Security-enhanced optical encryption based on JTC architecture with confused ciphertext

Abstract Security is the key issue of an optical cryptosystem. In this work, a security-enhanced optical encryption scheme based on JTC architecture with confused ciphertext is demonstrated. Firstly, the original image is decomposed into two phase-only masks. Then one of the masks is transformed into joint power spectrum (JPS) by using a JTC architecture. Finally, the JPS is confused by operations of rotation and superposition, and the obtained data is employed as the final ciphertext. As a consequence, the proposed scheme removes the linear character of the conventional JTC-based cryptosystem. Therefore, the proposed scheme achieve a high robustness against attacks based on linearity of the cryptosystem, especially the attack based on iterative Fourier transform (IFT). Furthermore, good performances of simplicity and low cost are remained at the same time. Some numerical simulations are presented to verify the validity and performance of the security-enhanced scheme.