An optical asymmetric encryption scheme with biometric keys

摘要： In this paper, an asymmetric cryptosystem for optical image encryption using biometric keys is proposed based on the phase retrieval algorithm and the phase-truncated Fourier transforms (PTFT) scheme which addresses the issue of key distribution with enhanced security in the optical encryption process. In the proposed system, the encryption keys include optically generated biometric keys and the random phase mask keys of the PTFT scheme, while the decryption keys are kept as the private key in terms of the binary key and the generated phase-only mask of the PTFT scheme. If a person is authorized to retrieve the biometric keys by providing the fingerprint hologram and reconstruction parameters at the receiver stage, then the proposed system satisfies the criteria of asymmetric cryptography with information authentication approach. The biometric key features, by using the digital holography are kept secure and is utilized in both the encryption and decryption operations so that the authenticity of the ciphertext by using the biometric keys can be verified during the decryption process. Numerical simulations are carried out to test the effectiveness and validity of the proposed system.