Research On Chaos Based Image Encryption Algorithm

Chaos refers to the non-linear deterministic dynamical systems appear similar to random process, this process is neither a cycle, then the non-convergence, and the right has a very sensitive dependence on initial values, chaotic systems possess these basic characteristics of just able to meet the confidentiality of communications and cryptography, the basic requirements. It research on chaos based digital image encryption algorithm.The basic knowledge of cryptography and the basics of chaos theory have been introduced. It included the password system model, the basic requirements of cryptography, security, password model, common password attack methods, chaotic encryption features, the image of the commonly used chaotic encryption method, common chaotic systems.Because low-dimensional chaotic system has simple in form, resulting in shorter time chaotic sequence, etc., but the key space is small, the sequence complexity is not high. The high-dimensional, such as cat map, Lorenz chaotic system, has complex structure, multi-output, and large key space. So we proposed a novel image cryption agrithm based on the cat and Lorenz chaotic system.The cat map will produce a fixed point (0,0), and encryption keys only depend on the initial value of chaotic systems and have nothing to do with plaintext, so it is easy to be exploited by an attacker, because it should make the data stream not only depends on the chaotic system at the same time with the explicit about. Therefore, we presents a complex chaotic system based on a new image encryption algorithm, the algorithm in the complex chaotic system to keep all the subsystems of the chaotic characteristics of the dynamic behavior than a single subsystem is more complex and experimental results also show that the algorithm has good cryptography features.The Liu chaotic system generates the sequence of complexity and randomness are not satisfactory. For advanced the chaotic array complexity and random-like, firstly, we have improved the Liu chaotic sequences, which makes the chaotic sequences have the ideal random characteristic property. Then the image was encrypted based on the improved Liu chaotic system sequences, and a new image encryption algorithm was proposed. The experiment results showed that the algorithm has stronger resistance for the exhaustion, count attack, the known-plaintext attack, and it is of high security.