Abstract: Usual color image encryption algorithms fail to take full account of the intrinsic relationship between the RGB color components and have unsatisfactory statistical analysis resistance capabilities．To enhance image scrambling degree and security,a new color image encryption algorithm was proposed based on mixed chaotic scrambling．First,the original image is scrambled by use of pseudo-random sequence generated by 2D logistic maps．Then,the R,G,B components are assembled into a whole and the extended pixels are disturbed by exploiting bit XOR operation and random rear-range．Finally,the encrypted image is obtained by repartitioning RGB components in extended 24-bit pixel．Experiments show that the proposed encryption scheme has good scrambling effectiveness,less time consumption and better security compared with some common color image encryption schemes.

Key words: Image encryption,2D logistic chaotic map,Bit rearrange,Color image