Optical image encryption based on coherent diffractive imaging using multiple wavelengths

Coherent diffractive imaging is an optical technique in which the information of an object is encoded in the diffraction intensity using a single-path wave propagation strategy. In recent years, coherent diffractive imaging has attracted much attention in many fields due to its marked advantages, such as robustness to vibration and the suitability for various wavelengths. In this paper, we propose to apply coherent diffractive imaging using multiple wavelengths for optical image encryption. A light wavelength is tuned during the encryption, and a series of diffraction intensity maps (i.e., ciphertexts) is sequentially recorded in the Fresnel domain. During image decryption, an iterative retrieval algorithm is further developed, and cryptosystem security and robustness of the proposed method are also analyzed. Numerical simulation results are presented to demonstrate feasibility and effectiveness of the proposed method. (C) 2011 Elsevier B.V. All rights reserved.