can better solve the encryption of digital image,and has the characteristics of sensitive to the key,large key space,good pixel diffusion of the encrypted image,which can effectively ensure the security of the encrypted image. |