Vol. 55, Issue 1, pp. 97-115 (2025)

Abstract

A secure cryptosystem based on improved version of Yang–Gu algorithm has been proposed along with lower–upper (LU) decomposition for compression in gyrator transform. Yang–Gu algorithm introduces nonlinearity whereas LU decomposition leads to compression in the proposed scheme. Two random phase masks and binary phase modulators are used in the encryption process. Random phase masks act as public keys and binary phase modulations are applied to generate private keys. Grayscale and medical images are used to validate the proposed cryptosystem against different types of attacks. The statistical attack including information entropy, histogram analysis, correlation distribution plots, and 3-D plots are analyzed for the robustness of the proposed scheme. The quality of the retrieved image is compared with original image using the value of the correlation coefficient. The proposed scheme also showed resistance against data shuffling attack and basic attacks. Key sensitivity analysis demonstrated that the scheme is highly sensitive to its private keys and gyrator transform parameters. Therefore, based on above discussed results, the proposed scheme enhances the security.