A new self-adaptive parallel image encryption algorithm is proposed. In the new algorithm

image is divided into horizontal or vertical groups according to encryption rounds

each group is divided into two sub-blocks

chaotic mapping of each sub-block is disturbed by adjacent sub-block pixels

a new pixel diffusion method is designed

and pixels are replaced by using S box. The experiments show that the new algorithm has the advantages of safety

simple and efficient

which is suitable for parallel implementation.