Image Encryption Algorithm Research Based On Spatiotemporal Chaotic Mappings

with thefast development of the information technology and the network switchingtechnology,information security issues become increasing prominent The rapid developmentof information technology on information security requirements of the increasingly high,thenev~theories and technologies is urgently needed to enhance the security of informationexchange Encrypting the image data is one important means of ensuring secure transmission ofdigital images Image encryption is different from the text Because the image has a largeamount of information and strong correlation between adjacent pixels,the traditional text oftheencryption algorithm for DES,IDEA,RSA can not fully meet the needs of cryptographicsecurity．Chaos is a uncertain or unpredictable phenomena under certain conditions Sequencesgenerated by chaos is pseudo-random,not long-term prediction,in ideal condition with infinitecycles,mad can provide a huge key space,a non-cycle without convergence Most importantly,the chaotic map of the extreme sensitivity of the initial changes,only minor differences in theinitial state of the two chaotic systems will produce two completely different mad unrelatedvalues of chaotic sequence in a short time The safe mad fast image encryption based on chaoshas been widely studied Compared with the general chaotic maps,spatiotemporal chaos assuperior dynamic performmace,it has been applied to chaotic cryptography．Chaotic system isan extension of the space system,which show-s the time mad space behavior of nonlineardynamic Coupled map lattices(CMLs)often used as the basic model of spatiotemporal chaosThis paper introduces the history and development status of the image encryption based onchaos theory,and we investigate the basic principle and methods of digital image encryptionand cryptology．Because of the wavelet trmasform to reduce date redundancy and improve datacompression rates,image encryption algorithm based on wavelet trmasform is proposedMeanwhile,according to chaotic maps of pseudo-random,certainty and extreme sensitivity onsystem parameters mad initial conditions,Lorenz chaotic maps and CMLs combined with digitalimage encryption is proposed to construct a good image encryption algorithm In this paper,wavelet transform mad chaotic map is investigated A method of sequence generation based onwavelet transform and chaotic mapping is proposed And then sequences are used to scramble and diffuse image coefficients after discrete wavelet transform The key space analysis,the keysensitivity tests,scrambling analysis and histogram comparison experiments are organizedExperimental results show-that the chaotic sequence encryption and decryption algorithmsextend the key space,the ciphertext distribution,can overcome the low--dimensional chaoticdynamical systems vulnerable Ciphertext files with secrete high security,key is simple and SOon The security risks of image encryption based on one-dimensional Logistic map and CMLsare studied.