Research Of Image Encryption Technology Based On Chaotic Theory

Along with the development and the rapid spread of the computer andnetwork communication technology, information security has become more andmore closer with our daily life. And image is a very important transportmedia,image encryption has become more and more attented by people. Becauseof the characteristics of the image itself,traditional encryption methods are not tobe good candidates for image applications. Because chaotic systems have thesensitivity of initial value, ergodicity, classes randomly characteristics so that itapplies to confidential communications with the borned condition, so the chaoticis applied to image encryption and attracted wide attention. Accomplishments tochaotic encryption of image in this paper were presented as follows:Firstly, in the based of the analysis of one-dimensional Logistic map, fromthe convenience, security and usability point of view,this paper first presents animage encryption algorithm based on one-dimensional chaotic sequence, thealgorithm uses one-dimensional random sequence generated by Logistic map toencrypt image. The main feature of this algorithm takes advantage ofone-dimensional mapping, encryption algorithm is concise and the speed ofencryption is very fast.Secondly, in the analysis of the lack of one-dimensional chaotic system, thealgorithm is improved,an new image encryption algorithm based oncombinations of chaotic key sequences is proposed. Algorithm first introducesthe generation and selection method of the combination of chaotic sequences,then describes the scrambling algorithm and alternative encryption algorithm.Image scrambling algorithm using two different chaotic sequence correspondingto the scrambling algorithm, depend on the conditions of the introduction of thedecision or not to choose the different scrambling sequence. The pixel valueencryption use a block encryption and dual encryption to encrypt the values of the pixels. Simulation results show that the algorithm can resist various attacks.Finally, this paper presents an encryption algorithm based on three-dimensional Lorenz chaotic system. First, scramble the image pixel location, andthen encrypting the pixel values of image.In the encryption process of the pixelvalue, the key sequence generation algorithm generates chaotic key sequence andthe encryption algorithm applys cipher feedback algorithm, the plaintext spreadthroughout the ciphertext. The results show that encrypted image that use thealgorithm can achieve good results.