The Research Of Chaotic Image Encryption Schemes And Related Problem In Information Security

With the rapid development of information technology and multimedia applica-tion, multimedia information such as sound, image, video, etc has become an indis-pensable part of modern life. The security of multimedia information has become animportant issue in the field of mathematics, communications, information technologyand image processing. How to design a secure and reliable information security tech-nology becomes more and more urgent. Due to some intrinsic features of images suchas bulk data capacity, high redundancy and high correlation, so, traditional encryptionschemes (DES, RSA, IDEA, AES, etc.) is not suitable for image encryption. Chaos isa complicated, unpredictable and seemingly random behavior in a deterministic nonlin-ear system. It has become a vital choice for image encryption because of its sensitivityof initial value and control parameter. In this paper, we design several kinds of imageencryption algorithm with the help of chaos, hyper-chaos, composite chaotic systemtheory and number theory knowledge. The main content of the paper are summarizedbelow:(1) Considering the traditional image encryption structure, permutation and diffu-sion are two independent procedure, we design an image encryption algorithm with twoconsecutive diffusion process by Chebyshev chaotic map and quadratic residue cipher.Every pixel is diffused twice by scanning the plain image only once, the experimentalanalysis shows the efficiency and security of the algorithm. (2) We analyze the good chaotic property of2d hyper-chaos discrete dynamic sys-tem, and we establish a classic Fridrich permutation-diffusion image encryption algo-rithm, and utilize2d Hyper-chaos discrete nonlinear dynamical system to scramble theimage pixel position twice, then the Chinese remainder theorem is used to change theimage information distribution by changing the pixel value.(3) We study the sensitivity to initial value and control parameter of composite dis-cretechaoticsystems, andprovideanew2dcompositediscretechaoticsystem. Consid-eringtheredonotexistinformationexchangebetweendifferentpixelsinpixel-levelim-ageencryptionalgorithm,abit-levelimageencryptionalgorithmusingtwo-dimensional2-d Logistic map and compound chaotic system are presented. Compared with the tra-ditional pixel-level image encryption algorithm, the information of different pixels isexchanged in this bit-level permutation and diffusion procedure. It can strengthen thesecurity of the pixel-level algorithm.(4)Weproposeanimageencryptionalgorithmwithabit-levelpermutationbygen-eralized Arnold map and pixel-level diffusion by affine cipher. In permutation phase,we scramble the plain image according to a random search way by generalized Arnoldmap in row direction and column direction, respectively. In the diffusion stage, we em-ploy affine cipher to do the pixel-level image diffusion. The simulation results show theproposed algorithm effectively enhances the Fridrich image encryption architecture.(5) We study the importance of the random number generation problem in imageencryption technology and cryptography field. A novel kind of iris and chaotic-basedrandom number generator (ICRNG) is developed from the unique randomness and ex-ternal noise(which is very tricky in biometrics authentication and identification)in the.This method combines biometric feature extraction and random number generation ina novel way. Experiments demonstrate that ICRNG not only has good performance ingeneration speed, but also has a good randomness performance, which means ICRNGcombines the advantages of pseudorandom number generator and true random numbergenerator.