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We report a novel optical method of interference-based multiple-image encryption and authentication via lateral shift multiplexing and sparsification. We encode multiple original images into two ciphertexts only containing partial information of the multiple images when the secret key generated randomly is laterally movable within a predefined interval, and we analytically derive the two other keys of each original image. Information discrimination for each original image as well as its silhouette is still prohibited in spite of the utilization of one, two, three, or even four masks for decryption. The three secret keys of each original image significantly improve the security of the proposed method, and binary amplitude masks are included in the decryption and authentication procedure. Moreover, the proposed scheme completely eliminates the cross-talk problem and destroys any high correlation between the plaintexts and ciphertexts. Numerical simulations are executed to prove the effectiveness and security of this scheme. [ABSTRACT FROM AUTHOR]

A scheme for asymmetric image encryption and authentication based on interference is proposed here by using sparse representation and random modulus decomposition. An original image is encoded into a complex value image in the Fresnel domain and then sparsely sampled to acquire the sparse spectrum. The sparse spectrum generates four phase-only masks using random modulus decomposition and the interference principle. No information concerning the original image, including its silhouette, can be extracted even if one, two, or three of the four phase-only masks are used for decryption. The parameters of random modulus decomposition provide additional keys for further strengthening the security of our scheme, and the four phase-only masks are all employed for decryption and authentication. Numerical simulations are used to verify the feasibility and security of this scheme. [ABSTRACT FROM AUTHOR]