Asymmetric watermarking scheme for color images using cascaded unequal modulus decomposition in Fourier domain

Abstract

In this paper, an asymmetric cryptosystem with unequal modulus decomposition in the Fourier domain is presented. The input-colour image is decomposed into its red, green, and blue components. Each component is bounded with random phase mask and undergoes Fourier Transform followed by unequal modulus decomposition. One of resulting masks acts as first private key and other one is again Fourier Transformed and undergoes unequal modulus decomposition. Further two masks are obtained, where one acts as second private key and other is phase truncated to obtain encrypted image. Encrypted image is attenuated by a factor and appended with host image to obtain watermarked image. Numerical simulations on MATLAB are performed for authenticating and validating proposed scheme. Statistical, correlation distribution, information entropy and histogram analyses are performed to demonstrate scheme efficacy. The results illustrate that the scheme resists classical cryptographic, special and occlusion attacks. The proposed scheme is also highly sensitive to its private keys and attenuation factor.

KEYWORDS:

• Color image
• Fourier transform
• watermarking scheme
• unequal modulus decomposition

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by award reference number 1172 (CSIR-UGC NET DEC.2018) from University Grants Commission, Department of Higher Education, Ministry of Education, Government of India.