An asymmetric image encryption mechanism using QR decomposition in hybrid multi-resolution wavelet domain. (November 2020)

• Record Type: Journal Article
• Authors: Rakheja, Pankaj; Singh, Phool; Vig, Rekha
• Is Part Of: Optics and lasers in engineering. Volume 134(2020)
• Publication Date: 2020-11
• Subjects: Fractional Fourier transform -- Hybrid multi-resolution wavelet -- QR decomposition -- Sparse matrix; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2020.106177
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: An asymmetric image encryption mechanism using QR decomposition technique in hybrid multi-resolution wavelet domain. The ciphertext obtained through QR decomposition is a sparse matrix stored using CSR method. The proposed scheme along with having enlarged key space has higher robustness against noise and occlusion attacks. Abstract: In this paper, an asymmetric image encryption mechanism using QR decomposition technique in hybrid multi-resolution wavelet ( HMW ) domain is presented. QR decomposition technique utilized here makes the system asymmetric, as the obtained permutation matrix serves as ciphertext and the product of orthogonal and triangular matrices act as decryption keys. It also enables compression as the ciphertext obtained through QR decomposition is a sparse matrix which can be stored using CSR method. The HMW is obtained by utilizing existing orthogonal transforms: Walsh transform and fractional Fourier transform ( frFT ). Here the fractional orders of fractional Fourier transform ( frFT ) matrices are employed here to generate HMW, which function as supplementary keys. Therefore, they enhance the key space and strengthen the proposed system. The proposed encryption system exhibits non-linearity and enlarged key-space to dodge any brute-force attack. Computer-based simulations have been carried out on the grayscale images to verify and validate the proposed encryption mechanism. And the results obtained clearly demonstrate the robustness of the proposed mechanism against occlusion and noise attacks.