The Study About Satellite Image Encryption Technology Based On Baker Map Of Chaos Theory

Traditional encryption technology is well applied in text encryption. But due to some intrinsic features of images, such as bulk data capacity, high correlation among pixels and incomplete decryption also has visibility... traditional encryption algorithms are not suitable absolutely for image encryption.Some recent researches show that the class of two-dimensional maps uses features of images and can be well used in image encryption. The initial idea came from Shannon's classic encryption paper. The maps are the process of stretch-and-fold which permute the positions of image pixels and can be used in image encryption. These image encryption algorithms have high security and rapid encryption speed. They have good prospects.This paper analyzes and simulates encryption algorithms of two-dimensional maps with Baker map. Baker map include Version A and Version B. The paper formulize Version B of Baker map. Based on the formula, this paper designs an algorithm to enhance the security of encryption. Simulations show it was valid.This paper proposes a new Line maps. The new maps can encrypt images by the process of stretch-and-fold. The maps are invertible and consist of the left Line map and the right Line map. In this paper, the algorithms of the Line map for square image and for rectangle image are introduced respectively. Simulations and analyses prove it has a high security, rapid encryption speed and some other nature. Using the map to encrypt Satellite images, the speed of this encryption algorithm is 10 times more than DES. At the same time, the image encryption algorithm has enough security.The advantages of chaotic maps encryption algorithms can be described as follows: the map can be formulated using equations; the map is invertible; the image encryption and decryption based on the chaotic maps have no message loss; suitable for hardware realization; the key can be determined among integers and has no any other limit, that means the key length can be any long number to satisfy different security requirements; the size of the ciphered-image using the map is equal to that of the plain-image; suitable for the encryption of large size images, such as satellite images . So it is valuable for images encryption.