Sparse phase information for secure optical double-image encryption and authentication

A novel optical encryption and authentication method by sparse phase information was proposed. Phase-only component of double-image encryption function was generated and considered for sparse strategy. Partial information of these phase values was subjected to the authentication process. The sparse strategy of the phase data permits simultaneous data reduction to achieve the general requirements of storage and transmission. Cryptanalysis of the proposed method was carried out in terms of chosen-plaintext and chosen-ciphertext attacks. The sparse strategy for phase data makes it difficult to recognize the confidential information shown by double-image encryption and authentication system, thus, the security level of the overall process was increased. Computational simulations displayed the feasibility and more security of the proposed method.