Research On Digital Image Encryption Algorithm Based On Chaotic

With the development of the modern communications technology and network technology, image information has become an important carrier of information humans communicating. In order to ensure information security, a higher demand has been proposed about encryption of information properties of. Since image data is informative and high redundancy, which the text has good results in information encryption algorithm is not suitable for image encryption. Therefore, how to guarantee the security of digital image information has become into a research on topical issues.For the characteristics of Image data and at the same time for improving the efficiency and security of image encryption, the current the Chaos Theory has been used to many image encryption algorithms. Chaotic system is a highly complex nonlinear dynamic system, with pseudo-randomness and uncertainties, as well as the initial conditions and the extreme sensitivity of system parameters, and generated chaotic sequence with a non-cyclical and the class of stochastic characteristics. At the same time chaotic sequence has good password properties, and is very suitable for information encryption. Using chaotic sequences to encrypt image, encryption image has lot of Characteristics such as gray level distribution, adjacent pixels of the associated small, encryption effective and safe.This paper first introduces the definition of chaos, the basic concepts, characteristics and identification methods and several typical chaotic systems. In this paper, the current of several common image encryption methods have been studied. On this basis encryption algorithm -based Logistic chaotic map was proposed for digital image encryption. The algorithm uses two one-dimensional Logistic chaotic sequences combining dispersed images taken from original pixel to pixel separately and pixel scrambling encryption replacement value. Because the algorithm uses two chaotic sequences to encrypt image, improve the security of the algorithm. In addition, for the limitation of two-dimensional chaotic map image encryption algorithm applies only to a square image, this paper proposed an algorithm of image adding. The algorithm uses chaotic sequences of two values as a key addition to the addition of a rectangular image into a square image. Using the idea of image segmentation encrypt a square pixel image to scrambling encryption, the last using the proliferation of function to replace pixel value. Through the addition of a rectangular image can be realized based on two-dimensional chaotic map image encryption algorithm to encrypt a rectangular image.Using Matlab to carry out encryption and decryption experiments to the encryption algorithm based on Logistic chaotic map and image encryption algorithm based on two-dimensional chaotic map, and carried out a safety analysis, the results proved the feasibility and effectiveness of encryption algorithm.