A visually secure asymmetric image encryption scheme based on RSA algorithm and hyperchaotic map

This paper proposes a visually secure asymmetric image encryption scheme based on Rivest-Shamir-Adlemen (RSA) algorithm and hyperchaotic map. It combines the advantages of the RSA and chaos-based image encryption algorithms. First, to fully encrypt the image information, the plain image is encrypted into a cipher image by applying the row and column encryption algorithms. Second, the image secret key is converted into a ciphertext by utilizing the RSA algorithm to increase the security, and then the ciphertext is transformed into an image and permuted using the Arnold map to enhance the robustness of the embedded image. We then obtain the key cipher image. Finally, the cipher image and the key cipher image are embedded into a carrier image (CI) to obtain a visually secure image. It simultaneously achieves the image information security and image visually security. To further improve the security, the RSA keys management technique is applied and the initial conditions of the hyperchaotic map are updated in real time based on the plain image. In addition, the encryption scheme is suitable for multi-user image transmission with high security requirements and image transmission without the secure channel for key transmission. The simulation results and performance analysis validate the effectiveness, security and robustness of the proposed scheme.