Multiple color image encryption and authentication based on phase retrieval and partial decryption in quaternion gyrator domain

In this paper, a multiple color image encryption and authentication scheme by using phase retrieval in quaternion gyrator domain and partial decryption is introduced. The quaternion representation is firstly employed to combine three color channels into a single-channel architecture. Then each color image is respectively encoded into a phase-only function according to quaternion gyrator transform based double phase encoding through phase retrieval technique. Subsequently, all phase-only functions are modulated to obtain the final ciphertext. To remain the content of secret images under cover, only a small part of the encrypted data that is selected by multiplying the random binary amplitude mask is preserved for decryption, where nonlinear quaternion correlation is developed to further perform authentication. Since the proposed encryption algorithm is asymmetric, such interest can significantly enhance security of the cryptosystem. The numerical simulations have demonstrated the feasibility and validity of the proposed scheme as well as its better performance compared with other schemes.