A novel grayscale image encryption algorithm based on logistic map

A grayscale image encryption algorithm is proposed based on logistic map. Firstly, two random grayscale images are generated by two different logistic maps, which have the same size as the plaintext image. Secondly, an enlarged image is constituted with the plaintext and random images, in which the positions and intensity values of the pixels are changed by using the confusion-diffusion process. Finally, the new plaintext and random images with stationary white noise distribution are recovered from the modified enlarged image, and then combined to the color ciphertext which has camouflage property to some extent. This encryption scheme is efficient when encrypting, storing or transmitting because it only uses three initial values of the logistic maps as private keys. Simulation results and security analysis verify the feasibility and effectiveness of this method.