Optical color image encryption based on fingerprint key and phase-shifting digital holography

Abstract In this paper, an optical color image encryption scheme based on fingerprint key and three-step phase-shifting digital holography is proposed. In the proposed encryption scheme, the fingerprint is served as secret key directly, and the random phase masks generated from the fingerprint using secure hash algorithm and chaotic map are just used as interim variables. With the help of the fingerprint-based random phase masks located in the linear canonical transform domain and the three-step phase-shifting digital holography, the primary color image that is hidden into a greyscale carrier image can be encrypted into three noise-like holograms. Since the fingerprint key shared by the sender and authorized receiver is strongly linked with the user and need not be transmitted via the networks, the security of the proposed encryption scheme will be enhanced greatly. In addition, the parameters of chaotic map and linear canonical transform can also provide additional security to the proposed encryption scheme. Numerical simulations and analysis have been carried out to verify the feasibility, security and robustness of the proposed encryption scheme.