Robustness Analysis of a Hyperchaos-Based Digital Image Encryption Algorithm under Noise Attacks

Abstract

Images are susceptible to degradation by noise from different sources as they undergo various processes. The effect of noise degradation affects the visual information fidelity, structural content and the decryption performance of an image encryption algorithm. In this paper, the effects of noise attacks on the performance of a hyperchaos-based digital image encryption algorithm is evaluated. In hyperchaos-based encryption algorithm, chaotic dynamics are used to encrypt the pixels of images. Two noise models, namely Gaussian noise and salt and pepper noise were added to test images, prior to encryption operations, in order to test for the robustness of the algorithm to noise attacks. The mean square error, peak signal – to – noise ratio, structural content and normalized correlation coefficient of the plain and decrypted images were evaluated. The results obtained indicated that noise has insignificant effect on the decryption performance of the algorithm, as the noise-degraded images and their decrypted counterparts were very identical. Thus, the image encryption algorithm is tolerant of noise and can therefore be used in noisy channels.