The Applications And Research Of Image Encryption Algorithm Based On Chaotic Maps

Some basic knowledge of the chaos’s theory and concepts of cryptography hasbeen introduced in this dissertation, and also a little analysis about the close relationshipbetween the chaotic systems and the encryption systems of the cryptography has beendone. On the basis of this relation, a few study about algorithms have been studied.Aiming at the defects which exist in such image encryption algorithms that onlyuse the significant properties of chaotic systems， such as sensitivity to controlparameter and initial condition， to scrambling and diffusion，and random likebehavior， a new image encryption way that has connection with the pending plainimage has been put forward in this article. Firstly, partial plaintext information isextracted， which is used to dominate the engender of keys that planed for encryptingthe plaintext， then in the process of encryption the feature of the binary is carried onblock cipher， finally a diffusion encryption for above image is further treated.Theoretical analysis and simulation demonstrate that the algorithm has a big key space，and it’s cipher image is very sensitive to keys， so it has a good ability of anti-plaintextattacks and anti-statistics attacks， and is more safety than only scrambling anddiffusing for image，moreover the experimental results is very satisfactory，thus it canbe widely used in the field of information security.In this dissertation, spatiotemporal chaos system is also put it to encrypted image.The basic idea give the initial values to chaos system and by which we get a matrix,which characterized by both rows and columns are chaotic sequences, then it is used forimage encryption. During the process of the encryption, the first step is changing theimage matrix to a new binary matrix, and sort the rows of the matrix that we first get,and then according to the corresponding sequence we get, binary image matrix will besorted, and then the same work will be done in pace with the column. At the last, thechaotic sequence which generated by a simple one-dimensional chaotic was used fordiffusion encryption. The experiments show that the algorithm has good results, whichhas strong robustness and can resist statistical attacks, entropy attacks and correlationattacks.And finally, a summary of the full text is given, and also prospects the problem thatstill exist that need to be continue studied.