Study On Image Encryption Algorithm Based On Chaotic System

With the rapid development and wide applications of Internet technology and media technology, more and more information has been quickly and conveniently transmitted through the network, at the same time there arouses the potential problems of the information security. Therefore, how to protect information security has become a hot topic. Encryption technology is the best method to protect information security, which is greatly practical and urgent to develop key technology.However, on one side, most encryption methods are designed for text information; on the other side, some encryption schemes are easily to be attacked. There are many disadvantages in traditional encryptions, and a lot of encryptions for images are put forward. In fact, there are more or less disadvantages in one signal encryption.This paper studies on chaotic technology and its application in digital image encryption. Chapter 1 is the introduction of this thesis. It gives the outline of the research work. This thesis firstly introduces the principle of image encryption in Chapter 2, which is useful for our understanding of following chapters, and later in Chapter 3 introduces the basic knowledge of chaos, including its concept, characteristics and models, then make analysis for several classical chaotic maps. These are the foundation of our research work.Because of the weak security of low dimension chaotic systems, in Chapter 4, we discuss an image encryption method which uses super high dimension chaotic system and combines traditional scramble encryption method, naming"A New Image Encryption Algorithm Based-on Lorenz System". In Chapter 5, we discussed a new image encryption algorithm based-on the Chua's Circuit system. We generate the real number value chaotic sequences by using the key value and disperse them into scramble transformation matrix, naming"An Image Encryption Algorithm Based-on Chua's Circuit Chaotic System". Finally the conclusion is given, including the advantage and disadvantage of the work.This paper analyses the image encryption algorithms from these aspects, including sensitive dependence on the key, capability of image resume, confusion degree, histogram and stability. The conclusion can be drawn that these algorithms can encrypt/decrypt image effectively, with the good effect of confusion, no distortion decrypted and high speed execution. At the same time, algorithms have the certain ability against destroying and noise.Both theory analysis and experimental test have proved the security of the proposed cryptosystems.