Optical image encryption using multimodal biometric keys under the framework of phase-shifting digital holography

In this paper, an optical image encryption using multimodal biometric keys under the framework of three-step phase-shifting digital holography is proposed. In the encryption process, first, the grayscale image is encrypted into the DNA compilation result by using DNA encoding with an iris chaotic mask; then, the DNA compilation result is encrypted into the three ciphertext holograms using phase-shifting digital holography and modified double random phase encoding (MDRPE) with the fingerprint and finger vein chaotic masks. In the decryption process, first, authentication is performed by decrypting and verifying three types of biometric features: iris, fingerprint, and finger vein; if the authentication is successful, the iris chaotic mask for subsequent decryption and the conjugate chaotic masks for both fingerprint and finger vein are generated by the decryption system. Finally, the final decryption image is obtained by utilizing digital holographic reconstruction technology and DNA decoding technology. To demonstrate the feasibility of the proposed method, a series of numerical simulations are performed, and the simulation results confirm that the proposed method shows high feasibility and robustness against various attacks, and the integration of multimodal biometric keys contributes to a high level of security, where each biometric key exhibits strong robustness against potential attacks.