Abstract
This paper presents an efficient optical image cryptosystem based on double random phase encoding (DRPE) and Arnold's Cat map. The proposed image cryptosystem utilizes two layers to enhance the security level over the classical DRPE. The first layer is a pre-processing layer, which is performed with the chaotic Cat map on the original image. In the second layer, the classical DRPE is utilized. Matlab simulation experiments show that the proposed optical image cryptosystem enhances the security level of the DRPE, and at the same time it has a better immunity to noise.