Optical asymmetric double-image encryption and authentication in an interference-based scheme using sparse representation

We report an optical asymmetric scheme for double-image encryption and authentication based on interference using sparse representation. We employ sparse representation and interference to process the Fresnel spectra related with the two original images, and then respectively acquire two ciphertexts and two pairs of private keys. Each original image possesses its corresponding two private keys. Furthermore, the decrypted image is compared with its corresponding plaintext with the aid of a nonlinear correlation for authentication. In the proposed scheme, any information concerning each primary image and comprising its silhouette cannot be recognized even though one, two, or even three masks of the two ciphertexts and two private keys are utilized for decryption. The Fresnel spectrum functions which have different diffraction distances enhance the security of the proposal significantly. Moreover, the proposal also avoids the crosstalk problem. The effectiveness and security of this proposed method are demonstrated via numerical simulations.