Optical color image encryption based on a voice key under the framework of speckle-illuminated Fourier ptychography

Abstract

In this paper, an optical color image encryption scheme based on a voice key under the framework of speckle-illuminated Fourier ptychography is proposed. The human voice serves as the secret key directly, and the random phase masks generated from the human voice using the chaotic map and secure hash algorithm are just used as interim variables. With the help of voice-based random phase masks located at different diffraction distances, the primary color image can be encrypted into a series of noise-like intensity cipher images under different speckle patterns’ illumination. During the decryption process, the primary color image can be recovered from the noise-like intensity cipher images with a Fourier ptychographic recovery algorithm, voice-based random phase masks, and their conjugate. Since the voice key is strongly linked with the user, it does not need need to be transmitted from the sender to the authorized receiver via the networks. The security of the proposed encryption scheme will be enhanced greatly. Additionally, the speckle patterns for illumination and diffraction distances can also provide additional security to the proposed encryption scheme. Simulation results and analysis show that the proposed encryption scheme has high security and can resist some common attacks.