An Image Encryption Scheme Based on Hybrid Fresnel Phase Mask and Singular Value Decomposition

Background: An asymmetric cryptanalysis is suggested in Affine and Fresnel transform using Hybrid Fresnel phase Mask (HFM), Hybrid Mask (HM) and Singular Value Decomposition (SVD) to deliver additional security to the scheme. The usage of Affine Transform (AT) provides randomness in the input plane which benefits in enlarging the key space and SVD gives the nonlinearity in the process. Objective: In the FrT domain, usage of hybrid masks and AT in an asymmetric cryptosystem with SVD is to make encoded procedure difficult. Methods: On the plain image we firstly apply affine transform and then convoluted it with HFM, in FrT domain with propagation distance Z1 and the obtained part is convoluted with HM in FrT with propagation distance Z2 and then lastly on the encoded image SVD is applied. Results: Validity of the suggested scheme has been confirmed by using MATLAB R2018a (9.4.0.813654). The capability of the recommended scheme has been tested by statistical simulations such as histogram, entropy and correlation coefficient. Noise attack analysis has also done so that the system becomes robust against attacks. Conclusion: Asymmetric cryptosystem is recommended using pixel scrambling technique i.e. affine transform which shuffles the pixels hence helps for security of the system. Usage of SVD in the algorithm is to make the system robust. Performance and strength analysis are carried out for scrutiny of the forte and feasibility of the algorithm.