Multiple-image encryption based on position multiplexing of Fresnel phase

A multiple-image encryption approach based on the position multiplexing of Fresnel phase is proposed. Encryption keys are generated according to different distances' propagation of Fresnel phase and used as filters in typical 4f system. The proposed method can achieve multiple-image encryption by an analytical algorithm without iteration. Basic theories are described and corresponding formulas are derived. Single image and multiple-image encryption are numerically simulated while the encrypted security and the decrypted image quality are investigated as well. Numerical results are presented to demonstrate the validity of the proposed multiple-image encryption method.