Abstract: In order to improve the security of image, aiming at the defects of traditional image analysis algorithm, such as weak ability resistance attacks and small key space, we proposed an image security analysis algorithm based on the fusion of chaotic system and shift register. Firstly, we analyzed security of image to find the limitations of single shift register and chaotic system. Secondly, initial value of chaotic system was determined by sequence generated by shiftregister, and a new pseudorandom sequece was generated by continuous iteration, and using pseudorandom sequence as key stream to encrypt image. Finally, we simulated image encryption effect and security analysis. The results show that proposed algorithm improves work efficiency of the image encryption system, can resist a variety of attacks, and obtains the ideal image encryption effect and can ensure the security of image transmission on the network.

Key words: shift register, image security, encryption algorithm, chaotic time series, pixel autocorrelation