Color image chaos encryption algorithm combining CRC and nine palace map

The color image encryption algorithm based on the chaos theory is not strong enough. In this paper, we proposed a color image chaos encryption algorithm combining Cyclic Redundancy Check (CRC) and nine palace map. Firstly, the pixel data of the plain image were moved and shuffled based on the theory of nine palace map. And the R, G and B components were extracted and converted into a binary sequence matrix that was then cyclically shifted based on the technology of generating CRC code. Finally, the encrypted image was derived from the XOR operation with random key matrix. The average entropy of encrypted image by our algorithm is 7.9993, which is slight improved compared with the coupled hyper chaotic Lorenz algorithm in previous studies. In addition, the algorithm has the advantages of large key space, high key sensitivity, anti-robust attack, and feasible encryption efficiency.