Asymmetric optical image encryption using random Hilbert mask based on fast walsh hadamard transform
Mehak Khurana, Hukum Singh · 2017
A new image asymmetric encryption technique using Radial Hilbert mask (RHM) based on Fast Walsh Hadamard Transform (FWHT) is proposed for security enhancement. In this technique, bits of the secret image to be transmitted is randomized by shuffling the bits randomly. The obtained scrambled image is then masked with RHM and random phase mask (RPM) using asymmetric encryption in FWHT domain to get final encrypted image. FWHT has been used in the cryptosystem as protects from the quantization error and image can be perfectly reconstructed. The proposed scheme also includes RHM which increases the key space and makes it robust to many attacks. The proposed cryptosystem's robustness has been analyzed on the basis of different parameters by simulating on MATLAB 8.1.0 (R2012b). The simulation result highlights the robustness, suitability and effectiveness of the proposed cryptosystem.