A novel image encryption scheme based on non-adjacent parallelable permutation and dynamic DNA-level two-way diffusion

As a medium that can convey information vividly, the application of digital images is increasingly widespread. Under various application environments, researchers are expected to provide more secure and efficient protection for digital images. In this paper, a novel image encryption scheme is proposed, which is based on non-adjacent parallelable permutation and dynamic DNA-level two-way diffusion (IES-NP-DDT). To achieve higher encryption efficiency, each encryption step of this scheme is designed with the parallelizability of operations in mind. Firstly, the plain image is logically divided into adjacent blocks and permutation blocks. And the permutation blocks are then randomly permutated in parallel by multiple computing units. Next, the permutated image is split and encoded into four DNA planes. When encoding each 2-bit plane, the computing units dynamically adopt encoding rules according to chaotic sequences. Combined with the dynamic DNA decoding, the excellent nonlinearity of the diffusion process is ensured. Finally, determined by the hash value, key components and chaotic values, various two-way DNA-level diffusions are carried out in parallel on the DNA planes. Consequently, a smallest change of any pixel is efficiently diffused to the whole image. Extensive simulation tests and theoretical analyses conducted in this paper have demonstrated the excellent performance of IES-NP-DDT.