Cryptosystem based on two-step phase-shifting interferometry and the RSA public-key encryption algorithm

Asymmetric cryptosystem based on optical scanning cryptography and elliptic curve algorithm

We propose an asymmetric cryptosystem based on optical scanning cryptography (OSC) and elliptic curve cryptography (ECC) algorithm. In the encryption stage of OSC, an object is encrypted to cosine and sine holograms by two pupil functions calculated via ECC algorithm from sender’s biometric image, which is sender’s private key. With the ECC algorithm, these holograms are encrypted to ciphertext, which is sent to the receiver. In the stage of decryption, the encrypted holograms can be decrypted by receiver’s biometric private key which is different from the sender’s private key. The approach is an asymmetric cryptosystem which solves the problem of the management and dispatch of keys in OSC and has more security strength than the conventional OSC. The feasibility of the proposed method has been convincingly verified by numerical and experiment results.

Asymmetric Encryption of Invisible Structured Light 3D Imaging

The research proposes a novel invisible structured light 3D object encryption method. The system projects invisible light on the target plane to achieve three-dimensional object reconstruction. The encryption is conducted using keys from eight stripe patterns and two fingerprint patterns using an elliptic curve encryption algorithm to generate eight corresponding ciphertexts. The three-dimensional object is reconstructed using eight fringe patterns with the elliptic curve decryption algorithm. The proposed method greatly reduces the interference of background light in the system to achieve a better 3D imaging accuracy. The elliptic curve cryptosystem is able to ensure 3D object information transmission security. The simulation results validated the robustness and effectiveness of the proposed scheme. The proposed method has practical security-sensitive applications.

Efficient asymmetric image authentication schemes based on photon counting-double random phase encoding and RSA algorithms

Recently, double random phase encoding (DRPE) has been integrated with the photon counting (PC) imaging technique for the purpose of secure image authentication. In this scheme, the same key should be securely distributed and shared between the sender and receiver, but this is one of the most vexing problems of symmetric cryptosystems. In this study, we propose an efficient asymmetric image authentication scheme by combining the PC-DRPE and RSA algorithms, which solves key management and distribution problems. The retrieved image from the proposed authentication method contains photon-limited encrypted data obtained by means of PC-DRPE. Therefore, the original image can be protected while the retrieved image can be efficiently verified using a statistical nonlinear correlation approach. Experimental results demonstrate the feasibility of our proposed asymmetric image authentication method.

Optical Hash function based on two-beam interference

An approach for constructing an optical Hash function, also known as a one-way cryptosystem, based on two-beam interference (OHF-TBI) is proposed. The purpose of this method is creating the "digital fingerprint" of any precoding message with arbitrary length. This approach consists of three steps, in which the main step is a one-way processing procedure with a compression mechanism. To achieve the function of one-way property and compressibility, we designed a cascaded process on the basis of the two-beam interference principle and phase-truncation operation. The performance of the mentioned OHF-TBI is verified by theoretical analysis and a set of numerical simulations.

Dual-channel in-line digital holographic double random phase encryption

We present a robust encryption method for the encoding of 2D/3D objects using digital holography and virtual optics. Using our recently developed dual-plane in-line digital holography technique, two in-line digital holograms are recorded at two different planes and are encrypted using two different double random phase encryption configurations, independently. The process of using two mutually exclusive encryption channels makes the system more robust against attacks since both the channels should be decrypted accurately in order to get a recognizable reconstruction. Results show that the reconstructed object is unrecognizable even when the portion of the correct phase keys used during decryption is close to 75%. The system is verified against blind decryptions by evaluating the SNR and MSE. Validation of the proposed method and sensitivities of the associated parameters are quantitatively analyzed and illustrated.

Space-based optical image encryption

In this paper, we propose a new method based on a three-dimensional (3D) space-based strategy for the optical image encryption. The two-dimensional (2D) processing of a plaintext in the conventional optical encryption methods is extended to a 3D space-based processing. Each pixel of the plaintext is considered as one particle in the proposed space-based optical image encryption, and the diffraction of all particles forms an object wave in the phase-shifting digital holography. The effectiveness and advantages of the proposed method are demonstrated by numerical results. The proposed method can provide a new optical encryption strategy instead of the conventional 2D processing, and may open up a new research perspective for the optical image encryption.

An encryption method with multiple encrypted keys based on interference principle

An encryption and verification method with multiple encrypted keys based on interference principle is proposed. The encryption process is realized on computer digitally and the verification process can be completed optically or digitally. Two different images are encoded into three diffractive phase elements (DPEs) by using two different incident wavelengths. Three DPEs have different distances from output plane. The two wavelength parameters and three distance parameters can be used as encryption keys, which will boost security degree of this system. Numerical simulation proves that the proposed encryption method is valid and has high secrecy level.