Reusing the permutation matrix dynamically for efficient image cryptographic algorithm

• An image encryption scheme with dynamic reuse of the permutation matrix is developed.
• The diffusion key stream is dynamically obtained from the permutation matrix.
• No chaotic operation is needed for image diffusion, the efficiency is thus promoted.
• Simulations and security analyses prove the superior security and high efficiency.

In traditional type of chaotic image ciphers with the architecture of permutation–diffusion, one-dimensional chaotic map is always employed for generating key stream in the diffusion procedure. However, the workloads derived from the iteration-then-quantization of the key stream generation operations severely downgrade the overall encryption efficiency of such cryptosystems. In this paper, we demonstrate how to obtain the diffusion key stream from the permutation matrix, which is produced and preserved in the permutation phase. No extra chaotic iteration and quantization is required in the diffusion procedure, the operation efficiency is thus improved. A complete cryptosystem is built using Bake map for image permutation. Simulations and security analyses have been carried out and the results illustrate the superior security and high efficiency of the proposed scheme.