An iterative optical image encryption based on double random phase

This paper presents a new optical image encryption and decryption algorithm based on the methodology of virtual optics. The main properties of the algorithm are that the original image is divided into two parts of equal size, one part is encrypted by double random phase optical encryption system, and its ciphertext will be converted to two phase masks as the key to encryption another part. Two main modules are included in the algorithm. One is to encryption the two parts of the original by double random phase optical iterative encryption system. The other is using nonlinear transformation generated new key. The algorithm can be implemented simple and a huge key space. The analysis and the simulation results implied that the algorithm is of favorable security and efficiency and better image quality for decrypted image.