Research On Symmetric Image Encryption System Based On Chaotic Map

In the information age,digital images have become an important medium for information transmission for their strong intuitiveness and the ability that carrying large amount of information.With the rapid development of Internet technology,a large number of digital images carrying sensitive information are transmitted on a common channel,which bring increasing serious security problem,especially for digital images related to medical,military or commercial affairs.In recent years,due to the unique characteristics of chaotic systems,the research of chaotic-based digital image encryption system has become a research hotspot in the field of information technology.However,many chaotic-based digital image encryption systems have drawbacks such as failure to effectively resist the choice of plaintext/ciphertext attacks and low encryption efficiency.This paper focuses on overcoming the shortcomings of existing digital image encryption systems and researching digital image encryption systems with high efficiency and high security.In this paper,three new digital image encryption systems based on chaotic mapping are proposed,which are all plain-related image encryption systems,and the detailed experimental analysis of three systems is given.The experimental results show that all three systems can achieve high security and high efficiency.The firsrt one is a symmetric plaintext-pelated color image encryption system based on bit permutation.In contrast with the similar studies,a plaintext-related random access bit-permutation mechanism(PRRABPM)is presented.This method is used in the permutation stage to shuffle the RGB components of a color image at the same time,making these three components interact with each other.Furthermore,the key streams used in random access bit-permutation mechanism operation is extremely dependent on plain image in an ingenious way,which makes the encryption system sensitive to key and original images.Thus,the proposed encryption system can efficiently resist the chosen-plaintext and chosen-ciphertext attacks.The second one is a simple chaotic map-based image encryption system using both plaintext related permutation.In the permutation stage,the values of the parameters of cat map are related to plain images.It means that different original images correspond to different parameters.Thus,the permutation stage is related to plain image.In the diffusion stage,the first encrypted pixels' value is determined by both secret keys and the parameter of cat map.Furthermore,we use previously encrypted pixels to encrypt current encrypting pixels.Thus,the diffusion stage is also related to plain image,which can achieve high key sensitivity and plaintext sensitivity to resist chosen/known plaintext attacks or differential attacks effectively.In addition,plaintext related permutation and diffusion operation is performed for only one round to process the original image to obtain the cipher image.Thus,our scheme has high efficiency.The second one is a symmetric color image encryption system with permutation-diffusion simultaneous operation,which is a new plaintext-related cryptosystem in which the permutation-diffusion operation is performed in a simultaneous manner.More specifically,the simultaneous permutation-diffusion operation(PDSO)leads to the confusion and diffusion interacted each other,and thus generates better security level as well as higher efficiency of encryption process.The proposed encryption scheme only requires a single PDSO in the corresponding encryption process,in which the first encrypted pixel's position in cipher image is randomly chosen and its value is determined by both pixels in the original image and the elements in key-streams obtained by three one-dimensional chaotic mappings,and the current encrypting pixel's value is set to be associated with the previous encrypted pixel.Under our framework,the proposed encryption scheme is highly sensitive to minor differences in both secret key and plain image,resulting in resisting chosen/known plaintext attacks effectively.