A novel structure of fast and efficient multiple image encryption

A huge volume of image data is created every day, and it requires a fast and efficient encryption to keep them confidential. A chaos-based encryption is considered as the most suitable one for image encryption, and multiple image encryption is one of approaches to achieve the fast and efficient performance. However, the existing methods of multiple image encryption is with a lack of diffusion effect, inefficiency in using random number generated by chaotic map, and low speed. In this paper, a novel structure of chaos-based encryption is proposed to encrypt multiple images at the same time, in which the permutation and diffusion are integrated and they share the same chaotic map. The exclusive-OR operation is chosen for calculation and data manipulation during encryption. Therefore, the proposed structure allows to improve the efficiency and to reduce the time consumption for the encryption. In addition, the chaotic map is perturbed frequently and its dynamics is dependent on the content of images. It creates the dynamical session key, so the proposed structure can resist from the types of chosen-plaintext and chosen-ciphertext attacks. Two exemplar ciphers employing the proposed structure are demonstrated with the use of Logistic and Standard maps. The simulation results will be analysed and compared with those of existing methods to show the feasibility and effectiveness of the proposed structure of multiple image encryption.