A Chaotic Encryption Algorithm for Palette Image

According to the feature of palette image, a chaotic encryption algorithm for image of palette format is proposed in this paper. In the algorithm, the index matrix of pixel and the palette are both encrypted. In the encryption procedure of the index matrix, the position and value of an index are both encrypted, after multi-rounds, the ciphered index matrix is obtained, and in the masking procedure of palette, the masking operation performed only on the values for the purpose of efficiency. The encryption procedure of index matrix of pixel is independent from that of palette, so the two procedures can be performed selectively for deferent security requirements.