Continuous Chaos And Hash Transform-based Image Encryption Technology

With the development of the Internet and maturation of the digital signal processing technology, applications of digital imaging are prevalent and rapidly increasing today, such as digital TV, remote education and news picture etc. Transfer image data through networks is efficient and economical. But the main obstacle in the widespread deployment of digital image services in the Internet has been enforcing security. People hope that there are safe and secret encryption schemes to prevent important data from being stolen by hacker.In this paper, we first discuss some aspects about encryption theory, such as its history, classification, security and algorithm analysis. Then, we introduce the theory about chaos system and encryption based chaos, including some new developments on image encryption. But some traditional encryption schemes appear not to be ideal for image applications, such as DES, IDEA, RSA etc. So a new image encryption scheme based on chaos and hash function transpositions is presented.In the new image encryption system, image encryption is implemented by changing the position and value of every pixel. And the changing are dependent on the multi-dimension and continuous chaos system and hash function transpositions. Because the signals using in hash function are drawn out chaotic system, so it can enhance the security of encryption system. Simulation testing and theory analysis show that the key space is very big and encrypted image is sensitive to key ,and the tiny change of key will make big contrasts between original image and encrypted image. So the security of this algorithm is high and enough to resist various attacks.