Research On Image Information Encryption Algorithm Based On Chaotic System

Image encryption is the most effective method of multimedia security protection,and it is widely used in data hiding,security authentication and content protection.In recent years,with some scholars' in-depth research on chaotic encryption algorithms.It will replace the traditional encryption scheme and become the first choice of new image encryption algorithm.Therefore,more and more image encryption algorithms combined with chaos system are constantly proposed,but these technologies are not long time consuming,clear text sensitivity is not strong enough,or chaos system design is not good enough.For example,some encryption algorithms use continuous hyperchaos as the choice of encryption chaos system.Although the randomness of chaotic sequence is guaranteed and the security of encryption algorithm is improved,but the time cost is too high.Therefore,it is urgent to design a new encryption algorithm,which can improve the sensitivity of plaintext and reduce the time cost.In this paper,we design new encryption scrambling and diffusion algorithms,and propose several new image encryption schemes.Compared with the existing encryption algorithms,the main characteristics are to improve the sensitivity of key and the sensitivity of encryption algorithm to plaintext image.The specific research contents include:1.A scheme of image encryption with bit level scrambling multiplication diffusion(BLSMD)structure is proposed.Firstly,the input image is divided into 8 bit planes,and then it is randomly divided into three parts.Secondly,the scrambling process of each part is realized by using binary tree,flipping and circular index respectively.It can not only effectively replace pixels,but also displace the bits in each pixel.Finally,the scrambling results are diffused by GF(257)domain multiplication to obtain the encrypted image.Scrambling and diffusion operation depend on the key and clear text image,which will greatly improve the security of the algorithm.2.Introduces an image encryption algorithm based on cyclic index table scrambling and partition diffusion(CITSPD).Firstly,the circular index table is obtained by generating the datum sequence,cyclic shift and transposition.Secondly,the plaintext image is transformed into wavelet coefficients and the circular index table is used to scramble.Then,the image is disturbed by different noises,and further divided into four sub-regions.Finally,the sub-region is diffused in the forward and reverse regions,and the encrypted image is obtained.The main features of the algorithm are: Chaos key flow and encryption process are highly sensitive to plaintext,which can effectively resist the attack of clear text and known plaintext,by designing different reverse diffusion and forward diffusion schemes,it can effectively resist noise attack;by increasing pixel value and reducing large pixel value as much as possible,diffusion effect can be effectively enhanced.The experimental test and safety analysis confirm the superiority of the scheme.3.A scheme of image hiding encryption based on region pixel value scrambling and Huffman coding is designed.The scheme consists of two parts,scrambling diffusion structure encryption algorithm and carrier image based encryption image hiding.The scrambling part is based on the improvement of(CITSPD)scrambling method,which means that the pixel values in the block area are scrambled to other block areas to reduce the correlation between adjacent blocks,based on the parameter fine tuning method,an improved diffusion algorithm is proposed,which can effectively improve the performance of diffusion algorithm when the plaintext image and key are effectively combined,the encrypted image is hidden in the carrier image.Thus,the image information is encrypted safely.