Optical 3D information encryption and rapid decryption via interferenceless coded aperture correlation holography

Abstract

Holographic encryption has obvious advantages in large key space and anti-attack ability, but the corresponding coherent noise and optical alignment requirement greatly affect the encryption efficiency and decryption quality. Here, we present an optical 3D information encryption method based on the interferenceless coded aperture correlation holography (I-COACH), which consists of a coded phase mask and a lens. The speckle pattern, which is the convolution of the point spread hologram (PSH) with the object intensity distribution recorded in the image sensor plane, is used as the ciphertext, and these pre-recorded PSH are utilized as the decryption key. Due to the spatial decorrelation characteristics of the PSH at different axial positions, the plaintext can be decrypted only when the ciphertext is cross-correlated with the PSH of its corresponding axial position. Therefore, a 3D object composed of multiple 2D planes can only be decrypted by the PSH of its corresponding depth. For rapid and efficient decryption, we introduce the space division multiplexing technology. By multiplexing coded phase masks at different positions, the PSH at two positions can be simultaneously recorded in single-shot. In addition to improving the encryption efficiency and decryption quality, both numerical simulation and experimental results demonstrate the excellent security and robustness of the proposed I-COACH based 3D information encryption method.