A Novel and Efficient Multiple RGB Images Cipher Based on Chaotic System and Circular Shift Operations

In real time scenarios, the single image encryption schemes are not that efficient when a bunch of color images is to be encrypted. This problem should be addressed due to computational cost incurred by multiple executions of single color-image encryption scheme. The objective of this research work is to provide a new and efficient multiple color images cipher scheme. This cipher is based on chaotic system, circular shift operations and SHA-384 hash codes. First of all, an arbitrary number of RGB images are input. They are combined in a rectangular fashion to get their hash code. Then this big color-image is decomposed into its three basic components, i.e., red, green and blue. To scramble the pixels of these components, they are shifted circularly both the row-wise and column-wise. Further, XOR operation has been performed to realize the effects of diffusion in these components. Lastly, these components are joined together to get the final RGB cipher image. Apart from the 384-hash codes, a salt key of 384-bit has also been used in the proposed cipher to heighten the security effects. The SHA-384 hash codes render the required key space and plaintext sensitivity. The simulation results and the performance analyses carried out at the end clearly prove the efficiency, effectiveness, robustness and the real-world applicability of the proposed multiple RGB images cipher. Besides, the encryption throughput 7.716 Mb/s of the proposed scheme outperforms many of the existing ones.