A multiple-image encryption method based on bimodal biometric keys

In this paper, a multiple-image encryption method based on bimodal biometric keys is proposed, which has the advantages of high level of security, high encryption efficiency, high security and good convenience as well as strong robustness of bimodal biometric keys. In the encryption process, each plaintext image is firstly encoded into corresponding QR code and subsequently encrypted by using a compressive encryption method with fingerprint chaotic measurement matrix of each encryption user and a filtering encryption method in discrete cosine transform domain with iris chaotic mask of each encryption user successively, then the encryption complex amplitude is generated with the help of grating modulation technology and matrix splicing technology, thereafter the encryption complex amplitude is finally encrypted into two hologram ciphertexts by using a two-step phase-shift digital holography with fingerprint chaotic phase mask of encryption administrator. In the decrytion process, the decryption administrator first passes the fingerprint authentication and then the decryption complex amplitude is generated, thereafter multiple-image decryption can be achieved through the fingerprint authentication and iris authentication of each decryption user. In order to demonstrate the feasibility of the proposed multiple-image encryption method, a series of numerical simulations are performed, and the simulation results show that the proposed method exhibits high feasibility as well as level of security and the bimodal biometric keys possess high security and strong robustness.