Improving for chaotic image encryption algorithm based on logistic map

Encryption technology is an important measure to ensure the security of digital image, this paper´s main purpose is to research how to encrypt images by chaos. Based on analyzing traditional Logistic chaotic image encryption method, this paper proposed an improved encryption algorithm. The new algorithm produced nine chaotic sequences only by one secret-key, six sequences were used to scramble the position of image pixels, and the others were used to confuse and diffuse image pixels value. The algorithm was implemented by MATLAB 7.8. The simulation results and the performance analysis show that the algorithm has large secret-key space, high security, fast encryption speed and strong robustness. The algorithm uses only a logistic map, but achieves a multi-chaos encryption effect.